杆件摆放方式对平行弦木桁架承载力的影响

Mechanical Properties of Parallel-chord Wood Truss Components with Different Chord Arrangements

通过对两种摆放方式(规格材立置和平置)的平行弦木桁架进行静载试验,测试其上下弦各节点挠度,分析杆件摆放方式对木桁架刚度、承载能力和破坏模式等力学性能的影响。结果表明,规格材杆件立置的平行弦木桁架具有较高的刚度和极限承载力,破坏以杆件劈裂为主;而杆件平置的木桁架破坏主要发生在齿板连接的节点处。木桁架弦杆接长对其承载能力影响显著,此处安全性能要求更高,必要时应对对接节点处进行加强处理。

Parallel-chord wood trusses are widely used in floor plane systems of light timber frame structures. In practice, components of parallel-chord wood trusses could be arranged in two ways. One is lumber-on-edge truss and another is lumber-on-flat truss. In this study, deflection of top and bottom nodes of these two kinds of parallel-chord wood trusses were measured through static load tests, bearing capacity,rigidity and failure modes of the nodes were analyzed. The results showed that lumber-on-edge trusses provided a better ultimate bearing capacity and higher rigidity with components’ failure as the main failure mode. When it turned to lumber-on-flat trusses, nodes failure was the main failure mode. Chord extension in wood trusses has significant influence on its bearing capacity. Therefore, butt joints shall be strengthened since the safety performance requirement is normally high.