北方村落木结构民居榫卯节点抗震性能试验研究

现存的传统村落木结构民居，由于受风雨侵蚀及战乱、地震、火灾的破坏，发生不同程度的损伤和破坏，榫卯节点残损情况直接影响整个民居房屋结构的安全。以北方地区传统村落“四梁八柱”木结构民居榫卯节点（馒头榫）为研究对象，考虑不同残损类型及程度，制作5个足尺梁柱节点模型，通过拟静力低周往复加载试验研究其破坏模式、弯矩-转角滞回响应及骨架曲线、加载刚度、变形、强度及耗能能力等力学性能。试验结果表明:馒头榫节点破坏模式表现为榫头拔出、榫与卯口挤压变形；相比于完好节点，残损馒头榫节点抗弯承载力、加载刚度和耗能能力明显降低，且“捏拢”效应加剧；榫头松动是导致节点力学性能降低的直接原因；垂直加载方向虫蛀节点力学性能劣化程度强于平行加载方向虫蛀节点，更易导致耗能能力降低。

Experimental Study on Seismic Performance of Mortise-tenon Joints of Traditional Wood Residences in North China Villages

The existing traditional wood residences in villages have experienced different levels of degradation of structural performance, due to long-term weatherworn and damage from war, earthquake and fire. The damaged mortise-tenon joints play a critical role on the safety of these buildings. In this study, taking mortise-tenon joints of “four beams and eight pillars” wood residences in ancient villages of North China as the research object, five full size beam-column joints (Mantou joints) were fabricated with different manually simulated damage types and degrees. The failure modes, hysteretic curves of moment-angle, envelope curves, stiffness, strength, deformation and energy dissipation of theses joists were studied by low-reversed cyclic loading test. It indicates the tenon pulling out and extrusion deformation between mortise and tenon are main failure modes. The rotational moment, strength, stiffness and energy dissipation capacity of damaged joints are significantly lower than those of the intact joint, and the pinch effect of damaged joints are more obvious. The looseness of tenon is the direct reason for degradation of mechanical properties of joints. The termites decay direction perpendicular to loading direction has more serious deterioration for mechanical performance of joints than that of parallel direction, which more easily results in decrease of energy dissipation.