Seismic Assessment Of Wall-Diaphragm Connections In New Zealand Unreinforced Masonry Buildings

Abstract

This study presents the seismic assessment of wall-diaphragm connections in New Zealand unreinforced masonry buildings, particularly on the bolted connections applied to the existing timber members of the floor and roof diaphragms. Because of the lack of data on the local indigenous hardwood bolted connections, the experimental study to assess their strength performance was initiated. Materials tested were recycled Matai and Rimu hardwoods, which are typically used in the construction of diaphragms in New Zealand unreinforced masonry buildings. The basic properties of the timber used were determined by conducting the following tests: (1) moisture content and density tests; (2) embedding strength tests parallel to the timber grain; and (3) yield compression strength tests perpendicular to the timber grain. The main timber bolted connection tests were conducted in accordance with the ISO/DIS 10984-2. Eleven groups of different bolted connection details with at least ten replicates for each group were tested. A steel-wood-steel connection type was applied to all tested specimens. Based on the current design equations of New Zealand code, European Yield Model, and Row Shear Model, the strength prediction values were compared with the test results obtained. From the comparison made, the effectiveness of those equations to predict the bolted connection strength was identified. The use of European Yield Model and Row Shear Model equations to assess the bolted connection strength in New Zealand hardwoods is recommended. A procedure that was particularly developed to assess the wall diaphragm connections in New Zealand unreinforced masonry buildings is also presented in this thesis.