古木结构中抬梁式和穿斗式木构架受力性能试验研究

为从木构架层次把握我国古建筑木结构的基本受力性能，根据相关文献和现场测绘设计并制作了抬梁式木构架和穿斗式木构架各1榀，进行了恒定轴压下的水平单调加载试验。通过试验研究获得了两类典型木构架的破坏模式、荷载-位移关系、榫卯节点的破坏形态、柱顶侧移-加载位移关系、榫卯节点的拔榫量-转角关系等。研究结果表明，在加载过程中，木构架中榫卯节点逐个破坏，半榫节点发生脱榫破坏，透榫发生变截面处顺纹撕裂破坏和榫头下侧受弯破坏，最终两榀木构架均发生整体倾覆破坏；抬梁式木构架和穿斗式木构架的极限位移角分别为1/6.6、1/4.0，均具有良好的变形能力，但抬梁式木构架的水平荷载承载效率明显低于穿斗式木构架；柱顶侧移随着加载位移的增加而近似线性增加；榫卯之间的初始缝隙在加载初期逐渐闭合，会引起部分榫卯节点拔榫量为负值，之后，主要榫卯节点的拔榫量随节点转角的增大而增大。

Experimental investigation on mechanical behavior of post-and-lintel timber frame and column-and-tie timber frame in ancient timber structures

To investigate the basic mechanical behavior of the ancient timber buildings in China in terms of the timber frame, one post-and-lintel timber frame and one column-and-tie timber frame were designed and fabricated on the basis of the related literature and field sketch. Both timber frames were then tested under constant axial compression and monotonic lateral loading. The failure mode, load-displacement relationship, failure forms of mortise-tenon joints, lateral displacement at column top versus loading displacement relationship, tenon pull-out versus rotation relationship were acquired from the tests. The research results show that the mortise-tenon joints in both timber frames successively failed during the loading procedure,the Ban mortise-tenon joint failed due to pulling out, the Tou mortise-tenon joint failed due to the tearing along the grain in the variable cross section and the bending damage near the tenon roof and both timber frames eventually failed due to entire overturn. The ultimate drift ratios of the post-and-lintel timber frame and column-and-tie timber frame are 1/6.6 and 1/4.0, respectively, indicating that both timber frames possess favorable deformability. However, the lateral load-bearing efficiency of the former is obviously smaller than that of the latter. The lateral displacement at column top increases nearly linearly with the loading displacement. The gradual closure of the initial gap between joints at the early stage of loading caused negative tenon pull-out for some joints, and then, the tenon pull-out increase with the rotation for most joints.