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Abstract: This paper presents the results of an experimental and numerical study of the compressive capacity of longitudinally cracked wooden columns retrofitted using self-tapping screws. The screws were driven into the wood perpendicular to the wood grain to alleviate the propagation of existing cracks and to improve the structural integrity of the cracked columns. Full-scale concentric and eccentric compression tests were conducted to investigate the failure modes and maximum load carrying capacity of such columns. A 3D finite element model was developed, verified, and then used for a parametric study. The test results indicated that the cracks (of 6 mm wide) caused a resistance loss of up to 19% compared with an intact column, but most of this resistance loss can be remedied by using self-tapping screws. It was also found that such resistance loss and recovery are dependent on the seriousness of the cracking, and generally increase with the increased initial mid-height deflection and decreased screw spacing, whereas a screw spacing of 100 mm would be sufficient for most cases considered in this study.

Given increasing interest of retrofitting of timber structures in modern-day rehabilitation and restoration, as well as the realistic environment at which the experiments were conducted, the manuscript addresses an issue that is very important from the practical point of view; as such, it is important in field and useful to the profession. It is also an issue that poses theoretical, as well as experimental challenges, and, as such, it is also useful to research in academia and deserves a broader dissemination.

新型自攻螺丝修复纵裂木柱抗压性能

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