A novel computational model is proposed in this paper considering reliability analysis in the modelling of reinforced concrete beams at elevated temperatures, by assuming that concrete and steel materials have random mechanical properties in which those properties are treated as random variables following a normal distribution. Accordingly, the reliability index is successfully used as a constraint to restrain the modelling process. A concrete damage plasticity constitutive model is utilized in this paper for the numerical models, and it was validated according to those data which were gained from laboratory tests. Detailed comparisons between the models according to different temperatures in the case of deterministic designs are proposed to show the effect of increasing the temperature on the models. Other comparisons are proposed in the case of probabilistic designs to distinguish the difference between deterministic and reliability-based designs. The procedure of introducing the reliability analysis of the nonlinear problems is proposed by a nonlinear code considering different reliability index values for each temperature case. The results of the proposed work have efficiently shown how considering uncertainties and their related parameters plays a critical role in the modelling of reinforced concrete beams at elevated temperatures, especially in the case of high temperatures.

No abstract

Due to the growing significance of structural theories concerning the composite structure analysed and designed plastically, this paper introduces a new optimisation method for controlling the plastic behaviour of a full-scale composite integral abutment bridge by employing complementary strain energy of residual forces that existed within the reinforcing rebars. Composite bridges are structures made of components such as steel and concrete, which are frequent and cost-effective building methods. Thus, various objective functions were used in this work when applying optimum elasto-plastic analysing and designing the composite integrated bridge structure that was tested experimentally in the laboratory. In contrast, the plastic deformations were constrained by restricting the complementary strain energy of the residual internal forces aiming to find the maximum applied load and the minimum number of steel bars used to reinforce the concrete column part of the structure. The numerical model employed in this paper was validated and calibrated using experimental results, which were considered inside ABAQUS to produce the validated numerical model, using concrete damage plasticity (CDP) constitutive model and concrete data from laboratory testing to solve the nonlinear programming code provided by the authors. This paper presents a novel optimization method using complementary strain energy to control the plastic behaviour of a full-scale composite integral abutment bridge, with the original contribution being the incorporation of residual forces within reinforcing rebars to limit plastic deformations. Following that, a parametric investigation of the various optimisation problems revealed how models performed variously under different complementary strain energy values, which influenced the general behaviour of the structure as it transitioned from elastic to elasto-plastic to plastic; also results showed how the complementary strain energy value is connected with the amount of damaged accrued in both concrete and steel.

The built environment and its components require a continuous and uninterrupted flow of information between its various players. In this paper a conceptual framework is proposed describing the role of these players as well as the nature of the links between them. The authors introduce a new term, a conceptual framework which can be used as a platform called BENIP (Built ENvironment Information Platform).

The most flame retardants and non-combustible non-woven fabrics are made of oxidized and carbon fibres due to their strong thermal stability. The burning of non-woven fabrics consists of complex combustion mechanisms: their surface, micro and macrostructures together define their combustion features. By microstructure, we mean oxidized polyacrylicnitrile fibres, which finally constitute the base material of the macrostructure. The macrostructure represents the different forms of the product, in which the material results during production. In this paper, the effect of the macrostructure of non-woven fabrics on flammability has been studied. It has experimentally shown that by defining the oxygen index, we can demonstrate the surface and thickness inhomogeneity, which is invisible or cannot be detected by mechanical tests. A feature of non-combustible non-woven fabrics is that their flammability depends on their thickness and area weight; however, the combustion phenomena of felt fabrics depend primarily on their macrostructure. Different oxygen contents have different combustion phenomena, thus an oxygen index can be assigned to each one. Thermoanalytical test results clearly showed the temperature at which the thermal decomposition of the fibres begins, which gives the surface flame when combusted.