RELIABILITY-BASED ANALYSIS ON THE VEHICLE WEIGHT LIMIT OF HIGHWAY BRIDGES

Vehicle weight limits of highway bridges at various reliability levels were established based on structural reliability theory. This study refers to the probability distribution of load effects and bridge resistances, and uses the basic load combination and the ratio of live to dead load effects to calculate the live load influence coefficients at the design level and the minimum permissible level of reliability. Then, taking the three axles and five axles trucks as standard vehicles, this study suggests the safe and the maximum permissible vehicle weights for highway bridges. Finally, considering the difference in bridge resistances, this study presents an analysis method to determine the weight limit for general highway bridges. Results show that the vehicle weight limits proposed in this paper are consistent with current bridge design specifications, and can be used in load posting and permit checking for overweight trucks.