周云+张军凯+陈松柏+易伟建

摘 要：由于有限元建模中存在不确定性因素的影响，大跨度拱桥初始设计模型的理论分析结果与现场测试数据之间存在一定差异.为了消除模型校验技术中的认知不确定性和随机不确定性，从而更好地进行结构识别，本文以来华大桥和巴溪洲大桥为例，对其中若干关键问题进行了讨论.通过合理地现场勘察与精确的有限元模拟相结合，基于灵敏度分析方法进行不确定性参数筛选，并最终采用最小二乘法进行参数优化，实现了可靠的结构工作状况评估与响应预测.研究包括现场静动力试验、有限元模拟、模型校验、响应预测和校验合理性评估等.基于精确建模和模态参数的校验技术可以有效地减小有限元模型与现场静动力试验结果之间的误差，使用未经试验结果校验的设计模型，进行两座桥梁校验系数的评估，分别存在着21%和23%的误差.

关键词：模型校验；大跨度拱桥；静动力试验；工作模态分析；结构识别

中图分类号：U446.1 文献标志码：A

文章编号：1674-2974（2017）05-0010-10

Abstract：Various uncertainties of the FE modeling may have significant impact on structural identification and result in obvious discrepancy between FE model analysis and field test results. In order to eliminate epistemic uncertainty and aleatory uncertainty during model calibration procedure， which contributes to achieve reliable condition assessment and response prediction， two long-span bridges were taken for examples， and several critical issues were discussed. By means of field inspection and blueprint review， simultaneously combined with the precise modeling， uncertain parameter selection was carried out based on sensitivity analysis， and parameter optimization was eventually performed by the least square method to complete the working condition assessment and response prediction. Research in this paper consists of in-situ experiments， precise finite element modeling， model calibration， and model admissibility check. Discrepancies between FE model and field test results can be mitigated by efficient model calibration method， and initial design model generally shows 20% and 23% relative difference.

Key words：model checking； long-span bridge； static and dynamic test； operational modal analysis； structural identification

在大跨度桥梁结构中，拱桥具有跨越能力大、自重轻、外形美观等优点[1].然而，由于拱桥是以推力为主的结构，其施工质量难以控制，且构件的性能变化难以观测[2].大跨度拱桥的构件参数存在一定的不确定性，对其进行状态评估的难度较大.通过结构识别技术确定其真实工作状况，对桥梁的使用、维护、评估以及决策支持具有重要意义.随着结构识别……