دانلود رایگان مقاله انگلیسی چیدمان نوار و بهینه سازی وزن مخصوص دیوار برشی RC - الزویر 2018

Abstract

Optimization problems can be defined and formulated with either discrete or continuous variables. This paper presents a continuous optimization method for the design of reinforced concrete shear walls, based on the concept of boundary element and with the reinforcement layout taken into consideration. Contrary to the discrete method, where algorithm must be provided with a set of previously prepared default designs, the continuous optimization algorithm generates and evaluates a wall design in each iteration. The objective function of the algorithm minimizes the cost of the wall, which depends on the reinforcement details (rebar diameter and layout) and the wall dimensions (the cost of concrete and formworking). This objective function consists of the boundary element dimensions and the reinforcement layout variables (cross-sectional area and spacing of rebars). Shear wall design requirements and restrictions are formulated as constraints in accordance with ACI318-11 provisions for special ductility. After obtaining optimal wall design for seismic loads, design details such as wall dimensions and reinforcement details are determined accordingly. The optimization is performed by the use of several metaheuristic algorithms, including PSO, FA, WOA, and CSA. The comparison of the results of continuous and discrete optimization methods show that the shear wall designs obtained by the continuous approach are less expensive and closer to the global optimum.

5. Conclusion

The optimization of RC shear wall design should account for seismic conditions as well as economic criteria. In this study, RC shear wall design optimization was performed in accordance with seismic criteria suggested in ACI318-11.

The main advantage of the proposed method is the continuous nature of the design algorithm, which, eliminates the need for a database of previously prepared designs (which itself requires extensive time and effort. Furthermore, the solutions given by the discrete approach are not necessarily optimal, because they are dictated by the prepared design database. The continuous method lacks this flaw, but is more difficult to code, since the algorithm must incorporate all primary elements of wall design (reinforcement layout, rebar spacing, etc.) into the optimization process.

A comparison between the discrete method and the proposed continuous method showed that, even after considering the real-world applicability conditions in the proposed method (Plan-C), its outputs were more economical (about 5%) than the results of the discrete method.