摘要
本文以三跨连续斜交小箱梁桥为例,应用有限元软件Midas civil分别建立了斜交角度为0~60°(步长为5°)的全桥模型。分析了不同斜交角度对桥梁结构固有振型和频率的影响,对现有桥梁规范中用于连续梁桥冲击系数计算的基频的计算公式给予修正。分析表明:三跨连续斜交小箱梁桥前两阶竖弯频率均随斜交角度的增大而增大,其中1阶竖弯频率所受影响最为显著,当斜交角度大于25°时,斜交角的影响不能忽略,其增大值最大可达31.6%;而第3阶竖弯频率受斜桥弯扭耦合效应的影响,随斜交角度的增大其频率变化不超过0.9%,在计算正、负弯矩处基频时应予以考虑。简支转连续与整体浇筑两种方法施工的结构动力特性区别不大,全桥模型中是否设置桥墩对结构频率影响不大。实桥动载试验验证了本文所提出的基频修正公式是合理的。
In this paper,whole bridge finite element model of a three-span continuous skew box girder bridge is established in Midas civil,with skew angle of 0~60°(step length of 5°).The influence of different skew angles on natural modes and frequencies of bridge structures is analyzed,and the formula of fundamental frequency in current bridge codes used in calculating impact coefficient of continuous beam bridges is modified.The analysis shows that,for three-span skew continuous box girder bridge,the vertical bending frequency increases with skew angle increase,in which the first-order vertical bending frequency is most affected,and the increase value can reach up to 31.6% when the skew angle is greater than 25°,the influence of skew angle can’t be neglected.But the third-order vertical bending frequency change does not exceed 0.9% with the increase of the skew angle,because of bending-torsional coupling effect of the skew bridge,which should be taken into account when calculation the fundamental frequency at positive and negative bending moments.There is little difference in structural dynamic characteristics between the two construction methods of simply supported to continuous and integral concreting.Whether the pier is installed in the whole bridge model has little effect on the structure frequency.The real bridge dynamic load test verifies that fundamental frequency correction formula proposed in this paper is reasonable.
作者
王荣霞
王雅静
曹宏琨
张宇明
WANG Rongxia;WANG Yajing;CAO Hongkun;ZHANG Yuming(School of Civil Engineering and Transportation,Hebei University of Technology,Tianjin 300401,China;Langfang Designing Institute of Traffic Investigation,Langfang 065000,China)
出处
《地震工程与工程振动》
CSCD
北大核心
2019年第3期122-133,共12页
Earthquake Engineering and Engineering Dynamics
基金
国家自然科学基金项目(51478074)
2016年廊坊市科技支撑计划项目(2016013073)
2017年廊坊市科技支撑计划项目(2017013003)~~
关键词
三跨连续斜交小箱梁桥
模态分析
竖弯频率
简支转连续
Midas梁格模型
three-span continuous skew small box girder bridge
modal analysis
vertical bending frequency
simply supported continuous
Midas beam lattice model
