基于剩余寿命等效的钢筋混凝土构件地震损伤模型

Seismic damage model for reinforced concrete members based on equivalent remaining life

基于剩余寿命等效的概念,提出了钢筋混凝土构件地震损伤改进模型。其基本思想是认为以某损伤参数(如刚度、位移延性、能量等)建构的损伤指数与疲劳损伤指数(如纵筋累积疲劳损伤),在损伤指数D=1.0条件下都可以表示构件失效。这样在某时刻以不同损伤指数表达的构件剩余寿命(1.0-Di)与损伤指数增量ΔDi之比,都等于使构件完全失效时对应的继续循环加载周数。利用这种等效关系定义了新的损伤指数,可以在构件的反应参量和破坏机理之间建立起联系。作为实际应用给出了一种基于截面刚度退化的低周反复荷载作用下钢筋混凝土桥墩损伤模型。

A new seismic damage model for reinforced concrete members based on the concept of remaining life equivalence is developed. It is assumed that a damage index expressed as a function of the damage parameter can be related to the fatiguebased damage index when they are equal to 1.0, both mean the member has been completely destroyed. This would cause the ratio of the member's remaining life defined as (1.0-Di) by each damage index Di to damage index increment ΔDi to be constant and equal to the remain number of cycles to failure after any cycle of loading. Therefore the damage index can be computed by introducing above equivalent relationship. Because possible choices for the damage parameters including stiffness, displacement ductility, energy dissipation capacity and damage in longitudinal reinforcement can be modeled by using lowcycle fatigue theories, the proposed damage model takes into account members′ response quantities and seismic damage mechanism. A damage model based on stiffness degradation for RC bridge piers under cyclic loading is presented as an example.