Bridge-Vehicle Interaction Force Identification From Bridge Responses

Truck weight data have been valuable for bridge and pavement design. However, the traditional ways to acquire that are expensive and subject to bias, and this has led to the development of Weigh-in-Motion (WIM) techniques. Most of the existing systems have been developed to measure only the static axle loads. These all prompt the need to develop a system to measure the dynamic interactive forces using an unbiased random sample of vehicles. This paper aims to introduce two methods of force identification from bridge responses. The first method is based on a closed form solution to identify moving constant loads, which can be applied to obtain equivalent static axle weights as other traditional WIM techniques. The second method is an advancement of the first and can be used to identify moving time-varying forces. A bridge-vehicle system is developed to simulate the interactive force and the corresponding bridge responses. The generated responses are then used to identify the interactive forces based on the above mentioned methods. The identified forces are compared with the simulated interactive forces. The applicability of the methods and their sensitivity towards noise will also be discussed