三跨连续钢-混凝土组合箱梁桥力学特性分析

Analysis of Mechanical Characteristics of Three Span Continuous Steel-concrete Composite Box Girder Bridge

钢-混凝土组合结构桥具有自重轻、刚度大、延性高以及较好的结构整体性和稳定性等优点,已经广泛地应用于我国的桥梁工程中,但对于成桥后桥梁力学特性的研究较少。因此,依托福州前横路升级改造项目三跨连续钢-混凝土组合箱梁桥梁工程,通过荷载试验收集分析应变、挠度和桥梁模态数据。结果表明:荷载作用下各测点应变和挠度均小于理论值,沿横向分布与理论值趋势基本相同,实测腹板中性轴与理论中性轴基本一致,表明桥梁刚度较高、整体性较好;偏载作用下横向增大系数在1.107~1.254之间,桥梁抗扭刚度较大,不易发生倾覆;桥梁在环境激振作用下第1阶模态自振频率为3.430 Hz,大于理论值2.590 Hz,与理论模型相比具有更高的刚度。

Steel-concrete composite structure bridge has the advantages of light weight,high stiffness,high ductility and good structural integrity and stability.It has been widely used in bridge engineering in China,but there is little research on the mechanical characteristics of the bridge after completion.Therefore,based on a municipal three span continuous steel-concrete composite box girder bridge project in Fuzhou Qianheng Road,the strain,deflection and bridge modal data are collected and analyzed through load test.The results show that the strain and deflection of each measuring point under load are less than the theoretical value,the transverse distribution trend is basically the same as the theoretical value,and the measured web neutral axis is basically the same as the theoretical neutral axis,indicating that the bridge has high stiffness and good integrity;Under the action of eccentric load,the transverse increase coefficient is between 1.107 and 1.254,the torsional stiffness of the bridge is large,and it is not easy to overturn;The first order mode self-vbration frequency of the bridge under environmental excitation is 3.430 Hz,which is greater than the theoretical value of 2.590 Hz.Compared with the theoretical model,it has higher stiffness.