Ramesh Malla, Ph.D., F.ASCE, F. EMI
Professor, Civil and Environmental Engineering
University of Connecticut
Dynamic Characteristics and Response of More than Century Old Steel Truss Railroad Bridge Structures under Service Load Conditions
Railroad plays a major role for passenger and freight mobility in the United States. Compared to highways, in railroad transportation system a single train can carry the freight of several hundred trucks, thus reducing highway gridlock, the cost of maintaining existing highways, and the need to build expensive new ones. According to the ASCE 2021 Infrastructure Report Card, the infrastructure-related issues are the largest source of train delays in many of the major railroad corridors in the nation, including the Northeast Corridor (NEC) between Boston and Washington, D.C., the busiest rail corridor in the United States. Most of the New England railway bridges were design and built more than a century ago. Thus, they are very old and are made of outdated material and design codes. Sustaining a viable railroad system requires that infrastructure be maintained through capital investments to upgrade, improve, or replace facilities. Therefore, it is imperative to determine their current conditions, especially structural load carrying capacity, and behavior due to the actual moving vehicle/train loading and their types to ensure the bridge and users’ safety. This paper presents the results delineating the dynamic behavior/response of open-deck steel truss type railroad bridge(s) located in Connecticut and built more than a century ago. This study uses Finite Element model to simulate and field tests to verify and model update to understand the structural dynamic characteristics (e.g. vibration frequencies and mode shapes) and response under different moving service dynamic loads from various trains travelling in their normal operating speeds.