胶合木T梁弯曲承载力试验研究

Experimental research on flexural bearing capacity of larch glulam T-beam

为了增强结构整体性与耐久性,节省材料,降低造价,提出一种理论上适合工程应用的正交胶合木T梁这一新的构件形式。采用兴安落叶松板材和结构胶,制作了正交T梁、平行T梁(高跨比1/7.6)及矩形梁(高跨比1/9.2)共3组试件,进行静力弯曲承载力试验,对比分析各类构件的应变、挠度及极限承载力。结果表明:1)3类梁受弯时均为中部顺纹剪切破坏,正交T梁的抗弯承载力比矩形梁提高了33%,比平行T梁低30%;2)基于刚度等效原则,提出了将正交T梁等效为平行T梁,然后采用Rammer抗剪强度公式来计算其弯曲剪切强度的策略;3)分析表明所提出的策略合理、可靠,扩展了Rammer公式的适用范围。研究成果可为工程应用提供理论依据。

In order to enhance the integrity and durability of the structure and save material and cost, a new type of cross glulam T-beam, which is suitable for engineering application in theory, is proposed. Three groups of specimens, including cross T-beam, parallel T-beam (high span ratio 1/7.6) and rectangular beam (high span ratio 1/9.2), were made by using Xing’an larch panel and structural adhesive. Static bending capacity test was carried out to compare and analyze the strain, deflection and ultimate bearing capacity of various components. The experimental results show that (1) the three types of beams were all damaged by longitudinal shear in the middle, and the flexural capacity of cross T-beams was 33% higher than that of rectangular beams and 30% lower than that of parallel T-beams.(2) Based on the stiffness equivalence principle, a strategy for calculating the bending shear strength by equating the cross T-beam with a parallel T-beam and then using the Rammer shear strength formula was proposed.(3) The analysis shows that the proposed strategy is reasonable and reliable, extending the applicable scope of Rammer formula. The research results can provide a theoretical basis for engineering application.