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  • 1.
    Ahmad, Afaq
    et al.
    Department of Civil Engineering, University of Engineering and Technology, Taxila, Rawalpindi 46600, Pakistan.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Alajarmeh, Omar
    Centre for Future Materials (CFM), School of Civil Engineering and Surveying, University of Southern Queensland, Toowoomba 4350, Australia.
    Chairman, Nida
    Department of Civil and Architectural Engineering, University of Westminster, London W1B 2HW, UK.
    Yaqub, Muhammad
    Department of Civil Engineering, University of Engineering and Technology, Taxila 47080, Pakistan.
    Investigation of Circular Hollow Concrete Columns Reinforced with GFRP Bars and Spirals2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 4, artikel-id 1056Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Glass fiber-reinforced polymer (GFRP) reinforcements are useful alternatives to traditional steel bars in concrete structures, particularly in vertical structural elements such as columns, as they are less prone to corrosion, and impart increasing strength and endurance of buildings. There is limited research on the finite element analysis (FEA) of the structural behavior of hollow glass fiber-reinforced polymer reinforced concrete (GFRPRC) columns. The hollow portion can be used for the service duct and for reducing the self-weight of the members. Numerical analysis of the compressive response of circular hollow concrete columns reinforced with GFRP bars and spirals is performed in this study. This article aims to investigate the axial behavior of hollow GFRP concrete columns and compare it with that of solid steel reinforced concrete (RC) columns as well as hollow steel RC columns. The Abaqus software is used to construct finite element models. After calibration of modeling using an experimental test result as a control model, a parametric study is conducted. The columns with the same geometry, loading, and boundary conditions are analyzed in the parametric study. It is resulted that the hollow GFRP concrete columns provide a greater confinement effect than the solid steel RC columns. The average variation in the ultimate axial load-carrying capacities of the experimental results, from that of the FEA values, is noted to be only 3.87%, while the average difference in the corresponding deformations is 7.08%. Moreover, the hollow GFRP concrete columns possess greater axial load and deformation capacities compared with the solid steel RC columns.

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  • 2.
    Ahmed Waqas, Hafiz
    et al.
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Sahil, Mehran
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Poshad Khan, Adil
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Ejaz, Ali
    National University of Science and Technology, Risalpur 23200, Pakistan.
    Shafique, Taimoor
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Tariq, Zain
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Ahmad, Sajeel
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi 23640, Pakistan.
    Onuralp Özkılıç, Yasin
    Necmettin Erbakan University, Konya, Turkey.
    Performance Prediction of Hybrid Bamboo-Reinforced Concrete Beams Using Gene Expression Programming for Sustainable Construction2023Ingår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 16, nr 20, artikel-id 6788Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The building and construction industry’s demand for steel reinforcement bars has increased with the rapid growth and development in the world. However, steel production contributes to harmful waste and emissions that cause environmental pollution and climate change-related problems. In light of sustainable construction practices, bamboo, a readily accessible and ecofriendly building material, is suggested as a viable replacement for steel rebars. Its cost-effectiveness, environmental sustainability, and considerable tensile strength make it a promising option. In this research, hybrid beams underwent analysis through the use of thoroughly validated finite element models (FEMs), wherein the replacement of steel rebars with bamboo was explored as an alternative reinforcement material. The standard-size beams were subjected to three-point loading using FEMs to study parameters such as the load–deflection response, energy absorption, maximum capacity, and failure patterns. Then, gene expression programming was integrated to aid in developing a more straightforward equation for predicting the flexural strength of bamboo-reinforced concrete beams. The results of this study support the conclusion that the replacement of a portion of flexural steel with bamboo in reinforced concrete beams does not have a detrimental impact on the overall load-bearing capacity and energy absorption of the structure. Furthermore, it may offer a cost-effective and feasible alternative. 

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  • 3.
    Alaneme, George U
    et al.
    Department of Agricultural Engineering, Michael Okpara University of Agriculture, Umudike, P.M.B. 7267, Umuahia, 440109, Abia, Nigeria; Department of Civil Engineering, Kampala International University, Kampala, Uganda.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Ibe Iro, Uzoma
    Department of Agricultural Engineering, Michael Okpara University of Agriculture, Umudike, P.M.B. 7267, Umuahia, 440109, Abia, Nigeria.
    Ganasen, Nakkeeran
    Department of Civil Engineering, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, 603203, India.
    Otu, Obeten N
    Department of Civil Engineering, University of Cross River State, Calabar, Nigeria.
    Udeala, Richard C
    Department of Agricultural Engineering, Michael Okpara University of Agriculture, Umudike, P.M.B. 7267, Umuahia, 440109, Abia, Nigeria.
    Ifebude, Blessing O
    Department of Agricultural Engineering, Michael Okpara University of Agriculture, Umudike, P.M.B. 7267, Umuahia, 440109, Abia, Nigeria.
    Onwusereaka, Emmanuel A
    Department of Agricultural Engineering, Michael Okpara University of Agriculture, Umudike, P.M.B. 7267, Umuahia, 440109, Abia, Nigeria.
    Numerical Analysis and Parametric Study on Multiple Degrees-of-Freedom Frames2023Ingår i: Civil Engineering Journal, ISSN 2676-6957, Vol. 9, nr 7, s. 1709-1736Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The design of multiple degrees-of-freedom frames is critical in civil engineering, as these structures are commonly used in various applications such as buildings, bridges, and industrial structures. In this study, a six-degrees-of-freedom beam-column element stiffness matrix was formulated by superposition of beam and truss elements stiffness matrices and was adapted to statically analyze indeterminate frame structures. The development of a numerical model for the frame structures was achieved using the finite element method in the current study. Also, the investigation of the effects of various parameters such as frame geometries, material properties, and loading conditions was conducted on the internal forces developed in the frame structures. Three different parametric study cases that presented the frame structures with varying geometries and loading conditions were analyzed utilizing this matrix approach for the sake of emphasis and to evaluate the flexibility and adequacy of this formula to analyze the indeterminate frames using the MATLAB software. The analysis method comprised the derivation of the system displacements employing the relationships between the stiffness matrix and fixed end forces as the force vector and taking the attained displacements, which would be transformed to the local coordinates to obtain the member forces. The computed results from the element stiffness matrix approach were further statistically compared with the results achieved from the finite element software (SAP2000) applying the analysis of variance (ANOVA). The statistical results showed a P-value > 0.05, which indicated a good correlation between the compared results and adequate performance for the derived beam-column element matrix formula method. 

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  • 4.
    Alavi, Sayyed Hadi
    et al.
    K.N. Toosi University of Technology, Tehran 19697, Iran.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Mashayekhi, Mohammadreza
    K.N. Toosi University of Technology, Tehran 19697, Iran.
    Zolfaghari, Mohammadreza
    K.N. Toosi University of Technology, Tehran 19697, Iran.
    Optimizing Interpolation Methods and Point Distances for Accurate Earthquake Hazard Mapping2024Ingår i: Buildings, E-ISSN 2075-5309, Vol. 14, nr 6, artikel-id 1823Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Earthquake hazard mapping assesses and visualizes seismic hazards in a region using data from specific points. Conducting a seismic hazard analysis for each point is essential, while continuous assessment for all points is impractical. The practical approach involves identifying hazards at specific points and utilizing interpolation for the rest. This method considers grid point spacing and chooses the right interpolation technique for estimating hazards at other points. This article examines different point distances and interpolation methods through a case study. To gauge accuracy, it tests 15 point distances and employs two interpolation methods, inverse distance weighted and ordinary kriging. Point distances are chosen as a percentage of longitude and latitude, ranging from 0.02 to 0.3. A baseline distance of 0.02 is set, and other distances and interpolation methods are compared with it. Five statistical indicators assess the methods. Ordinary kriging interpolation shows greater accuracy. With error rates and hazard map similarities in mind, a distance of 0.14 points seems optimal, balancing computational time and accuracy needs. Based on the research findings, this approach offers a cost-effective method for creating seismic hazard maps. It enables informed risk assessments for structures spanning various geographic areas, like linear infrastructures.

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  • 5.
    Alharthai, Mohammad
    et al.
    College of Engineering, Najran University, Najran, 66446, Saudi Arabia.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Badawi, Moataz
    College of Engineering and Islamic Architecture, Umm Al-Qura University, Makkah, Saudi Arabia.
    Ghalla, Mohamed
    Kafrelsheikh University, Kafrelsheikh, Egypt.
    Elsamak, Galal
    Kafrelsheikh University, Kafrelsheikh, Egypt.
    Abdelmgeed, Fathi A.
    Kafrelsheikh University, Kafrelsheikh, Egypt.
    Numerical study on enhancing shear performance of RC beams with external aluminum alloy plates bonded using steel anchors2024Ingår i: Results in Engineering (RINENG), ISSN 2590-1230, Vol. 22, artikel-id 102143Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article compromises a three-dimensional numerical study employing the Abaqus program to investigate the behavior of reinforced concrete (RC) beams externally strengthened in shear using aluminum alloy (AA) plates bonded utilizing steel anchors. Based on previous experimental tests, a numerical validation study was conducted in two parts. The first part modeled the interaction behavior using different bonding methods between steel plates and the surface of the RC beams, whether utilizing epoxy adhesive only, steel anchors only, or a dual system between them. The second part modeled the performance of shear-defected RC beams that externally strengthened by the AA plates using epoxy adhesive. To take into account debonding collapse due to epoxy adhesive bonding, the interaction between the AA plates and beam surface was simulated with a cohesive-damage interaction. Comparing the numerical results with previous experimental studies shows the success of the numerical model in simulating the performance of different bonding methods, as well as the behavior of the RC beams defected in shear and strengthened by the AA plates, which qualified it to study some additional variables. From the study it was found that by utilizing only epoxy adhesive, the strengthening technique using the AA plate over the entire shear span zone (AASP method) was capable of increasing the ultimate capacity of the defected beam by 104%, which represents 77% of the load of the non-defected beam. It was also demonstrated that the AA plates were susceptible to collapse by the out-of-plane buckling when bonded using the steel anchors only. By utilizing a dual system for bonding the AA plates consisting of epoxy adhesive and steel anchors, the AASP method was capable of enhancing the ultimate capacity of the defected beam by 164% and changing its failure pattern to the preferred ductile bending pattern.

