HPFL加固受火RC梁抗剪性能研究

Study on RC beams'shear behavior strengthened with HPFL

对高性能复合砂浆钢筋混凝土加固受火RC梁的抗剪承载力进行理论推导,并结合实验数据和工程实例验证理论公式的合理性.结合国内外对火灾后钢筋混凝土结构中混凝土和钢筋强度变化的研究,考虑火灾和火灾后冷却条件对混凝土和钢筋强度及性能的影响,提出计算模型.假定钢筋和混凝土之间无相对滑移,忽略混凝土的抗拉强度,不考虑温度—应力的耦合作用,采用等效截面法得到等效截面为T形截面,以桁架-拱模型和软化桁架理论为基础,结合极限平衡原理,考虑拉应变存在条件下混凝土抗压强度的软化.分析结果表明,推导所得的计算公式与试验数据比较吻合,高性能复合砂浆钢筋网加固方法能使梁的抗剪承载力得到显著提高,能满足实际工程的应用.

Combined with an engineering example and experiment data, theoretical formula of the reinforced concrete （RC） beam＇s shear capacity with high-performance ferrocement laminate （HPFL） after fire was deduced and verified. Consider!ng the impacts on the strength of concrete and steel, the calculation model was put forward on the basis of domestic and international scholars＇ research on the changes of concrete＇s and steel＇s strength after fire. It was assumed that there was no relative slipping between steel and concrete and the tensile strength of concrete was ignored. Combined with the limit equilibrium principle, the softening of concrete compressive strength under the condition of the tensile strain was considered. Regardless of the coupling ac- tion of temperature-stress, the equivalent section method was adopted on the basis of truss-arch model. The results show that this method of reinforcement significantly improves the shear ca- pacity of the reinforced beam. The calculation results are in good agreement with the experimen- tal ones. The results can be referenced for beams strengthened with high-performance ferroce- ment.