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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.
    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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  • 3.
    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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  • 4.
    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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  • 5.
    Ameen, Arman
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Choonya, Gasper
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Experimental Evaluation of the Ventilation Effectiveness of Corner Stratum Ventilation in an Office Environment2019Ingår i: Buildings, E-ISSN 2075-5309, Vol. 9, nr 7, artikel-id 169Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An experimental study was conducted in a room resembling an office in a laboratory environment. The study involved investigating the ability of corner-placed stratum ventilation in order to evaluate the ventilation’s effectiveness and local thermal comfort. At fixed positions, the air temperature, air velocity, turbulence intensity, and tracer gas decay measurements were carried out. The results show that corner-placed stratum ventilation behaves very similar to a mixing ventilation system when considering air change effectiveness. The performance of the system was better at lower supply air flow rates for heat removal effectiveness. For the heating cases, the draught rates were all very low, with the maximum measured value of 12%. However, for the cooling cases, the maximum draught rate was 20% and occurred at ankle level in the middle of the room.

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  • 6.
    Ameen, Arman
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Mattsson, Magnus
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Boström, Hanna
    Lindelöw, Hanna
    Assessment of Thermal Comfort and Air Quality in Office Rooms of a Historic Building: A Case Study in Springtime in Continental Climate2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 1, artikel-id 156Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One of the most important aspects of working in an office environment is ensuring that the space has optimal thermal comfort and an indoor environment. The aim of this research is to investigate the thermal comfort and indoor climate in three office rooms located at one of the campus buildings at the University of Gävle, Sweden. The evaluated period is in the month of April during springtime. During this period, parameters such as temperature, relative humidity, CO2, supply air flow rate, and room air velocities are measured on site. The results of the measurement show that the indoor temperature is on average lower in the rooms facing north, at 21–23.5 °C, compared to the rooms facing south, which reach high temperatures during sunny days, up to 26 °C. The results also show that the ventilation air supply rate is lower than the requirement for offices in two of the office rooms. The ACH rate is also low, at ≈ 1 h−1 for all the rooms, compared to the required levels of 2–4 h−1. The CO2 levels are within the recommended values; on average, the highest is in one of the south-facing rooms, with 768 ppm, and the maximum measured value is also in the same room, with 1273 ppm for a short period of time.

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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.
    Yamasawa, Haruna
    Kyushu University, Fukuoka, Japan..
    Kobayashi, Tomohiro
    Osaka University, Osaka, Japan..
    Numerical Evaluation of the Flow Field of An Isothermal Dual-Corner Impinging Jet for Building Ventilation2022Ingår i: Buildings, E-ISSN 2075-5309, Vol. 12, nr 10, artikel-id 1767Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The corner impinging jet ventilation is a new air distribution system for use in office environments. This study reports the mean flow field behavior of dual isothermal corner-placed inlets based on an impinging jet in a square-shaped room with the size of 7.2 m × 7.2 m. A detailed numerical study is carried out to evaluate the influence the different configuration parameters, such as the inlet placement, same side or opposite side, and supply airflow rate, have on the flow field. The results show that the highest velocity peak for all cases is obtained at x = 0.5 m and the lowest at x = 3.5 m. The velocity profiles development remains similar when increasing the flow rate. For the zone evaluation, the results show that Case 1 and 2 (V = 20 L/s) meet the requirement of not exceeding 0.15 m/s during the heating season in the occupied zone according the BBR standard both for same-side and opposite-side configurations. For Case 4, the optimal placement of the inlets is opposite to each other when V = 30 L/s for the BBR requirements. Case 1, 2, 3, 4, 5, and 7 all meet the requirement of not exceeding 0.25 m/s during the cooling season both for the same-side and opposite-side configurations. For Case 8, the optimal placement of the inlets is opposite to each other when V = 50 L/s.

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  • 8.
    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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  • 9.
    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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  • 10.
    Bahrami, Alireza
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Ågren, Felicia
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Kollberg, Kim
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Strengthening solutions for deep reinforced concrete beam with cutout opening2021Ingår i: Buildings, E-ISSN 2075-5309, Vol. 11, nr 8, artikel-id 370Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Since reinforced concrete (RC) buildings have long service life, cutout openings are generally needed in their load‐bearing walls as a sustainable solution in order to meet new requirements of their users. However, the cutout openings decrease the load‐bearing capacity of the walls, which may result in the failure of the buildings. In this paper, we investigate the possibility of making a door opening in a load‐bearing RC wall of an existing building in Gävle in Sweden. The wall studied in the current paper rests on two individual supports at its two ends; thus, it is considered as a deep beam. However, it is called an examined wall (EW) here. The StruSoft FEM‐Design software is used in this study to model, analyze, and design the building based on the Eurocodes and Swedish national annex. The potential need for the EW to be strengthened when the cutout opening is made is also evaluated. It is concluded that strengthening the EW with cutout opening is needed. Different strengthening solutions are proposed for the EW. Moreover, the situation of the EW with the solutions is assessed with regard to the utilization ratio, deflection, and weight. Consequently, it is demonstrated that the proposed strengthening solutions function well for the EW.

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  • 11.
    Frelin, Anneli
    et al.
    Högskolan i Gävle, Akademin för utbildning och ekonomi, Avdelningen för utbildningsvetenskap, Utbildningsvetenskap, Didaktik.
    Grannäs, Jan
    Högskolan i Gävle, Akademin för utbildning och ekonomi, Avdelningen för utbildningsvetenskap, Utbildningsvetenskap, Didaktik.
    Designing and building robust innovative learning environments2021Ingår i: Buildings, E-ISSN 2075-5309, Vol. 11, nr 8, artikel-id 345Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Prior research shows that creating innovative learning spaces that work well for pupils and teachers is a challenge and implicates different stakeholders. The aim of this article is to inquire into how educational visions evolve and are expressed through the different phases of two school design processes; and visualise how stakeholders’ roles in the processes result in innovative learning environments and practices that work well. The data consists of photographs from school visits, briefs, and interviews. The material is analysed with a particular focus on educational vision, organisation and working methods. An analytical model showing the stakeholders’ levels of participation at each stage is revised and developed. The results indicate four common themes: Continuity – several stakeholders involved in more than one phase. Preparation – processes were long-term, continuous, and iterative, with future users testing and evaluating prototypes and other innovative interior design elements to be used in the new spaces. Alignment – early and extensive considerations of the school’s organisation and working methods. Participation – multi-professional teams with representation of a pedagogical perspective at the higher levels of participation. From this can be concluded that achieving robust innovative learning environments involves stakeholders’ regard to aspects of knowledge, education, organization and economy. 

