基于纤维单元的钢筋混凝土桥墩地震损伤评价

基于纤维模型的粱柱单元特别是柔度法单元有着较高的计算精度，已被较多地用于评价钢筋混凝土桥墩的位移（廷性）能力。随着基于性能／位移抗震设计理论的发展，相继提出了残余位移、极限曲率及曲率延性系数、纵筋和混凝土的最大应变、纵筋低周疲劳损伤等桥墩地震损伤量化指标。选用刚度法和柔度法纤维单元，考虑材料非线性、几何非线性和结点锚固...

Seismic damage evaluation of RC bridge columns based on fiber elements

For the advantage of high computational accuracy, fiber beam-column elements are widely used in evaluation of displacement ductility capacity of RC bridge columns. With the development of bridge performance/displacement based seismic design, several damage indices have been suggested, such as ultimate curvature and curvature ductility factor of critical section, maximum strain of confined concrete and reinforced steels, low cycle fatigue damage indices of longitudinal reinforcement etc. To study the accuracy degree of damage indices calculated with fiber elements and the main influencing factors, stiffness-based and flexibility-based fiber elements are chosen to compute aforesaid damage indices compared with test data of RC bridge columns, with consideration of material non-linearity, geometrical non-linearity and bond-slip of anchoring steel. The study results show that the damage indices caculated by flexibility-based element are greater than those by stiffness-based element. Force-displacement curves and residual deformation calculated by both elements match the experiment with adequate accuracy. Section curvatures and tensile strain of longitudinal steel by stiffness element are colser to experimental data than those by flexibility element, but both elements underestimate section curvatures if loading displacement amplitude or shear span ratio is large. Both element overestimate tensile strain of longitudinal steel and underestimate compressive strain of concrete.