Browsing by Author "Collins, William Norfleet"
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- Fracture Behavior Characterization of Conventional and High Performance Steel for Bridge ApplicationsCollins, William Norfleet (Virginia Tech, 2014-11-13)The work described herein examines the fracture behavior of steels used in bridge applications. As part of Transportation Pooled Fund (TPF) Project 5-238, Design and Fabrication Standards to Eliminate Fracture Critical Concerns in Steel Members Traditionally Classified as Fracture Critical, researchers aim to take advantage of advances made in both steel production technology and in the field of fracture mechanics. Testing and analysis of both conventional and High Performance Steel (HPS) grades of bridge steel was conducted as part of this study. This includes both Charpy V-Notch testing, as well as more rigorous elastic-plastic fracture toughness testing. Analysis includes the application of the master curve methodology to statistically characterize fracture behavior in the ductile to brittle transition region. In addition, a database of historic bridge fracture toughness data was compiled and re-analyzed using plasticity corrections to estimate elastic-plastic fracture toughness. Correlations between Charpy V-Notch impact energy and fracture toughness, which forms the basis for the current material specification, were also examined. Application of fracture toughness characterization of both new and historic data results in updated methodologies for addressing fracture in bridge design.
- Live Load Testing and Analysis of the Southbound Span of U.S. Route 15 over Interstate-66Collins, William Norfleet (Virginia Tech, 2010-07-30)more funding must be allocated for their rehabilitation or replacement. The Federal Highway Administration's (FHWA) Long-Term Bridge Performance (LTBP) Program has been developed to help bridge stakeholders make the best decisions concerning the allocation of these funds. This is done through the use of high quality data obtained through numerous testing processes. As part of the LTBP Pilot Program, researchers have performed live load tests on the U.S. Route 15 Southbound bridge over Interstate-66. The main performance and behavior characteristics focused on are service strain and deflection, wheel load distribution, dynamic load allowance, and rotational behavior of bridge bearings. Data from this test will be used as a tool in developing and refining a plan for long-term bridge monitoring. This includes identifying the primarily loaded girders and their expected range of response under ambient traffic conditions. Information obtained from this test will also aid in the refinement of finite element models by offering insight into the performance of individual bridge components, as well as overall global behavior. Finally, the methods and results of this test have been documented to allow for comparison with future testing of this bridge, which will yield information concerning the changes in bridge behavior over time.