Effects of Bending Moments on the Tensile Performance of Multiple-bolted Timber Connectors: Part I. A Technique to Model Such Joints
Keywords:
Bolted timber connectors, multiple bolts, combined loading, bending moments, tensile loading, wafer modeling technique, design optimizationAbstract
The susceptibility of multiple-bolted timber joints to bending moments is considered in the light of several recent building failures. This study describes an experimental technique to model wood behavior in the plane perpendicular to the axes of multiple bolts in joint members that are subjected to simultaneous bending and tensile loads. Modeled joints consist of 0.8-mm-thick wood wafers sandwiched between clear plastic plates, with steel dowels representing bolts passing through them. Combined loads are applied by mounting the arrangement on a servohydraulic testing machine. Load and displacement data (both axial slip and bending) were recorded during testing to failure, and failure mechanisms were recorded photographically. Results of tests with two dowel configurations (conventional "three-in-a-row" and modified "triangular") suggest that relatively small bending moment levels can reduce the tensile performance of joints, and that bolt configuration is an important factor affecting this susceptibility. The modeling method may be a useful tool for developing joint designs with reduced susceptibility to bending moments and for investigating the effects of variables such as wood quality, growth ring orientation, and moisture content. The behavior of corresponding whole double-shear joints tested under a similar range of loading regimes and with wood of two grades will be reported in a companion paper.References
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