Prediction and mitigation of traffic induced ground vibrations in an urban zone

Ground vibrations generated by heavy trucks and buses are a common source of environmental problem. They can reach levels that may cause nuisance to residents, damage to near-by structures, and perturbation in the functioning of sensitive equipment. These vibrations are produced mainly when the vehicle wheel’s pass over a speed reducer such as a road hump or a speed cushion. This study aims to investigate the size and nature of these vibrations and suggests a suitable method to reduce the vibration levels. Using a half-car model with four degrees of freedom, the dynamic response of vehicle to the road irregularity is simulated. The equation of motion of the fully coupled system (vehicle-road unevenness) is solved step by step in the time domain, and then the resultant load is used in 3D numerical model to predict the traffic induced vibrations in the free field. The proposed model is validated and used to analyze the effect of different types of traffic calming on the vibrations levels in the free field. Furthermore, Numerical simulations are carried out to study the efficiency of trench barriers. The results show that some road unevenness geometry under certain vehicle speed could result in very high dynamic effects and thus a perceptible level of traffic induced vibration. A significant vibration reduction can be achieved using a suitable measure like a trench barrier.