工程竹木梁受弯性能试验研究

Experimental Study on Bending Performance of Engineered Bamboo Timber Beam

为研究工程竹木梁受弯性能,设计足尺花旗松胶合木梁、胶合竹梁、重组竹梁和胶合竹木梁试件进行受弯性能试验,分析试件破坏模式、承载力、变形特点。试验结果表明,4种梁破坏均由下部纤维在跨中被拉断引起,与胶合木梁易受木节等缺陷的影响相比,工程竹梁和胶合竹木梁力学性能更稳定;胶合竹梁、重组竹梁和胶合竹木梁极限荷载平均值分别较花旗松胶合木梁提高28%,91%,38%,达到极限荷载时的跨中位移平均值分别提高94%,63%,118%;胶合竹木梁极限荷载及达到极限荷载时的跨中位移均略大于胶合竹梁,表明通过工程竹材与速生木材的组合使用,胶合竹木梁受弯性能得到增强,胶合竹强度和变形能力得到充分利用。

Full scale Douglas fir laminated timber beams,laminated bamboo beams,bamboo scrimber beams and glued-laminated-timber-bamboo beams were designed and tested under bending loads to investigate the bending performance of engineered bamboo timber beams. The failure modes,bending capacities and deformation characteristics were studied. The results show that failure of the four groups of beams was caused by tensile fracture of the bottom fiber in mid-span. Compared with the laminated timber beams,the mechanical properties of the engineered bamboo timber beams and glued-laminated-timberbamboo beams are more stable as they are less affected by the defects. Compared with the Douglas fir laminated timber beams,the average bending capacities of laminated bamboo beams,bamboo scrimber beams and glued-laminated-timber-bamboo beams are increased by 28%, 91% and 38%, the corresponding mid-span deformation are increased by 94%,63% and 118%. The average bending capacity and corresponding mid-span deformation of the glued-laminated-timber-bamboo beams are slightly higher than that of laminated bamboo beams,indicating that the bending performance of the glued-laminated-timber-bamboo beams is improved,under the composite action of engineered bamboo and fast-growing timber. The strength and deformation capacity of laminated bamboo are fully utilized.