Analysis on the applicability of vehicle load model to long-span bridges based on specifications

Abstract

The present specification’s vehicle load is primarily focused on the design requirements and effect characteristics of short- and medium-span bridges. With the significant growth in bridge spans, the specification’s applicability demands special consideration. This paper calculated the vehicle load effect of four long-span highway suspension bridges using the specifications, discussed the impact of different spans and structural forms on the specification’s applicability, and verified the specification model’s limitations for the super-long-span bridges. The calculations revealed that when the spans and number of lanes increased, the effects contributed by concentrated load and uniform load, as defined by the specification, increased dramatically. The discrepancy among the loading results induced by the calculation mode for different specifications is more noticeable in the regional effect for the double-layer structure, and the greatest difference in the axial force effect of the mid-span hanger is 18.4%. In general, current specifications cannot reflect the load carried by long-span bridge structures. It is unreasonable to adopt the specifications to design the long-span bridges directly.