Research On Typical Vehicle Load Limits Based On Reliability

With the rapid development of automobile transportation and social economy in China, the use of large single truck, semi-trailer, full-trailer and the other heavy duty vehicle types are increasing. Due to its total weight is generally higher than the design of the vehicle load standard value, the normal operation of the bridge constitutes a major security risk.The development of heavy vehicles reduces the durability of the bridge structure greatly, shorten the service life of the structure is the main reason of causing bridge maintenance costs rising and the damage of bridge increasing in recent years. In this paper, based on the simplified load analysis model of highway bridges proposed by the research group,choosing 6?30m medium and small span reinforced concrete beam bridge, according to the bearing capacity limit state equation to calculate the typical vehicle load limit value based on the theory of reliability. The following works will be carried out this thesis:1 .This paper analyzes the current situation of overloading in China,expounds the judging standards of overloading and discusses the present situation of the theory of vehicle load limit at home and abroad.2.Trough calculating the vehicle load effect of different design grade, comparing the internal forces of the medium and small span simple supported beam bridges in the United States and China, it lays the foundation for our country to draw lessons from other countries in the development of vehicle load standard.3.Taking the load effect of resistance and dead load of the bending member as independent random variables, taking the limit value of the standard value of the vehicle load as constant, an analytical model of the vehicle load limit factor is established.4.Based on the five typical vehicle models proposed by Zhang Xigang research group, the calculation of vehicle load limit is carried out.Select 6?30m different span simply supported reinforced concrete bridge,take reliability model of bridge load limit analysis as an application,calculating the typical vehicle load limit under safety class ? and class ?,to analysis the change law of limit load of simply supported beam with the span.