Study On The Impact Factor Test Of Long-span Continuous Curved Rigid Frame Bridge With High Piers

Although curved continuous rigid frame bridge with high piers and long span is seldomadopted in foreign countries，for its unique structure,it has been gradually applied in westernregion mountainous zone of China. And its design theory have obtained many research results,but the results of vibration impact factor of curved continuous rigid frame bridge with highpiers are rare, what’s more some recently proposed impact theory has not been confirmed.Therefore,to carry out the study on the impact factor of curved continuous rigid frame bridgewith high piers by using actual bridge test not only has a considerable theoreticalsignificance but also has practical value in engineering.As a part of the National Natural Science Foundation of China “impact factor ofcontinuous rigid frame bridge with high pier and long-span under random vehicle”(No.51008028),taking two high-pier and long-span continuous rigid frame bridges as the projectbackground,this paper carries out the study on actual bridge test and improves the impactfactor expression,and the research on dynamic effect of this kind of bridge under randomvehicle load is carried out.With a bridge in Yunnan province as a model,the fundamentalfrequency computational formula of curved continuous rigid frame bridge with different tiebeams high piers and long span is deduced,and verified by the actual bridge Xunhe and LuoheBridge;Based on the actual bridge vibration signal of Xunhe Bridge,the fundamentalfrequency computational formula of curved continuous rigid frame bridge with nolongitudinal beam high piers and long span is verified;A typical time history curve of Xunhebridge measured signal is analysed under different filtering range.Finally,by using theprinciple of regression statistics, the impact factor of these bridges based on weightedcorrection method and the traditional test method has carried on the statistical analysis,and theimpact factor expression obtained amendment.The results show that the influence tie beam ofcurved continuous rigid frame bridge’s pier on the fundamental frequency of structure can notbe ignored,the improved fundamental frequency computational formula of curved continuousrigid frame bridge with high piers and long span has a lager applicable range and highprecision;For the special structure,it is not necessary to make a low-pass filtering to the measured dynamic load vibration data before calculating the impact factor of curvedcontinuous rigid frame bridge with high piers and long span,and the precision could meet theengineering requirements already.And making1Hz as the low-pass cut-off frequency to solvethe approximate static strain time history curve is appropriate.The fundamental frequency computational formula and the impact factor expression ofcurved continuous rigid frame bridge with high piers and long span this paper proposed wouldperfecte the design theory of bridge structure, provide reliable basis and reference for thedynamic evaluation method of long-span continuous curved rigid frame bridge with high pier,and can promote the application and development of this kind of bridge inthe westmountainous area of China.