ABSTRACT
At present, Random vehicle load simulation is widely used in the evaluation of large multi-span cable-stayed bridge effects. But various simulation methods have no unified standard in terms of vehicle flow input parameters, and it is difficult to accurately and comprehensively describe the characteristics of real-time vehicle flow at the bridge site. The traditional traffic flow simulation focuses on the traffic characteristics of the traffic flow, while the bridge structure load response evaluation focuses on the load characteristics of the traffic flow. Therefore, it is necessary to introduce the concept of load flow on the basis of traffic flow. A series of parameters are used to describe the changing characteristics of the traffic flow, and the traffic flow is used as a carrier to introduce another dimension of the parameter to describe the quality dimension characteristics of the traffic flow containing average and extreme multiple information. Therefore, constructing a two-dimensional parameter model of flow, density, speed, load concentration, vehicle weight division value, and heavy vehicle ratio at the probability level complies with the principles of refining and summarizing massive data. Based on three typical measured vehicle flows and a large cable-stayed bridge, this paper analyzes the two-dimensional parameters and load response of the measured vehicle flows. The results show that the two-dimensional parameters can better describe the quantity and quality characteristics of traffic flow; the sensitivity of different structural effects to traffic flow parameters is selectively different. The two-dimensional parameter model can provide more comprehensive input information for traffic flow simulation, provide a basis for specific effect traffic flow simulation, and has engineering significance.
