预应力混凝土连续箱梁单梁模型与梁格模型有限元对比分析与研究

Finite Element Comparison, Analysis and Research on Single-beam Model and Beam-grillage Model of Prestressed Concrete Continuous Box Girder

摘要:

以某预应力混凝土变截面连续箱梁为研究对象，采用MIDAS Civil对其分别进行单梁模型和梁格模型的内力计算，通过两种模型的计算结果与静载试验实测结果的对比分析，探究基于两种模型计算变截面连续箱梁受力状态和结构变形的可靠性和合理性。研究结果表明：在恒载和设计荷载作用下，对于预应力混凝土连续箱梁，在采用单梁模型和梁格模型进行计算分析时，两种模型的计算结果基本相同；在偏载作用下，通过静载试验计算结果分析，梁格模型内力计算结果比单梁模型内力计算结果均偏小，并且两种模型误差超过了5%，对结果影响评价的准确度不容忽略；梁格模型能够准确地计算连续箱梁在横桥向的应力分布、应力大小和结构变形，相较于单梁模型，梁格模型更能反映结构的空间受力特性，表明采用梁格法计算分析变截面连续箱梁桥更符合工程要求。

Abstract:

Taking a prestressed concrete continuous box girder with variable cross-section as the research object, MIDAS Civil is used to calculate the internal force of the single-beam model and the beam-grillage model respectively. The calculation results and the static load measured results of the two models are compared and analyzed to explore the reliability and rationality of the force state and the structural deformation of the continuous box girder with variable cross-section calculated according to the two models. The research results show that under the action of constant load and design load, for the prestressed concrete continuous box girder, the calculation results of the two models are basically the same when the single-beam model and the beam-grillage model are used for the calculation and analysis. Under the action of bias load, through the analysis of the calculation results of the static loading test, the internal force calculation results of the beam-grillage model are smaller than those of the single-beam model, and the error of the two models exceeds 5%. The accuracy of the impact evaluation on the results cannot be ignored. The beam-grillage model can accurately calculate the stress distribution, stress magnitude and structural deformation of the continuous box girder in the transverse direction, and the beam-grillage model can reflect the spatial force characteristics of the structure better than the single-beam model, which indicates that the variable cross-section continuous box girder bridge calculated and analyzed by using the beam-grillage method is more suitable for the engineering requirements.