This issue of Structures and Buildings presents six papers on different technical and scientific topics. Two papers focus on material behaviour while four papers are devoted to structural behaviour.
The paper by Tang et al. (2015) discusses the technical feasibility of using ground granulated blast-furnace slag in structural concrete for high-value applications in China. The effects of the slag on concrete compressive strengths were investigated experimentally at different curing temperatures. The results obtained by the authors from the isothermal calorimetry tests were also used to simulate the heat liberation process in suspended concrete slabs using finite element analyses. They concluded that partial replacement of CEM I cement with ground granulated blast-furnace slag contributes to a reduced peak hydration temperature and this has a beneficial effect in hot-weather concreting.
Accordingly to Yuen and Kuang (2015), reinforced concrete (RC) structural walls can render excellent lateral stability and ductility to medium- to high-rise buildings, but the high axial compression loading can reduce their inherent ductility. In their paper, these authors collected 474 sets of experimental data and a comprehensive statistical analysis was conducted to evaluate and quantify the effect of the axial compression ratio on the structural performance of RC structural walls. They found that the provisions on axial compression ratio limits in Eurocode 8 generally satisfy the target ductility level but a distinction needs to be made between non-squat and squat walls due to their different structural behaviours.
The paper by Akbari Hamed and Mofid (2015) investigates the behaviour of braced steel shear panel systems, combining the advantages of seismic resisting systems including braced frames and steel shear walls. They mentioned that this new lateral load-resisting system solves some of the defects of current special steel shear walls, such as imposing significant loads on boundary elements along with gravity load effects. Two equivalent models for designing braced steel shear panels using commercial software were introduced, both providing the best estimation for the values of lateral stiffness and strength, when both the tensile and compressive braces are considered.
Amouzegar and Riahi (2015) studied the capability of endurance time analysis as an appropriate tool in performance-based earthquake engineering and seismic performance of a comprehensive database of reinforced concrete moment-resisting frames was assessed using endurance time and time history analysis. Results were compared with the results of pushover analysis, and the endurance time analysis results were found to be more compatible with the results of time history analysis. In this paper, it is shown that input motions of the endurance time method, generated based on a design response spectrum, can be used to assess frames at different seismic hazard levels correctly.
The fifth paper in this issue, by Khoshnoudian et al. (2015), presents an investigation on the optimum design of passive tuned mass damper system, taking into account soil–structure interaction and using a multi-objective optimisation approach to minimise kinematic variables (displacement, velocity and acceleration) of the structure. They show that taking the effects of soil–structure interaction into account leads to (i) performance improvements of the damper and (ii) considerable reduction of the maximum value of the displacement of soil–structure–damper system.
According to Dundu and Rupieper (2015), the elongation variation between the theoretical and real elongation of a post-tensioned tendon is used as one of the measures of quality in post-tensioning, but most often the elongation variation limits are exceeded in practice. Dundu and Rupieper (2015) analysed the data of bonded tendons from numerous post-tensioned structures. In their paper, the influence of material properties on the elongation variation of tendons in these structures was determined.
I hope the interested reader finds these papers stimulating and informative. As in the past, comments, suggestions and discussions from readers on the papers in this issue are most welcome through the submission of discussion articles.
