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U.S. 11 Lake Pontchartrain Bridge Rail Replacement (405160-16):
PROBLEM STATEMENT
The U.S. 11 Lake Pontchartrain Bridge crosses over Lake Pontchartrain just northeast of New Orleans in Orleans Parish, Louisiana. This bridge is approximately 4.72 miles in length. This bridge was constructed in the late 1920’s and consists of 2 lanes with a 2-rail concrete bridge rail and posts constructed on top of a concrete curb. TTI has received several drawings of the bridge and bridge railing structures. We understand that the existing bridge rail was severely damaged during hurricanes Katrina & Rita in 2005. Repair of the existing bridge railing is not feasible since the original rail design is deficient with respect to the current LRFD Strength requirements as well as the performance requirements as provided in NCHRP Report 350 Requirements for Test Level 3. A new retrofit bridge rail design that meets the current LRFD Test Level 3 strength requirements as well as meets the performance requirements of NCHRP Report 350 Test Level 3 is needed for this project.
BACKGROUND
Several bridge rail retrofit design have been developed at TTI for a host of different states as well as for the FHWA. In addition, hundreds of crash tests have been performed at TTI on various Test Level 3 bridge rail designs. For this project, TTI will review several different Test Level 3 bridge rail designs that meet the performance requirements of NCHRP Report 350. TTI will use a vast database of information to design and develop a suitable bridge rail design that meets the LRFD strength requirements of Test Level 3.
OBJECTIVE
Develop a new retrofit bridge rail design to be used for the US 11 Lake Pontchartrain Bridge that meets the current LRFD Strength and NCHRP Report 350 performance requirements.
BENEFITS
This new retrofit bridge rail will utilize the existing 9-inch high concrete curb and deck. The new retrofit design will utilize either a mechanical or adhesive anchoring system. The new retrofit bridge rail will save time and construction cost when compared to full replacement of the existing bridge rail. The new retrofit bridge rail design will meet the current LRFD strength requirements for Test Level 3. In addition, the new bridge rail design will meet the crash performance requirements of NCHRP Report 350.
WORK PLAN -- Perform Engineering Analysis/Design/Drawings
The researchers will review the design details of several different bridge rail designs that have been successfully crash tested with respect to NCHRP Report 350 Requirements. TTI researchers will work closely with Louisiana Department of Transportation personnel to select the appropriate design parameters to be used for this project. The principal investigator for this project will perform engineering calculations on the new bridge rail retrofit design to insure that the new retrofit design meets the current LRFD strength requirements for Test Level 3 conditions. TTI will develop suitable drawings and details that can be used for construction and fabrication of the new retrofit bridge rail. These calculations, along with detailed drawings of the new retrofit bridge rail, will be provided in a brief letter report for this project. This is the only task associated with this project. At the conclusion of Task 1, it may be necessary to perform additional full-scale testing to finalize the design. Additional supplements may be needed.
Technical Memo on US 11 Lake Pontchartrain Bridge Rail Replacement
QUARTERLY PROGRESS REPORTS:
December 2008 Progress Report
October 2008 Progress Report
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