Abstract:
Numerous bridges were required along the new SR-158 roadway connecting Mobile, Alabama to the Mississippi state line. One of the new bridge structures was approximately 2,520 ft in length consisting of 21 bents (20 spans). The foundation design was 36in. Precast Prestressed Concrete piles (PCC) which required predrilling and jetting to install the piling in an environmentally sensitive area.Â
The value engineering proposal submitted by the Contractor included the installation of 30in. steel pipe piles with dynamic and static load testing paid for and directed by the Contractor. The piles were installed using vibratory and impact hammer techniques.Â
Six dynamic and static load tests were performed during the project. The dynamic testing was used to estimate the resistance during installation with the impact hammer. The required dynamic resistance was estimated with a calibrated setup factor based on static testing. This procedure differed from the Owner standard practice and resulted in realized savings shared between the Owner and Contractor while reducing the environmental impact.
This presentation will provide a project history of the factors that led to the value engineering proposal, discussion of the dynamic and static load testing employed for the setup factor which differed from the Owner at the time, emphasis on the required dynamic resistance before ending the initial drive for static testing, and performance of the static load test for confirmation of resistance.