FRP格栅增强ECC加固钢管混凝土柱设计理论研究

为实现快速修复加固钢管混凝土，将轻质高强的纤维增强聚合物（FRP）格栅与高延性水泥基复合材料（ECC）结合，提出FRP格栅增强ECC加固钢管混凝土柱技术，克服外粘FRP加固技术的界面粘结耐久性差等缺点，达到提升钢管混凝土柱受力性能、耐久性能和抗火性能的多重效果。研究湿喷ECC配合比和工作性能，分析硬化后ECC的宏观力学性能和细观结构，获得满足工作性能和力学性能要求的湿喷ECC；开展FRP格栅增强ECC复合材料力学性能研究，建立相应的抗拉本构关系模型；在此基础上，开展FRP格栅增强ECC加固钢管混凝土柱轴压和偏压性能试验，研究FRP格栅类型和厚度、ECC厚度、长细比等因素对加固柱力学性能的影响，提出加固柱受压承载力设计方法；通过FRP格栅增强ECC加固钢管混凝土柱低周反复加载试验，研究不同轴压比下，上述因素对加固柱滞回特性的影响，提出加固柱抗震设计方法。

To achieve the objection of quickly repairing and strengthening for concrete filled steel tube (CFST), a new strengthened technique is developed using FRP grid reinforced engineering cementitious composite (ECC) as composite strengthened layer to improve the mechanical behavior, durability and fire-resistance of CFST columns, to overcome disadvantages of externally bonded FRP technique such as performance of fire-resistance and poor durability. The research plan focus on mechanical behavior of CFST columns strengthened with FRP grid reinforced ECC. The optimal mixture proportions of wet spraying ECC are determined by analyzing the microstructure and mechanical properties. And then FRP grid reinforced wet spraying ECC is conducted under uniaxial tensile loading and four point bending loading tests. Based on the experimental results and the Richard-Abbot analytical model, a stress-strain model of FRP grid reinforced ECC is established. A series of tests are conducted on CFST columns strengthened with FRP grid reinforced ECC under axial and eccentrical loads to study the effect of type and thickness of FRP grid, thickness of ECC and slenderness ration on mechanical properties of strengthened CFST columns. The experimental study, theoretical analysis and numerical simulation are combined to propose a design method of CFST columns strengthened with FRP grid reinforced ECC under axial and eccentrical loads. Based on the low period cyclic load tests of CFST columns strengthened with FRP grid reinforced ECC, the effect of type and thickness of FRP grid, thickness of ECC and slenderness ratio on hysteresis behavior and energy absorption capacity under the different axial-load level are study. A seismic design method of CFST columns strengthened with FRP grid reinforced ECC is proposed.