Numerical analysis of inclined demountable precast concrete walls with rocking-based composite columns for seismic protection of building structures

Abstract

With the aim of simultaneously reducing all seismic demands, this paper proposes a novel structural system comprising inclined demountable walls with rocking base composite columns (IDWC). The proposed IDWC system combines the concepts of using inclined demountable walls in each story and rocking-based concrete filled steel tube (CFST) columns as the wall boundary elements. In particular, through inclined walls, the number of walls in each story is reduced, while with the use of rocking CFST columns, damage to the boundary elements can be mitigated. In total, 18 two-dimensional numerical models are developed and static as well as dynamic analyses are conducted to evaluate the performance of conventional and demountable wall systems of 4-, 10- and 15-stories height. For each height, 4 IDWC models, with various wall arrangements, and a vertical demountable wall model are analyzed and compared with a conventional reinforcement concrete wall model. For the studied models, micro and macro numerical models are developed and verified through experimental data. After performing cyclic and time history nonlinear analyses, it is shown that IDWC models have lower initial stiffness and higher energy dissipation capacity than the conventional model. According to these results, inter-story drift, floor acceleration, and base shear in IDWC models are reduced by up to 30%, 41%, and 45%, respectively, compared to the conventional model. Also, it is demonstrated that with the use of rocking CFST columns, the wall boundaries remain undamaged, which ensures any residual drifts after severe earthquakes are insignificant. Meanwhile, as the incremental dynamic analysis results show, the collapse capacity of IDWC models is up to 53.5% higher than that of conventional models.