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  • 12.
    Ganasen, Nakkeeran
    et al.
    Department of Civil Engineering, SRM Institute of Science and Technology, Kattankulathur 603203, India.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Loganathan, Krishnaraj
    Department of Civil Engineering, SRM Institute of Science and Technology, Kattankulathur 603203, India.
    A Scientometric Analysis Review on Agricultural Wastes Used as Building Materials2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 2, artikel-id 426Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The rapid urbanization of developed countries and the difficulty in disposing of agricultural wastes have created opportunities for the construction industry to use agricultural wastes. A wide variety of agricultural waste materials are already in use with concrete as substitutes for cement and aggregates, as well as reinforcing materials. This study reviews the available literature published from 1935 to 2022 on agricultural wastes being used as building materials. The research utilizes a bibliographic approach based on the Scopus database. This article retrieves data employing the Scopus database and incorporates 671 articles based on the keywords, agricultural wastes used as building materials. The scientometric analysis is the second step, wherein the patterns of the obtained articles are investigated with various factors such as countries with the most publications, sources that have the most publications, most frequently appearing keywords, and articles with more relevant research works. A summary of the results obtained at various stages of the research is depicted in each phase. Detailed quantitative and qualitative discussions are also conducted to achieve the three main objectives: the summarization of quantitative data, discussion of the existing application, and identification of future research directions. These findings serve the future endeavor of agricultural waste-to-building materials’ incineration academic research. The scientometric review paves the way for academics from various nations to impart novel ideas and information and foster research collaboration.

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  • 13.
    Hayati, Abolfazl
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Akander, Jan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Eriksson, Martin
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    A case study of mapping the heating storage capacity in a multifamily building within a district heating network in mid-Sweden2022Ingår i: Buildings, E-ISSN 2075-5309, Vol. 12, nr 7, artikel-id 1007Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The building sector accounts for a third of the total energy use in Sweden, and district heating provides half of the heating needs. The peak demand loads within a district heating network occur both regularly and irregularly and impose a burden on the energy company to fulfill the demand, often by using more expensive and less environmentally friendly resources (e.g., fossil fuels) instead of the waste heat from industry or biofuels. Heat storage during hours of less demand and prior to colder periods can be used for load management and sustainable planning of energy supply, as well as reduction of total greenhouse gas emissions. Thus, heat supply to the building can be lowered temporarily during the peak power period to utilize the stored thermal energy within the building thermal inertia. The use of indoor temperature decay and the delivery of heating power to a multifamily building are studied here, and heating storage capacity and thermal inertia are calculated. During the performed decay test, the energy supply was estimated to be reduced by 61% for 5 h, which resulted in only a 0.3 °C temperature decay. Therefore, the suggested method can shave eventual peaks in supplied heat with minimal influence on the thermal comfort.

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  • 14.
    Holmgren, Mattias
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi.
    Sörqvist, Patrik
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi.
    Are mental biases responsible for the perceived comfort advantage in "green" buildings?2018Ingår i: Buildings, E-ISSN 2075-5309, Vol. 8, nr 2, artikel-id 20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Previous research has shown that merely calling an indoor environment environmentally certified will make people favor that environment over a conventional alternative. In this paper we explore whether this effect depends on participants deliberately comparing the two environments, and whether different reasons behind the certification influence the magnitude of the effect. In Experiment 1, participants in a between-subjects design assigned higher comfort ratings to an indoor environment that had been labeled "environmentally certified" in comparison with the exact same indoor environment that was unlabeled, suggesting that the effect arises even when participants do not compare the two environments when making their estimates. The results from Experiment 2 indicate that climate change mitigation (as the reason for the certification) is a slightly better trigger of the effect compared to climate change adaptation. The results suggest that studies on psychological effects of "green" buildings should experimentally control for the influence from participants' judgmental biases.

  • 15.
    Huang, Bingzhang
    et al.
    Liuzhou Institute of Technology, Liuzhou 545004, China.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Javed, Muhammad Faisal
    GIK Institute of Engineering Sciences and Technology, Topi, Swabi 23460, Pakistan.
    Azim, Iftikhar
    Government of Khyber Pakhtunkhwa, Peshawar 25000, Pakistan.
    Iqbal, Muhammad Ayyan
    Department of Civil Engineering, University of Engineering and Technology, Lahore 39161, Pakistan.
    Evolutionary Algorithms for Strength Prediction of Geopolymer Concrete2024Ingår i: Buildings, E-ISSN 2075-5309, Vol. 14, nr 5, artikel-id 1347Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Geopolymer concrete (GPC) serves as a sustainable substitute for conventional concrete by employing alternative cementitious materials such as fly ash (FA) instead of ordinary Portland cement (OPC), contributing to environmental and durability benefits. To increase the rate of utilization of FA in the construction industry, distinctive characteristics of two machine learning (ML) methods, namely, gene expression programming (GEP) and multi-expression programming (MEP), were utilized in this study to propose precise prediction models for the compressive strength and split tensile strength of GPC comprising FA as a binder. A comprehensive database was collated, which comprised 301 compressive strength and 96 split tensile strength results. Seven distinct input variables were employed for the modeling purpose, i.e., FA, sodium hydroxide, sodium silicate, water, superplasticizer, and fine and coarse aggregates contents. The performance of the developed models was assessed via numerous statistical metrics and absolute error plots. In addition, a parametric analysis of the finalized models was performed to validate the prediction ability and accuracy of the finalized models. The GEP-based prediction models exhibited better performance, accuracy, and generalization capability compared with the MEP-based models in this study. The GEP-based models demonstrated higher correlation coefficients (R) for predicting the compressive and split tensile strengths, with the values of 0.89 and 0.87, respectively, compared with the MEP-based models, which yielded the R values of 0.76 and 0.73, respectively. The mean absolute errors for the GEP- and MEP-based models for predicting the compressive strength were 5.09 MPa and 6.78 MPa, respectively, while those for the split tensile strengths were 0.42 MPa and 0.51 MPa, respectively. The finalized models offered simple mathematical formulations using the GEP and Python code-based formulations from MEP for predicting the compressive and tensile strengths of GPC. The developed models indicated practical application potential in optimizing geopolymer mix designs. This research work contributes to the ongoing efforts in advancing ML applications in the construction industry, highlighting the importance of sustainable materials for the future.

