地震作用下钢筋混凝土墩柱损伤指数计算方法

Calculated Method of Damage Index for Reinforced Concrete Pier Under Earthquake Action

为研究钢筋混凝土墩柱损伤模型对实际损伤状态预测的有效性,利用72个钢筋混凝土墩柱的低周反复试验结果对6个有代表性的损伤模型进行了计算分析,利用定性和定量相结合的方法探究了基于损伤状态的经验性损伤程度辨识方法对损伤程度判别的影响。考虑钢筋混凝土墩柱的最大变形和累积耗能,提出了双参数损伤模型,并给出了理想破坏模式下模型参数的确定方法。基于统计分析方法,确定了钢筋混凝土墩柱的特征损伤状态和损伤程度区间。结果表明:在加载中前期,所提出的双参数损伤模型的损伤指数增长趋势与Park-Ang损伤模型基本一致;在加载后期,损伤指数快速增长,具有一定的合理性,对特征损伤状态的区分度相对较高;各损伤模型在钢筋混凝土墩柱的混凝土保护层轻微压碎、混凝土显著剥落、纵筋屈曲3种损伤状态下变异系数均较大,在极限状态下损伤指数变异系数有所下降,各损伤模型对特征损伤状态的辨识度各具优势;微小损伤状态与中等损伤的判断还需要一定的经验累积。

In order to study the validity of exiting damage models for evaluating the damaged states of reinforced concrete(RC)piers,six representative damage models were calculated and analyzed by using 72 reinforced concrete piers with low frequency cyclic loading test.The influence of empirical damage degree identification method based on damage state on damage degree discrimination was explored by combining qualitative and quantitative methods.Considering the maximum deformation and cumulative energy dissipation of reinforced concrete piers,a two-parameter damage model was proposed,and the determined method of model parameters under ideal failure mode was given.Based on the statistical analysis method,the characteristic damage state and damage degree interval of reinforced concrete piers were determined.The results show that the damage index growth trend of the proposed two-parameterdamage model is basically consistent with Park-Ang damage model in the early and middle stages of loading;the damage index increases rapidly in the late stage of loading,which has a certain rationality,and the distinction degree of characteristic damage state is relatively high.The variation coefficients of damage models with the damage states of concrete cover slight crushing,concrete significant peeling and longitudinal bar buckling of RC piers,are all large.However,the variation coefficients of damage index under the limit state of RC piers are small comparatively.Each damage model has its own advantages in determining the damage state.Each damage model has its own advantages in identifying the characteristic damage state,and the judgment of minor damage state and moderate damage also needs some experience accumulation.