LAUSR

The coupling ratio (CR) has been widely used to quantitatively reflect the degree of coupling action between the component walls and link beams of a coupled wall. However, the CR index is very difficult to evaluate at early design stages. In order to develop alternative design parameters that can be easily utilized and ensure the dual lateral force resisting mechanism of coupled walls, nine prototype coupled walls were designed considering various aspect ratios of wall pier (αw) and span-to-depth ratios of coupling beams (αb). The incremental dynamic analyses on the seismic fragility was conducted to examine the influences of αw and αb on the fragility characteristics and the margin capacities corresponding to different performance limit states. The double-factorial quadratic response surface method was used to further reveal the interactive impact of αw and αb on the overall behavior of coupled walls. Then the combinations of αw and αb that can produce the optimal values of response variables were obtained. The curve-fitting technique was used to find the relationship between optimal αb and αw. It is indicated that αb and αw can effectively serve as the alternative parameters to CR and ensure optimal overall structural performance of RC coupled walls.