考虑钢筋锈蚀的复合受扭混凝土箱梁时变承载力研究

对考虑钢筋锈蚀的复合受扭钢筋混凝土箱梁时变承载力进行研究。针对复合受扭混凝土箱梁中混凝土开裂面与钢筋斜交的情况，推导了综合考虑钢筋混凝土粘结滑移效应及正交配筋效应的钢筋修正本构模型。引入钢筋和混凝土材料的时变劣化模型，结合复合受扭钢筋混凝土箱梁的修正板-桁架模型，编制了复合受扭钢筋混凝土箱梁时变承载力的计算程序。与纯扭锈蚀构件和复合受扭构件的试验对比，验证了所提出钢筋修正本构模型的适用性较好。算例结果表明：在假定的一般大气环境和受力条件下，考虑钢筋锈蚀的复合受扭钢筋混凝土箱梁构件100年后抗扭强度降低约15%。

STUDY ON TIME-DEPENDENT LOAD CARRYING CAPACITY OF CONCRETE BOX BEAMS SUBJECTED TO COMBINED TORSION CONSIDERING REINFORCEMENT CORROSION

Time-dependent load carrying capacity of reinforced concrete (RC) box beams subjected to combined torsion by considering reinforcement corrosion is investigated in this paper. A modified constitutional relationship for reinforcement is derived by considering that the crack surface is not perpendicular to steel bar, as well as the bond slip effect between steel bar and concrete. Introducing the time-dependent degradation models of reinforcement and concrete, combined with a modified plate-truss model, the calculation for studying the time-dependent carrying capacity of RC box beams subjected to combined torsion is carried out. The test results of pure and combined torsional RC members verify the applicability of the modified constitutional relationship. The numerical results show that the torsional strength of the calculated corroded RC box beam model will decrease by approximately 15% after 100 years under the assumed environment and loading conditions.