Development of hysteretic model for LEM-filled CFS shear walls under cyclic loading

Lightweight EPS materials (LEM)-filled cold-formed steel (CFS) shear wall, as a novel-type CFS shear wall, is extensively used in low-and multi-storey rural residences. The previous experiments have revealed that this type of wall appeared significant load-bearing properties and elastic stiffness, and the hysteresis loop appeared obvious stiffness degeneration, slipping and pinching effect. This paper developed a hysteretic model for seismic analysis of these shear walls. Four feature points including elastic, yield, peak and ultimate point are put forward to determine the skeleton curve. Besides, the feature points are determined by considering the stress type of bending and shearing respectively. Through analyzing the typical hysteresis loop, four characteristic points were obtained to express the characteristic of the hysteretic loop. Through the combination of the skeleton curve and hysteretic rule, a multi-linear hysteretic model was established to represent the hysteretic curves. The repre-sentative characteristic points of the hysteretic loop were obtained based on test data and the existing literature. The generated skeleton and hysteretic curves were compared with test results and the comparison results showed great agreements in terms of feature points and hysteretic loops. The method would provide a meaningful theoretical basis to assessing the seismic response of the LEM-filled CFS shear wall.