Development of Joint Which Enable to Make Strong and Ductile Timber Frame Structures.

在这项研究中，我们打算开发坚固和延展性的连接方法，可以连接轴向构件相互之间的各种木框架结构。首先，对于住宅的使用，采用直径为25毫米，长为120毫米的小螺杆（LSB）组成木质对角线系统，不会在基础构件上产生喷浆。通过对长91 cm、高273cm的剪力墙试件进行侧剪试验，评价斜向体系的抗剪强度、刚度和延性。试验结果表明，新开发的对角线体系在推拉荷载作用下的许用强度相同，但在拉荷载作用下的极限强度要小10%左右。对现有的半刚性连接技术进行了研究，并通过全尺寸框架试验对其结构性能进行了评价。作为我们自己独创的半刚性连接方法，我们开发了直径30 mm、长280 mm的中等尺寸lbs，首先在douglas -fir GLT上对其拔拔强度和刚度加载性能进行了评估。试验结果表明，与垂直于晶粒加载的拔拔刚度相比，平行于晶粒加载的拔拔刚度高2 ~ 6倍。而侧粒加载的极限强度为端粒加载的2倍。在任何情况下，强度和刚度都与嵌入面积成正比，因此可以从这些实验中确定LSB的允许设计值。最后，对跨度为360 cm、高度为270 cm的胶合木半刚性门式刚架试件及其节点均采用llb节点进行横向加载，评价框架结构的抗剪性能。试验结果表明，强度和刚度与预测值基本一致。由此得出结构上合理的连接方法，使木结构具有较强的韧性。

In this study, we intended to develop strong and ductile joint methods which could connect axial members with each other for various wooden frame structures. At first, for the use of residential houses, a small lagascrewbolt (LSB) of 25 mm diameter and 120 mm long was applied for composing wooden diagonal system which did not cause spriting at sill member. Shear strength, stiffness and ductility of the diagonal system were evaluated by lateral shear test on shear wall specimens having 91 cm long and 273cm height. Test results showed that the newly developed diagonal system had same allowable strength for both push and pull loading, but also showed that about 10% smaller ultimate strength wen it was loaded by pull load.Next attentions were paid on the existing semi-rigid jointing techniques which could composed of joints with less steel wares, and their structural performance were evaluated by full-scale frame experiments. As our own original semi-rigid jointing method, we developed medium size LSBs of 30 mm diameter and 280 mm long, their pull-out strength and stiffness loaded performances were first evaluated on Douglus-fir GLT Test results showed that pull-out stiffness parallel to the grain was as higher as two to six times of those compared with perpendicular to the grain loading. While ultimate strength of side grain loading was stronger as two times of end grain loading. In any cases, strength and stiffness was proportional to the embedment area so allowable design values for LSB could be determined from these experiments. Finally, glulam semi-rigid portal frame specimens of 360 cm span and 270 cm height and their joints were all composed of LSB-joints were laterally loaded to evaluate shear performance of the frame structure. Test results showed that strength and stiffness were almost same as those predicted. In consequent, we think that structurally reasonable jointing methods were obtained which enable to built strong and ductile timber structures.