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  • 16.
    Khadra, Alaa
    et al.
    Högskolan Dalarna.
    Akander, Jan
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Myhren, Jonn Are
    Högskolan Dalarna.
    Greenhouse Gas Payback Time of Different HVAC Systems in the Renovation of Nordic District-Heated Multifamily Buildings Considering Future Energy Production Scenarios2024Ingår i: Buildings, E-ISSN 2075-5309, Vol. 14, nr 2, artikel-id 413Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The European Union (EU) has implemented several policies to enhance energy efficiency. Among these policies is the objective of achieving energy-efficient renovations in at least 3% of EU buildings annually. The primary aim of this study was to offer a precise environmental comparison among four similar district-heated multifamily buildings that have undergone identical energy efficiency measures. The key distinguishing factor among them lies in the HVAC systems installed. The chosen systems were as follows: (1) exhaust ventilation with air pressure control; (2) mechanical ventilation with heat recovery; (3) exhaust ventilation with an exhaust air heat pump; and (4) exhaust ventilation with an exhaust air heat pump with a Photovoltaic (PV) panel. This study involved a life cycle assessment that relied on actual material data from the housing company and energy consumption measurements. This study covered a period of 50 years for thorough analysis. A sensitivity analysis was also conducted to account for various future scenarios of energy production. The findings revealed that the building with an exhaust air heat pump exhibited the lowest greenhouse gas emissions and the shortest carbon payback period (GBPT), needing only around 7 years. In contrast, the building with exhaust ventilation without heat recovery showed the highest emissions and the longest carbon payback period (GBPT), requiring approximately 11 years. Notably, the results were significantly influenced by future scenarios of energy production, emphasizing the crucial role of emission factors in determining the environmental performance of distinct renovation scenarios.

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  • 17.
    Khan, Inamullah
    et al.
    National University of Sciences and Technology, Islamabad 44000, Pakistan.
    Khattak, Abdul Wahab
    National University of Sciences and Technology, Islamabad 44000, Pakistan.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Khattak, Shahab
    Abasyn University, Peshawar 25100, Pakistan.
    Ejaz, Ali
    National University of Sciences and Technology, Islamabad 44000, Pakistan.
    Engineering Characteristics of SBS/Nano-Silica-Modified Hot Mix Asphalt Mixtures and Modeling Techniques for Rutting2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 9, artikel-id 13092352Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Flexible pavements are mostly affected by meteorological factors in addition to traffic loads, which results in premature pavement failures like rutting and moisture-induced damage. This study focuses on the impacts of adding various contents of nano-silica (NS), i.e., 2%, 4%, 6%, and 8% (percentage weight of asphalt), along with a constant value of 4.5% styrene-butadiene-styrene (SBS). To assess the effectiveness of modified and unmodified mixtures, the indirect tensile strength (ITS) test, resilient modulus (MR) test, and wheel tracking test were conducted. The MR test was performed at dual temperature values, i.e., 25 °C and 40 °C, and demonstrated different metrological conditions in this region. The tensile strength ratio was used to estimate the mitigation of water losses in hot mix asphalt (HMA) mixtures (specimens) utilizing ITS test results of the conditioned and unconditioned specimens. Moreover, a model was developed for the rutting potential of the modified specimens using multi expression programming (MEP), a sophisticated technique that employs experimental data and suggests an equation for different input variables. The results indicated that the addition of NS to SBS-modified bitumen enhanced different mechanical properties of the specimens, including the stiffness and moisture and rutting resistances. The temperature had adverse effects on the stiffness of the specimens, while the modifiers had a direct relationship with the stiffness. The two-way factorial method justified the effect of the temperature and modifiers on MR with 95% precision, while the MEP model for rutting showed an R2 value of >0.95, which revealed a good relationship between the experimental and predicted data. Furthermore, NS and SBS had a good impact on the mechanical properties of the HMA specimens.

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  • 18.
    Kumar, K. Rajesh
    et al.
    Centre for Methods and Materials, Department of Civil Engineering, SR University, Warangal 506371, Telangana, India.
    Vijay, Thiruchengode Jothimani
    Department of Civil Engineering, PSNA College of Engineering and Technology, Dindigul 624622, Tamil Nadu, India.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Ravindran, Gobinath
    Centre for Methods and Materials, Department of Civil Engineering, SR University, Warangal 506371, Telangana, India.
    Structural Behavior of Concrete Beams Reinforced with Biaxial Geogrid2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 5, artikel-id 1124Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In recent decades, corrosion in steel reinforcement has been one of the fundamental risks in steel-reinforced concrete (RC) structures. Geosynthetics can be an alternative approach to solve corrosion problems. The current experimental research work investigates the structural performance of geogrid-reinforced concrete (GRC) elements. Initially, five different geotextiles and biaxial geogrid materials were selected and embedded in the concrete specimens separately to study their mechanical properties. The results of the testing showed that the geogrid embedded specimen behaved more mechanically than the conventional concrete (CC) specimens due to increased bonding characteristics. The limiting moment and load-carrying capacities of the RC and GRC beams were determined with reference to limit state design principles. In order to compare the structural performance of the beams, two RC beams and two GRC beams with the size of 150 mm × 300 mm × 2100 mm were cast. The structural performances in terms of the load-carrying capacity, energy absorption, stiffness degradation, and ductility were examined. The results of the tests indicated that even though the load-carrying capacity of the GRC beams was slightly lower, they demonstrated enhanced performance by 42%, 40%, and 68% higher in the energy absorption, stiffness degradation, and ductility properties, respectively, than those of the RC beams on average. The augmented inelastic performance and better bonding properties of the GRC beams aid in noticeable structural performance.

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  • 19.
    Lane, Anna-Lena
    et al.
    RISE Research Institutes of Sweden.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Thollander, Patrik
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Success factors and barriers for facility management in keeping nearly-zero-energy non-residential buildings energy-efficient over time2024Ingår i: Buildings, E-ISSN 2075-5309, Vol. 14, artikel-id 242Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Energy efficiency is a cornerstone of climate change mitigation. For buildings, facility management is an essential part of achieving efficient energy use while keeping tenants satisfied. This interview study explores success factors and barriers for facility management in maintaining energy efficiency over time in four approximately 10-year-old non-residential premises built as so-called nearly zero-energy buildings (nZEB) in Sweden. The study highlights the importance of functional digital tools, benchmarks, and building professionals’ involvement in ensuring energy efficiency. It also emphasizes the need for involvement communication and strategies to engage facility management in energy efficiency efforts. The study suggests that in-house and public policies can play a crucial role in sustaining high ambitions for energy efficiency. Access to professional support that is self-evident to use is identified as a critical success factor. Additionally, the research presents an analytic model that can be used in future studies to assess facility management organizations’ potential for maintaining energy performance in buildings over time.

