Post-Earthquake Reconnaissance of Unreinforced and Retrofitted Masonry Parapets

Unrestrained unreinforced clay brick masonry (URM) parapets are freestanding wall elements found atop a large number of vintage URM buildings. Parapets are considered to be one of the most vulnerable nonstructural components that are prone to out-of-plane collapse when subjected to earthquake induced shaking. Using data collected during the earthquake reconnaissance efforts, 959 URM parapets were identify to be in existence in the Christchurch (New Zealand) area prior to 2010, with 60% (580) of them having collapsed during the 2010/2011 Canterbury earthquake sequence. Construction details and observed performance of both as-built and retrofitted parapets were documented. The reported study provides an inventory of observed parapet failure modes and a critical review of commonly encountered parapet retrofits and their respective seismic performance.