Research on Quasi-Elastic–Plastic Optimization of Reinforced Concrete Frame–Shear Wall Structures

Precise determination of structural elastic–plastic displacement and component states under rare earthquakes is crucial for structural design. This article proposes a quasi-elastic–plastic optimization method for reinforced concrete structures. First, an approximate formula for calculating the yield bending moment of shear walls is provided through analysis of 64 shear walls. Second, a quasi-elastic–plastic analysis method is proposed. Using the elastic response spectrum analysis, strain energy for each component is calculated, and stiffness reduction factors for walls, beams, and columns are derived based on the energy equivalence principle. Finally, combining the elastic response spectrum analysis and the quasi-elastic–plastic analysis, various constraint indicators at the elastic and elastic–plastic design stages are calculated, and structural size optimization is completed using the particle swarm optimization method. The feasibility of this method is validated with examples of a 15-story reinforced concrete frame structure and a 15-story frame–shear wall structure. The quasi-elastic–plastic optimization with the particle swarm optimization efficiently completes elastic–plastic optimization for reinforced concrete structures, determining section sizes that meet performance standards while reducing material usage.