魏洋, 纪雪微, 周梦倩, 赵龙龙, 端茂军. 销栓型竹-混凝土组合结构的力学性能[J]. 农业工程学报, 2017, 33(3): 65-72. DOI: 10.11975/j.issn.1002-6819.2017.03.009
    引用本文: 魏洋, 纪雪微, 周梦倩, 赵龙龙, 端茂军. 销栓型竹-混凝土组合结构的力学性能[J]. 农业工程学报, 2017, 33(3): 65-72. DOI: 10.11975/j.issn.1002-6819.2017.03.009
    Wei Yang, Ji Xuewei, Zhou Mengqian, Zhao Longlong, Duan Maojun. Mechanical properties of bamboo-concrete composite structures with dowel-type connections[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(3): 65-72. DOI: 10.11975/j.issn.1002-6819.2017.03.009
    Citation: Wei Yang, Ji Xuewei, Zhou Mengqian, Zhao Longlong, Duan Maojun. Mechanical properties of bamboo-concrete composite structures with dowel-type connections[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(3): 65-72. DOI: 10.11975/j.issn.1002-6819.2017.03.009

    销栓型竹-混凝土组合结构的力学性能

    Mechanical properties of bamboo-concrete composite structures with dowel-type connections

    • 摘要: 为了研究销栓型竹-混凝土组合结构的组合效应,进行了竹-混凝土剪力连接件与竹-混凝土组合梁的力学性能试验与理论分析。研究结果表明:销栓型剪力连接件承受荷载时表现出较大的滑移变形能力,属于延性破坏,对于3个具有相同参数的销栓型竹-混凝土剪力连接件,其荷载-滑移曲线变化趋势具有较好的一致性,荷载-滑移曲线表现为弹性、弹塑性、完全塑性3个阶段;竹-混凝土组合梁的破坏模式表现为竹梁底部的竹纤维断裂,在加载后期,截面的界面上、下存在应变差,表现出部分组合界面滑移的特征,组合梁相对于对比竹梁,其极限荷载提高了89%,对应跨中位移为跨度1/250时的荷载提高了274%,归因于竹材和混凝土共同工作形成了组合截面,其承载力和截面刚度大幅度提高。基于试验结果,提出了销栓型剪力连接件荷载-滑移曲线模型,能够描述荷载-滑移曲线3个阶段的明显特征,可用于该类型竹-混凝土组合梁受力全过程的精细化数值分析,考虑剪力连接件的剪切滑移刚度,建议采用等效截面刚度法预测竹-混凝土组合梁的位移。结果表明,将等效截面刚度折减0.8的系数,荷载-位移曲线计算结果与试验结果吻合较好,研究成果为新型竹-混凝土组合结构的设计与应用提供参考。

       

      Abstract: Abstract: Bamboo is a novel engineering structural material, and it can be effectively applied in some specific structures of low-rise, multi-storey buildings and landscape bridges. Bamboo structures have a lot of advantages such as environmental protection, ecology, low caron, and so on. Existing studies have shown that the ordinary bamboo structures have insufficient load bearing capacity, low section stiffness and limited spanning capability as flexural members. In this paper, concrete and bamboo materials were composited to form a novel bamboo-concrete composite structure, in which the bamboo and the concrete materials were located in the lower and upper cross-section respectively, and the 2 types of materials worked together, connected by the dowel type connections. To investigate the mechanical properties of bamboo-concrete composite structures with dowel type connections, the mechanical test and theoretical analysis of bamboo-concrete composite connections and beams were carried out. Three dowel-type shear connections with identical parameters were designed and prepared for the push-out shear test. The test results showed that the dowel-type shear connections exhibited an excellent slip deformation capacity under the loading and the failure mode was the ductile failure. The load-slip curves of 3 connection specimens were quite homogeneous and consisted with 3 stages of elasticity, elasticity-plasticity and full plasticity. Based on the test results, the load-slip models that could describe the obvious features in the 3 stages of the load-slip curves were provided for the dowel-type shear connections, which could be used in the fine numerical analysis of the load-displacement curve for the dowel-type bamboo-concrete composite structures. One dowel-type bamboo-concrete composite beam and one bamboo beam were investigated by four-point bending test. The failure mode of bamboo-concrete composite beam was the bamboo fiber fracture on the bottom of the beam and no concrete crushing was found in the upper compression zone. At the later loading stage, there was a strain jump in the interface of 2 kinds of materials, and the interface slip increased from the mid-span to the both ends of the beam. The phenomena showed the characteristics of partial composite structures. Ultimate load enhanced by 89% and the load corresponding to the limiting value of deflections for beams prescribed in Chinese timber structures code of the bamboo-concrete composite beam increased by 274% compared to values for the bamboo control beam, respectively. Due to the composite effect generated by the 2 kinds of materials, the load-carrying capacity and the section stiffness of the bamboo-concrete composite beam were greatly improved. According to the test results, the equivalent stiffness method was suggested, in which slip stiffness of shear connections was considered to predict the displacement of the bamboo-concrete composite beam, and when the reduction factor of 0.8 was used for the equivalent sectional stiffness, the predicted load-displacement curves were in good agreement with the experimental curves. This study demonstrates that the bamboo-concrete composite structures have excellent flexural performance, and can be used for the flexural members in some potential landscape bridge or building structures.

       

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