Dynamic Response of RC Bridges due to Heavy Vehicles

Abstract

As a South Asian country, Sri Lanka is having a promising development in infrastructures in the country. Amidst of them, concrete bridges that are constructed in highways and expressways have substantial effect on developing transportation sector. The performance evaluation of bridges starts with the inspection of the bridge to determine the present condition. Currently, Structural Health Monitoring (SHM) in most of the developed countries is characterized by traditional visual inspection along with referencing of old inspection reports to maintain an accurate account of the bridges condition. This paper presents evaluating method for current condition of reinforced concrete bridges by evaluating dynamic characteristics of the bridge. Accelerations of the bridge were measured by imposed in moving vehicles. For the measurements, tri-axial accelerometer was used. Analysing of the acceleration is complex due very large number of readings and acceleration values required to filter from other disturbances. Matlab program was developed to filter and analyse the acceleration readings. In addition, displacements were calculated from the acceleration waveforms to evaluate bridge stiffness for different moving loads. The effect of the loads generated by moving vehicles on the displacement of the bridge is varying with the speed of the vehicle. To simulate that in model of the structure, an appropriate method was applied. By considering both result taken from actual acceleration measurements and the model, current condition state of the bridge was evaluated.