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.

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.

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.

Durability is of great importance when considering sustainable energy systems. In turn it lays emphasis on assessing performance over time of energy systems and components. This paper presents a study on optical degradation of a building-integrated Unglazed Solar Collector (USC) surface, by exposing USC specimens to a natural and semi-natural field exposure test. Particular interest is devoted to the semi-natural field exposure test method evaluation, and the degradation of optical properties. The study showed that about 11 months of field exposure testing did not cause any significant optical (total solar absorptance and IR emittance) or material (surface coating) degradation; although measurements revealed a decrease in specular reflectance as diffuse increased. It was likely due to surface pollution that predominantly consisted of quartz. The study also showed that it is possible to achieve a considerable increased moisture exposure on test surfaces (seminatural field exposure test), through a relatively simple cooling device (Direct-Air Peltier-Element) and rough control strategy.

The EU-project ENV4-CT98-0796 MMWood has the following objective: To develop and validate for the SMEs an integrated Maintenance and management system for historic (wooden) buildings, adapted to the needs and purposes of various user group levels. The system will specifically contain - A documentation system for outer and inner parts of historic (wooden) building parts and components. - Soft- and hardware tools for the building inspection in the course of maintenance tasks, - an environmental risk factor assessment module, - a standardized maintenance assessment module based on complementation of the Wood-Assess process of assessing the symptoms, causes, effects, consequences, risks and remedial actions for environmental damages to the historic buildings and - a cost and maintenance planning module. In the project Damage Atlases for the following materials are given: Wood (including Surface Treatment), Adjoining Materials in Wood Constructions, Rendering, Brick and Natural Stone. These Damage Atlases use the same general layout, following closely the guidelines and protocol developed in a previous EU-project with the acronym "Wood-Assess". The general layout given for these damages is built up with the following questions: - Type of material; - Description of the symptom; - Investigation methods; - Condition degrees referred to pictures; - Extent of the symptom; - Possible causes/degradation agents; - Total condition degree; - Consequences and risks; - Recommended actions. In this paper the general layout of these Damage Atlases is extensively described and included are also some examples of the treated damages. These Damage Atlases are also put into the PC-based maintenance and management system developed in the same project (a first version was developed in the Wood-Assess project ENV4-CT95-0110, which was reported in some detail in the previous CIB congress in Gavle).

Europe's rich culture in wooden buildings are rapidly degrading due to environmental impact, wrong conservation techniques and lack of resources and technological tools for appropriate conservation. These issues were addressed in the former EU-project ENV4-CT95-0110 Wood-Assess , which has been finalised (Haagenrud et al, 1999). In a new EU-project MMWood (ENV4-CT-98-0796) a PC-based system for maintenance management of buildings has been developed. The project had the following objectives: To develop and validate for the SMEs an integrated Maintenance Management system for historic buildings, adapted to the needs and purposes of various user group levels. Based on the Wood-Assess concept and results the modular GIS (Geographical Information System) based system, MMWood, will specifically contain - A documentation system for outer and inner parts of buildings and components; - Soft- and hardware tools for the building inspection in the course of maintenance tasks; - An environmental risk factor assessment module; - A standardized maintenance assessment module; - A cost and maintenance planning module. Main developments from the Wood-Assess project are the inclusion of the maintenance management phase, extension of the damage atlas to include also adjoining materials in wood constructions, rendering, brick and natural stone, and a fully integrated field inspection system, allowing the user to import/export all background and recorded data between the field inspection and the total maintenance management system.

An environmental risk factor assessment module was elaborated as a part of the EU-projectMMWood (ENV-CT98-0796). The Environmental Risk Factor may be an important aid in providingnecessary data for predicting service life for buildings or building elements.The objective of the work package was to provide and synthesise the necessary environmental data forexploiting the service life functions established elsewhere and the methods and models developed inWoodAssess.In WoodAssess (presented at the previous CIB congress in Gävle) the methodology for assessing andmapping environmental risk factors and areas for wood on regional, local, and micro scale in Europewas demonstrated. The methodology is developed further, and more materials used in connection withwooden houses, like stone, bricks, rendering, painted rendering, and painted wood, are now included.Environmental data, as climatic and pollution data are collected for different regions in Europe. Thedata are either from meteorological stations or as geographical data (GIS) from simulation modelsbased on emission data. Meteorological data from measurements are also transformed to geographicalinformation. By use of the environmental data and service life functions the expected service life iscalculated for each object/region and material.A reference situation, defined by cold climate and unpolluted air, is used to calculate the referenceservice lives. From this the percentage reduction in service life can be calculated for eachobject/region and material.By use of the meteorological data, combined with geographical information as topography, sunny andshaded areas, a Scheffer's Climatic Risk Index (SCRI) for potential wood decay was calculated forobjects and regions. Better digital maps combined with models for precipitation, temperature andrelative humidity will form a proper basis for a more detailed modelling of SCRI.In this paper the methods for assessment of environmental data and service life are presented, and theresults as calculated service life and reference levels are included. Service life is presented both assingle values and as geographical information (GIS) on different geographical scales (local andregional scale).