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  • 6.
    Ali, Liaqat
    et al.
    Southern University of Science and Technology, Shenzhen, China.
    Isleem, Haytham F.
    Qujing Normal University, Qujing 655011, Yunnan, China.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Jha, Ishan
    Indian Institute of Technology-BHU, Varanasi, Uttar Pradesh, India.
    Zou, Guang
    Southern University of Science and Technology, Shenzhen, China.
    Kumar, Rakesh
    National Institute of Technology Patna, India.
    Sadeq, Abdellatif M.
    Qatar University, Doha, Qatar.
    Jahami, Ali
    University of Balamand, Tripoli P.O. Box 100, Lebanon.
    Integrated behavioural analysis of FRP-confined circular columns using FEM and machine learning2024Ingår i: Composites Part C: Open Access, ISSN 2666-6820, Vol. 13, artikel-id 100444Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study investigates the structural behaviour of double-skin columns, introducing novel double-skin double filled tubular (DSDFT) columns, which utilise double steel tubes and concrete to enhance the load-carrying capacity and ductility beyond conventional double-skin hollow tubular (DSHT) columns, employing a combination of finite element model (FEM) and machine learning (ML) techniques. A total of 48 columns (DSHT+DSDFT) were created to examine the impact of various parameters, such as double steel tube configurations, thickness of fibre-reinforced polymer (FRP) layer, type of FRP material, and steel tube diameter, on the load-carrying capacity and ductility of the columns. The results were validated against the experimental findings to ensure their accuracy. Key findings highlight the advantages of the DSDFT configuration. Compared to the DSHT columns, the DSDFT columns exhibited remarkable 19.54 % to 101.21 % increases in the load-carrying capacity, demonstrating improved ductility and load-bearing capabilities. Thicker FRP layers enhanced the load-carrying capacity up to 15 %, however at the expense of the reduced axial strain. It was also observed that glass FRP wrapping displayed 25 % superior ultimate axial strain than aramid FRP wrapping. Four different ML models were assessed to predict the axial load-carrying capacity of the columns, with long short-term memory (LSTM) and bidirectional LSTM models emerging as superior choices indicating exceptional predictive capabilities. This interdisciplinary approach offers valuable insights into designing and optimising confined column systems. It sheds light on both double-tube and single-tube configurations, propelling advancements in structural engineering practices for new constructions and retrofitting. Further, it lays out a blueprint for maximising the performance of the confined columns under the axial compression.

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  • 7.
    Ameen, Arman
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    El Tayara, Khaled
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Energy Performance Evaluation of Historical Building2022Ingår i: Buildings, E-ISSN 2075-5309, Vol. 12, nr 10, artikel-id 1667Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Retrofitting measures in old buildings aimed at reducing energy usage have become important procedures meant to counteract the effects of climate change and greenhouse gas emissions. The aim of this study is to evaluate energy usage, thermal comfort, and CO2 emissions of an old building by changing parameters such as building orientation, shading systems, location, low energy film application, and alternative energy supply in the form of a geothermal heat pump. When evaluating the buildings in terms of geographical location with or without applying the low energy film, the results show that the city of Gävle in Sweden requires the most heating energy, 150.3 kWh/m2∙year (B0) compared to Jakarta (L0), which requires 23.8 kWh/m2∙year. When examining the thermal comfort, cases B4 and L4 demonstrate the best results in their respective categories (B0–B4 are cases without low energy film and L0–L4 are cases with applied low energy film). The results for the CO2 emissions levels for B0–B4 and L0–L4 indicate that B4 has the highest value, 400 kg CO2 eq/year higher than B0, and L1 has the lowest value, 731 kg CO2 eq/year lower than B0. The economic feasibility study illustrates that the installation of a geothermal heat pump with at least a coefficient of performance of 4.0 leads to a shorter payback period than solely applying LEF.

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  • 8.
    Ameen, Arman
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Elousa Ansa, Ibai
    Assessment of Thermal Comfort and Indoor Air Quality in Library Group Study Rooms2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 5, artikel-id 1145Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Human performance and health are among the most relevant topics in the modern society, especially at young ages, when academic performance is indispensable. Thus, as humans spend most of their lifetime inside a building, thermal comfort and indoor air quality are an essential aspect of a room. The aim of the current study is to numerically evaluate the main thermal comfort parameters such as PMV and PPD as well as indoor air quality, i.e., CO2 concentration, in library group study rooms at the University of Gävle in Sweden. Rotroninc Measurement Solutions CL11 sensors were utilized for temperature measurements. Simulation models were created and validated based of building data as well as temperature measurements. Several simulations were conducted throughout a year, covering different periods. The results show that even though the ventilation system, with only temperature control, works as intended for maintaining the thermal comfort, the CO2 concentration rises above 1000 ppm when more than one student occupy the rooms, which is not recommended by different thermal comfort ruling institutions. Consequently, a modification to the ventilation system control is recommended, changing it from temperature control to CO2 and temperature control.

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  • 9.
    Amin, Fayiz
    et al.
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi, KPK, Pakistan.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Waqas, Hafiz Ahmed
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi, KPK, Pakistan.
    Naveed, M.
    University of Wollongong, Australia.
    Ejaz, Ali
    Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Swabi, KPK, Pakistan.
    Hanif, Muhammad Usman
    National University of Sciences and Technology, H-12, Islamabad, Pakistan.
    Ejaz, Ali
    National University of Science and Technology, Risalpur, 23200, Pakistan.
    Influence of arch action on load-carrying capacity of double-sized industrial precast slabs: A combined numerical and experimental study2024Ingår i: Results in Materials, ISSN 2590-048X, Vol. 23, artikel-id 100575Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The precast industry offers slab panels of different geometries according to the field conditions. These slab panels are popular in temporary constructions and beneficial in sustainability but have some financial limitations and local constraints. For a long time, the construction industry has used the arch action method, which restricts the stresses to the compression zone in concrete members and develops the required load-carrying capacity. For the same motives, industrial buildings have preferred semi-circular precast roofs, but the morphology was not suitable. For the proposed slab in this research, firstly, the typical industrial precast slab panel was doubled in width to minimize the time and efforts required for its casting, curing, and placement. Secondly, that doubled-in-width slab was provided with the arch action to confine the stresses to compression and benefit from the section entirely. Lastly, the top of the slab was kept flat to take advantage of the roof space. All these changes aimed for structural stability, reduced material’s weight, improved load-carrying capacity, appropriate mobilization, and financial viability. A numerical approach and practical testing were adopted using the finite element modeling software, ABAQUS, to analyze load–deflection responses of both slabs through the concrete damage plasticity model. The proposed slab exhibited better performance as its capacity enhanced by about 1.5 times that of a typical slab. Although the volume of the material in the proposed slab increased slightly from 0.040 m3 to 0.045 m3, the reductions in joint filler materials, reinforcements, and efforts required for mixing and lifting machinery compensated for this increase significantly. Hence, the slab can be recommended for the industry to save the costs while taking heavier loads efficiently.

  • 10.
    Awoyera, Paul O.
    et al.
    Covenant University, Ota, Nigeria.
    Akin-Adeniyi, Ayomide
    Covenant University, Ota, Nigeria.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Bendezu Romero, Lenin M.
    Universidad Cesar Vallejo, SJL, Lima, Peru.
    Structural performance of fire-damaged concrete beams retrofitted using bamboo fiber laminates2024Ingår i: Results in Engineering (RINENG), ISSN 2590-1230, Vol. 21, artikel-id 101821Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fire-induced damage is a serious threat to the structural integrity of reinforced concrete (RC) beams, necessitating an effective retrofitting strategy to restore and improve their performance. This study investigates the structural performance of fire-damaged RC beams retrofitted with bamboo fiber laminates. A comprehensive analysis was performed, incorporating degradation rules to quantify the effect of temperature on both the load-carrying capacity and ultimate deflection of the RC beams. Eight conventionally designed and reinforced RC beams were tested, with two serving as controls. The remaining six beams were tested in pairs at three different temperatures (400 C, 600 C, and 800 C) for 2-h exposure, with one beam featuring the bamboo fiber laminates in each pair. The bamboo fiber laminates enhanced the load-carrying capacity and deflection of the fire-damaged beams when subjected to incremental loading until failure. The deflection was improved by 48.78% at 400 C, restoring the load-carrying capacity to control levels. The load-carrying capacity was increased by 29.5% at 600 C, while the deflection was restored by 39.37%. The load-carrying capacity was enhanced by 37% at 800 C, while the deflection was improved by 4.83%. According to the findings, bamboo fiber laminate is a viable alternative to synthetic fibers for retrofitting fire-damaged beams.

