复合材料网格箍筋在构件中受力性能的研究

MECHANICAL BEHAVIOR OF FRP GRIDS AS TRANSVERSE REINFORCEMENT IN CONCRETE MEMBER

复合材料(简称“复材”)网格箍筋具有耐腐蚀强度高的特点,但其为弹脆性材料,无屈服点,仅通过传统拉伸试验不能全面反映复合材料网格箍筋在混凝土结构件中的发挥效率。本文设计了角部破坏试验与直线段破坏试验,并进行测试,研究了复材网格箍筋破坏模式和受力性能。其中角部破坏试验可以获得复材网格箍筋在混凝土构件中对应的破坏模式(节点破坏和杆件破坏),可判断出节点强度是否能保证杆件性能充分发挥。直线段破坏试验可定量测得节点破坏时杆件的发挥效率。基于试验结果,本文提出了一个强度简化计算模型,并对轴压荷载下混凝土方柱中的复材网格箍筋的发挥效率进行了预测,预测结果与试验结果吻合较好。

Fibre-reinforced polymer (FRP) grids have the advantages of high-strength and anti-corrosion, and could be applied in concrete members as transverse reinforcements. Due to its linear elastic character and brittle failure modes, conventional material test methods are not able to capture the status and the failure modes of the grids in concrete structural members. In this work, two novel test methods, namely diagonal burst test and straight-line burst test, are proposed, with which failure modes and mechanical behaviour of FRP grids are obtained experimentally. Through the diagonal burst test, two typical failure modes, i.e. joint failure and rod failure,could be achieved. The strength of the joint can be tested to ensure the efficiency of grid rods in structural members. The straight-line burst test can obtain the strength efficiency when the grids fail in joint failure mode. According to the test results, a simplified strength model for FRP grids is proposed. The strength efficiency of FRP grids in square concrete columns subjected to axial compression is predicted with the proposed model. The predictions show good agreement with the test results.