According to recent estimates, more than 50,000 bridges in the U.S. are characterized as “structurally deficient.” As part of the solution to such widespread bridge deterioration in New England, Professors Simos Gerasimidis and Sergio Breña of the UMass Civil and Environmental Engineering (CEE) Department have received $667,000 in funding from the Massachusetts Department of Transportation (MassDOT) and the New England Transportation Consortium (NETC) for a series of research projects studying bridges suffering from corrosion deterioration across the region.
“These projects aim to improve our understanding of the behavior and safety of critical transportation infrastructure,” Gerasimidis explains in the UMTC article linked above. “They are an important first step towards assessing the remaining structural strength of deteriorated bridges after many decades in service.”
These grants and others have made UMass Amherst a regional leader in analyzing deteriorating bridges across New England.
Among the many aspects of structural deficiency in bridges, as the UMTC article explains, corrosion is considered a common cause for steel bridge deterioration, especially in northern parts of the country. This corrosion can be primarily attributed to water chronically leaking through deck joints, with the water containing high concentrations of chemicals used for winterizing surfaces from roadways. The corrosion can then cause severe strength and thickness loss of the bridge beams.
As Gerasimidis says about the work being done by himself and Breña, “This is the first time that real naturally corroded bridges have been tested in a laboratory setting, making this research very important. We have been fortunate to have received real beams from decommissioned bridges for testing in our Brack Structural Engineering Laboratory.”
The Brack facility boasts a crane that can lift up to 60,000 pounds, which enables testing of full-size structural elements such as beams and girders. The facility’s floor is comprised of 55 tie-down locations, each with the capacity to load up to 200,000 pounds in multiple configurations. Thus the Brack facility can support work on larger projects, including research involving sustainable buildings and bridge components by experimenting with new materials and methods and testing their endurance and strength.
Because of this facility, as Breña says, “The capability of testing large-scale structural components at the Brack Structural Testing Laboratory has allowed UMass Amherst to become the focal point for bridge research in New England.”
One main challenge that this research is trying to address is to develop techniques that accurately assess the residual capacity of beams in their corroded stage. By studying more than 200 bridges in Massachusetts, Gerasimidis and Breña have identified and characterized the corrosion phenomenon within the Commonwealth and are now expanding their research to the rest of New England with funding from NETC.
The UMTC article goes on to explain that, along with experimental testing, Gerasimidis and Breña are using advanced finite-element modeling techniques to predict remaining bridge capacity and to generalize their findings for implementation in current bridge design codes. Their research has identified the factors that significantly impact the remaining strength of deteriorated girders, with the primary goal to develop new code procedures and calculation methods that better resemble the computational and experimental results.
The UMTC article also notes that the research studies of Gerasimidis and Breña aim to develop effective and consistent procedures for collecting important data from deteriorated steel beams, including a list of measurements and tasks for inspectors to follow during inspections. In addition, this research is investigating the use of new technologies such as LiDAR or drones for bridge inspection, data collection, and evaluation.
The Gerasimidis Research Group employs numerical, analytical, and experimental methods to describe the stability of structural systems across scales. “Our research interests lie in the areas of infrastructure resilience, structural stability, new architected metamaterials, metamaterials for metastructures, thin-walled structures, deteriorated bridges, and energy structures,” says Gerasimidis.
Breña is the CEE associate department head and has more than 23 years of experience in laboratory and field testing of structures and structural systems. In addition to his work with the field performance of integral abutment bridges and live-load testing of existing bridges, his research interests include design and behavior of reinforced and prestressed concrete structures, use of fiber-reinforced materials in civil infrastructure applications, and field performance of bridges and buildings. (August 2020)