Experimental and Numerical Studies of Nonstationary Random Vibrations for a High-Pier Bridge under Vehicular Loads

Abstract

In the current study, the nonstationary random responses of moving wheels induced by road roughness in a time domain were obtained and treated as the nonstationary inputs to study the nonstationary vibration of a high-pier bridge under vehicles with variable speed. A full-scale vehicle model with 12 degrees of freedom was used; vehicle wheels were considered as patch contact instead of point contact with the bridge road surface. The vehicle-bridge coupling equations were established by combining the equations of motion of both the bridge and vehicle using the displacement relationship and the interaction force relationship at the contact patches. The midspan deflections caused by the stationary and nonstationary inputs were compared with the measured responses under different parameters including vehicle acceleration and vehicle deceleration. The verified results showed that the proposed method can accurately simulate the vibration of the bridge under vehicles moving with variable speeds. Using the stationary random process to model the road surface disturbance to vehicles with variable speeds, the dynamic effects can be either underestimated or overestimated. The proposed method was then used to study the ride comfort for vehicles moving with a variable speed on high-pier bridges.