Abstract

The seismic response and laboratory testing of pre-1980s reinforced concrete (RC) shear walls commonly exhibit undesirable concrete crushing and rebar buckling in the wall end-zones leading to a flexural compressive failure. The lack of ductility of these walls is attributed to low reinforcement ratios and absence of special boundary elements (SBE) as required by modern design code. Thus, the authors are proposing a fiber reinforced polymer (FRP) retrofit method to provide confinement to the end-zones of pre-1980s walls equivalent to that of an SBE.

Current industry applications of FRP have largely been for shear strengthening of RC beams, columns, and slabs. In contrast, the large-scale experimental study described in this paper aims to determine the effectiveness of FRP sheets

2024 SEAOC CONVENTION | PORTLAND, OR

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and splay anchors as confinement of pre-1980s wall end-zones to increase the compressive strain capacity, delaying both concrete crushing and rebar buckling that precipitate the flexural compression failure. This is anticipated to increase wall drift capacity and potentially change the failure mechanism to one that is more ductile. Results from this study would demonstrate the feasibility of this FRP wall retrofit method to industry practitioners, especially attractive due to the relatively low-cost nature and minimally invasive implementation.

The Cal Poly research team previously conducted a pre-1980s wall test (Ostrom, 2018; de Sevilla & Luong, 2020) and modelling in PERFORM-3D (Doan & Williams, 2020). The wall specimen design discussed herein, R2-FRP, was proportioned from walls tested by Lu et al. (2017) to achieve a flexural compression failure, with predictions per ASCE 41-23 and Priestley’s (2007) Lumped Plasticity model confirming this target response.

Disciplines

Architectural Engineering

Number of Pages

15

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URL: https://digitalcommons.calpoly.edu/aen_fac/157