Owner
Texas Department of Transportation TxDOT
Client
AECOM
Cost
$750 million USD for the Drainage Tunnel and Pump Station Segment
Timeframe
March 2025
— July 2026
Services performed
As part of the Construction Engineering and Inspection (CEI) Team on behalf of TxDOT services included constructability review of design packages, review of contract documents, and contractor’s means and methods. Supervising and inspecting all SEM works on site. Preparing site documentation such as daily technical reports, daily inspection reports, including photographs. Providing technical advisory on site regarding SEM works for tunnel adits, deaeration chambers, and drop shafts.
Description
The Texas Department of Transportation (TxDOT) will reconstruct and lower I-35 as a part of the I-35 Capital Express Central project. The planned improvements will require effective flood and stormwater management. This segment will construct 6.5 miles of 22-foot diameter drainage tunnels. Nine (9) access shafts including adits & deaeration chambers will also be added along I-35 to ensure proper maintenance and operational access to the new infrastructure. The segment will also include the construction of a pump station to improve stormwater management along the corridor.
Geology
The Project site geology is limited to part of the Balcones Fault Zone north of the Colorado River, east of Waller Creek, and west of Boggy Creek, characterized by highly variable and faulted subsurface conditions. Geology consists primarily of Austin Chalk, with some anticipated exposure of the Eagle Ford Shale.
Location
Austin, TX USA
Highlights
- Oversee construction of large-diameter drainage tunnels, adits, deaeration chambers, and shafts.
- Delivering comprehensive CEI services, including site supervision, quality assurance, safety compliance and contract coordination.
- Tunnel construction in dense urban environment beneath and in proximity to existing I-35 and residential areas.
Airport Shaft – TBM Tail Tunnel
Airport Shaft – TBM Starter Tunnel