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  • 11.
    Awoyera, Paul O.
    et al.
    Covenant University, Ota, Nigeria.
    Althoey, Fadi
    Najran University, Najran, Saudi Arabia.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Apuye, Pius U.
    Covenant University, Ota, Nigeria.
    Bendezu R, L.M.
    Ricardo Palma University, Lima, Peru.
    Alotaibi, Badr S.
    College of Engineering, Najran, Saudi Arabia.
    Meza, Jesus M.P.
    Ricardo Palma University, Lima, Peru.
    Abuhussain, Mohammed A.
    College of Engineering, Najran, Saudi Arabia.
    Structural retrofitting of RC slabs using bamboo fibre laminate: Flexural performance and crack patterns2024Ingår i: Heliyon, E-ISSN 2405-8440, Vol. 10, nr 2, artikel-id e23999Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Enhancing the durability of structural elements is a viable approach to promote sustainability in civil engineering. Research has shown that well-maintained slabs outperform degraded ones, which deteriorate rapidly due to insufficient upkeep. The occurrence of cracking and deformation in slabs subjected to sustained loads significantly impacts their functionality. However, the implementation of appropriate retrofitting techniques utilizing locally available materials can effectively minimize deflection and crack propagation while also improving flexural capacity. This particular study aimed to evaluate the flexural performance of slabs that were retrofitted using bamboo fibre laminate (BFL). Also, the study investigated two alternative replacement methods alongside the conventional mix; one involved replacing all fine aggregates with ceramic fine aggregate and the other involved a complete replacement of coarse aggregates with ceramic coarse aggregate. These mixes were represented in both the retrofitted and non-retrofitted samples. The retrofitting process included using the combined external bonding and near surface-mounted method. Twelve slab samples were made, with six being non-retrofitted and the other six retrofitted with BFL. Each of the samples had dimensions of 300 mm × 300 mm × 50 mm for reinforced concrete (RC) slabs. The slabs were tested employing the three point-bending system, and the retrofitted slabs with the conventional mix exhibited the highest ultimate failure load and flexural strength (62.1 kN), which compared to the non-retrofitted slabs of the same mix was a 60.76% increase. Additionally, the study did a thorough analysis of the presence of flexural and diagonal shear cracks, as well as the occurrence of debonding between BFL and the slabs. Non-destructive tests were also conducted on the slab samples to further confirm accurate results. These findings offer helpful insights into the development and application of a sustainable retrofitting material that can remarkably improve RC slabs.

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  • 12.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Study of eccentric and buckling-restrained bracing systems used in frames2021Ingår i: Journal of Civil, Construction and Environmental Engineering, ISSN 2637-3882, Vol. 6, nr 4, s. 120-125Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present paper studies eccentric braces (EBs) and buckling-restrained braces (BRBs) used in steel frames. The eccentrically braced frames (EBFs) and buckling-restrained braced frames (BRBFs) that have respectively employed the EBs and BRBs are considered with different types of links as shear, moment-shear and moment links depending on their link length which is an important factor in the design of the EBFs and BRBFs. The BRB consists of a steel core and its surrounding steel tube filled with concrete. The concrete confinement prevents buckling of the steel core. The analysed EBFs and BRBFs by the finite element software ABAQUS under earthquake records are taken into account. Effects of the links of the EBFs and BRBFs on the performance of the frames are discussed. The results uncover that most of the lateral displacements of the EBFs and BRBFs having the shear link are smaller than their counterparts having the moment-shear and moment links, whilst, all the base shear capacities of the former are the greatest. However, majority of the EBFs and BRBFs with the moment link dissipate less energy than their counterparts with the shear and moment-shear links, whereas, most of the link rotations of the former are smaller than the latter. In addition, the BRBFs generally demonstrate better performance than their EBF counterparts.

  • 13.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Sustainable Structures and Buildings2024Samlingsverk (redaktörskap) (Refereegranskat)
    Abstract [en]

    This open access book includes detail on various structures, buildings, and building materials from different structural and sustainability perspectives. It describes how the building industry is vital for the achievement of the sustainable development goals, namely, economic growth, social progress, and the effective protection of the environment. The aim of this collection is to foster the design and construction of sustainable structures and buildings to reduce the environmental load, connect with the environment, and benefit the health of occupants. Presenting the knowledge, trends, and developments from a group of contributors in the field working with different kinds of structures, structural components, buildings, and building materials, the book is ideal for  practitioners working in commercial settings, as well as engineering students and researchers concerned with sustainability issues.

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  • 14.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Ameen, Arman
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Halvarsson, Mattias
    Aho, Mikael
    Potential Electricity Production of Roof-Mounted Solar PV Systems in a Row House Area in Sweden2023Ingår i: Sustainable Technology for Society 5.0: Case Studies, Examples, and Advanced Research Findings / [ed] Tilottama Singh, Richa Goel, Jan Alexa Sotto, CRC Press, 2023, s. 167-182Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Sweden's energy policy goal is to have completely renewable electricity production by the year 2040; thus, alternatives such as wind and solar energies are being investigated for electricity supply, where mainly solar energy has the potential for small and medium-sized systems for houses of private individuals and companies. As a part of this development, the tenant-owner's association, Stenbär, in the city of Gävle in Sweden has considered installing solar PV systems, which has become the basis for this research. The aim of this chapter is to investigate the potential areas for a solar cell plant, and how much electricity this could produce per year. The simulations are performed by using the computer software IDA ICE 5.0 beta. It is demonstrated that there is a good potential to produce a large amount of solar energy in the area. As the system produces a surplus during the summer half of the year, there is also the possibility of selling the electricity.

  • 15.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Ameen, Arman
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Nkweto, Henry
    Energy Audit of Two Multifamily Buildings and Economic Evaluation of Possible Improvements2023Ingår i: Urban Transition: Perspectives on Urban Systems and Environments / [ed] Marita Wallhagen and Mathias Cehlin, IntechOpen , 2023Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    AbstractThe energy use of buildings is gradually increasing, which is due to economic growth and an increase in population. Several studies have indicated that the implementation of energy-saving measures (ESMs) such as thermal insulation results in more energy saving; however, most ESMs are not economically viable. This chapter outlines ESMs using the IDA ICE computer software. The evaluation of the energy performance of two multifamily buildings is conducted, and possible ESMs are suggested such as thermal insulation, changing windows, installing a new air handling unit, installing a heat exchanger in showers, improving thermal bridges, replacing lighting bulbs, increasing external insulation plus temperature reduction, and changing schedules for air discharge control. The economic feasibility of these suggestions is assessed using the life cycle cost analysis to determine their economic viability. This involves the determination of the life cycle cost and life cycle cost saving to decide the best option. The most important factor in determining life cycle cost saving is the modified uniform present value. The addition of the attic insulation, installing a heat exchanger in showers, replacing lighting bulbs, and changing schedules meet the economic requirement within a feasible time frame.

  • 16.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Awn, Rim Fares
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Corona, Jaqueline
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Eriksson, Bengt
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    How Aware and Active is the Swedish Building and Real Estate Sector in Climate-Smart Concrete?2022Ingår i: International Journal of Engineering Trends and Technology, E-ISSN 2231-5381, Vol. 70, nr 1, s. 126-138Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Carbon dioxide has long proven to be one of the greenhouse gases that affects our planet's climate and environment. With the forthcoming European Union goals and Sweden's own net-zero goal, it is required that the building and real estate sector works with climate-smart materials to construct future buildings. The net-zero goal by 2045 requires a common effort from all companies to find innovative solutions in order to reduce carbon dioxide emissions sharply. This study investigates how aware and active the building and real estate sector is in climate-smart concrete (CSC) through a survey and comparison of environmental product declarations (EPDs). Climate-smart is a term for concrete that contains a lower percentage of Portland cement clinker than traditional concrete. This research aims to examine how far the development has taken place and to evaluate how the market has adopted the newly available products. It is als assessed which alternative additive materials are the most common as well as advantages and disadvantages of the CSC. A questionnaire is created, and the survey is sent out to companies. A comparison is made between three different EPDs of the CSC and two references for concrete with the ordinary Portland cement clinker. Reference concrete 1 is a standard value, and reference concrete 2 is an EPD value. A reference building is used to calculate the volume and weight of its utilized concrete. The three types of the CSC are compared with the reference concrete 1, and the results show a carbon dioxide reduction of 29.3%. However, the comparison of these three types of the CSC with the reference concrete 2 demonstrates a carbon dioxide reduction of 2.8%. In addition, it is concluded that the future will require the building and real estate sector to invest time and training to work with the CSC further.

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  • 17.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Azizian, Dawod
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Assessment of glulam and reinforced concrete beams in multi-storey building2022Ingår i: Civil and Environmental Engineering, ISSN 1336-5835, Vol. 18, nr 1, s. 66-75Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study assesses glulam and reinforced concrete (RC) beams in a multi-storey building in Gävle in Sweden. StruSoft FEM-Design software is used to conduct the current study. First, the building having the RC beams is modelled, analysed, and designed. Utilisation ratio, stress, weight, reaction force, stability, and deflection of the building are examined. It is concluded that the building can function well with RC beams. Then, the RC beams are replaced with glulam beams and the building is again analysed. It is revealed that larger cross-sections are needed for the replaced glulam beams in most of the spans compared with the RC beams in order for them to have acceptable results from the utilisation ratio viewpoint. However, for large spans of 8 m, a timber column is used in the mid-span for all the storeys as a strengthening alternative so that a shorter span for these glulam beams can be adopted which leads to acceptable results. Stresses of the RC and glulam beams are also evaluated. The building having the glulam beams is 23.79 % lighter than the building having the RC beams. The maximum reaction force of the building having the glulam beams is obtained 24.27 % lower than the building having the RC beams. Stability and deflection of the building in both cases are discussed as well.

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  • 18.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Blomberg, Emil
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Boqvist, Simon
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Lauridsen, Markus
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Eriksson, Bengt
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Experimental Investigation of Ultimate Shear Force Capacity of Glulam Reinforced with Glued-in Threaded Rods2023Ingår i: The Open Construction & Building Technology Journal, ISSN 1874-8368, Vol. 17, s. 1-12Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Abstract:

    Background:

    Glued-in threaded (GIT) rods have been considered an effective timber connection method having several advantages, such as high load-carrying capacity, great stiffness, and good fire resistance. This type of connection has widely been utilized in newly built modern timber structures and for reinforcing the existing ones.