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  • 20.
    Mohammed Nabi Anwarbasha, Gulshan Taj
    et al.
    Sona College of Technology, Salem 636005, India.
    Chakrabarti, Anupam
    Indian Institute of Technology Roorkee, Roorkee 247667, India.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Venkatesan, Vasugi
    Vellore Institute of Technology, Chennai 600127, India.
    Vikram, Abdhullapuram Sachidhanandam Vijay
    Global Institute of Engineering and Technology, Melvisharam 632509, India.
    Subramanian, Jeyabharathi
    K.S.R. College of Engineering, Tiruchengode 637215, India.
    Mahesh, Vutukuru
    SR University, Warangal 506371, Telangana, India.
    Efficient Finite Element Approach to Four-Variable Power-Law Functionally Graded Plates2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 10, artikel-id 2577Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many findings and conclusions about the analysis of functionally graded material plates/shells exist in past documents in the literature. Accurate micromechanical modeling of such elements is vital for predicting their responses in different operating environments by virtue of their functional properties along the direction of interest. Applying a single-parameter-dependent law leads to a plate/shell configuration in which the top surface is dominated by the ceramic part, while the bottom surface is occupied by a metal segment. But in actual practice, the situation arises where a designer/analyst should develop a model that incorporates all the possible combinations of the constituents at the top and bottom to meet current demands. In this study, the volume fraction value of a material was governed by a generalized four-parameter law for defining the material profile and incorporating different combinations of profiles. Aluminum/zirconia plates were considered for a study of their mechanics under different support conditions. Different conclusions were derived from this research, and it was perceived that the plate that had symmetric properties with respect to the neutral plane showed better performance than any other profile combinations. Out of the diverse results that are presented, symmetric profiles were recorded as having lower deflection values than those of the other profiles adopted in the study.

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  • 21.
    Murthi, Palanisamy
    et al.
    Centre for Construction Methods and Materials, SR University, Warangal 506371, India.
    Lavanya, Velpula
    Department of Civil Engineering, SR University, Warangal 506371, India.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Poongodi, Kolandasamy
    Department of Civil Engineering, SR University, Warangal 506371, India.
    Performance Evaluation of Polypropylene Fiber-Reinforced Pavement Quality Concrete Made with Waste Granite Powder2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 5, artikel-id 1294Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This research was conducted to evaluate the influence of waste granite powder (WGP) and polypropylene (PP) fibers on the performance of M35-grade pavement quality concrete (PQC). WGP was mixed in PQC as replacement for cement and was varied from 0% to 25%. The pozzolanic concert of WGP was examined by the strength activity index. The performance of PP fibers in PQC was assessed after the addition of fibers from 0.25% to 1.25% by volume of concrete. The mechanical properties of PQC were evaluated including the compressive strength, flexural strength, and various durability related properties such as the acid attack, absorption test, sorptivity test, and chloride penetration depth test. The results showed that PQC blended with WGP enhanced the strength slightly up to the replacement level of 15%. The addition of PP fibers rooted the reduction of the slump value; however, it improved the mechanical properties up to the presence of 0.5% PP fibers in PQC. The relationship between the compressive strength and flexural strength of WGP blended with PP fiber-reinforced PQC was established.

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  • 22.
    Nagaraju, T. Vamsi
    et al.
    Department of Civil Engineering, SRKR Engineering College, Bhimavaram 534204, India.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Prasad, Ch. Durga
    Department of Electrical and Electronics Engineering, SRKR Engineering College, Bhimavaram 534204, India.
    Mantena, Sireesha
    Department of Geoengineering, Andhra University, Visakhapatnam 530003, India.
    Biswal, Monalisa
    Department of Electrical Engineering, National Institute of Technology, Raipur 492010, India.
    Islam, Md. Rashadul
    School of Engineering, Colorado State University, Pueblo, CO 81001, USA.
    Predicting California Bearing Ratio of Lateritic Soils Using Hybrid Machine Learning Technique2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 1, artikel-id 255Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increase in population has made it possible for better, more cost-effective vehicular services, which warrants good roadways. The sub-base that serves as a stress-transmitting media and distributes vehicle weight to resist shear and radial deformation is a critical component of the pavement structures. Developing novel techniques that can assess the sub-base soil’s geotechnical characteristics and performance is an urgent need. Laterite soil abundantly available in the West Godavari area of India was employed for this research. Roads and highways construction takes a chunk of geotechnical investigation, particularly, California bearing ratio (CBR) of subgrade soils. Therefore, there is a need for intelligent tool to predict or analyze the CBR value without time-consuming and cumbersome laboratory tests. An integrated extreme learning machine-cooperation search optimizer (ELM-CSO) approach is used herein to predict the CBR values. The correlation coefficient is utilized as cost functions of the CSO to identify the optimal activation weights of the ELM. The statistical measures are separately considered, and best solutions are reported in this article. Comparisons are provided with the standard ELM to show the superiorities of the proposed integrated approach to predict the CBR values. Further, the impact of each input variable is studied separately, and reduced models are proposed with limited and inadequate input data without loss of prediction accuracy. When 70% training and 30% testing data are applied, the ELM-CSO outperforms the CSO with Pearson correlation coefficient (R), coefficient of determination (R2), and root meansquare error (RMSE) values of 0.98, 0.97, and 0.84, respectively. Therefore, based on the prediction findings, the newly built ELM-CSO can be considered an alternative method for predicting real-time engineering issues, including the lateritic soil properties.

