Modal Analysis and Load Identification Techniques for a Rapidly Emplaced Bridge System

Fig. 1 - Lightweight Bridge at Luna
Fig. 1 - Lightweight Bridge at Luna
Fig 2. - Lightweight Bridge w/vehicle
Fig 2. - Lightweight Bridge w/vehicle
This project's goals are first to determine through experimental procedures the vibration behavior of a military-type deployable bridge under various types of loading conditions, e. g.: moving mass, moving load and moving oscillator travelling along the bridge at different speeds; and second, to develop a valid approach to identify the type of load the bridge is subjected to from experimental data only.

This project's goals are first to determine through experimental procedures the vibration behavior of a military-type deployable bridge under various types of loading conditions, e. g.: moving mass, moving load and moving oscillator travelling along the bridge at different speeds; and second, to develop a valid approach to identify the type of load the bridge is subjected to from experimental data only.

It starts with obtaining a Finite Element Model simulation of a comparable structure in order to obtain analytical results which can be further compared and therefore validated with existing bibliography analysis. Once reference natural frequencies, mode shapes and damping ratios have been found, the second stage of the project is to perform impact testing to the structure to confirm that the analytical results previously determined are in concordance with the experimental results. Finally, after validating the structure's dynamic parameters a third stage of the project is to analyze the relationship between the bridge and the loads it withstands. To perform this, acceleration response to moving loads is gathered from different locations of the structure and analyzed with the appropriate tools.

The ultimate objective for this project is to determine with considerable accuracy the type of vehicle crossing the bridge (related to its mass), as well as the amount of vehicles that have crossed a determined bridge throughout its usable lifespan.

Collaborators: Luna Innovations Incorporated
Grant: Army Corps of Engineers
Faculty Investigators: Shirley J. Dyke
Purdue Students: Chul Min Yeum and Christian Silva