Study On Secondary Load Spectrum Of Bridge In Plateau Mountainous Area

With the rapid economic development of Yunnan Province,its transportation industry has also achieved rapid development.Due to the abundant mineral resources in Yunnan Province,and the proportion of heavy-load traffic is also higher than other regions,however there are few studies on the fatigue load spectrum of highway bridges in Yunnan Province,especially for the study of the fatigue load spectrum of secondary highway bridges.This paper relies on the National Natural Science Fund — a regional fund project " Study on fatigue load spectrum of highway bridge in plateau mountain area"(51568029),and studies the fatigue load spectrum of secondary highway bridges in plateau mountain area,the main works are as follows:(1)By investigating the vehicle information of representative secondary roads in Yunnan province,get all kinds of vehicle data,and classify the eight representative vehicle models obtained from the survey according to the number of axles of the vehicle,then analyze the vehicle data after the classification,specifically including: statistical analysis of vehicle weight distribution,statistical analysis of vehicle speed distribution and determine the statistical characteristics and distribution parameters of each type of vehicle.(2)Determine the frequency spectrum of fatigue vehicle load for secondary highway bridges in Yunnan Province and the standard fatigue vehicle model.(3)Combined with the above statistical analysis results,based on Monte Carlo method,with the help of computer development environment Visual Fortran 6.0 and Fortran language,work out the random traffic flow program to simulate the random traffic flow.Combined with the above random traffic flow,analyze the fatigue problem of concrete reinforcement.Use the finite element software to obtain the mid-span bending moment influence lines of five different span small box girders on the secondary road.Then,the random traffic flow is loaded to the influence line to analyze the fatigue response of the secondary road bridge in the plateau mountain area.(4)Based on the linear fatigue damage accumulation theory,analyze the applicability of the fatigue load spectrum obtained by this paper to the fatigue analysis of the secondary highway bridges in plateau mountainous area by calculating and comparing the fatigue damage degree of bridge under different fatigue load spectrum.