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  • 23.
    Petrovic, Bojana
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Dalarna University.
    Zhang, Xingxing
    Dalarna University.
    Eriksson, Ola
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Wallhagen, Marita
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Life Cycle Cost Analysis of a Single-Family House in Sweden2021Ingår i: Buildings, E-ISSN 2075-5309, Vol. 11, nr 5, artikel-id 215Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The objective of this paper was to explore long-term costs for a single-family house in Sweden during its entire lifetime. In order to estimate the total costs, considering construction, replacement, operation, and end-of-life costs over the long term, the life cycle cost (LCC) method was applied. Different cost solutions were analysed including various economic parameters in a sensitivity analysis. Economic parameters used in the analysis include various nominal discount rates (7%, 5%, and 3%), an inflation rate of 2%, and energy escalation rates (2-6%). The study includes two lifespans (100 and 50 years). The discounting scheme was used in the calculations. Additionally, carbon-dioxide equivalent (CO(2)e) emissions were considered and systematically analysed with costs. Findings show that when the discount rate is decreased from 7% to 3%, the total costs are increased significantly, by 44% for a 100-year lifespan, while for a 50 years lifespan the total costs show a minor increase by 18%. The construction costs represent a major part of total LCC, with labor costs making up half of them. Considering costs and emissions together, a full correlation was not found, while a partial relationship was investigated. Results can be useful for decision-makers in the building sector.

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  • 24.
    Petrović, Bojana
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik. Department of Energy Technology and Construction Engineering, Dalarna University, Falun, Sweden; NORSUS (Norwegian Institute for Sustainability Research), Kråkerøy, Norway .
    Eriksson, Ola
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Zhang, Xingxing
    Department of Energy Technology and Construction Engineering, Dalarna University, Falun, Sweden.
    Wallhagen, Marita
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Carbon Assessment of a Wooden Single-Family Building: Focusing on Re-Used Building Products2024Ingår i: Buildings, E-ISSN 2075-5309, Vol. 14, nr 3, artikel-id 800Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Previous research has shown a lack of studies with comparisons between primary (virgin) and secondary (re-used) building materials, and their embodied emissions. The creation of different scenarios comparing the environmental impact of virgin vs. re-used materials is also motivated by the scarcity of raw materials in the world and the emergency of mitigating greenhouse gas (GHG) emissions from buildings. The aim of this study was to investigate scenarios, including new vs. re-used building products, applying the LCA method for a wooden single-family building. The findings showed a 23% reduction potential for total released (positive) CO2e when comparing the Reference scenario with Scenario I, using re-used wooden-based materials. Further, Scenario II, using all re-used building materials except for installations, showed a 59% CO2e reduction potential compared to the Reference scenario. Finally, Scenario III, which assumes all re-used building products, showed a 92% decreased global warming potential (GWP) impact compared to the Reference scenario. However, when including biogenic carbon and benefits (A5 and D module), the Reference scenario, based on newly produced wooden building materials, has the largest negative GHG emissions. It can be concluded that the re-use of building products leads to significant carbon savings compared to using new building products.

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  • 25.
    Prashant, Kumar
    et al.
    Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
    Arora, Harish Chandra
    Department of Structural Engineering, CSIR-Central Building Research Institute, Roorkee 247667, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India .
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Kumar, Aman
    Department of Structural Engineering, CSIR-Central Building Research Institute, Roorkee 247667, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India .
    Krishna, Kumar
    Department of Hydro and Renewable Energy, Indian Institute of Technology, Roorkee 247667, India.
    Development of a Reliable Machine Learning Model to Predict Compressive Strength of FRP-Confined Concrete Cylinders2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 4, artikel-id 931Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The degradation of reinforced concrete (RC) structures has raised major concerns in the concrete industry. The demolition of existing structures has shown to be an unsustainable solution and leads to many financial concerns. Alternatively, the strengthening sector has put forward many sustainable solutions, such as the retrofitting and rehabilitation of existing structural elements with fiber-reinforced polymer (FRP) composites. Over the past four decades, FRP retrofits have attracted major attention from the scientific community, thanks to their numerous advantages such as having less weight, being non-corrodible, etc., that help enhance the axial, flexural, and shear capacities of RC members. This study focuses on predicting the compressive strength (CS) of FRP-confined concrete cylinders using analytical models and machine learning (ML) models. To achieve this, a total of 1151 specimens of cylinders have been amassed from comprehensive literature studies. The ML models utilized in the study are Gaussian process regression (GPR), support vector machine (SVM), artificial neural network (ANN), optimized SVM, and optimized GPR models. The input parameters that have been used for prediction include the geometrical characteristics of specimens, the mechanical properties of FRP composite, and the CS of concrete. The results of the five ML models are compared with nineteen analytical models. The results evaluated from the ML algorithms imply that the optimized GPR model has been found to be the best among all other models, demonstrating a higher correlation coefficient, root mean square error, mean absolute percentage error, mean absolute error, a-20 index, and Nash–Sutcliffe efficiency values of 0.9960, 3.88 MPa, 3.11%, 2.17 MPa, 0.9895, and 0.9921, respectively. The R-value of the optimized GPR model is 0.37%, 0.03%, 5.14%, and 2.31% higher than that of the ANN, GPR, SVM, and optimized SVM models, respectively, whereas the root mean square error value of the ANN, GPR, SVM, and optimized SVM models is, respectively, 81.04%, 12.5%, 471.77%, and 281.45% greater than that of the optimized GPR model.

