胶合竹-混凝土组合梁抗弯试验与分析

Experimental and Analytical Investigation of Bending Performance of Glubam-Concrete Composite Beams

选择销连接件(SC)、凹槽连接件(NC)和半装配式预紧力凹槽连接件(PNC)制作构件,开展了5根足尺胶合竹-混凝土组合(BCC)梁的抗弯试验,试验参数包括连接件类型和数量。试验结果表明,BCC梁的抗弯刚度和承载力随连接件数量增加而提高,且胶合竹梁指接头的受力性能对抗弯性能有显著影响;采用NC和PNC两类脆性连接件的组合梁,在荷载峰值后具有较为明显的承载力恢复现象,破坏前表现出一定的延性特征。对试验结果的分析表明,BCC梁具有较高的初始组合效应,且组合效应相对稳定,表现出良好的抗弯性能;采用PNC连接件的半预制装配式组合梁的抗弯性能与对应的现浇试件没有显著差别,具有良好的应用前景;欧洲规范EC5中的γ法高估了BCC梁的承载力,不适合直接预测BCC梁的抗弯承载力。

This paper describes the results of bending tests on glued laminated bamboo(glubam)and concrete composite(BCC)beams.Five large-scale BCC specimens,including three types of connection details,were designed and tested:screw connector(SC),notch connector(NC)and pre-tightening notched connector(PNC).Experimental variables include connection types and numbers of connectors.Test results show that the bending stiffness and bearing strength of BCC beams increase with number of connectors increasing,and actual quality of finger joints has significant effect on the mechanical performance of BCC beams.For NC and PNC series,a considerable strength recovery was observed after peak load.This is an important outcome as it ensures a moderate ductile behavior of the composite beam with brittle connectors.All BCC beams with different connectors exhibited satisfactory performance under short-term loading conditions.The semi-prefabricated composite beam with PNC showed the similar bending capacity compared with the corresponding casting insitu BCC specimen,indicating a good prospect in the prefabricated and assembled structures.Theγ-method,provided by Eurcode 5,overestimates the load carrying capacity of BCC beams and it is not suitable for BCC beams.