大断面胶合木张弦曲梁及拼接节点静载受弯试验研究

现代大断面胶合木结构采用内嵌双钢板节点形式较为美观，构造相对合理，但因工艺复杂，相关研究不多，故应用较少。文章设计制作了1个内嵌双钢板销式连接的大断面胶合木拼接节点足尺试件，通过静载抗弯承载力破坏性试验，研究节点的失效模式和破坏机理。进而将此节点应用于30m大跨度胶合木张弦曲梁中，设计1个1∶1足尺试件并进行堆载试验，研究张弦曲梁的受力机理、承载能力以及宏观、微观结构响应，并考察拼接节点螺栓群的工作状态。拼接节点试验表明：该节点在纯弯加载过程中未出现钢销滑移等现象，节点最终因受拉区销孔处木材达到承压强度而破坏，说明此类拼接节点受力合理，连接可靠。跨度为30m的张弦曲梁试验表明：该梁施加预应力后，其竖向刚度显著提高、变形减小，在弹性范围内工作，受力性能良好。

Experimental study on bending behavior of large-section #br# glulam string curved beam and splicing joint

Modern large-section glued-wood structures are beautiful with embedded double-steel joints and are relatively reasonable in configuration. However, due to the complicated technological process and few related studies, there are few applications. A full-scale specimen of large-section glued-wood splicing joint with double-steel pin connection was designed and manufactured. The failure mode and failure mechanism of the joint were studied through the destructive test of the flexural bearing capacity under static load. Furthermore, this joint was applied to a 30-meter long-span glulam beam, and a 1∶1 full-scale specimen was designed and loaded to study its working function, bearing capacity, and macro-and micro-structure response. The tests of splicing joints show that the joint does not exhibit steel pin slipping during pure bending loading, and the joint is eventually damaged because the wood at the pin hole in the tension zone reaches the compressive strength, indicating that such joints are reasonable in stress states. The tests on a 30-meter spanned string beam show that after the beam is pre-stressed, its vertical stiffness is significantly increased and its deformation is reduced; it works in the elastic range and exhibits good mechanical properties.