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  • 26.
    Rashid, Farhan Lafta
    et al.
    Petroleum Engineering Department, College of Engineering, University of Kerbala, Karbala 56001, Iraq.
    Dulaimi, Anmar
    Petroleum Engineering Department, College of Engineering, University of Kerbala, Karbala 56001, Iraq;School of Civil Engineering and Built Environment, Liverpool John Moores University, Liverpool L3 2ET, UK;College of Engineering, University of Warith Al-Anbiyaa, Karbala 56001, Iraq.
    Hatem, Wadhah Amer
    Technical Institute of Baquba, Middle Technical University, Baquba 32001, Iraq.
    Al-Obaidi, Mudhar A.
    Technical Institute of Baquba, Middle Technical University, Baquba 32001, Iraq;Technical Instructor Training Institute, Middle Technical University, Baghdad 10074, Iraq.
    Ameen, Arman
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Eleiwi, Muhammad Asmail
    Electromechanical Engineering Department, College of Engineering, University of Samarra, Samarra 34010, Iraq.
    Jawad, Sarah Abbas
    Department of Energy Engineering, College of Engineering-Al-Musayab, University of Babylon, Babylon 51002, Iraq.
    Bernardo, Luís Filipe Almeida
    Department of Civil Engineering and Architecture, University of Beira Interior, GeoBioTec-UBI, 6201-001 Covilhã, Portugal.
    Hu, Jong Wan
    Department of Civil and Environmental Engineering, Incheon National University, Incheon 22022, Republic of Korea;Incheon Disaster Prevention Research Center, Incheon National University, Incheon 22022, Republic of Korea.
    Recent Advances and Developments in Phase Change Materials in High-Temperature Building Envelopes: A Review of Solutions and Challenges2024Ingår i: Buildings, E-ISSN 2075-5309, Vol. 14, nr 6, s. 1582-1582Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of phase change materials (PCMs) has become an increasingly common way to reduce a building’s energy usage when added to the building envelope. This developing technology has demonstrated improvements in thermal comfort and energy efficiency, making it a viable building energy solution. The current study intends to provide a comprehensive review of the published studies on the utilization of PCMs in various constructions of energy-efficient roofs, walls, and ceilings. The research question holds massive potential to unlock pioneering solutions for maximizing the usefulness of PCMs in reducing cooling demands, especially in challenging high-temperature environments. Several issues with PCMs have been revealed, the most significant of which is their reduced effectiveness during the day due to high summer temperatures, preventing them from crystallizing at night. However, this review investigates how PCMs can delay the peak temperature time, reducing the number of hours during which the indoor temperature exceeds the thermal comfort range. Additionally, the utilization of PCMs can improve the building’s energy efficiency by mitigating the need for cooling systems during peak hours. Thus, selecting the right PCM for high temperatures is both critical and challenging. Insulation density, specific heat, and thermal conductivity all play a role in heat transfer under extreme conditions. This study introduces several quantification techniques and paves the way for future advancements to accommodate practical and technical solutions related to PCM usage in building materials.

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  • 27.
    Ravindran, Gobinath
    et al.
    SR University, Warangal 506371, Telangana, India.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Mahesh, Vutukuru
    SR University, Warangal 506371, Telangana, India.
    Katman, Herda Yati Binti
    Universiti Tenaga Nasional, Putrajaya Campus, Kajang 43000, Malaysia.
    Srihitha, Katakam
    SR University, Warangal 506371, Telangana, India.
    Sushmashree, Alamadri
    SR University, Warangal 506371, Telangana, India.
    Nikhil Kumar, Alugoju
    SR University, Warangal 506371, Telangana, India.
    Global Research Trends in Engineered Soil Development through Stabilisation: Scientific Production and Thematic Breakthrough Analysis2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 10, artikel-id 2456Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Soil, a naturally occurring resource, is increasingly used as a construction material. Stabilisation strengthens soil, which is weak as an engineering material. Stabilising soil changes its physical qualities, enhancing its strength. Soil stabilisation increases the shear strength and load-bearing capacity. Soil stabilisation refers to any endeavour to change natural soil for engineering purposes using physical, chemical, mechanical, or biological methods, or a mix of these. Strengthening road pavements includes improving the load-bearing capacity, tensile strength, and performance of unstable subsoils, sands, and waste materials. Due to market demands and scientific advances, the number of soil-stabilising additives has increased. These innovative stabilisers include reinforcing fibres, calcium chloride, sodium chloride, and cross-linking water-based styrene acrylic polymers, which are geopolymers that boost the load-bearing capacity and tensile strength of soil. Many materials are being explored for soil stabilisation. In this article, the authors investigated the direction of soil stabilisation research. Scientometric analysis identifies stabilisation challenges and research trends in the field. This study analysed research patterns by countries, authors, institutions, keywords, and journals from 1959 to 2023; in 2021, 150 articles were published, which was the highest number in a year. Citations peaked at 3084 in 2022. With 253 publications and 3084 citations, India was the most productive country. Iran and France published the fewest, 34 and 33, respectively. The Islamic Azad University and the National Institute of Technology had the fewest published articles with 17 articles. This work can help track soil stabilisation research and will serve as an information document for future research.

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  • 28.
    Ren, Honghao
    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.
    Cehlin, Mathias
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Wallhagen, Marita
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Miljövetenskap.
    Flexural Behavior of Cross-Laminated Timber Panels with Environmentally Friendly Timber Edge Connections2024Ingår i: Buildings, E-ISSN 2075-5309, Vol. 14, nr 5, artikel-id 1455Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As a sustainable construction material, timber is more promoted than steel, concrete, and aluminum nowadays. The building industry benefits from using timber based on several perspectives, including decarbonization, improved energy efficiency, and easier recycling and disposal processes. The cross-laminated timber (CLT) panel is one of the widely utilized engineered wood products in construction for floors, which is an ideal alternative option for replacing reinforced concrete. One single CLT panel has an outstanding flexural behavior. However, CLT cannot be extended independently without external connections, which are normally made of steel. This article proposes two innovative adhesive-free edge connections made of timber, the double surface (DS) and half-lapped (HL) connections. These connections were designed to connect two CLT panels along their weak direction. Parametric studies consisting of twenty models were conducted on the proposed edge connections to investigate the effects of different factors and the flexural behavior of CLT panels with these edge connections under a four-point bending test. Numerical simulations of all the models were done in the current study by using ABAQUS 2022. Furthermore, the employed material properties and other relevant inputs (VUSDFLD subroutines, time steps, meshes, etc.) of the numerical models were validated through existing experiments. The results demonstrated that the maximum and minimum load capacities among the studied models were 6.23 kN and 0.35 kN, respectively. The load–displacement responses, strain, stress, and defection distributions were collected and analyzed, as well as their failure modes. It was revealed that the CLT panels’ load capacity was distinctly improved due to the increment of the connectors’ number (55.05%) and horizontal length (80.81%), which also reinforced the stability. Based on the findings, it was indicated that adhesive-free timber connections could be used for CLT panels in buildings and replace traditional construction materials, having profound potential for improving buildings’ sustainability and energy efficiency.

