Proceedings of the 21st Annual Members' Conference, 1996, San Francisco, CA, (DFI)
Retrofitting the San Francisco Bay Bridge Approach Ramp with Tubex G.I. Piles
Ing. Han C.M. Breek & Mark Presten
Caltrans started the retrofit activities on the San Francisco-Oakland Bay Bridge, toward the end of 1995. The retrofit of the East Approach Structure is the first of 19 proposed projects. The Seismic retrofit was planned to ensure that the San Francisco – Oakland Bay Bridge can withstand maximum credible earthquake of magnitude 7.3 along the Hayward Fault. The retrofit is planned to be such that there will not be any disruption of service after the event. Since the Tubex grout injected pile was considered for use in the seismic retrofit of the East Approach Structure, an indicator pile test program for Tubex G.I. piles was performed earlier. This program was initiated to answer questions regarding pile wall thickness required for lateral loads, pile constructability, the need to fill the piles with concrete and vertical tensile and compressive pile capacities. As a result of this test program, it was decided for bent E-33 till E-39 to use Tubex grout-injected piles. Not only because of its excellent performance under various tension, compression and lateral tests, but also because Tubex G.I. piles are soil displacement piles, installed vibration free. Moreover Tubex G.I. piles can be installed under restricted headroom.
|article #90; publication #18 (AM-1996)|