Nonlinear Analysis and Optimization of Recycled Aggregate Concrete Cross-Sections Based on Restoring Force Models

This research presents a simplified approach using a uniaxial restoring force model to analyze the seismic response of recycled aggregate concrete (RAC) frames. Nonlinear simulations were conducted to explore how factors like axial compression ratio, reinforcement ratio, and cross-sectional geometry affect the ductility and seismic performance of RAC sections. The findings reveal that a reduction in the axial compression ratio from 0.60 to 0.57 results in a 15% increase in ductility, while a higher reinforcement ratio leads to a 20% enhancement. In addition, rectangular sections were found to be more sensitive to variations in material strength than square sections, offering key insights for structural optimization. The method proposed here also enhances computational efficiency by minimizing resource consumption and improving the convergence of nonlinear iterative procedures. These findings provide a theoretical foundation for optimizing the design and seismic evaluation of RAC structures, promoting their broader application in engineering practice.