Innovative Drilled Shaft Installation Process Through Existing Bridge Foundations

- Organization:
- Deep Foundations Institute
- Pages:
- 10
- File Size:
- 2397 KB
- Publication Date:
- May 1, 2022
Abstract
The Highway 146 Bridge Expansion Project across the Clear Creek Channel in Houston, Texas was
designed on driven precast concrete piles. However, during construction, the piles along one side of the
bridge along the main channel encountered obstructions and couldn’t be installed. These obstructions
turned out to be the remnants of a previous bridge foundation at this location, which was unknown to
the designers since that bridge had been demolished 40 years ago. Those old foundations were massive
20 ft by 40 ft (6 m by 12 m) pile caps 11 ft (3.3 m) thick supported on precast concrete piles 37 to 55 ft
(11 to 17 m) long. The foundation re-design for these locations involved installing a single 78 inch (2
m) diameter drilled shaft up to 125 ft (38 m) long to replace the originally planned driven pile supported
pile cap. The drilled shafts would need to be installed within very tight tolerances since they were
supporting a single bridge column directly above it. In addition to drilling through the obstructions,
this work would need to be completed from barges in 30 ft (9 m) of water capable of dealing with both
the current and tides affecting this area. The shafts were installed using a multi-step process. The first
step involved coring a larger diameter 100 inch (2.5 m) hole through the reinforced concrete pile cap
and removing the concrete inside. This was followed by the installation of a 72 ft (22 m) long permanent
casing to and removing the soil and existing precast piles inside. Finally, the drilled shaft excavations
were advanced to the completion depths (uncased) using bentonite slurry as the support fluid.
Citation
APA:
(2022) Innovative Drilled Shaft Installation Process Through Existing Bridge FoundationsMLA: Innovative Drilled Shaft Installation Process Through Existing Bridge Foundations. Deep Foundations Institute, 2022.