Laboratory Testing of Strengthened Cavity Unreinforced Masonry Walls
Publication: Journal of Structural Engineering
Volume 144, Issue 3
Abstract
An experimental campaign consisting of nine pressure-controlled quasi-static airbag tests on unreinforced masonry (URM) walls and accompanying material testing was completed to investigate methods for seismic retrofit of out-of-plane loaded cavity walls. Three control walls were tested to serve as a baseline for wall strength comparisons: (1) a double-leaf unstrengthened cavity wall; (2) a cavity wall with improved cavity connections; and (3) a single-leaf wall strengthened using a near-surface-mounted (NSM) fiber-reinforced polymer (FRP) strip. The experimental program was concluded by six tests that were conducted on walls strengthened using a NSM FRP strip and having cavity connections in the form of either standard bent metal ties, proprietary helical anchors, or industrial foam. The tests were designed to measure the ability of the different cavity connections to maintain the cavity gap until a ductile wall failure mechanism forms by FRP debonding. Three of the walls were previously damaged by testing in either unstrengthened or FRP-strengthened conditions. These tests were intended to study FRP retrofit effectiveness of precracked walls or the relative ability of different types of cavity connections to resist forces until a global FRP debonding occurs. For each of the six cavity connection configurations, the FRP-strengthening technique was shown to significantly improve the wall strength. The minimum strength increase was 282% compared with that of the control cavity wall. The compiled data are presented followed by general discussions on the design of seismic retrofit for cavity walls.
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Acknowledgments
The authors gratefully acknowledge the financial support of the Australian Research Council through its Cooperative Research Centre (CRC) program and specifically the Bushfire and Natural Hazards CRC. The authors express their gratitude toward the technical team at the University of Adelaide’s structural laboratory for their assistance with material and wall testing. The views and opinions expressed in this paper are those of the authors and not necessarily those of the sponsors.
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Published In
Journal of Structural Engineering
Volume 144 • Issue 3 • March 2018
Copyright
©2018 American Society of Civil Engineers.
History
Received: Mar 9, 2017
Accepted: Sep 14, 2017
Published online: Jan 6, 2018
Published in print: Mar 1, 2018
Discussion open until: Jun 6, 2018
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