All ETDs from UAB

Advisory Committee Chair

Nasim Uddin

Advisory Committee Members

Ashraf Al-Hamdan

Christopher Waldron

Mohammad Haider

Robert Peters

Document Type

Dissertation

Date of Award

2020

Degree Name by School

Doctor of Philosophy (PhD) School of Engineering

Abstract

Structural health monitoring of bridges serves a critical role in maintaining a safe transportation network. Compared to the traditional resource-consuming direct approaches which usually require labor-intensive inspection and deployment of multiple sensors directly on the bridge, the indirect approach has been gained more and more attention due to its mobility and potential economy characteristics. The indirect approach utilizes the dynamic responses from the vehicle that interacts with the bridge so that the health status of the monitored bridges can be timely and effectively reflected via their structural dynamic characteristics such as frequencies, mode shapes, and damping properties. This research explores the vehicle-based structural health monitoring of bridges as an indirect approach both theoretically, experimentally, and numerically. Firstly, the theoretical vehicle bridge interaction models considering both the vehicle and bridge damping effects, and multiple bridge modal contributions for the bridge with various common boundary conditions including simply supported, both ends fixed, fixed simply supported, and one end fixed the other end free (cantilever) boundary condition are established, and closed-form solutions are obtained. The feasibility of extracting multiple bridge frequencies and mode shapes from the vehicle response is discussed based on the analytical solutions, and critical parameter effects including bridge damping, vehicle frequency, speed, mass, and damping are studied. The vehicle-based indirect approach is then explored experimentally on a lab-scale bridge with support deterioration with a comparison to the direct approach. The experimental study shows that the integrity of the structural dynamic characteristics and the stability of the corresponding standard deviation may serve reliably as the damage indicators to account for the statistical effect. Lastly, as a complementary approach, the bridge weigh-in-motion technique which utilizes the bridge measurement to calculate the vehicle axle weights is numerically studied on a continuous bridge with multiple locations and severities of damages. The numerical study shows that both the bridge damage severity and locations can be reflected by the vehicle weight history and the corresponding statistical analysis as the vehicle passes over the bridge. This study may provide a reference for developing vehicle-based bridge monitoring techniques so that countless bridges could be more efficiently and comprehensively monitored.

Included in

Engineering Commons

Share

COinS