    Objective:

    The purpose of this experimental research is to investigate how the ultimate shear force capacity (USFC) of glulam is affected if it is reinforced with GIT rods and to study the interaction between the glulam and GIT rods. The results of this research can help researchers and engineers to select a suitable method of reinforcing the glulam with GIT rods at a superior inclination angle (IA) to the fiber direction in order to achieve higher USFCs.

    Methods and Experimental Tests:

    A total of forty glulam samples were tested for failure. The experimental tests consisted of five different series of samples with eight samples in each series. Sample series 1 were unreinforced glulam. Sample series 2 and 4 were glulam reinforced with the GIT rods at two different IAs of 45° and 90° to the fiber direction, respectively. Sample series 3 and 5 were glulam reinforced in the same way as sample series 2 and 4, but they were split in the middle. The samples were tested for failure using a standard testing machine. The machine was connected to a computer that recorded all the values obtained from the tests.

    Results:

    The results of the study were obtained as force-displacement graphs. The stiffness of the samples and interaction between the glulam and GIT rods were also calculated. The results achieved from the experimental tests of different series were compared and discussed.

    Conclusion:

    The experimental tests resulted in a 12.5% increase in the average USFC of sample series 2. However, the average USFC of sample series 4 was not enhanced significantly. The interaction between the glulam and GIT rods was obtained as 31.8% for the samples with reinforcing at the IA of 45° to the fiber direction and 3.8% for the samples with reinforcing at the IA of 90° to the fiber direction. Reinforcing the glulam with the GIT rods demonstrated the potential of enhancing its USFC. However, reinforcing the glulam with the GIT rods at the IA of 45° to the fiber direction was found to be superior to reinforcing the glulam with the GIT rods at the IA of 90° to the fiber direction.

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  • 19.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Deniz, Suleyman
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Moalin, Hassan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Vertical Extension of a Multi-Storey Reinforced Concrete Building2022Ingår i: International Journal of Applied Mechanics and Engineering, ISSN 1425-1655, Vol. 27, nr 1, s. 1-20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The global population is increasing annually; thus, there is a need for more housing and buildings worldwide. As cities grow outward and buildable lands become scarce, it is necessary to increase the height of existing buildings in cities, especially where the height of the buildings is low. For crowded cities, the storey extension is an increasingly popular measure that can meet market demand for centrally located houses. This paper examines the possibility of the vertical extension of an existing (reference) reinforced concrete building in Gävle in Sweden. The StruSoft FEM-Design program is employed to carry out the research. The building is firstly modelled, analysed and designed completely. Thereafter, a storey extension is conducted vertically. The stresses and utilisation ratios of the load-bearing elements of the reference and extended buildings are assessed. It is found that some of the load-bearing elements of the building after the extension need strengthening. Different practical strengthening solutions are proposed. It is concluded that the building can successfully withstand the vertical extension after applying these proposed solutions. The maximum vertical reaction forces of the reference and extended buildings are obtained and compared. A comparison of the deflections of the buildings is made. The structural stability of the buildings is evaluated as well. 

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  • 20.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Edås, Martin
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Magnenat, Kevin
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Norén, Johan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    The behavior of cross-laminated timber and reinforced concrete floors in a multi-story building2022Ingår i: International Journal of Advanced and Applied Sciences, ISSN 2313-626X, Vol. 9, nr 6, s. 43-50Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The behavior of cross-laminated timber (CLT) and reinforced concrete (RC) floors in a multi-story building is investigated in this article. The load-bearing capacity, fire resistance, and sound insulation characteristics of the floors are the main focus of this research. In order to achieve this goal, a four-story building having RC floors is modeled, analyzed, and designed using the StruSoft FEM-Design software (FEM) following the Eurocodes and Swedish national annex. The building is considered to be in the city of Gävle in Sweden. Then, the RC floors of the building are replaced with the CLT floors, and the same process is done utilizing FEM. The utilization ratios (the ratios of the applied loads to the load-bearing capacities), vertical deflections, weights of the RC and CLT floors, and reaction forces of the buildings are evaluated and compared. The results show that the RC floors meet the deflection requirements well which contribute to the focus on their utilization ratios. The designed RC floors are acceptable from the vertical deflection and utilization ratio perspectives. However, the CLT floors cannot meet the vertical deflection requirements, and thus, need strengthening. The CLT floors are strengthened with supporting timber beams and columns which result in acceptable vertical deflections and utilization ratios. Fire resistance and sound insulation conditions of the RC and CLT floors are assessed by calculations based on the requirements of the Swedish National Board of Housing, Building, and Planning regulations (BBR) as well. The RC floors have the ability to be soundproof and have no difficulties in meeting the fire resistance requirements R60 of BBR. A cross-section is proposed for the CLT floors which can meet the fire resistance requirement R60 and sound insulation requirement C of BBR. The maximum reaction forces of the buildings and total weights of the floors are larger in the case of RC than CLT.

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  • 21.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran..
    Heidari, M.
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran..
    Dynamic analysis of steel eccentrically braced frames with shear link2020Ingår i: International Journal of Engineering Research and Technology, ISSN 0974-3154, Vol. 13, nr 2, s. 233-239Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper offers the dynamic analysis of steel eccentrically braced frames (EBFs) with shear link under earthquake loads. The analysis was carried out using the finite element software ABAQUS. The verification of the EBF modelling was established by the comparison of the modelling result with that of the experimental test. Then, an EBF was designed with a shear link. Three different severe earthquake records of Tabas, Northridge, and Chi-Chi were selected for the analyses. Since the modelling accuracy was revealed, the method was utilised for modelling the developed EBF. The EBF was then analysed under the mentioned records. From the obtained results, the lateral displacements and energy dissipations of the frame and also shear link rotations were investigated. With regard to all the effects of the records as the lateral displacement and base shear of the frame and also the shear link rotation, it was found that the hierarchy of the records from their effects viewpoint on the EBF has been the Tabas, Chi-Chi, and Northridge earthquakes. In addition, the hierarchy of the energy dissipations of the records by the EBF has been the Tabas, Chi-Chi, and Northridge earthquakes, as well. Therefore, the developed EBF demonstrated a good performance in the energy dissipation of the earthquake records. 

  • 22.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Heidari, M.
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Dynamic behaviour of steel eccentrically braced frames having moment-shear link2020Ingår i: Journal of Engineering and Applied Sciences, E-ISSN 1819-6608, Vol. 15, nr 23, s. 2793-2799Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This research is concerned with the dynamic behaviour of steel eccentrically braced frames (EBFs) having moment-shear link. The finite element software ABAQUS is used to analyse the EBFs. An experimentally tested EBF is modelled and the comparison of its obtained result with that of the experimental test validates the modelling method. An EBF is also designed having a moment-shear link. The designed EBF is modelled based on the verified modelling method. Then, the EBF is analysed under three selected earthquake records of Tabas, Chi-Chi, and Northridge. The lateral displacements, base shears, and energy dissipations of the EBF and also moment-shear link rotations are obtained from the results and compared. It is concluded that the largest to smallest values for the lateral displacement and base shear of the EBF, and also link rotation are all related to the Tabas, Chi-Chi, and Northridge records, respectively. However, the EBF dissipates the energy of the Tabas record more than the Northridge record, while, the latter is more than the Chi-Chi record.

  • 23.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Heidari, M.
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Effectiveness of composite steel-concrete buckling-restrained braces (BRBs) for steel frames2021Ingår i: International Journal of Advanced Research in Engineering and Technology, ISSN 0976-6480, Vol. 12, nr 3, s. 42-55Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Effectiveness of composite steel-concrete buckling-restrained braces (BRBs) for steel frames is assessed in this paper. The buckling-restrained braced frames (BRBFs) are investigated by employing the ABAQUS software. This software uses the finite element method. A BRB which has been tested experimentally is modelled in this research in order to verify the modelling. Then, the result of the modelling is compared with that of the experimental test. Since there is a good agreement between the results, the verification of the modelling is accomplished. A BRBF is subsequently designed having moment-shear link. The dynamic analyses of the BRBF with moment-shear link are conducted under three different earthquake records of Tabas, Chi-Chi, and Northridge. The obtained results from the analyses include the lateral displacements, base shears, and energy dissipations of the BRBF and also moment-shear link rotations. These results are compared and discussed. The achieved results from the analyses of the BRBF are also compared with those of its corresponding steel eccentrically braced frame (EBF). The results signify the effectiveness of the BRBF having moment-shear link over the EBF with regard to the lateral displacement, base shear, energy dissipation, and link rotation.

  • 24.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Heidari, M.
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Evaluation of structural response of composite steel-concrete eccentrically buckling-restrained braced frames2020Ingår i: Journal of Applied Engineering Science, ISSN 1451-4117, Vol. 18, nr 4, s. 591-600Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The main purpose of this paper is to evaluate the structural response of composite steel-concrete eccentrically buckling-restrained braced frames (BRBFs). The finite element (FE) software ABAQUS is employed to nonlinearly analyse the BRBFs. Comparing the modelling and experimental test results validates the FE modelling method of the BRBF. Three different strong earthquake records of Tabas, Northridge, and Chi-Chi are selected for the nonlinear dynamic analyses. A BRBF is then designed having a shear link. Afterwards, the designed BRBF is analysed under the selected earthquake records using the validated modelling method. The lateral displacements, base shears, and energy dissipations of the frame and shear link rotations are achieved from the analyses of the BRBF. The results are compared and discussed. The obtained BRBF results are also compared with their corresponding steel eccentrically braced frame (EBF) results. It is concluded that the BRBF can generally accomplish the improved structural response compared with the EBF under the earthquake records. Meanwhile, the BRBF has larger base shear capacity than the EBF. Moreover, the BRBF dissipates more energy than the EBF.

