基于空间网格模型的非对称连续梁病害分析

Analysis on Diseases of Asymmetric Continuous Girder Based on Spatial Grid Model

阐述了目前变截面连续梁桥开裂的现状及病害产生的原因以及计算分析现状,指出了设计中计算所采用单梁模型、平面梁格模型与实体模型的不足,从而引出实用精细化分析方法 -空间网格模型并详细介绍空间网格模型的原理。以病害桥梁为背景,描述检测结果并初步分析裂缝成因,以此为依据分析了超载、腹板温差等影响因素。从正应力和面内主拉应力的角度重点对比了腹板开裂位置与应力超限的范围,得出了温差不是引起腹板开裂的敏感因素,超载是引起腹板开裂的主要原因。进而表明,空间网格分析方法可为此类箱梁结构的分析提供有意义的指导。

The article sets forth the present situations and causes of cracks and diseases of the variable cross-section continuous girder bridge, and its calculation and analysis, points out the deficiencies of single-girder model, plane beam grillage model and solid model used for the calculation in the design so as to educe the practical fine analysis method-spatial grid model, and introduces the principle of the spatial grid model in detail. Taking the disease bridges as the background, the article describes the detection results and preliminarily analyzes the crack causes. On this basis, the article analyzes the influence factors of overload and web temperature difference. The article contrasts the cracking positions of web and the transfinite range of stress from the views of the normal stress and surface tension stress. The result shows that the temperature difference is not a sensitivity factor to cause the web cracking, and the overload is the main factor to cause the web cracking. The conclusion is that the spatial grid analysis method can provide the significant guidance for the analysis of such box girder structure.