Authors: Ali Awaludin Takuro Hirai Toshiro Hayashikawa Yoshihisa Sasaki
Publish Date: 2008/10/01
Volume: 54, Issue: 5, Pages: 362-368
Abstract
Previous experimental studies reported that bolt pretensioning greatly increases the initial stiffness and loadcarrying capacity of bolted joints It is also a matter of great importance to structural designers to understand the effect of pretension on the loadcarrying capacities of bolted joints and this study presents an extended yield model that considers the fastener’s pretension force In the extended yield model the loadcarrying capacity was defined as the load at a slip of 15 mm The ultimate fastener bending angle at the yielded cross section equivalent to this joint slip which was affected by the fastener’s axial force was iteratively evaluated in numerical analyses The introduction of bolt pretensioning largely increased the joint slip resistance at initial loading but it decreased the ultimate fastener bending angle This decrease of fastener bending angle resulted in a relatively low stiffness hardening or secondary stiffness which is caused by secondary axial forces associated with embedment of steel plates into the wood member Prediction was verified by the tests of 36 steeltotimber joints under three different pretension forces and two loading directions relative to the grain Some of the observed loadcarrying capacities of the joints particularly in loading perpendicular to the grain however were not as high as those expected by the numerical analyses considering the given pretension forces
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