钢板增强速生杨胶合木梁抗弯性能试验研究

Experimental study on flexural properties of steel plate reinforced fast-growing poplar glulam beams

为扩展速生杨木的应用领域,研究截面尺寸、跨高比和配钢率对速生杨胶合木性能的影响,对11个试件(包括1个原木试件、3个纯胶合木试件以及7个钢板增强速生杨胶合木试件)进行了抗弯性能试验。通过研究试件的破坏形态、荷载-位移曲线以及截面应变变化,得到了各试件抗弯承载力、初始刚度、弹性模量和延性等的变化规律。研究结果表明:原木和纯胶合木试件表现为脆性破坏,而钢板增强速生杨胶合木试件延性大,最终表现为塑性破坏;钢板增强速生杨胶合木试件的初始刚度和弹性模量分别提高了69.08%~72.83%和10.85%~69.57%;随着截面尺寸的增大,钢板增强速生杨胶合木试件的极限承载力提高了5.76%~32.35%;随着跨高比的减小,钢板增强速生杨胶合木试件的极限承载力提高了23.97%~30.13%;随着配钢率的增加,钢板增强速生杨胶合木试件的极限承载力分别提高了34.08%、66.63%和56.51%。钢板增强速生杨胶合木试件的极限承载力随着钢板厚度的增加先增大后减小。提出了钢板增强速生杨胶合木梁的抗弯承载力计算公式,并与试验结果进行了对比,结果吻合性较好。

In order to expand the application field of fast-growing poplar,considering the effects of section size,span height ratio and steel ratio,eleven specimens(including one log specimen,three pure glulam specimens and seven steel plate reinforced fast-growing poplar glulam specimens)were tested.The failure mode,load-displacement curve and section strain of the specimens were studied,and the variation laws of flexural capacity,initial stiffness,elastic modulus and ductility of each specimen were obtained.The results show that the specimens of log and pure glulam show brittle failure,while the specimens reinforced by steel plate have large ductility and finally show plastic failure.After the steel plate is reinforced,the initial stiffness of the specimen is increased by 69.08%~72.83%,and the elastic modulus is increased by 10.85%~69.57%.With the increase of section size,the ultimate bearing capacity of steel plate reinforced fast-growing poplar glulam specimens increases by 5.76%~32.35%.With the decrease of span height ratio,the ultimate bearing capacity of steel plate reinforced fast-growing poplar glulam specimens increases by 23.97%~30.13%.With the increase of steel ratio,the ultimate bearing capacity of steel plate reinforced fast-growing poplar glulam specimens increase by 34.08%,66.63%and 56.51%respectively.It can be seen that the ultimate bearing capacity of steel plate reinforced fastgrowing poplar glulam specimens first increased and then decreased with the increase of steel plate thickness under the same section.In addition,the calculation formula of flexural capacity of steel plate reinforced fast-growing poplar glulam beam was proposed and compared with the experimental results.The theoretical calculation results are in good agreement with the experimental results.