Effects of Pavement Roughness and Dynamic Tank Load on the Bridge Response

This study aims to investigate the dynamic Load allowance variation (DLA) of dynamic tank Loads and compare it with Iraq's standard specifications for road bridges. DLA is considered a simple measurement of the dynamic variation magnitude of the tank load for a specific combination of road roughness and speed. In addition to determining the stochastic dynamic response of the bridge. Al-Awsej bridge in Iraq, with a span of 33.2 m and a principal road with four pavement roughness classes (very good, good, average, and poor), was proposed as a case study in this analysis. A spectral closed-form solution was used for evaluating the dynamic tank load due to the passage of a tank type-72A at a constant speed of 40,50,60 and 70 km/hr along a bridge with different types of rough pavement surface. The results show the less value of DLA for very good pavement at 40 km/hr is about 0.032, and the largest value is about 0.293 at 70 km/hr for poor pavement. Also, road surface roughness greatly influences vehicle-bridge interactions and bridge responses. Where at 40 km/hr, the Root mean square of bridge deflection range from 0.31 to 2.75 mm and 0.39 to 3.14 mm at 70 km/hr.