基于监测数据的装配式T梁桥服役状态可靠度的评估方法

Service Condition Assessment of Prefabricated T-shape Beam Bridges based on Structural Health Monitoring Data using Reliability Analysis

为准确把握装配式T梁桥的服役状态,提出基于监测数据的装配式T梁桥服役状态评估方法。首先,采用应变数据并基于平截面假定反算主梁开裂高度,基于纤维模型建立主梁开裂高度和主梁抗力之间的对应关系;然后,基于动态称重系统监测数据,采用Rice公式极值外推法,建立主梁车辆荷载效应概率分布模型;最后,基于可靠度理论,建立主梁抗力和效应之间的功能方程,计算主梁可靠指标,评估主梁服役性能。结果表明,基于主梁应变数据可以计算得到主梁开裂高度,这样避免了传统主梁状态评估中需要人工检测裂缝的缺点,提高了结构评估的时效性;纤维模型可以准确反映截面裂缝开展全过程,基于纤维模型可以建立主梁开裂高度和主梁抗力之间的对应关系;背景桥梁在当前开裂高度和荷载水平下,主梁可靠指标满足要求,说明服役状态良好。

To accurately obtain the service status of prefabricated T-shape beam bridges,a method based on structural health monitoring data is proposed.Firstly,based on the assumption of plane section assumption,the cracking height of the main beam is calculated using real strain data.The corresponding relationship between the crack height and the bearing capacity of the main beam is also established based on the calculating results of fiber model.Then,in accordance with the monitored vehicle data,aprobability distribution model for the traffic load effect is established using the extrapolation method.Finally,based on reliability theory,a functional function between the bearing capacity and the traffic load effect is established and the service performance of the main beam is evaluated based on the calculated reliability index.The results indicate that the crack height of the background bridge meets the requirements under the current crack height and load level.