$1.7 billion wastewater system for Seattle
Opus was the principal design consultant and provided construction services for the installation of the 1650m long outfall to a depth of 200m.
The outfall includes 120m of 2100mm diameter steel pipe and 1530m of twin 1600mm diameter polyethylene (HDPE) pipe.
We came up with unique solutions to meet a number of challenges:
- Steep off-shore slopes and deep installation
- Stresses in the large pipes
- Seismic loading and soil liquefaction conditions
- Corrosion control systems
- Remote operating vehicle (ROV) operation of the 62 ports and gates.
This outfall project received multiple awards including:
- American Council of Engineering Companies – Gold Award: Water & Wastewater Engineering
- ASCE Seattle Section – Structural Engineering Honor
- ACEC Washington – 2010 Engineering Excellence Gold Award for Water & Wastewater Projects
- ACEC – 2010 National Engineering Excellence Award Finalist
- CEBC – Engineering Excellence
- CMAA – CM Project Achievement Award: Infrastructure Under $50 Million
- ENR Magazine – Best of the Best Projects 2009: Civil/Public Works
- IRWA Puget Sound Chapter – 2009 Project of the Year Runner-Up
- Northwest Construction Magazine – Best Heavy Civil Project of 2009
- NWCCC – 2009 Distinguished Project (Honorable Mention)
- Washington State Chapter APWA– Environmental Project of the Year: $25 million -$75 million