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  • 25.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Islamic Azad University, Iran.
    Heidari, M.
    Islamic Azad University, Iran.
    Investigation of steel frames equipped with steel eccentric braces and steel-concrete buckling-restrained braces having moment link2021Ingår i: Open Construction & Building Technology Journal, ISSN 1874-8368, Vol. 15, s. 55-69Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background:

    Different bracing systems of steel Eccentric Braces (EBs) and steel-concrete Buckling-Restrained Braces (BRBs) can be used in steel frames in order to make the frames stronger in resisting lateral loads. These steel frames with EBs or BRBs are generally called Eccentrically Braced Frames (EBFs) or Buckling-Restrained Braced Frames (BRBFs), respectively.

    Objective:

    This study aims to investigate steel frames with bracing systems of steel EBs and steel-concrete BRBs having moment link.

    Methods:

    The EBFs and BRBFs are nonlinearly analysed employing the finite element software ABAQUS. Experimental tests of the EBF and BRB are utilised for the validation of their modelling. The modelling is validated by comparing the modelling results with experimental tests results. Then, an EBF and a BRBF are designed having moment link. The extreme earthquake records of Tabas, Chi-Chi, and Northridge are selected for the dynamic analyses of the EBF and BRBF. The validated modelling method is applied to analyse the designed EBF and BRBF under the selected earthquake records.

    Results:

    The achieved results from the analyses are lateral displacements, base shears, and energy dissipations of the EBF and BRBF and moment linkrotations. These results are compared and discussed.

    Conclusion:

    It is concluded that the hierarchy of the lateral displacements of the analysed EBF and BRBF, having moment link, is related to the Tabas, Chi-Chi, and Northridge records because the lateral displacements of the frames are directly proportional to the peak ground accelerations of the records, and there is the same hierarchy for the records in terms of their peak ground accelerations. Lower lateral displacements are witnessed for the BRBF than the EBF subjected to the Tabas and Chi-Chi records. However, larger lateral displacement is observed for the BRBF than the EBF under the Northridge record. The same procedure as the lateral displacements is also revealed for the effectiveness of the BRBF with regard to its link rotations compared with the EBF. Moreover, the BRBF improves the base shear capacities and energy dissipations of the frame compared with the EBF. Consequently, the BRBF is generally demonstrated to be superior to the EBF from the structural performance point of view. Thus, the BRBF can be used more efficiently in structures subjected to large lateral loads compared with the EBF.

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  • 26.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Hornborg, Angelika
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Persson, Sofia
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Norén, Johan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Bengtsson Asplin, Björn
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Evaluation of Untreated and Surface-Treated Wooden Facades of Buildings in Sweden2023Ingår i: Coatings, ISSN 2079-6412, Vol. 13, nr 4, artikel-id 746Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this research, untreated and surface-treated wooden facades of buildings are investigated and compared with regard to durability, environmental impact, and cost using the document and literature studies supplemented with quantitative data. The investigation is based on the influence on the wood by external factors, either in its natural form or with a protective layer of a surface treatment. It is resulted from the study that from a durability viewpoint, it is not always advantageous to paint a wooden facade. Yakisugi, a thermal modification for wooden facades that involves burning the wood to create a protective surface layer, has shown better properties, which, in combination with a lower need for maintenance, can be considered the leading treatment for facades. From an environmental perspective, Yakisugi, like untreated wood, has demonstrated advantages compared with conventional paints. Paints often come with maintenance requirements that should be carried out correctly to avoid extensive costs. Cost is an important factor that can be decisive when users choose a surface treatment. What determines the cost is the relationship between durability and maintenance intervals. The need for the maintenance of paints leads to large financial costs during the working life of a wooden facade, which differs from Yakisugi or an untreated wooden facade that can be considered maintenance-free. In order to meet the growing environmental demands from a national level to a global scale, unconventional surface treatments for wooden facades should be promoted in the future.

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  • 27.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Imo-Imo Israel Eshiet, KennethDepartment of Civil Engineering, University of Wolverhampton, UK.
    Advances in Structural Integrity and Failure2024Samlingsverk (redaktörskap) (Refereegranskat)
    Abstract [en]

    The purpose of this book is to expand the knowledge and skills of civil and structural engineers and researchers and help them better understand, design, and analyze civil engineering applications. This book examines advancements in structural integrity and failure and underground construction. It offers profound insights into the mechanisms that can lead to the integrity or failure of structures and result in safe underground construction. It provides details on the fundamental principles, theories, behavior, and performance of different structural elements and underground construction. The book delves into the mechanics, design, and construction of reinforced concrete structures. It explores the design principles applied to reinforced concrete structures and considers critical structural elements like beams, slabs, columns, and foundations. It also demonstrates various advances in reinforced concrete technology, including high-performance concrete, fiber-reinforced concrete, self-compacting concrete, and the use of nanomaterials. It describes methods for the analysis and evaluation of reinforced concrete structures, non-destructive testing methods, structural health monitoring, finite element analysis, and causes of failure. In addition, the book proposes a design model for determining the flexural bearing capacity of reinforced concrete beams having reinforcement steel with reduced modulus of elasticity. Moreover, the book investigates the effects of loading rates on the mechanical properties of structural steel. It also evaluates the formation of welding defects in the process of connecting steel structures, which is inevitable, from the aspect of failure mechanics. In addition, it utilizes an equivalent shell-wire model to propose a simple accurate technique for nonlinear assessment of reinforced concrete shear walls with less computational cost. The book introduces tunnel design theory and method, support structure systems, construction technology, and equipment under complex geological conditions. Furthermore, it highlights procedures to design efficient dewatering systems considering the working conditions, stability, and impacts generated in the vicinity of construction, and to examine the state of retaining walls by using hydrogeological tools. Finally, it outlines the online monitoring and intelligent diagnosis mechanism of key equipment in the subway ventilation system.

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  • 28.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Jakobsson, Jonas
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Söderroos, Tobias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap.
    Factors Influencing Choice of Wooden Frames for Construction of Multi-Story Buildings in Sweden2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 1, artikel-id 217Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Construction of buildings with wooden frames higher than two stories has been permitted in Sweden since 1994. As construction of multi-story buildings with wooden frames is relatively new, people in the construction industry are more likely to construct these buildings with concrete frames. The current research evaluates the factors influencing the choice of wooden frames for construction of multi-story buildings in Sweden. The purpose of this study is to explain which advantages and disadvantages construction companies in Sweden consider with wooden construction and to highlight the factors for why multi-story buildings are built with wood to a lesser extent than with other materials. The main goal is to investigate what factors or assumptions construction companies base their decisions on, and whether experience and competence in wooden frames for construction of multi-story buildings are considered in short supply in Sweden today. The chosen method for this research is a descriptive survey study with a qualitative and quantitative approach. The survey is based on respondents from five leading building companies in Sweden with regard to the companies’ revenue. The respondents had either previous experience in constructing multistory buildings with wooden frames, experienced respondents (ERs), or no experience, unexperienced respondents (UERs). 63% of the respondents were ERs, while 37% of them were UERs. It is resulted that the respondents think there is a lack of competence and experience in wooden frames for construction of multi-story buildings in Sweden. Factors that have the greatest impact on decisions to construct with wooden frames are positive environmental and climatic aspects as well as production advantages. Factors that are considered as major obstacles to construct with wooden frames are cost, acoustics, and moisture problems.

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  • 29.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Lindqvist, Moa
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Lindqvist Berglund, Lisa
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Eriksson, Bengt
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Important Criteria for Swedish Construction Companies to Choose Environmentally Friendly Concrete2023Ingår i: Civil Engineering Journal, ISSN 2676-6957, Vol. 9, nr 1, s. 197-207Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Today, ordinary Portland cement-based concrete is one of the most important building materials and is widely used in new building construction, which is an environmental problem, as cement production accounts for 5%-8% of the world's carbon dioxide emissions. Thus, the need for using more environmentally friendly concrete (EFC) is growing. However, it is stated that Swedish construction companies are reluctant to change and adopt new construction methods and materials. This research aims to map the important criteria for Swedish construction companies to choose EFC for use in their projects. The study is carried out based on a literature study and a questionnaire survey. The questionnaire is designed considering the significant criteria of EFC derived from the literature study. The respondents from the Swedish construction companies were asked to rate these various criteria. The collected results are presented with bar graphs. The results show that the highest valued criterion by the respondents for the use of EFC in the projects is its long-term properties, while the lowest one is the possibility of introducing a specific ceiling for greenhouse gas emissions by the companies.

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  • 30.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Mahmoudi Kouhi, A.
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Compressive behaviour of circular, square, and rectangular concrete-filled steel tube stub columns2020Ingår i: Civil engineering and architecture, ISSN 2332-1091, E-ISSN 2332-1121, Vol. 8, nr 5, s. 1119-1126Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, the compressive behaviour of circular, square, and rectangular concrete-filled steel tube stub (CFSTS) columns is assessed. Nonlinear three-dimensional finite element models for simulating the behaviour of the columns are developed with the aid of the finite element analysis package ABAQUS. Modelling result is compared with the experimental test result to validate the modelling. It is found that the obtained load-axial strain curves of the columns from the finite element analysis and experimental test are notably close to each other and the modelling is finally validated. Then, the analyses of the developed models of the columns are done in accordance with the validated method. Various parameters are adopted in the analyses including the load eccentricity, cross-sectional shape, and steel tube thickness. It is concluded that as the load eccentricity of the columns is increased, their ultimate load-carrying capacity, energy absorption capacity, and stiffness are decreased. Also, the circular columns have generally better performance than their rectangular and square counterparts. The hierarchy of the cross-sectional shapes of the columns from the ultimate load-carrying capacity and energy absorption capacity viewpoints is the circular, rectangular, and square shapes. Although the initial stiffness and slope of the stiffness curves of the rectangular and square columns are slightly higher than those of the circular columns, their stiffness distribution is non-uniform. Furthermore, thicker steel tube leads to greater ultimate load-carrying capacity, energy absorption capacity, and stiffness. Failure modes of the columns are achieved and discussed as well.

