| San Francisco-Oakland Bay Bridge (SFOBB)- PIDP
Pile Installation Demonstration Project (PIDP)
In December 2000, Caltrans completed a Pile Installation Demonstration Program (PIDP) for the new bridge. Fugro collected geotechnical data during the program related to soil resistance and set up. The purpose of the PIDP was to:
- Document and evaluate hammer performance, pile drivability and driving behavior
- Demonstrate marine construction techniques and equipment
- Develop welding procedures, specifications, and document results
- Monitor airborne and underwater noise and ground vibrations due to pile driving
- Evaluate effectiveness of underwater noise attenuation barriers; and
- Observe marine mammal behavior
Three, 2.43 meter-diameter, 107 meter long steel pipe piles were driven to final tip elevation of ~ -101 meter (mean sea level). Two of the piles were battered piles (1:6) and one, a vertical pile. The piles were driven in four sections with two of the largest available offshore hydraulic hammers (Menck MHU 500 and MHU 1700). PDA monitoring was conducted on the last 3 sections of each pile. Also, a series of restrikes were conducted to evaluate the magnitude and rate of pile setup. The following geotechnical parameters were evaluated during the program:
- Soil plugging during driving
- Soil resistance to driving
- Blow counts required to drive the piles
- Pile stresses during Driving
- Pile setup; and
- Geotechnical pile capacity
The geotechnical analyses provided the following benefits:
- Reduced uncertainty associated with unprecedented pile type/size
- Provided bidding contractors with pile installation information
- Established minimum required hammer size and acceptance criteria
- Established setup criteria for staged construction
- Clarified conservatism in axial pile design
- Help validate methodologies used to predict soil resistance to driving and blow counts
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