文章编号：1674—2974（2019）01—0065—11
Abstract：Hoop head tenon-mortise joint is extensively adopted in an ancient timber structure in Guangfu， which is different from straight tenon-mortise joint or dovetail tenon-mortise joint in terms of mechanical performance. To analyze the mechanical properties of hoop head tenon-mortise joint，mechanism analysis was carried out and the moment-rotation calculation formulae were also derived， while the formulae were verified by experimental results. Using the formulae，the factors affecting the relationship of moment-rotation of hoop head tenon-mortise joint were investigated. The results indicate that within the range of parameters， the initial rotational stiffness and ultimate bending moment increase with the increase of the column diameter， mortise width， friction coefficient and unilateral compression width between tenon and mortise，while the ultimate bending moment increases with the increase of beam height， but the initial rotational stiffness is only slightly affected by the beam height. The results of this study can serve as a theoretical foundation for mechanical analysis as well as for seismic research of ancient timber structures in Guangfu.
Key words：ancient architecture;timber structures;hoop head tenon-mortise joint;force mechanism;moment-rotation relationship
中国古建筑木结构具有丰富的历史文化内涵和极高的科学价值，如何对它们进行有效的评估和保护一直是研究者们研究的热点.古建筑木结构中各构件之间常采用榫卯进行连接.榫卯节点通过交界面的挤压和摩擦来抵抗外力与耗散能量，其受力机理较为复杂.谢启芳等[1]、周乾等[2]对汶川地区古建筑的震害调研发现，古木建筑的破坏特征主要表现为榫卯节点拔榫或松动.开展对古木结构榫卯节点力学性能的研究并提出合适的修缮保护方法具有重要意义.
由于木结构榫卯节点呈现出典型的半刚性，且节点的转动刚度随着节点转角变化而变化，因而节点弯矩-转角关系是木结构研究中的一个重点问题.淳庆等[3]通过低周反复荷载试验和有限元模拟分析，研究了江南地区传统木构建筑半榫节点的受力性能.部分学者在试验研究基础上，根据节点弯矩-转角曲线的特点提出了相应的力学计算模型，以便应用于整体模型计算中.高大峰等[4]在榫卯节点试验的基础上建立了燕尾榫节点的弯矩-转角及荷载-位移四阶段恢复力模型.赵鸿铁等[5]根据试验中得到的燕尾榫节点弯矩-转角骨架曲线，拟合得到了节点的弯矩-转角的关系方程和恢复力模型.Kishi等[6]在试验基础上提出了节点弯矩-转角的3参数幂函数模型，结果表明该模型可以较好地反映节点的刚度特性.杨艳华等[7]在试验研究基础上，对原有3参数幂函数弯矩-转角模型进行改进，建立了适用于木结构榫卯节点的4参数幂函数模型.淳庆等[8]以中国南方典型榫卯节点为研究对象，将试验得到的典型节点的弯矩-转角骨架曲线简化为三折线模型并算出了模型各阶段的特征刚度.
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