Adaptility Study Of The Current Design For Vehicle Load Longitudinal Reduction Factors

In the design of highways and bridges, it is common to encounter problems like the layout of multiple lanes and increasing span of bridges. So it is necessary for us to consider the problem of multiple lanes’longitudinal reduction when we design highways and bridges based on reliable theory research, combined with newly tested vehicular load data and the standard vehicle load calculation formula of longitudinal reduction which gotten by analyzing the probability of radio between tested load effect and standard load effect, the paper proposed the suggested value of bridges’ longitudinal reduction factor that under China’s specific situation.From the1988, series reliability studys of highway engineering, after nearly20years of development, vehicle and traffic condition has been changed a lot, the load capacity of the vehicle, vehicle proportion, traffic flow characteristics such as on vehicle load model has important implications for the characteristic also have changed dramatically.In recent years, China’s road transportation management mode, transport operators’pursue for maximal profits and the great need of heavy-load transportation like coals, minerals have lead to the appearance of a large number of overload vehicles which heavily damaged some of the highways and bridges. The situation was so bad that China’s seven ministries jointly issued the provision for overload. Besides, China had invested tremendous manpower and material resources to change the situation. Though through five years hard working on overload vehicles, the phenomenon of overloading vehicles has lessoned a lot, however, there are still many reports about overload vehicles that damaged highways and bridges.In the process of bridges’operation, especially in bridges that the traffic flow is heavy and large-tonnage vehicles accounts for a large percent, the overload phenomenon is serious and the actual operation load and design load has a great difference. The former safety appraisal of bridges was mainly based on the safety that the design load to the structure and our safety appraisal to the safe operation period of bridge are to estimate whether the bridge span structure can satisfy a certain period of traffic load in future or current. It is necessary to have safety appraisal to the operation period of bridge, to have research on vehicle load and technical parameter, to make sure the using safety of structure during the operation period. In a word, to have a research on the longitudinal reduction factor of highways and bridges is necessary. This paper is mainly to study the safety of highways and bridges by analyzing the longitudinal reduction factor.