Abstract:
Unreinforced masonry (URM) buildings in New Zealand are typically constructed with rigid clay brick perimeter walls and comparatively flexible timber floor diaphragms. URM construction represents the predominant architectural heritage of our nation but the preservation of these buildings is threatened due their well established inadequacy to withstand earthquakes. Timber floor diaphragms are widely recognized to significantly influence the seismic response of URM structures and the accurate assessment of diaphragms is therefore crucial in any seismic assessment and retrofit of URM buildings. As part of a wider research program, a series of full-scale diaphragm tests were performed to generate the much needed data to critique the current state-of-the-art desktop procedures. In this contribution, the NZSEE and ASCE 41-06 procedures are used to predict full-scale diaphragm performance and are compared against experimentally determined values. It was found that inconsistency exists between the two assessment documents with considerable differences found in strength, stiffness and ductility predictions. The procedures published in NZSEE and ASCE 41-06 poorly predicted diaphragm response and require updated and representative values that include provisions to address the highly orthotropic nature of timber diaphragms. These documents should also be harmonized to ensure that transparency and consistency exists between international assessment procedures.