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  • 31.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Mahmoudi Kouhi, A.
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Energy absorption capacity of concrete-filled steel tube slender columns with different aspect ratios2022Ingår i: Current Applied Science and Technology, E-ISSN 2586-9396, Vol. 22, nr 1, s. 1-16Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present paper examines the energy absorption capacity of concrete-filled steel tube slender (CFTS) columns having different aspect ratios. The CFTS columns are nonlinearly analysed employing the finite element software ABAQUS. In order to validate the simulation of the columns, an experimentally tested CFTS column is simulated and its achieved result is compared with that of the tested column. Since it is concluded that there is a good agreement between the obtained results from the simulation and experimental test, the validation of the simulation is then established. The simulated columns are thereafter developed using different aspect ratios of 6, 10, and 13 and also considering the following parameters: load eccentricities, cross-sectional shapes, and steel tube thicknesses. The columns are nonlinearly analysed and the results are achieved from the analyses. The effects of the above-mentioned parameters on the energy absorption capacity of the CFTS columns are evaluated. From the results, it can be concluded that the energy absorption capacity of the columns is decreased by the increase of the load eccentricity or aspect ratio. Further, the energy absorption capacity of the circular CFTS column is greater than that of the rectangular and square CFTS columns. However, higher energy absorption capacity is accomplished for the rectangular column than the square column. Additionally, increasing the steel tube thickness leads to greater energy absorption capacity of the columns. Typical failure modes of the columns are assessed.

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  • 32.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Mahmoudi Kouhi, A.
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Load capacity and failure modes of axially and eccentrically loaded thin-walled steel tubular slender columns filled with concrete2020Ingår i: International Journal on Emerging Technologies, ISSN 0975-8364, Vol. 11, nr 5, s. 517-524Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The purpose of this paper is to investigate the load capacity and failure modes of thin-walled steel tubular slender columns filled with concrete under axial and eccentric loads. Different concrete compressive strengths and length/diameter (width) ratios are adopted for the slender columns. The columns are modelled and analysed by the use of the finite element software ABAQUS. The verification study of the three-dimensional nonlinear finite element modelling is carried out using its corresponding experimental test result. In order to establish the verification of the modelling, all specifications of the experimentally tested column are taken into account in the modelling. Comparing obtained results from the modelling and test uncovers that they agree well with each other. Thus, the accuracy of the modelling is demonstrated. Then, the same modelling method is utilised for modelling and analysing developed slender columns. Variables used for the columns include different load eccentricities, cross-sectional shapes, and steel tube thicknesses. Effects of these variables on the load capacity of the columns are examined. It is concluded that increasing the load eccentricity reduces the load capacity of the slender columns. The circular columns perform better than the square and rectangular columns. Also, enhancing the steel tube thickness results in larger load capacity of the columns. Columns with the large load capacity are desirable in terms of their structural performance in projects. Meanwhile, various failure modes of the columns are widely evaluated and discussed.

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  • 33.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Mahmoudi Kouhi, A.
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Stiffness of concrete-filled thin-walled steel tubular slender columns2021Ingår i: Civil and Environmental Engineering, ISSN 1336-5835, Vol. 17, nr 1, s. 252-258Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Concrete-filled thin-walled steel tubular slender columns are studied in this paper to evaluate their stiffness. The slender columns have various steel tube thicknesses, length/diameter (width) ratios, and concrete compressive strengths. The columns are loaded by axial and eccentric loads. Two experimental tests of the slender and stub columns are described. Also, the finite element software ABAQUS is utilised to simulate and analyse the columns. The tested columns are simulated taking into account all of their features in the tests to verify the simulation of the columns. The simulation results are compared with the tests results which reveal that good agreements exist between them. Thus, the proposed simulation method of the columns is verified. In order to assess the stiffness of the columns under different conditions, various load eccentricities (0 mm, 25 mm, and 50 mm), cross-sectional configurations (circular, rectangular, and square), and steel tube thicknesses (2 mm, 3.35 mm, and 5 mm) are adopted for the developed columns. The columns are simulated and analysed based on the verified simulation method considering the mentioned conditions. As a conclusion, the stiffness of the columns is generally reduced by the increase of the load eccentricity from 0 mm to 25 mm and 50 mm. Further, more uniform distribution of the stiffness is witnessed for the columns with lower eccentricities. In addition, the enhancement of the load eccentricity increased the reduction slope of the stiffness graph for the columns. Although the initial stiffness of the circular column is slightly lower than the rectangular and square columns, the stiffness has more uniform distribution which is preferred. Larger stiffness is achieved for the columns by increasing the steel tube thickness from 2 mm to 3.35 mm and 5 mm.

  • 34.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran..
    Matinrad, S.
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran..
    Resistance of blast-loaded steel and reinforced concrete beam-to-column connections2020Ingår i: International Journal of Engineering Research and Technology, ISSN 0974-3154, Vol. 13, nr 1, s. 12-27Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Resistance of steel and reinforced concrete (RC) beam-to-column connections to blast loading is presented in this paper. The steel and RC connections are analysed nonlinearly using the finite element (FE) software ABAQUS. Comparisons of the obtained results from the connections modelling with those of the experimental tests reveal the modelling accuracy. Then, the ETABS software is utilised to design 4 buildings including 2 steel buildings with 5 and 9 storeys and 2 RC buildings with the same number of storeys. The components of the selected beam-to-column connections of the ground floor of the buildings are designed. Then, different parameters are considered for the nonlinear analyses of the steel and RC connections. The studied parameters for the steel connections are as the size of cross-section, bolts arrangement, and using stiffeners in the beam web of the connections, while the parameters for the RC connections are as the size of cross-section, stirrups space, and making beam non-prismatic in the beam-column connection region. It was found that increasing the cross-sectional sizes of the beams and columns of the steel and RC connections considerably enhances the resistance of the connections. In addition, change of the bolts arrangement in the steel connections and reducing the stirrups space in the RC connections significantly influence the resistance of the connections. However, using stiffeners in the beam web of the steel connections and making the beam non-prismatic in the region of the beam-column RC connections have no remarkable effect on the connections resistance. Failure modes of the connections are also evaluated. 

  • 35.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Matinrad, S.
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Stress concentration in reinforced concrete connections subjected to blast loads2021Ingår i: Journal of Engineering and Applied Sciences, E-ISSN 1819-6608, Vol. 16, nr 14, s. 1434-1440Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Investigating the stress concentration in reinforced concrete connections under the blast loads is the purpose of the present paper. This goal was achieved by the design and analysis of the connections. The finite element package ABAQUS was used in this study to model and analyse the connections. A reinforced concrete connection which was tested experimentally was modelled and analysed in order to verify modelling. The results of modelling and experimental test were compared which demonstrated the accuracy of modelling. Afterwards, two reinforced concrete buildings with five and nine storeys were designed employing the ETABS software. A beam-column connection of the ground floor of each building was designed. The sizes of the cross-sections of the beams and columns and the spaces of their stirrups were considered differently. These connections were also modelled and analysed. The distances of the connections from the blast centre were considered as 2.5 m, 5 m, and 10 m and the blast powers were adopted as 500 kg, 1000 kg, and 2000 kg TNT equivalent mass of explosive for the analyses of the connections. The stresses created in the reinforcements of the connections owing to the blast loads were examined. It was demonstrated that as the connection was located farther from the blast centre, the stresses in the connection reinforcements were reduced. Also, the stresses in the connection reinforcements were increased by enhancing the blast power. Meanwhile, using larger cross-sections for the beam and column in the connection of nine-storey building than the connection of five-storey building transferred the stress concentration in the reinforcements to the beam and near the beam-column connection. By decreasing the stirrups spaces of the beam in the connection of five-storey building, the high stresses in the reinforcements were mainly transferred to the beam of the connection which could reduce the likelihood of the progressive collapse of the structure.

  • 36.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Matinrad, Sina
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Blast effects on reinforced concrete connections2019Ingår i: International Journal of Scientific and Technology Research, ISSN 2277-8616, Vol. 8, nr 11, s. 3604-3610Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study is concerned with the blast effects on reinforced concrete (RC) connections. The RC connections are analysed nonlinearly. The analyses are conducted by applying the finite element software ABAQUS. The first step is to do the verification of the modelling. To achieve this goal, an experimental test performed on an RC connection is simulated utilising ABAQUS. Comparing the analysis result with the experimental test result establishes the modelling verification. In the second step, a 5-storey building is designed by the use of the ETABS software. A connection of the ground floor is selected for further analyses in ABAQUS. In the third step, the components of the selected connection are designed. Then, various variables are taken into account as the distance of the connection from the blast centre (2.5 m, 5 m, and 10 m) and the blast power (500 kg, 1000 kg, and 2000 kg TNT equivalent mass of explosive) for the further analyses of the connection. In the fourth step, the connection is analysed considering the variables. Finally, effects of these variables on the behaviour of the connection are investigated and discussed. Failure modes of the connections due to the blast loading are presented. © IJSTR 2019.

