国产杉木正交胶合木抗压强度研究

Study on the Compression Strength of Chinese Fir CLT

研究了组坯层数和锯材厚度对国产杉木CLT的压缩性能和破坏模式的影响,并采用复合层板理论模型进行性能预测,结果表明:1)组坯层数和锯材厚度对于杉木CLT强轴和弱轴方向的抗压强度均有显著性影响。当锯材厚度相同而层数不同时,三层结构杉木CLT强轴方向的压缩强度比五层结构的高12.68%,而弱轴方向的压缩强度则低9.84%;当层数相同而锯材厚度不同时,锯材厚度为18 mm的杉木CLT强轴方向的抗压强度比锯材厚度为35 mm的杉木CLT高6.13%,而弱轴方向的抗压强度则高2.71%。2)抗压试件的破坏模式与加载方向有关。强轴方向受压时,其主要破坏模式为平行层层板的压碎破坏和楔形劈裂;弱轴方向受压时,则垂直层层板发生压碎破坏和楔形劈裂。3)复合层板理论模型可以较为准确地预测杉木CLT的抗压荷载,相对误差在10%以内,强轴方向的抗压荷载预测精度高于弱轴方向。

In this paper,the effects of the number of layers and thickness of lumber on the compression properties and failure modes of Chinese fir CLT were studied.The performance prediction was carried out by using the composite laminate theory.The results showed that:(1)The number of layers and the thickness of lumber had significant effects on the CLT’s compression strength.For CLT with the same thickness and different layers,the compressive strength in the major strength direction of CLT with 3-layer structure was 12.68%higher than that of CLT with 5-layer structure,while the compressive strength in the minor strength direction was 9.84%lower.For CLT with the same layers and different thickness,the compressive strength in the major strength direction of CLT with 18 mm thickness was 6.13%higher than that with 35 mm thickness,and the compressive strength in the minor strength direction was 2.71%higher.(2)Failure mode of specimens was related to the loading direction.The main failure mode in the major strength direction was crushing damage and wedge splitting of parallel laminates.The failure position of specimen in the minor strength direction occured in the vertical laminates.(3)The composite laminate theory can predict the load accurately,with the relative error within 10%,and the accuracy of load prediction in the major strength direction is higher than that in the minor strength direction.