About the research
The Sabula high truss bridge, which carries US 52 and IA 64 over the Mississippi River Overflow in eastern Iowa, will be replaced with a pretensioned prestressed concrete beam (PPCB) bridge in 2017. The structural systems planned for the new bridge include integral abutments, a drilled shaft-supported concrete pier cap system, and the PPCB and concrete deck system. The 376 ft long and 40 ft wide bridge will be longer and wider than the existing bridge. The additional width conveniently allows for the construction of the drilled shaft foundations of the new bridge located in the river overflow channel while keeping the old bridge open to normal traffic.
To further minimize construction time and traffic interruption, multiple innovative accelerated bridge construction (ABC) techniques have been proposed for use in this replacement bridge project. In fact, four construction options and their corresponding design plans have been provided the final construction approach will be selected by the contractor.
The design of the deck system, either partial-depth panels with precast overhang or full-depth precast (AccelBridge deck system), is unique and has not been used in Iowa in the past. The partially precast and post-tensioned pier cap is also an innovative ABC approach that has not been used in Iowa before.
The objective of this project is to validate design assumptions, identify potential constructability issues, and evaluate the performance of the structural components and construction approaches provided in the design documents. As the bridge construction approach is not yet finalized, research tasks are proposed with respect to all possible options including the following:
- PPCB-supported partially precast prestressed deck system with precast overhang panels
- PPCB-supported AccelBridge deck system
- Partially precast and post-tensioned pier cap system
The construction process for the selected option will be documented, and its pros and cons will be identified.