  • 37.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Matinrad, Sina
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Response of steel beam-to-column bolted connections to blast loading2019Ingår i: International Journal of Recent Technology and Engineering, ISSN 2277-3878, Vol. 8, nr 3, s. 3639-3648Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this research, response of steel beam-to-column bolted connections to blast loading is investigated. Nonlinear analyses of the connections are performed using the finite element software ABAQUS. In order to demonstrate the accuracy of the finite element modelling, an experimental test of a steel beam-to-column bolted connection is modelled. Comparison of the obtained result from the modelling with that of the corresponding experimental test verifies the modelling. Then, a 5-storey steel building is designed using ETABS software from which a beam-to-column connection of the ground floor is selected for the nonlinear analysis in ABAQUS. Thereafter, the components of the selected connection are designed. Finally, the connection is nonlinearly analysed considering parameters as the distance from the blast centre (2.5 m, 5 m, and 10 m) and blast power (500 kg, 1000 kg, and 2000 kg TNT equivalent mass of explosive). Effects of these parameters on the response of the connection are evaluated. Failure modes of the connections are assessed, too.

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  • 38.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran..
    Najarnasab, M.
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran..
    Analysis of steel plate girders with elliptical web openings2020Ingår i: Journal of Engineering and Applied Sciences, E-ISSN 1819-6608, Vol. 15, nr 4, s. 556-563Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this research work, steel plate girders (SPGs) having the web openings with the elliptical shape are analysed. The finite element ABAQUS software is applied. An experimentally tested SPG is used for the modelling verification. Then, the SPGs are developed. Three-dimensional (3D) finite element models of the SPGs are analysed nonlinearly considering various variables. The variables are adopted in order to deeply examine the performance of the SPGs using the finite element method. These variables include: 1) number of the openings, 2) arrangement of the openings, 3) using steel frame around the openings, 4) utilising diagonal steel stiffeners to connect the steel frame around the openings to the corners of the SPGs, and 5) thicknesses of the steel frame and the diagonal steel stiffeners. The obtained results are compared and discussed considering the effects of the variables. It is concluded that increasing the number of the openings has an adverse impact on the ultimate strength of the SPGs. The arrangement of the openings in the SPGs significantly affects their performance. The horizontal openings are superior to the vertical ones. Utilising the steel frame around the openings and/or the steel stiffeners improves the ultimate strength. Enhancing the thickness of the steel frame and/or stiffeners increases the ultimate strength. The assessment of the failure modes of the SPGs is also done. 

  • 39.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Najarnasab, Mahdi
    Department of Civil Engineering, Abadan Branch, Islamic Azad University, Abadan, Iran.
    Ultimate behaviour of perforated steel plate girders subjected to shear loading2020Ingår i: Open Construction & Building Technology Journal, ISSN 1874-8368, Vol. 14, s. 70-83Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background:

    The Perforated Steel Plate Girders (PSPGs) are those Steel Plate Girders (SPGs) that have openings in their web. The PSPGs are significant structural members to withstand bending mainly. The proper combination of steel plates is applied to fabricate the PSPGs. When the available rolled steel profiles cannot carry the applied loads, the use of beams made of the steel plates is unavoidable.

    Objective:

    The present paper presents the ultimate behaviour of PSPGs subjected to shear loading.

    Methods:

    In order to carry out the study, the finite element method is used as a practical design tool for predicting the ultimate behaviour of the PSPGs under shear loading. Two experimentally tested PSPGs are selected to conduct the modelling accuracy using ABAQUS. All the features of the tested specimens are considered in the modelling. The finite element modelling results are compared with the experimental tests results, which verify the modelling. Since the accuracy of the modelling is demonstrated, thereafter, the method is used for the nonlinear analysis of the developed PSPGs having different circular and rectangular openings. Various parameters are adopted in the analysis to vastly evaluate their effects on the ultimate behaviour of the PSPGs. The parameters include shape of the openings (circular and rectangular openings), number of the openings (2 and 4 openings), arrangement of the openings (horizontal and vertical openings), using steel frame around the openings, utilising diagonal steel stiffeners to connect the steel frame to the corners of the PSPGs, and thicknesses (2 mm and 4 mm) of the steel frame and the diagonal steel stiffeners.

    Results:

    The obtained results from the nonlinear analysis of the PSPGs are summarised considering various parameters. The results are compared and discussed, taking into account the effects of the parameters on the ultimate behaviour of the PSPGs.

    Conclusion:

    The study highlights that the shape of the openings affects the behaviour of the PSPGs. Accordingly, circular openings are preferred compared with the rectangular ones. Also, as the number of the openings is increased, the ultimate capacity of the PSPGs is reduced. The behaviour of the PSPGs is considerably affected by the arrangement of the openings in which the horizontal openings have better performance than the vertical ones. If the steel frame and/or the steel stiffeners are utilised, the ultimate capacity is enhanced. The ultimate capacity of the PSPGs is improved by increasing the thickness of the steel frame and/or stiffeners. The failure modes of the PSPGs with circular and rectangular openings are indicated and evaluated.

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  • 40.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Oliver, Nexén
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Jonsson, Jonas
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Comparing performance of cross-laminated timber and reinforced concrete walls2021Ingår i: International Journal of Applied Mechanics and Engineering, ISSN 1425-1655, Vol. 26, nr 3, s. 28-43Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The purpose of this research is to specify the differences between the performance of cross-laminated timber (CLT) and reinforced concrete (RC) walls. The study is done by using the finite element structural analysis and design software, StruSoft FEM-Design, in order to model, analyse and design a reference building located in the city of Gävle in Sweden. The building is firstly modelled, analysed and designed using RC walls and then the RC walls are replaced with CLT walls. In both buildings, other load-bearing elements such as slabs, beams and columns are made of RC while the roof beams are made of glulam. It is found that employing RC has advantages, especially regarding thickness. The results show that the CLT walls require larger dimensions than their RC counterparts. Meanwhile, it is demonstrated that the slabs, beams and columns made of RC in the building having the CLT walls require more reinforcement or larger thickness than the case of walls made of RC. Moreover, the total weight of the building having the CLT walls is 74% of the building having the RC walls. The lower weight of the building having the CLT walls has great advantages such as having lighter foundation and being cost-effective and also beneficial for the environment.

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  • 41.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Olsson, Markus
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Svensson, Karl
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Carbon Dioxide Emissions from Various Structural Frame Materials of Single-Family Houses in Nordic Countries2022Ingår i: International Journal of Innovative Research and Scientific Studies, ISSN 2617-6548, Vol. 5, nr 2, s. 112-120Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Since the choice of material for the construction of single-family houses has a major impact on the buildings' total carbon dioxide emissions, this study examines the carbon dioxide emissions from various structural frame (frame) materials used for single-family houses in the Nordic countries. The analysed frame materials are wood, concrete, and steel as they are the most frequently chosen for single-family houses in these countries. To map the carbon dioxide emissions from the frame materials, a literature review of existing life cycle analyses of the materials is conducted. To present the results, a typical wall is employed for each material; the width and height of the walls are 1 m, while the depth varies for the different materials. The walls are designed to illustrate the results, which are reported in kg CO2/m3. Moreover, the study includes interviews with housing manufacturers to get the building industry's views on the choice of frame material with regard to carbon dioxide emissions. The results show that there are major differences in the carbon dioxide emissions from the three frame materials. The wooden, steel, and concrete frames emit 96 kg CO2/m3, 209 kg CO2/m3, and 602 kg CO2/m3, respectively. The results confirm that the wooden frame has the lowest carbon dioxide emissions, which makes it the most environmentally friendly frame in the Nordic countries when compared with the steel and concrete frames.

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  • 42.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Rashid, S. M. Priok
    Department of Civil Engineering, Faculty of Engineering, Hajee Mohammad Danesh Science and Technology University, Dinajpur 5200, Bangladesh.
    A State-of-the-Art Review on Axial Compressive Behavior of Concrete-Filled Steel Tubes Incorporating Steel Fiber and GFRP Jacketing2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 3, artikel-id 729Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Several types of fibers have enhanced the structural response of reinforced concrete-filled steel tubes (CFSTs). This article presents a state-of-the-art review of studies done on the axial compressive behavior of steel and glass fiber-reinforced CFSTs. The aim of using fibers is to improve the response of the CFSTs. This research indicates the findings of experimental programs and analytical evaluations of the effects of the fiber incorporation on the behavior of the CFSTs. The results of this research work demonstrate that steel fibers (SFs) have enough evident improving effects on the failure mode and load-carrying capacity of the CFSTs. The SFs greatly increase the ductility of the CFSTs. To enhance the compressive strength and ductility of the CFSTs, adding the SFs by 1% to the concrete mix is more effective than adding by 1.5%. The use of the SFs mixed with expansion agent considerably increases the yield and ultimate loads of the CFSTs. More glass fiber-reinforced polymer (GFRP) sheets reduce buckling and develop the compressive strength of the CFSTs. The implementation of the GFRP jackets not only enhances the load-carrying capacity of the CFSTs, but also increases their ductility. The GFRP reinforcement techniques for the CFSTs are also effective in improving their structural stiffness and energy absorption capacity.

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  • 43.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Rashid, S. M. Priok
    Department of Civil Engineering, Faculty of Engineering, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh.
    Sustainable Development of Recent High-Rise Timber Buildings2024Ingår i: Sustainable Structures and Buildings / [ed] Alireza Bahrami, Springer , 2024, s. 1-16Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    High-rise timber building construction is becoming increasingly common across the world as construction and woodworking technology advances. The world is moving toward more sustainable development, and products like cross-laminated timber offer economical options for reducing the environmental impact. This chapter contributes to the theory and practice of sustainability assessment and extends the knowledge about high-rise timber buildings. The tallest timber buildings in different countries, such as Mjøstårnet and Treet in Norway and Brock Commons in Canada, are compared across the three dimensions of sustainability (environmental, economic, and social). According to previous research, none of the buildings are at the top in terms of sustainability, but the Brock Commons building in Canada has received the highest rank in all dimensions of sustainability. The issue of fire resistance for timber structures involves a paradox because it is widely recognized that heavy timber construction has outstanding fire resistance in severe fires. Design for burnout may require full or partial encapsulation of timber. Moreover, prefabrication of elements reduces duration and cost of projects. The goal of this chapter is to evaluate and assess the most effective modern high-rise timber buildings from both financial and environmental perspectives.

