50 m跨径简支梁桥动静力性能研究

Research on dynamic and static performance of 50 m-span simply supported girder bridge

以某50 m跨径简支梁桥为例,建立Midas Civil有限元模型,研究分析了大跨径简支桥梁的动力、静力力学性能,得出结论:50 m跨径简支梁桥结构基频为2.33 Hz,随着阶次的提升,桥梁频率由2.331 Hz提升到19.681 Hz,桥梁周期由0.429 s降低至0.051 s;桥梁前三阶次结构振型模态均为竖向弯曲,未出现横向扭转模态,说明桥梁的横向抗扭转刚度较强,竖向抗弯刚度弱于横向扭转刚度;预制阶段边梁翼缘应力最大值为-15.7 MPa,成桥阶段边梁翼缘最大应力值为-10.7 MPa,预制阶段中梁翼缘最大应力值为-14.6 MPa,成桥阶段中梁翼缘最大应力值为-8.6 MPa,各阶段边梁、中梁混凝土应力均在限值内。

This paper takes a 50 m-span simply supported beam bridge as an example,establishes a Midas Civil finite element model,and studies and analyzes the dynamics and statics of long-span simply supported bridges.Based on the mechanical properties,the following research conclusions are drawn that the fundamental frequency of the 50 m-span simply supported beam bridge structure is 2.33 Hz.As the order increases,the bridge frequency increases from 2.331 Hz to 19.681 Hz,and the bridge period decreases from 0.429 s to 0.051 s.The first three-order structural modes of the bridge are all vertical bending,and no transverse torsion mode appears.This shows that the bridge has a strong transverse torsional rigidity,and the vertical bending rigidity is weaker than the transverse torsional rigidity.The maximum stress value is-15.7 MPa,the maximum stress value of the flange of the side beam in the bridge stage is-10.7 MPa,the maximum stress value of the flange of the beam in the precast stage is-14.6 MPa,and the maximum stress value of the flange of the beam in the bridge stage is-8.6 MPa.The stress of the concrete of the middle beam is within the limit.