Eastside Interceptor Section 1 Capacity Restoration Project

Restoration Project Overview

The primary goal of the ESI Section 1 Capacity Restoration Project was to restore capacity to a section of the 108-inch Eastside Interceptor that was damaged during a 1965 earthquake. Vanir served as a subconsultant on the project and provided project controls (scheduling, estimating, change order resolution, pay request processing) and document control services using our document control system.

The work consisted of installing 1,820 linear feet of 72-inch diameter concurrent bypass line using micro-tunneling techniques that required the construction of a bifurcation structure, an intermediate access shaft, and a junction structure.

A secondary portion of the project involved the installation of approximately 1,300 linear feet of 12-inch water main; reconnection of lateral mains and existing domestic meters and service lines; and construction of 550 linear feet of 18-inch and 650 linear feet of 12-inch concrete storm sewer lines.

Micro Tunneling in Compressible Soils

The micro tunneling was completed successfully with no changes in a residential neighborhood that had very compressible soils. The new line had to be installed by trenchless means, since previous deep utilities that were installed had required extensive dewatering and caused house foundations to settle.


Renton, WA


King County Department of Natural Resources and Parks

Design Team

Tetra Tech/KCM Inc.


Frank Coluccio Construction Company

Construction Cost

$5.5 million