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  • 44.
    Bahrami, Alireza
    et al.
    Department of Civil and Structural Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Malaysia.
    Shanmugam, N. E.
    Department of Civil and Structural Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Malaysia.
    Behaviour of profiled composite beams2009Ingår i: Civil & Structural Engineering Seminar, Malaysia, 2009, s. 1-15Konferensbidrag (Refereegranskat)
    Abstract [en]

    Behaviour of profiled steel composite beams is studied in this paper. Finite element software LUSAS is used to carry out the non-linear analyses in order to study the ultimate load behaviour of the beams. Experimental results reported by other researchers are used to verify the finite element model. Different shapes, arrangements, and number of steel sheeting ribs have been studied by finite element analyses. Effects of the parameters on the ultimate capacity of the profiled composite beams have been examined. The results are presented in the form of load-deflection plots. It is concluded from the study that the ultimate load capacity of the profiled composite beams is influenced with different shapes, arrangements, and number of ribs and as the number of the ribs is increased the ultimate load capacity of the beams is increased, too.

  • 45.
    Bahrami, Alireza
    et al.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Shanmugam, N. E.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Finite element studies on profiled steel composite beams2011Ingår i: The IES Journal Part A: Civil & Structural Engineering, ISSN 1937-3260, E-ISSN 1937-3279, Vol. 4, nr 1, s. 1-7Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article is concerned with finite element studies on profiled steel composite beams to investigate their elastic and ultimate load behaviour. Finite element code LUSAS is used to carry out the non-linear analyses to determine the load carrying capacity of the beams. Results from the experimental studies reported by other researchers are first used to assess the accuracy of the finite element modelling. Analyses are carried out thereafter to study different shapes, arrangements and number of steel sheeting ribs. Effects of the parameters such as concrete compressive strength fc, yield stress fyp of the profiled steel sheeting, and thickness of the steel sheeting on the ultimate load capacity of the profiled steel composite beams are examined. The results are presented in the form of load-deflection plots and ultimate load values. It is concluded that the ultimate load capacity of the profiled steel composite beams can be predicted with an acceptable accuracy by the proposed finite element modelling. Results show that the load carrying capacity of the beams are influenced by shapes, arrangements and number of ribs. It is also found that compressive strength fc of the concrete, and yield stress fyp and thickness of profiled steel sheeting have significant influences on the performance of these beams.

  • 46.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Vall, Andreas
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Khalaf, Asaad
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Comparison of cross-laminated timber and reinforced concrete floors with regard to load-bearing properties2021Ingår i: Civil engineering and architecture, ISSN 2332-1091, E-ISSN 2332-1121, Vol. 9, nr 5, s. 1395-1408Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Floors of a building with the relatively new and environmentally sustainable structural material as cross-laminated timber (CLT) and traditional reinforced concrete (RC) are compared in this paper with regard to their load-bearing properties. StruSoft FEM-Design software is utilised to model, analyse and design an existing building using the CLT and RC floors. The building has three stories with a penthouse on the top floor. Modelling, analysis and design of the building can be summarised into five main steps. In step 1, the building with the RC floors is modelled, analysed and designed according to the geometries and specifications of the building. The RC floors of the building are then changed to the CLT floors with the similar thickness and the function of the building is checked for tensile and compressive stresses, utilisation ratio and deflection in step 2. Step 3 involves checking what reinforcing is required for the CLT floors to be approved with about the same thickness as the RC floors. In step 4, it is controlled whether a larger thickness of the CLT floors without reinforcing can withstand the identical conditions of the RC floors. From the obtained results, effects of thickness of the CLT floors and span width are examined. The structural stability of the building with the CLT and RC floors is controlled in step 5. Further, the CLT and RC floors of the building are compared in terms of their stresses, utilisation ratios and weights. The results of this paper demonstrate advantages of using the CLT floors. The CLT floors show good strength properties compared with their low weights. It is uncovered that the building with both of the CLT and RC floors is stable. Obtained results of the building with the CLT and RC floors from the StruSoft FEM-Design software are compared with those from calculations based on Eurocode 2 and Eurocode 5, which reveal good agreements with each other regarding their accuracy.

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  • 47.
    Bahrami, Alireza
    et al.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Wan Badaruzzaman, W. H.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Osman, S. A.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Behaviour of stiffened concrete-filled steel composite (CFSC) stub columns2013Ingår i: Latin American Journal of Solids and Structures, ISSN 1679-7817, E-ISSN 1679-7825, Vol. 3, nr 10, s. 409-439Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper investigates the behaviour of axially loaded stiffened concrete-filled steel composite (CFSC) stub columns using the finite element software LUSAS. Modelling accuracy is established by comparing results of the nonlinear analysis and the experimental test. The CFSC stub columns are extensively developed using different special arrangements, number, spacing, and diameters of bar stiffeners with various steel wall thicknesses, load eccentricities, concrete compressive strengths, and steel yield stresses. Their effects on the columns behaviour are examined. Failure modes of the columns are also illustrated. It is concluded that the parameters have considerable effects on the behaviour of the columns. An equation is proposed based on the obtained results to predict the ultimate load capacity of the columns. Results are compared with predicted values by the design code EC4, suggested equation of other researchers, and proposed equation of this study which is concluded that the proposed equation can give closer predictions than the others.

  • 48.
    Bahrami, Alireza
    et al.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Wan Badaruzzaman, W. H.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Osman, S. A.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Finite element analysis of ultimate load capacity of slender concrete-filled steel composite columns2011Ingår i: International Conference on Advanced Science, Engineering and Information Technology, Bangi-Putrajaya, Malaysia, 2011, s. 576-581Konferensbidrag (Refereegranskat)
    Abstract [en]

    Ultimate load capacity of slender concrete-filled steel composite columns is investigated in this paper. Nonlinear analyses are done by the use of finite element software, LUSAS, to study the ultimate axial load behaviour of the columns. Verification of the finite element modelling is done by comparing the result with the corresponding experimental result reported by other researchers. Analyses are carried out to assess different shapes and number of cold-formed steel sheeting stiffeners with various thicknesses of cold-formed steel sheets and their effects on the behaviour and ultimate axial load capacity of the columns. The results are presented in the form of axial load-normalized axial shortening plots. It is demonstrated that the ultimate axial load capacity of the slender concrete-filled steel composite columns can be accurately predicted by proposed finite element modelling. Obtained results from the study show that various thicknesses of cold-formed steel sheets, and different shapes and number of stiffeners influence the ultimate axial load capacity and behaviour of the columns. Also, the ultimate axial load capacity of the columns is improved by increase of number of stiffeners. Moreover, increase of thickness of cold-formed steel sheet enhances the ultimate axial load capacity.

  • 49.
    Bahrami, Alireza
    et al.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Wan Badaruzzaman, W. H.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Osman, S. A.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Investigation of concrete-filled steel composite (CFSC) stub columns with bar stiffeners2013Ingår i: Journal of Civil Engineering and Management, ISSN 1392-3730, E-ISSN 1822-3605, Vol. 19, nr 3, s. 433-446Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper is concerned with the investigation of concrete-filled steel composite (CFSC) stub columns with bar stiffeners. In order to study the behaviour of the columns, the finite element software LUSAS is used to conduct the non-linear analyses. Results from the non-linear finite element analysis and the corresponding experimental test are compared which reveal the reasonable accuracy of the three-dimensional finite element modelling. A special arrangement of bar stiffeners in the columns with various number, spacing and diameters of the bar stiffeners are developed and studied using the non-linear finite element method. Effects of various variables such as different number and spacing of the bar stiffeners and also steel wall thicknesses on the ultimate axial load capacity and ductility of the columns are examined. Moreover, effects of different diameters of the bar stiffeners, concrete compressive strengths and steel yield stresses on the ultimate axial load capacity of the columns are evaluated. It is concluded from the study that the variables significantly influence the behaviour of the columns. The obtained results from the finite element analyses are compared with those predicted values by the design code EC4 and suggested equations of the previous researches.

  • 50.
    Bahrami, Alireza
    et al.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Wan Badaruzzaman, W. H.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Osman, S. A.
    Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia.
    Nonlinear analysis of concrete-filled steel composite columns subjected to axial loading2011Ingår i: Structural Engineering and Mechanics, ISSN 1225-4568, E-ISSN 1598-6217, Vol. 39, nr 3, s. 383-398Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper investigates the nonlinear analysis of concrete-filled steel composite columns subjected to axial loading to predict the ultimate load capacity and behaviour of the columns. Finite element software LUSAS is used to conduct the nonlinear analyses. The accuracy of the finite element modelling is verified by comparing the result with the corresponding experimental result reported by other researchers. Nonlinear analyses are done to study and develop different shapes and number of cold-formed steel sheeting stiffeners with various thicknesses of cold-formed steel sheets. Effects of the parameters on the ultimate axial load capacity and ductility of the concrete-filled steel composite columns are examined. Effects of variables such as concrete compressive strength fc and cold-formed steel sheet yield stress fyp on the ultimate axial load capacity of the columns are also investigated. The results are shown in the form of axial load-normalized axial shortening plots. It is concluded from the study that the ultimate axial load capacity and behaviour of the concrete-filled steel composite columns can be accurately predicted by the proposed finite element modelling. Results in this study demonstrate that the ultimate axial load capacity and ductility of the columns are affected with various thicknesses of steel sheets and different shapes and number of stiffeners. Also, compressive strength fc of the concrete and yield stress fyp of the cold-formed steel sheet influence the performance of the columns significantly.

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