Seismic performance of next generation bridge components for accelerated bridge donstruction
- PI: M. Saiid Saiidi, University of Nevada, Reno
- Co-PI: David Sanders, University of Nevada, Reno
- Research assistant: Zachary B. Haber, University of Nevada, Reno
- Sponsor: California Department of Transportation
- Project monitor: Saad El-Azazy
- Project dates: August/September 2011
Projects summary
The use of prefabricated structural elements is an integral part of many accelerated bridge construction (ABC) efforts. The connection of these prefabricated elements to the rest of the structural system is critical to the performance of the structure under service loads and extreme events.
This project investigates the seismic response of rigid connections between precast columns and footing. Five half-scale column models will be tested by reversed cyclic loading. The baseline model used in this study is a conventional cast-in-place reinforced concrete column; this model is denoted in this study as "CIP". Caltrans Seismic Design Criteria (SDC) was used to determine internal reinforcing steel to achieve a displacement ductility of 5. Furthermore, all detailing used in the CIP model adhered to Caltrans specifications.
The four other column models to be tested in this study are composed of hollow precast concrete shells that are rigidly connected to the footing using mechanical rebar couplers located within the plastic hinge zone. After the rigid connection is made, the hollow shells are filled with self consolidating concrete (SCC).
Two different mechanical couplers were selected for testing based on an extensive review of available literature. Coupler selection criteria included
- Mechanical performance under static and dynamic loading
- Caltrans pre-qualification
- Applicability to rapid construction
The two coupler types selected were the HRC 500 series upset headed coupler and the NMB grout sleeve coupler. Two models incorporate partial pedestals in order to reduced demand on the coupler region.
The data compiled will be compared with the performance of the columns with that of similar cast-in-place construction and any necessary refinements will be identified based on the data and analyses. The ultimate objective is to make recommendations to Caltrans regarding precast column connection details, design methodology, and construction techniques.