受火后钢筋混凝土吊车梁加固方法的试验研究

为研究受火后钢筋混凝土吊车梁的维修加固方法，开展了粘贴CFRP布和粘贴钢板加固受火后足尺吊车梁受力性能的试验研究、理论分析和有限元分析。结果表明：未受火对比试件发生受拉区钢筋屈服、受压区混凝土压碎破坏；粘贴CFRP布加固试件的主要破坏模式为受拉区钢筋屈服和CFRP布拉断；粘贴钢板加固试件的主要破坏模式为受拉区钢筋和加固钢板受拉屈服以及受压区混凝土压碎。对于ISO 834等效受火60min后钢筋混凝土吊车梁，粘贴钢板加固效果优于粘贴CFRP布；ISO 834等效受火60min和90min后的钢筋混凝土吊车梁采用CFRP布加固后，极限荷载接近。加固后钢筋混凝土吊车梁试件跨中截面混凝土应变发展规律在混凝土腹板垂直裂缝完全发展前基本符合平截面假定。受火后加固试件的位移延性系数较未加固对比试件有所降低，粘贴钢板加固试件降低稍大。加固的受火后钢筋混凝土吊车梁极限荷载计算结果和有限元结果与试验结果误差绝对值为0.4%~7.8%，满足工程精度要求。

Experimental study on seismic performance of SRC frame after exposure to fire

Steel reinforced concrete (SCR) structures are used in high-rise buildings and skyscrapers widely, thus their mechanical properties after exposure to fire have attracted much attention. Based on low-cycle reversed loading tests of one steel reinforced concrete (SRC) frame after being exposure to fire and the other SRC frame without exposed to fire for comparison, the influence of fire on the seismic performance of SRC frame was studied. The hysteresis behavior, ductility, energy dissipation, load bearing capacity and stiffness degeneration were obtained from the tests, and the accumulative damage process and P-Δ effect of the two SRC frames under ambient temperature and after being exposure to fire were analyzed respectively. The test results show that the fire damaged SRC frame has lower bearing capacity, smaller stiffness, lower ductility, increased accumulative damage and more obvious P-Δ effect compared with undamaged SRC frame. Owing to the existence of the core steel in the section of the column and beam, the hysteresis loops of the fire-damaged SRC frame still keep plump, and a relatively large load bearing capacity is maintained before failure. Moreover, the fire-damaged SRC frame also has good energy dissipation capacity and resistance against cyclic load, and the plastic limit rotation exceeds 0.03rad, which still meets the requirement of GB 50011—2010 ‘Code for seismic design building’.