古建筑木结构残损性能评估与地震破坏机制的研究

The research project focuses on the key problem that Chinese historic timber structure safety and long heritage needed to be resolved urgently, emphasizing on the damaged performance of historic timber structure, failure mechanism and fine analysis under seismic loading. Through fast aging test of timber, beam and column members, degradation mechanism of historic timber structures are explored, and the time-dependent predictive models of performance degradation of the aging wood, beam and column members are established. Through the low cyclic reversed loading experiment of different loosing degrees’ tenon and mortise joints and different crooked angles’ brackets, the influences on the seismic performance of loose mortise-tenon joint and crooking brackets are studied, the resilience model and damaging grading methods are established. The shaking table test with seismic wave in three dimensions is conducted, the dynamic characteristics, failure mode, bearing capacity, ductility, energy dissipation and the final collapse mechanism are analyzed, and the failure mechanism and failure criterion under earthquake action are proposed. Based on experimental and theoretical analysis, the fine simulated analysis method of reflecting damage, column foot rotating - sliding friction, mortise-tenon joint and brackets laid layers deformation and dynamic characteristics of big roof beams are established. The research results have important implications for effectively enhancing the safety of existing historic timber building structures.

围绕古建筑木结构安全性及久远传承所急需解决的关键问题，重点研究古建筑木结构的残损性能、地震作用下的破坏机制及精细化分析方法。通过木材、梁柱构件的快速老化试验，探讨古建筑木结构性能退化机理，建立老化木材、梁柱构件性能退化的时变预测模型。通过不同松动程度的榫卯节点和不同歪闪角度下斗栱的低周反复加载试验，研究榫卯节点松动和斗栱歪闪等残损对古建筑木结构抗震性能的影响，建立残损古建筑木构件的恢复力模型和残损等级划分方法。进行残损古建筑木结构模型在三维地震输入下的振动台试验，分析其动力特性、破坏模式、承载力、延性、耗能能力和最终的倒塌机构，提出古建筑木结构在地震作用下的破坏机制和失效判定准则。基于试验和理论分析，建立可准确反映残损、柱脚转动-摩擦滑移、榫卯节点和斗栱铺作层大变形以及屋盖梁架层动力特性的古建筑木结构精细化仿真分析方法。研究成果对全面有效提升现存古建筑木结构的安全性及久远传承具有重要意义。

以我国重要文化遗产古建筑木结构为主要研究对象，以全面有效提升现存古建筑木结构的安全性及防灾性能为研究目标，围绕残损木结构古建筑的力学性能、地震作用下的破坏机制以及精细化分析方法展开研究，主要内容如下：.（1）进行了不同松动程度的透榫和燕尾榫节点抗震性能试验研究，全面深入地研究了不同松动程度的榫卯节点的滞回耗能性能；通过改变摩擦系数、材料性能、松动程度、轴向荷载、节点尺寸等参数，对不同松动程度的榫卯节点进行了精细化数值模拟及参数分析；.（2）根据低周反复荷载试验结果，提出了基于抵抗破坏潜能、和基于松动程度和抵抗破坏潜能的双参数残损方法，并对各节点试件进行残损评估，将残损评估等级进行了对比分析；.（3）采用精细化有限元模拟方法，完成了歪闪斗栱节点竖向受力性能模拟，研究了不同歪闪角度对斗栱的荷载-位移曲线、破坏形态及受力性能的影响；建立了歪闪斗栱在竖向荷载作用下的简化力学模型，计算得到了各层弹簧的刚度，并分析了歪闪斗栱的竖向传力机理。