Out-of-plane Proof Testing of Masonry Infill Walls

Proof testing of multiple fired-clay-brick unreinforced masonry (URM) infill walls set within reinforced concrete frames was undertaken using airbags to simulate out-of-plane (OOP) loading. The proof testing was conducted to provide engineers in various research and practitioner roles with verified wall behaviour for the purpose of seismic assessment of buildings. A total of 19 tests were performed in six buildings. It was observed that two-way OOP flexure can substantially improve the OOP load-carrying capacity of tested infill walls compared to one-way vertical OOP flexure and that boundary restraints and presumed 'arching' action from the building frame can significantly increase the OOP capacity of URM walls. In addition, the effects of simulated in-plane damage on the OOP capacity of a URM infill wall were investigated, and it was found that the damage reduced the OOP strength by up to 40%. On-site proof testing is demonstrated as a simple and cost-effective way to establish actual wall lateral capacities in cases where boundary conditions cannot be clearly established and existing analytical models predict low lateral capacities.