Analysis of Mechanical Characteristics of Three Span Continuous Steel-concrete Composite Box Girder Bridge
Steel-concrete composite structure bridge has the advantages of light weight,high stiffness,high ductility and good structur-al integrity and stability.It has been widely used in bridge engineering in China,but there is little research on the mechanical charac-teristics 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 distribu-tion trend is basically the same as the theoretical value,and the measured web neutral axis is basically the same as the theoretical neu-tral axis,indicating that the bridge has high stiffness and good integrity;Under the action of eccentric load,the transverse increase coef-ficient 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.
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