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Recently FIU has developed repair techniques that is capable of repairing damaged bridge elements using Ultra High Performance Concrete (UHPC). Technique is applicable to both flexural and axially dominated bridge elements.
U.S. transportation infrastructure consists of more than 60,000 miles of coastal roadways. Significant number of bridges located along these coastal roadways are subject to harsh environment resulting in corrosion and other damages. In addition to bridges located in the coastal areas, other bridges located in-land, also contain damages that needs development of accelerated repair techniques.
Several methods are currently used by bridge owners for repairing the damaged bridge elements that includes, wrapping damaged portions of bridge elements with Fiber Reinforced Polymers (FRP), Steel Jacketing and wrapping using conventional concrete. In aggressive marine environments, corrosion has been shown to continue after patch repairs and encapsulation using conventional repair materials.
The Accelerated UHPC shell retrofit technique developed at FIU has many advantageous over the existing retrofit techniques. A) UHPC is a very durable material with a very low permeability, B) the high compressive and tensile strength of UHPC, strengthen the damaged bridge elements, and C) the properties of UHPC allows tension development of steel reinforcement over a short length, in case some of the reinforcement in the retrofitted areas needs replacement.
Extensive investigation has been carried out at FIU to develop retrofitting techniques using UHPC shell concept for both flexural and axial bridge elements. In both cases damaged bridge elements could be repaired using UHPC over damaged elements. Additional consideration on the corrosion durability of this retrofitting technique will considered. Incipient anodes that result in the “Halo” effect is currently being investigated. The main objective of this project is to select an existing in-service bridge with damaged column element, retrofit it using UHPC shell, using cast in place technique, instrument it and monitor it to identify deterioration of the repair and substrate material as well as development of corrosion of steel within the column.
Following is brief description of the work to be conducted;
- Task 1 – Selection of Bridge
- Contacts have been established with Miami-Dade County through the engineer in charge and District 4 and 6 of FDOT to identify an in-service bridge with damaged column elements.
- Task 2 – Field Retrofit –
- A contractor will be identified for repairing one column of the identified bridge using UHPC shell and cast in place technique. Under this task, the selected column element will be retrofitted.
- Task 3 – Instrumentation–
- The retrofitted column will be instrumented for long term monitoring prior to retrofitting.
- Task 4 – Monitoring and Reporting
- A retrofitted column of the bridge will be monitored and data will be collected over a long period of time. The data collection will be continued beyond the project duration, as long as the instrument continues to function.
- Task 5 – Final Report –
- Final report summarizing the project activities will be developed.
Principal Investigator: Kingsley Lau
Co-Principal Investigator: Atorod Azizinamini