Simulation And Effect Analysis Of Vehicle Loads On A Prestressed Concrete Bridge

In the new era of China's rapid economic development, in order to satisfy the people's increasing material and cultural demand, all kinds of infrastructure develops rapidly, and the number of bridge grows continuously, which greatly promotes the material and cultural exchange and economics. Increasing traffic, frequently appeared overspeed and overweight vehicles, and the aging of the bridges, have all been causing certain impact on the stable operation of the bridge structures. The health monitoring and safety assessment of bridge structures become important in the research field of bridge structures. As one of the main loads for bridge structures, vehicle load has the characteristics of randomness and locality, which is the highlight and difficulty in the bridge health monitoring research.Taking a railway crossover bridge from Shandong as an engineering case, a bridge structure health monitoring system was implemented on it, 2 weeks' vehicle load data is extracted from the monitoring system for statistical analysis. Also, the vehicle load is simulated and the effect is evaluated. The main research contains:1. The basic statistical analysis theories of vehicle load are summarized, including of common distribution function types for statistical analysis, the ways to check the match between the fitted values and measured data, and Monte Carlo Simulation method.2. Vehicle load parameters such as interval time of vehicle arrival, lane distribution, vehicle type distribution, vehicle weight and speed, etc. are statistically analyzed and curve fitted, which provide the basis for the simulation of vehicle load. It is found that interval time of vehicle arrival obeys gamma distribution, lane distribution and vehicle type distribution are subjected to their proportional relations, vehicle weight obeys multi-modal logarithmic normal distribution, and vehicle speed complies with unimodal distribution(normal distribution, lognormal distribution and gamma distribution) or multi-modal logarithmic normal distribution.3. Based on the fitting model of the vehicle load parameters, a vehicle load simulation program is designed, which has two different procedures. It uses time or total vehicle number to determine the termination conditions.4. The finite element model of the bridge structure is established, input with the design load and actual vehicle load obtained from the monitoring system, and then with compared with their effects. The result shows that the monitored strain and deflection are within the range caused by design vehicle load.