Analytical Study of RC Structures with Soft-First Story Using Two-Dimensional Finite Element Analysis

Abstract

In structural design, RC shear wall boundary beams are commonly modeled as rigid, including in multi-story seismic wall structures with a soft-first story, and thus the verification (warranty design) of the boundary beams directly above a soft-first story is not commonly performed. However, the boundary beam of the shear wall above the soft-first story may not constrain the shear wall due to the beam deflection. Therefore, the possible failure should be considered in the structural design. This study conducted a finite element analysis on the previous test specimen to investigate the stress levels in the boundary beam of the shear wall above the soft-first story. The analytical results adequately captured the experimental results on load-deformation relationship and failure; therefore, the analytical model used in this research is validated, and additionally, insights were gained into the distribution of axial forces/bending moments acting on the boundary beams, which can be applied to structural design considerations.