正交胶合木销槽承压强度试验研究

Experimental study on dowel bearing strength of cross-laminated-timber(CLT)panels

正交胶合木(CLT)是一种绿色建材,具有可预制和正交各向异性等特点,应用前景非常广阔,而目前关于CLT力学参数的研究还处于起步阶段。通过对64组共计128个加拿大铁杉CLT试件开展半孔静力加载试验,得到试件的竖向荷载-位移曲线、破坏模态和销槽承压强度,分析了销栓直径、销栓与拼缝的位置关系、加载角度等多种变量对CLT销槽承压强度的影响。结果表明:销栓直径越小,销槽承压强度越大,销栓垂直于表层板且加载角度为90°时,拼缝降低了销槽承压强度,销栓垂直于表层板的承压强度大于销栓平行于表层板的承压强度。将试验结果分别与加拿大规范CSA O86-19、美国规范NDS-2018、美国CLT手册和《正交胶合木(CLT)结构技术指南》中销槽承压强度计算公式得到的计算结果进行对比,得到试验值与采用规范/手册相关公式计算结果的比值为0.46~2.38。在试验结果的基础上,对上述规范中销槽承压强度计算方法进行整合,汇总了适用于多种工况下加拿大铁杉CLT销槽承压强度的建议公式,试验值与建议公式计算值比值区间在1.10~1.57。

Cross-laminated-timber(CLT)is a novel type of green building material with characteristics of prefabrication and orthotropic,which has a wide application prospect.However,the research on the mechanical parameters of CLT is still on the way.In this paper,a total of 128 Canadian hemlock CLT specimens with a half hole were divided into 64 groups.The vertical load-displacement curves,failure modes,and dowel bearing strength were obtained.The effects of the dowel diameter,the position relationship between seams and the dowel,and the loading angle of dowel on the dowel bearing strength were analyzed.The results show that the smaller the diameter of the dowel,the greater the dowel bearing strength.When the dowel is perpendicular to the surface plate with a loading angle of 90°,the seams can reduce the dowel bearing strength.The bearing strength of the dowel perpendicular to the surface plate is greater than that of the dowel parallel to the surface plate.In addition,comparing the test results with the results calculated by CSA O86-19‘Engineering design in wood’,NDS-2018‘National design specification for wood construction’,the US CLT handbook,and‘Technical guide for cross-laminated-timber(CLT)structures’,it is concluded that the ratio of the test value to the calculated value is from 0.46 to 2.38.Finally,based on the test results of this study,a calculation method of the dowel bearing strength was summarized.The ratio between the test value and the calculated value of the proposed formulas is from 1.10 to 1.57.