In-field simulated seismic testing of as-built and retrofitted unreinforced masonry partition walls of the William Weir house in Wellington

Abstract

Unreinforced masonry (URM) partition walls of William Weir House in Wellington were subjected to out-of-plane forces to investigate the as-built wall characteristic behaviour. The lateral load resisting system of the 1932 reinforced concrete building was scheduled to undergo seismic strengthening, and due to the absence of reliable wall out-of-plane assessment data, consulting engineers adopted an experimental proof-testing approach. A team of student researchers from the University of Auckland tested four URM partition walls by subjecting the walls to out-of-plane uniform pressure applied by means of a system of airbags. The testing included two mid-storey and two top-storey URM partitions, which had developed prior minor structural cracks. The full-scale in-situ testing confirmed that the precracked partitions had sufficient strength to resist the current New Zealand seismic demand, and the experimental programme resulted in substantial financial benefits for the client as none of the walls were identified as demolition or strengthening candidates. In addition to the as-built out-of-plane tests, two tests were conducted on partition walls retrofitted using near surface- mounted (NSM) fibre-reinforced polymer (FRP) strips. The results of the as-built and the retrofitted wall testing are reported, the wall behaviour is evaluated against the current seismic demand and the assessment results are compared with the New Zealand Society for Earthquake Engineering (NZSEE) recommendations