Load-carrying capacity of steel-to-timber joints with a pretensioned bolt
Load-carrying capacity of steel-to-timber joints with a pretensioned bolt
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DOI：
10.1007/s10086-008-0962-8
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发表时间：
2008-10-01
影响因子：
2.9
通讯作者：
Sasaki, Yoshihisa
中科院分区：
文献类型：
--
作者：
Awaludin, Ali;Hirai, Takuro;Sasaki, Yoshihisa
先前的实验研究表明，螺栓预紧大大提高了螺栓连接的初始刚度和承载能力。对于结构设计师来说，了解预紧力对螺栓接头承载能力的影响也非常重要，本研究提出了考虑紧固件预紧力的扩展屈服模型。在扩展屈服模型中，承载能力定义为滑移 15 mm 时的载荷。在数值分析中迭代评估了相当于该接头滑移的屈服横截面处的最终紧固件弯曲角度，该角度受紧固件轴向力的影响。螺栓预紧的引入大大增加了初始加载时接头的抗滑移性，但降低了紧固件的极限弯曲角度。紧固件弯曲角度的减小导致相对较低的刚度硬化（或二次刚度），这是由与钢板嵌入木质构件相关的二次轴向力引起的。通过对 36 个钢木节点在三种不同预拉力和相对于纹理的两个加载方向下的试验验证了预测。然而，观察到的一些接头的承载能力，特别是垂直于纹理的承载能力，没有考虑到给定预紧力的数值分析所预期的那么高。
Previous experimental studies reported that bolt pretensioning greatly increases the initial stiffness and load-carrying capacity of bolted joints. It is also a matter of great importance to structural designers to understand the effect of pretension on the load-carrying 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 load-carrying 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 steel-to-timber joints under three different pretension forces and two loading directions relative to the grain. Some of the observed load-carrying 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.