Title: Ultra-High-Toughness Concrete Retrofitted Boundary Column Shear Walls: Tests and Capacity Prediction

Author(s): Hongmei Zhang, Giorgio Monti, Yuanfeng Duan, Zhiyuan Chen, and Chen Gu

Publication: Structural Journal

Volume: 120

Issue: 5

Appears on pages(s): 3-18

Keywords: boundary columns; cyclic loading test; retrofitting; seismic performance; shear wall; ultra-high-toughness

DOI: 10.14359/51738829

Date: 9/1/2023

Abstract:
The rapid growth of the construction industry in Asia and the consequent updating of design specifications put forward higher performance requirements for structural components, which results in a large number of existing shear walls that are not compliant with the current seismic standards. A prospective retrofitting method, which is based on replacing the existing boundary concrete or attaching external boundary columns to nonconforming shear walls, is experimentally studied. Four shear-wall specimens were designed according to the current Chinese design code: one using plain concrete boundary columns and three using ultra-high-toughness boundary columns (UHTBCs), adopting three different strengthening strategies relevant to the boundary size and the connection form. Cyclic performance, damage patterns due to UHTBCs, and connection form are discussed based on the experimental results, from which it was ascertained that shear walls with UHTBCs show improved seismic performance, compatible with the requirements of the current seismic design code, even for the reduced-boundary UHTBCs and non-connection specimens. The predictive equation for the sectional moment capacity of shear walls with UHTBCs was discussed as a practical tool for retrofitting applications. This study highlights the most important features of a rapid retrofitting measure to improve the resilience of existing nonconforming shearwall structures, while also proving to be an effective measure for newly constructed structures.