重组竹横纹局部受压承载力试验研究

为了解不同工况下重组竹横纹局部受压的力学性能,对5组不同工况下的重组竹试件进行了横纹局压试验,采用0.5 mm/min的速度加载至试件破坏,得到试件的破坏特征、极限承载力和每组试件的荷载-位移曲线。试验结果表明,重组竹横纹局压极限承载力比较稳定,其变异系数均小于0.1; 不同工况对试件的极限承载力和破坏形态有明显影响,承压区周围的围压面越多,其承载力越大。结合已有的木材横纹局压承载力计算方法和试验结果,考虑到重组竹本身硬度较大的特性,将重组竹顺纹和横纹方向的应力扩散长度均取为20 mm,得到了重组竹横纹局压的承载力计算公式,其计算结果均小于每组试件极限承载力的平均值,表明本研究得到的计算公式具有较高可行性。
To investigate the mechanical performance of partial compression perpendicular to grain of bamboo scrimber, and five groups of bamboo scrimber specimens with a total number of 40 were used for the compression tests, and each specimen group has same dimension in direct compression zone. The compression load was applied to the specimen with a velocity of 0.5 mm/min until failure, and the failure mode and ultimate bearing capacity under the different loads and load-displacement curves of each specimen were reported. The results showed that the ultimate bearing capacity of bamboo scrimber under partial compression perpendicular to grain was stable, the variable coefficients of each specimen group were all lower than 0.1, and the different loading condition had significant impact on the ultimate bearing capacity and mode. Moreover, the more the quantity of confining pressure face, the higher the bearing capacity can be obtained, and confining pressure also raised the compression stiffness under partial compression loading. Based on the existed calculation equation for bearing capacity of partial compression perpendicular to the grain of timber and the test results, and considered the high hardness of the bamboo scrimber, the stress dispersion length perpendicular to grain and parallel to grain were set to 20 mm, the calculation equation of partial compression perpendicular to grain of the bamboo scrimber was developed. Furthermore, and the calculated results according to advised calculation equation were all lower than the average values of the experimental ultimate bearing capacities of each specimen group, which verified that the calculation equation developed in this study was practicable