应用碳纤维筋控制桥墩地震损伤方法初探

Elementary study on usefulness of carbon fiber for controlling bridge pier seismic damage

为了减轻地震损伤和提高桥梁损伤以后的恢复能力,提出了在塑性铰区域配置部分碳纤维筋的桥墩抗震设计概念.用碳纤维筋替换部分纵向钢筋,利用碳纤维弹性模量与钢材相近而且强度高的材料特性来改善桥墩在强地震作用下损伤以后的变形性能.以一实际桥墩为例,用截面分层法计算碳纤维含量对截面弯曲性能的影响,确认了配置少量碳纤维可以提高纵向钢筋屈服以后的二次刚度结构特性.应用非线性地震响应分析方法,以不同强度和不同形式的地震波作为输入条件,根据桥墩的残余变形、最大曲率响应和能量吸收量等方面的比较结果验证了碳纤维筋对减轻地震损伤的作用.分析结果表明,如将普通纵筋的5%改配为碳纤维筋,在强地震荷载作用下桥墩残余位移以及最大曲率响应均小于普通钢筋混凝土桥墩.

A new design concept of arranging partial carbon fiber bars in the plastic hinge region of piers was presented to reduce seismic damage, improve restoration capacity and reduced deformation of bridges during strong earthquake movement. A practical pier was used and the influence of carbon fiber content on the sectional flexural property was analyzed using fiber method. The results showed that the post yield stiffness of the pier can be increased by arranging partial carbon fiber bars in the plastic hinge region. The elasto-plastic seismic responses of the pier were analyzed in the aspect of residual deformation, maximum curvature and energy absorbability under different earthquake movement. The results showed that if 5 % steel bars are substituted by carbon fiber bars, the residual deformation and maximum curvature decrease compared with the reinforced concrete pier.