以《公路桥梁技术状况评定标准》(JTG/T H21—2011)中的跨中挠度限度为损伤指标来进行主梁的易损性分析,提出了一种针对维修加固桥梁的抗震韧性评价方法。以一座在多年运营发生破坏后进行过主梁维修加固的五跨连续梁桥为例,采用有限元建模和模型修正的方法,利用增量动力分析,研究了维修加固前后桥梁的主梁构件在不同强度地震作用下易损性的变化; 利用经验统计方法探讨了既有桥梁弹性模量与跨中挠度的关系,提出了基于跨中挠度的功能损失函数; 结合案例桥梁具体维修加固工法,初步建立了恢复函数曲线,计算了维修加固前后桥梁的抗震韧性指标。分析结果表明:针对维修加固桥梁,利用跨中挠度作为损伤指标进行抗震韧性评估是可行的,从易损性曲线可以得到维修加固对于抗震性能的提升是较为明显的; 维修加固对于韧性提升是随着破坏等级的提升递减的,对轻微破坏较为明显,至结构失效时则差异较小。
This paper uses the mid-span deflection limit in the “Highway Bridge Technical Condition Assessment Standard(JTG / T H21-2011)” as the damage index to analyze the vulnerability of the main girder,and proposes an evaluation method for the seismic resilience of repaired bridges.Taking a five-span continuous girder bridge that has been repaired and strengthened as the main girder after years of operational damage,using finite element modeling and model modification methods,20 sets of seismic waves were selected using incremental dynamic analysis(IDA).Changes in the vulnerability of the bridge's main beam members before and after maintenance and reinforcement under earthquakes with different intensities; the relationship between the time-varying elastic modulus of the existing bridge and the mid-span deflection was explored using empirical statistical methods,and a functional loss based on mid-span deflection was proposed function; Combined with the case bridge specific repair and reinforcement construction method,a preliminary recovery function curve is proposed; on this basis,the seismic resilience index of the case bridge before and after repair reinforcement is calculated.The analysis results show that it is feasible to use the mid-span deflection as the damage index to evaluate the seismic resilience for the maintenance and strengthening of the bridge.From the vulnerability curve,it can be obtained that the maintenance and reinforcement is more obvious for the improvement of the seismic performance.Resilience decreases with the increase of the damage level,which is more obvious for minor damage and the difference in structural failure is small.
