The Carolina Trunk Sewer Rehabilitation project replaces an aging sewer trunk serving southwest Portland. The project is being constructed within a highly constrained urban corridor characterized by steep terrain, narrow streets, residential properties, existing infrastructure, and proximity to Interstate 5. The new alignment will improve accessibility and long-term reliability of this critical wastewater infrastructure.
Stiver Engineering provided specialty structural, hydraulic, and construction engineering services supporting multiple elements of the sewer rehabilitation and temporary bypass system. Our work included gravity bypass design, hydraulic evaluation, tie-in structures, thrust restraint and pipe support, manholes, pipe collars, bulkhead anchorage, and pipe encasement. ENR also identifies Stiver Engineering as the designer of the project’s temporary gravity bypass.
Temporary Gravity Bypass Design
Stiver Engineering designed a temporary gravity bypass system to maintain sewer flow during construction. The design addressed alignment, elevations, flow requirements, site constraints, and coordination with surrounding construction activities and was adapted as project conditions evolved.
Structural and Pipe Support Design
Stiver Engineering designed structural components supporting the temporary bypass and its connections to existing infrastructure. Our work included tie-in structures, pipe support and restraint, and structural solutions accommodating changes in pipe alignment, elevation, and project geometry.
Manholes, Pipe Collars & Specialty Structures
Our team provided structural engineering for manhole and junction structures, pipe collars, bulkheads, anchorage, and related components required to integrate the bypass system and support construction.
Pipe Encasement Design
Stiver Engineering also provided structural design for pipe encasement, addressing stability, reinforcement, anchorage, and applicable loading conditions. Engineering support continued as field information and construction requirements developed.
Through its involvement, Stiver Engineering delivered coordinated engineering solutions supporting the construction and continued operation of critical wastewater infrastructure within a highly constrained urban environment.