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  • 29.
    Shabbir, Faisal
    et al.
    University of Engineering and Technology, Taxila, Pakistan.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Ahmad, Ibrar
    University of Engineering and Technology, Taxila, Pakistan.
    Shakouri Mahmoudabadi, Nasim
    The University of Memphis, Memphis, TN 38152, USA.
    Iqbal, Muhammad
    University of Engineering and Technology, Taxila, Pakistan.
    Ahmad, Afaq
    The University of Memphis, Memphis, TN 38152, USA.
    Özkılıç, Yasin Onuralp
    Necmettin Erbakan University, Konya, Turkey.
    Experimental and Numerical Investigation of Construction Defects in Reinforced Concrete Corbels2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 9, artikel-id 13092247Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reinforced concrete corbels were examined in this study for the cracking behavior and strength evaluation, focusing on defects typically found in these structures. A total of 11 corbel specimens were tested, including healthy specimens (HS), specimens with lower concrete strength (LC), specimens with less reinforcement ratio (LR), and specimens with more concrete cover than specifications (MC). The HS specimens were designed using the ACI conventional method. The specimens were tested under static loading conditions, and the actual strengths along with the crack patterns were determined. In the experimental tests, the shear capacity of the HS specimens was 28.18% and 57.95% higher than the LR and LC specimens, respectively. Similarly, the moment capacity of the HS specimens was 25% and 57.52% greater than the LR and LC specimens, respectively. However, in the case of the built-up sections, the shear capacity of the HS specimens was 9.91% and 37.51% higher than the LR and LC specimens, respectively. Likewise, the moment capacity of the HS specimens was 39.91% and 14.30% higher than the LR and LC specimens, respectively. Moreover, a detailed nonlinear finite element model (FEM) was developed using ABAQUS, and a more user-friendly strut and tie model (STM) was investigated toward its suitability to assess the strengths of the corbels with construction defects. The results from FEM and STM were compared. It was found that the FEM results were in close agreement with their experimental counterparts.

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  • 30.
    Sharma, Ujjwal
    et al.
    Ixrlabs Learning Solutions Pvt. Ltd., Jaipur 302021, India.
    Gupta, Nakul
    GLA University, Mathura 281406, India.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Onuralp Özkılıç, Yasin
    Necmettin Erbakan University, 42100, Konya, Turkey.
    Verma, Manvendra
    GLA University, Mathura 281406, India.
    Berwal, Parveen
    Galgotias College of Engineering and Technology, Greater Noida 201310, India.
    Althaqafi, Essam
    College of Engineering, King Khalid University, Abha 61421, Saudi Arabia.
    Amir Khan, Mohammad
    Galgotias College of Engineering and Technology, Greater Noida 201310, India.
    Islam, Saiful
    College of Engineering, King Khalid University, Abha 61421, Saudi Arabia.
    Behavior of Fibers in Geopolymer Concrete: A Comprehensive Review2024Ingår i: Buildings, E-ISSN 2075-5309, Vol. 14, nr 1, artikel-id 136Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Over the last decades, cement has been observed to be the most adaptive material for global development in the construction industry. The use of ordinary concrete primarily requires the addition of cement. According to the record, there has been an increase in the direct carbon footprint during cement production. The International Energy Agency, IEA, is working toward net zero emissions by 2050. To achieve this target, there should be a decline in the clinker-to-cement ratio. Also, the deployment of innovative technologies is required in the production of cement. The use of alternative binding materials can be an easy solution. There are several options for a substitute to cement as a binding agent, which are available commercially. Non-crystalline alkali-aluminosilicate geopolymers have gained the attention of researchers over time. Geopolymer concrete uses byproduct waste to reduce direct carbon dioxide emissions during production. Despite being this advantageous, its utilization is still limited as it shows the quasi-brittle behavior. Using different fibers has been started to overcome this weakness. This article emphasizes and reviews various mechanical properties of fiber-reinforced geopolymer concrete, focusing on its development and implementation in a wide range of applications. This study concludes that the use of fiber-reinforced geopolymer concrete should be commercialized after the establishment of proper standards for manufacturing.

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  • 31.
    Thongchom, Chanachai
    et al.
    Department of Civil Engineering, Faculty of Engineering, Thammasat School of Engineering, Thammasat University, Pathumthani 12120, Thailand.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Ghamari, Ali
    Department of Civil Engineering, Ilam Branch, Islamic Azad University, Ilam, Iran.
    Benjeddou, Omrane
    Department of Civil Engineering, College of Engineering, Prince Sattam bin Abdulaziz University, Al-Kharj 16273, Saudi Arabia.
    Performance Improvement of Innovative Shear Damper Using Diagonal Stiffeners for Concentrically Braced Frame Systems2022Ingår i: Buildings, E-ISSN 2075-5309, Vol. 12, artikel-id 1794Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Although concentrically braced frame (CBF) systems enjoy high elastic stiffness and lateral strength, they show a low seismic energy absorption capacity. This dilemma is due to the buckling of CBFs’ diagonal members under compressive loading. To overcome the shortcoming, researchers have proposed the use of dampers to improve the behavior of CBF systems. Among the proposed dampers, the metallic shear damper is the most popular thanks to its suitable performance as well as its economic profit. The main shortcoming of the shear dampers is low stiffness. Therefore, in this article, an innovative approach is proposed to improve the behavior of the shear dampers. Subsequently, strengthening the shear damper with X-stiffeners is proposed, and its behavior is evaluated numerically and parametrically. Results indicate that by adding the X-stiffeners, the ultimate strength and elastic stiffness of the shear dampers are enhanced considerably. However, the properties of the stiffeners do not impact the stiffness in the nonlinear zone. Moreover, the behavior of the dampers is affected by parameters such as the ratio of the strength of the web plate to the flange plates, the ratio of the X-stiffeners to the flange plates, and the r factor. To consider the parameters to predict the behavior of the damper, required equations are proposed which demonstrate a good agreement with finite element results.

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  • 32.
    Ulla Khan, Athiq
    et al.
    Visvesvaraya Technological University, Belgavi-590018 Karnataka, India.
    Sateesh Kumar, Nanjundaswamy
    Visvesvaraya Technological University, Belgavi-590018 Karnataka, India.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Onuralp Özkılıç, Yasin
    Necmettin Erbakan University, 42100, Konya, Turkey.
    Imran, Mohammed
    Ghousia College of Engineering, Ramanagara 562159, Karnataka, India.
    Althaqafi, Essam
    College of Engineering, King Khalid University, Abha 61421, Saudi Arabia.
    Islam, Saiful
    College of Engineering, King Khalid University, Abha 61421, Saudi Arabia.
    Behavior of Confined Self-Compacting Concrete under Compression at Elevated Temperatures2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 12, artikel-id 3115Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The performance of self-compacting concrete (SCC) is gaining popularity in constructiondue to its exceptional strength and durability. However, the properties of combined steel andconcrete at elevated temperatures lack experimental data from previous research. This study aimedto investigate the behavior of the SCC core with a steel tube at ambient and elevated temperaturesvarying from 100 ◦C to 800 ◦C with 100 ◦C intervals for each test specimen. Tests were conducted oncircular steel tubes filled with SCC for different grades (M25, M30, and M40) under compression atelevated temperatures. Experimental observations revealed that the stress–strain curve increasedwith increasing the cross-sectional area and grade of concrete. However, increasing the temperatureand length-to-diameter ratio reduced the stress–strain curve. At elevated temperatures, confined SCCexperienced a smaller decrease in the overall modulus of elasticity when compared to unconfinedconcrete. Within the compressive elastic region (from 30 ◦C to 400 ◦C), there was a significantrelationship between lateral strain and longitudinal strain, which was followed by a sudden increasebeyond 400 ◦C. Equations for various design parameters were proposed based on the peak load andconfinement factor of confined SCC-filled steel tubes (SCCFSTs) via multiple regression. Moreover,this study developed load–axial shortening curves, identifying significant properties such as the yieldstrength of confined SCCFSTs, including the load-carrying capacity. The predicted numerical analysisresults were well aligned with the experimental results, and the findings contributed valuable insightsfor designing resilient and durable combined SCC and steel tube infrastructures.

