Post-tensioned segmental concrete bridges have been used in the United States since the mid 80's. Post-tensioning is very economical and efficient for bridges with very long spans. A segmental concrete bridge uses post-tensioning to connect concrete bridge segments and make a long span bridge. A problem that has occurred in some segmental concrete bridges is the corrosion of the post-tensioned strands. A tendon failure can be detrimental to service level bridge performance and reduce the flexural strength.
The Varina-Enon Bridge has a history of corrosion related issues and the objective of this project was to investigate the consequences of transverse tendons rupture. In addition, to determine the behavior of tendons with grouted duct and smoot duct when a stand broke. Also, the results of this project identify if the bridge can perform adequately with no repair or if these failures would develop problems in the long term.
A full scale specimen of a post-tensioned slab with two tendons was built at the laboratory. The full scale specimen was built to contain tendons similar to top flange near the delta frames in the Varina-Enon Bridge, where a transverse tendon was broken. An artificial corrosion process was conducted to corrode the tendons and investigate the effect of break on the slab. The specimen was instrumented with BDI strain gauges to monitor the behavior of the specimen, when the strand rupture occurred due to the accelerated corrosion. In addition, a finite element model was designed similar to the full scale specimen to compare the collected data with the data obtained from the analysis. / Master of Science / Bridges play a very important role in the Transportation Systems all over the world. According to American Society of Civil Engineering (ASCE), United States bridges get a C+ grade. The ASCE rating indicates that the US bridges need to be built more efficiently and be monitored more frequently. Regular inspection of bridges is very essential and will be beneficial in many ways. For instance, engineers can detect the possible flaws and problems that are in the bridge such as corrosion in structural elements. It is important to address these issues since these bridges are in service and being used by the public. Based on how serious the issues are, engineers will decide if the bridge can perform adequately with repair or it is is structurally inefficient and needs to be replaced. Moreover, rehabilitations method to keep the structure in service will save a lot of money compare to replacing the bridge. The Varian Enon Bridge, which carries Interstate 295 across the James River in Richmond, is a critical link in Richmond transportation a In the recent inspections of this bridge, Virginia Department of Transportations (VDOT) detected abnormal behavior of few structural elements. In this research, a full scale mock-up of a section of the Varina Enon Bridge was built at the lab. The purpose of this project was to conduct testing on the mock-up to investigate the cause of abnormal behavior of these few structural elements similar to the ones in Varina Enon Bridge. Furthermore, a final report was prepared for VDOT to decide if the bridge will perform adequately with no strengthening or providing forewarning of trouble that could develop with time.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/89563 |
| Date | 17 May 2019 |
| Creators | Mohammadian, Mehrshid |
| Contributors | Civil and Environmental Engineering, Roberts-Wollmann, Carin L., Hebdon, Matthew H., Koutromanos, Ioannis |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf, application/vnd.openxmlformats-officedocument.wordprocessingml.document |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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