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为了改善小跨高比连梁的抗震性能,采用纤维增强混凝土(FRC)替代连梁中的普通混凝土,考虑跨高比、箍筋间距和FRC强度等因素的影响,设计了7个小跨高比FRC连梁试件和1个普通混凝土连梁对比试件。通过拟静力试验,观察连梁试件在低周反复荷载作用下的破坏过程和形态,研究其滞回特性、变形能力、耗能能力及刚度退化等。结果表明:8个小跨高比连梁试件发生了剪切破坏或弯曲剪切破坏;跨高比和配筋相同的FRC连梁的受剪承载力和位移延性系数比普通混凝土连梁分别提高了9.71%和24.31%,达到破坏荷载时的累积耗能是普通混凝土连梁的1.5倍,采用FRC可提高连梁的承载能力、延性和耗能能力;随着跨高比增大和箍筋数量的增加,连梁的变形和耗能能力提高。基于试验结果和受剪机制分析,提出了小跨高比连梁的受剪承载力计算式,其计算值与试验值吻合较好。
In order to improve the seismic performance of the beam with small span ratio, we adopted the fiber reinforced concrete (FRC) instead of the ordinary concrete in the continuous girder. Considering the influence of span ratio, spacing of stirrups and FRC strength, seven small span height Compared with FRC beam specimens and an ordinary concrete beam comparison specimens. Through the quasi-static test, the failure process and the shape of the continuous beam specimens under low cyclic loading were observed, and the hysteresis characteristics, deformation capacity, energy dissipation capacity and stiffness degradation were studied. The results show that shear failure or bending shear failure occurs in eight specimens with small span ratio beams. The shear capacity and displacement ductility of FRC beams with the same span ratio and reinforcement are respectively smaller than those of ordinary concrete beams Increased by 9.71% and 24.31%, respectively, and the accumulated energy consumption at breaking load reached 1.5 times that of ordinary concrete. The FRC can increase the bearing capacity, ductility and energy dissipation capacity of the girder. As the span ratio increases and the stirrup Increasing the number of beams with deformation and energy consumption increased. Based on the test results and the analysis of the shear mechanism, the formulas for calculating the shear capacity of the beam with small span ratio are proposed. The calculated values are in good agreement with the experimental values.