Effect of vehicle speed and road surface roughness on the impact factor of simply supported bridges due to IRC Class A and B loading

Abstract

Indian Road Congress (IRC)-06 specifies consideration of impact factor for dynamic analysis of bridge loaded with Class A and Class B vehicles. As per IRC-06 specifications, the impact factor is estimated based only on the span length of the bridge. In the present study, the effect of vehicle speed, road surface roughness condition and span length of the bridge on the impact factor is investigated. The dynamic response of a simply supported bridge loaded with IRC Class A and Class B vehicle loads are considered for the study. For simplifications, the vehicles are idealized as a series of moving mass spring damper system. The interaction between the bridge and vehicle is accomplished by coupling the equation of motion using the interaction force at the contact point of the wheel and bridge. The coupled equation of motion is solved using Newmark's beta method. The model is validated using past available literature. The vehicle is considered to move at a consistent speed between 20 and 100 km/h. The excitation caused due to the presence of road surface roughness at various vehicle speeds on the bridge response with span lengths varying between 20 and 100 m is investigated. Parametric studies are also conducted using frequency ratio. From the studies, it is observed that the response of the bridge subjected to IRC Class A vehicle is 40% higher than the response of the bridge subjected to IRC Class B vehicle. It is also observed from the parametric study that, the bridge response becomes critical when the vehicle moves at resonance speed and the amplitude increases with deterioration of road surface condition. The results of the impact factor study show that IRC-06 specifications underestimate the response of the bridge for high speed moving vehicles under different road surface conditions. The findings of this study can be utilized to update the IRC specifications at the time of analysis and design of both short and as well as long-span highway bridges.

Dynamic Response Study of Overhead Contact System Portal Structure Based on Vehicle–Track–Bridge Coupled Vibration

“…As the electrified railway transportation industry develops rapidly, to be er adapt to the complexity of railway networks, railway construction often employs elevated railway bridges instead of traditional roadbeds, significantly increasing the proportion of bridges in the railway network. Therefore, research on the dynamics of vehicle-track-bridge coupled systems becomes more necessary and urgent [7][8][9]. Models of railway bridges and vehicles based on three-dimensional finite element and multibody dynamics were constructed, and the influences of speed, load, and damping on the dynamic response of the system were studied through numerical analysis [10].…”

Investigating the impact of the velocity of a vehicle with a nonlinear suspension system on the dynamic behavior of a Bernoulli–Euler bridge

“…For instance, in the Rayleigh method, inaccuracy will rise when the dynamic system is nonlinear, which will cause the damping forces to have an unrealistically large value compared to the restoring forces. Also, in the very recent work done by Nunia and her colleagues [19], the Newmark-beta method is used to solve the coupled dynamic equation of motion of the bride-vehicle. However, the Newmark-beta method is suitable for linear elastic systems, and its performance in nonlinear systems is still not clear.…”