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  • 33.
    Wallhagen, Marita
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöteknik.
    Eriksson, Ola
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöteknik.
    Sörqvist, Patrik
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Miljöpsykologi.
    Gender Differences in Environmental Perspectives among Urban Design Professionals2018Ingår i: Buildings, E-ISSN 2075-5309, Vol. 8, nr 4, artikel-id 59Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Urban design professionals are key actors in early design phases and have the possibility to influence urban development and direct it in a more sustainable direction. Therefore, gender differences in environmental perspectives among urban design professionals may have a marked effect on urban development and the environment. This study identified gender differences in environment-related attitudes among urban design professionals involved in the international architectural competition 'A New City Centre for Kiruna' in northern Sweden. Participants' self-rated possibility to influence environmental aspects was higher for males than for females. Conversely, the importance placed on environmental aspects had higher ratings among females, although the differences regarding the rating of personal responsibilitywere small. The gap between the participants' self-rated belief in their ability to influence and rated importance of environmental aspects was larger among female participants. Females placed great importance on environmental aspects even though they felt that their possibility to influence these was rather low. Conversely, male participants felt that they had the greatest possibility to influence, although some males rated the importance of environmental aspects thelowest. The gender differences identified are important froman equality and environmental perspective as they may influence pro-environmental behavior among urban design professionals and ultimately influence the environmental performance of the built environment.

  • 34.
    Wallhagen, Marita
    et al.
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Teknisk miljövetenskap. KTH, MIljöstrategisk Analys - fms.
    Glaumann, Mauritz
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Teknisk miljövetenskap. KTH Royal Institute of Technology, School of Architecture and the Built Environment,, Division of Environmental Strategies Research, Department of Urban Studies, Environmental Strategies Research - fms.
    Eriksson, Ola
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Teknisk miljövetenskap.
    Westerberg, Ulla
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för bygg- energi- och miljöteknik, Byggnadsteknik.
    Framework for Detailed Comparison of Building Environmental Assessment Tools2013Ingår i: Buildings, E-ISSN 2075-5309, Vol. 3, nr 1, s. 39-60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Understanding how Building Environmental Assessments Tools (BEATs) measure and define “environmental” building is of great interest to many stakeholders, but it is difficult to understand how BEATs relate to each other, as well as to make detailed and systematic tool comparisons. A framework for comparing BEATs is presented in the following which facilitates an understanding and comparison of similarities and differences in terms of structure, content, aggregation, and scope. The framework was tested by comparing three distinctly different assessment tools; LEED-NC v3, Code for Sustainable Homes (CSH), and EcoEffect. Illustrations of the hierarchical structure of the tools gave a clear overview of their structural differences. When using the framework, the analysis showed that all three tools treat issues related to the main assessment categories: Energy and Pollution, Indoor Environment, and Materials and Waste. However, the environmental issues addressed, and the parameters defining the object of study, differ and, subsequently, so do rating, results, categories, issues, input data, aggregation methodology, and weighting. This means that BEATs measure “environmental” building differently and push “environmental” design in different directions. Therefore, tool comparisons are important, and the framework can be used to make these comparisons in a more detailed and systematic way.

  • 35.
    Yooprasertchai, Ekkachai
    et al.
    King Mongkut’s University of Technology Thonburi, Bangkok 10140, Thailand.
    Bahrami, Alireza
    Högskolan i Gävle, Akademin för teknik och miljö, Avdelningen för byggnadsteknik, energisystem och miljövetenskap, Energisystem och byggnadsteknik.
    Saingam, Panumas
    School of Engineering, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
    Hussain, Qudeer
    Dr. House Consultants Co., Ltd., Bangkok 10330, Thailand.
    Ejaz, Ali
    National University of Science and Technology, Risalpur 23200, Pakistan.
    Joyklad, Panuwat
    Faculty of Engineering, Srinakharinwirot University, Nakhonnayok 26120, Thailand.
    Incorporation of Steel Fibers to Enhance Performance of Sustainable Concrete Made with Waste Brick Aggregates: Experimental and Regression-Based Approaches2023Ingår i: Buildings, E-ISSN 2075-5309, Vol. 13, nr 11, artikel-id 2820Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Each year, an enormous amount of construction waste is produced worldwide. The reuse of construction waste in construction works is a sustainable solution. The present research work utilized recycled brick aggregates in the production of concrete. The resulting concrete exhibited substandard splitting tensile, flexural, and compressive properties. Steel fibers were used to improve these substandard properties of recycled brick aggregate concrete. The volume fractions of 1%, 2%, and 3% for steel fibers were mixed in concrete, whereas recycled brick aggregates were obtained from solid fired-clay bricks, hollow fired-clay bricks, and cement–clay interlocking bricks. The compressive strength was enhanced by up to 35.53% and 66.67% for natural and recycled brick aggregate concrete, respectively. Strengthened flexural specimens demonstrated up to 8765.69% increase in the energy dissipation. Specimens strengthened with steel fibers showed substantially improved splitting tensile, flexural, and compressive responses. Separate equations were proposed to predict the peak compressive strength, strain at peak compressive strength, elastic modulus, and post-peak modulus of recycled brick aggregate concrete. The proposed regression equations were utilized in combination with an existing compressive stress–strain model. A close agreement was observed between experimental and predicted compressive stress–strain curves of recycled brick aggregate concrete.

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