铁路简支箱梁扭转变形性能分析

Analysis of Torsion Deformation Performance of Railway Simply Supported Box Girder

混凝土简支箱梁在工程上得到了广泛应用,畸变与扭转对薄壁箱梁产生不利的影响。为研究铁路简支箱梁在畸变与扭转作用下的变形特征,利用杆系单元与实体单元建模,分别对铁路简支箱梁的3种梁型在偏载荷载作用下进行数值求解,得到其单线ZK活载工况以及偏载试验工况下的扭转变形,与偏载试验所得到的数据进行对比。采用材料力学公式法、乌曼斯基第二理论解析法,分析杆系单元、实体单元在偏载荷载作用下所表现的扭转变形差异,得到最佳的三维建模方式。研究结果表明,利用杆系单元建模分析结果与实际相差较大,实体单元更接近于实际,约束扭转中翘曲正应力对跨中最大扭转角的影响很大,利用实体单元模拟偏载试验更为恰当。研究结果可为简支梁设计偏载试验时合理模拟运营过程中的单线列车荷载提供理论参考。

Concrete simply-supported box girders have been widely used in engineering.Distortion and torsion have adverse effects on thin-walled box girders.In order to study the deformation characteristics of simply-supported railway box girder under the action of distortion and torsion,the model is built using beam/link element and solid element.The behaviors of three types of simply-supported box girders are numerically solved under offset load.The torsional deformation of single line ZK under live load and offset load test is obtained,which is compared with the data obtained from offset load test.Using material mechanics formula method and Umanski’s second theoretical analysis method,the difference of torsional deformation in beam/link element and solid element models under partial load is analyzed,and the best 3D modeling method is obtained.The modeling result using beam/link element is different from the actual structural performance while the result using the solid element is close to the actual one.In constrained torsion,the warpage normal stress has a great effect on the maximum mid-span torsion angle.Thus,it is more appropriate to use solid element to simulate offset load test.The research results may provide theoretical guidance for reasonable simulation of single-line train load in operation process when designing offset load test of simply-supported beam.