木质组合梁抗弯性能试验研究

Bending Tests Investigation on Composite Timber Beam

通过12根矩形截面梁、24根T型组合梁和6根工字型组合梁,共计42根木质梁试件的2点加载受弯试验,研究了木基结构板—矩形截面木搁栅组合梁的抗弯性能.结果表明,木质梁试件破坏前能产生较大的变形,最终破坏主要有4种模式:纯弯段腹板弯曲破坏、沿腹板顺纹方向劈裂破坏、弯剪区沿腹板截面高度剪切破坏和梁端部局部扭转.木质组合梁中连接翼缘与腹板的钉连接节点在梁受弯时滑移变形较小,因此其能有效地传递翼缘与腹板之间的组合作用.T型组合梁与矩形截面梁相比,刚度和承载力有明显增加,工字型组合梁与T型组合梁相比,受弯性能进一步提高.因此可按组合梁理论进行更加合理的木楼盖相关设计.

42 timber beams including 12 rectangular beams （RB） ,24 composite T-beams（CTB）, and 6 composite I-beams （CIB） were tested to experimentally examine the bending performance of the composite timber beam. Four failure modes were identified, namely, a flexural failure of the web in the pure bending region, a splitting failure along the wood grain of the web, a shear failure of the web in bending shear region, and a local rotation at the end of beam. The relative slip between the web and the flange in the composite timber beam was small enough to ensure the composite action and load sharing between the flange and the web. The tests demonstrated that, as expected, the bending stiffness and capacity of the CIB was the largest, followed by the CTB, and ending with the RB. The results of these tests clearly demonstrate that composite action should be taken intoaccount to economically design timber floors.