应力滞后效应对湿式外包钢加固小偏压钢筋混凝土构件极限承载能力影响的研究

Study on the influence of stress hysteresis on ultimate bearing capacity of small eccentric compression reinforced concrete members strengthened with wet-connected envelop iron

湿式外包钢加固钢筋混凝土构件是一种在实际工程中使用较为广泛的传统加固方法。以平截面假定为依据,从理论上推导后加角钢与原混凝土以及混凝土中钢筋的应力-应变关系,建立外包型钢加固小偏压柱的力-力矩平衡方程。对一些具体工况的小偏压柱进行加固前后的应力状态分析和承载力计算,并将计算结果与采用《混凝土结构加固设计规范》(GB 50367—2013)公式计算所得到的结果进行对比,结果表明规范公式在大多数情况下是安全的,但是对于加固前轴压比较大、偏心距较大的一些特殊情况安全富裕不够,建议在实际工程设计和规范修改时加以考虑。

The wet-connected envelop angle iron reinforced concrete member is a traditional reinforcement method and widely applied in various practical projects. Based on the plane-section assumption,the stress-strain relationship between the angle steel and the original concrete and the reinforcement in the concrete was deduced theoretically,and the forcemoment equilibrium equation of the small eccentric compression pillars which strengthened by angle iron was established.The stress state analysis and bearing capacity calculation before and after the reinforcement of some small biased columns in specific working conditions were conducted,and the calculation results were compared with the results obtained by using the calculation formula of Concrete structure reinforcement design specification( GB 50367—2013). The results show that the standard formula is safe in most cases,but it is not safe enough for some special cases where the front axle pressure is relatively large and the eccentricity is large. It is recommended that consideration be given to actual engineering design and specification modification.