Western Terminus Replacement Project
Project Details
HDD
- 42-inch HDPE treated effluent
- 1,200-foot wetland crossing
Geotechnical Conditions
- Young Bay Mud
- High groundwater
Challenges
- Accelerated design timeline
- Environmental restrictions
- Minimizing impacts to residents
Project Overview
As a subconsultant to Brown and Caldwell, Bennett Trenchless Engineers provided trenchless design services for the HDD installation of 1,200 feet of 42-inch HDPE treated effluent pipeline under an environmentally sensitive area in San Lorenzo, CA. Challenges included the large diameter and length of the HDD crossing, and the presence of soft Young Bay Mud soils. The more severe challenges of the project included a significantly accelerated design timeline, work area constraints, numerous environmental restrictions, a very tight construction window, maintaining access to a bike path that ran through the construction zone, minimizing disruption to nearby residents, and managing a high risk of hydrofracture.
In addition, the project had a significantly accelerated design timeline; construction was completed within one year of receiving the Notice to Proceed for design. Bennett Trenchless provided preliminary and final design services, specifications, hydrofracture and settlement risk evaluations, cost and schedule estimates, and submittal review assistance.
Project Details
HDD
- 42-inch HDPE treated effluent
- 1,200-foot wetland crossing
Geotechnical Conditions
- Young Bay Mud
- High groundwater
Challenges
- Accelerated design timeline
- Environmental restrictions
- Minimizing impacts to residents
Project Overview
As a subconsultant to Brown and Caldwell, Bennett Trenchless Engineers provided trenchless design services for the HDD installation of 1,200 feet of 42-inch HDPE treated effluent pipeline under an environmentally sensitive area in San Lorenzo, CA. Challenges included the large diameter and length of the HDD crossing, and the presence of soft Young Bay Mud soils. The more severe challenges of the project included a significantly accelerated design timeline, work area constraints, numerous environmental restrictions, a very tight construction window, maintaining access to a bike path that ran through the construction zone, minimizing disruption to nearby residents, and managing a high risk of hydrofracture.
In addition, the project had a significantly accelerated design timeline; construction was completed within one year of receiving the Notice to Proceed for design. Bennett Trenchless provided preliminary and final design services, specifications, hydrofracture and settlement risk evaluations, cost and schedule estimates, and submittal review assistance.