不同松动程度下古建筑燕尾榫节点残损评估方法研究

Study of assessment method of dovetail joint residual damage in ancient building under different levels of looseness

参照《清式营造则例》,制作了5个缩尺比为1∶3.2的燕尾榫节点试件,并进行了低周反复荷载试验;根据试验结果,提出了基于抵抗破坏潜能、松动程度和抵抗破坏潜能双参数的两种残损评估方法。研究结果表明:试件的破坏形态主要表现为榫头的拔出,卯口木材纤维的翘起,随着节点松动程度的增加,滞回环捏拢效应越来越明显;基于抵抗破坏潜能的残损评估仅考虑了单因素对燕尾榫节点残损的影响,未考虑松动程度的影响,对节点的残损评估不够全面,且其结果离散性较大;而基于松动程度和抵抗破坏潜能的双参数残损评估方法,考虑了松动程度和抵抗破坏潜能对节点残损的影响,更加全面和合理。

Five dovetail joint specimens with scale ratio of 1 : 3.2 were produced by reference to Construction Examples of Qing Dynasty, and low-cycle repeated loading experiment was carried out. Based on experimental results, two different damage assessment methods are proposed in this paper, including destruction-resistance-potential-based and double parameters of level of looseness and destruction-resistance-potential-based, respectively. Results indicate that the main failure form of specimen is pulling out of dovetail joint, and the wood fiber is warped. With the increase of joint loosening degree, the effect of hysteresis ring pinch becomes more and more obvious. The single factor of influence was considered in damage assessment methods of destruction-resistance-potentialbased to evaluate the damage of the joints. The results are very discrete and the influence of looseness is not considered. Therefore, the damage assessment is not comprehensive. While the damage assessment method of loose degree and destruction-resistance-potential-based has considered the effect of both loose degree and destruction-resistance-potential on damage of joints, and the method is comprehensive and reasonable.