Bolted wood–steel and wood–steel–wood connections: verification of a new design approach

This paper covers the verification tests carried out at the Royal Military College of Canada on wood–steel–wood and wood–steel bolted connections. Thirty groups of specimens were tested. Specimen configurations were selected in such a way to include fundamental brittle and ductile failure mode cases. Comparisons between experimental results and predictions from proposed equations developed from steel–wood–steel bolted connections are given. Proposed design equations were found to provide better predictions of the ultimate loads than current CSA Standard O86.1 design procedures especially for bearing. However, row shear-out predictions seem to overestimate the strength. An adjustment using the reduced (effective) thickness concept is therefore proposed. Experimental observations on specimens that failed in row shear-out indicated that shear failure occurred over a reduced thickness. Stress analysis confirms findings on the reduced thickness. The research program is described in this paper along with the results and the proposed design equations for wood–steel–wood and wood–steel bolted connections loaded parallel-to-grain.Key words: wood–steel–wood, wood–steel, bolt, connection, strength, failure, design, thickness.