Pipe Ramming a 60-In. Casing Under BART
Abstract
The San Francisco Public Utilities Commission (SFPUC) needed to install a new 900-mm (36-in.) diameter steel transmission water main under two active BART tracks and eight traffic lanes of Interstate 280 (I-280). BART is a major rapid-transit commuter-rail system in the San Francisco Bay Area. Normally, access and work under the tracks are limited to non-revenue service hours (typically from 1:30 to 4 a.m.). A trenchless design was developed and accepted by BART to first use pipe ramming and then tunneling with a small boring unit (SBU) to place 21.3 m (70 ft) of 1,525-mm (60-in.) diameter casing under the tracks during the revenue hours over a long weekend with a reduction of train speeds. The pipe ramming was to be completed through severely sheared and fractured shale and serpentine. After the shaft encountered hard greywacke rock, the method was changed to tunneling with an SBU. The contractor was able to auger bore a 90-m (295-ft) long, 1,525-mm (60-in.) diameter casing under BART and the adjacent interstate. This paper addresses permitting agency interface, design, and construction issues faced by the project and how the issues were successfully resolved.
2009
International No-Dig Show Proceedings
Saed Toloui
San Francisco Public Utilities Commission
Glenn Boyce
Jacobs Associates
Kevin Barteaux
San Francisco Public Utilities Commission