NASTT Abstract

Victoria Harbor HDD Project: A Comprehensive Comparison of Detailed 3D Pullback Modelling and Actual Pullback

Authors:
Samuel Wilson, CCI Inc, Edmonton, Alberta

Abstract
The Capital Regional District (CRD) of Victoria, BC is constructing a new wastewater treatment facility. To connect existing infrastructure to the facility, a pipeline was required to cross the Victoria Harbor between Ogden Point and McLoughlin Point. Due to the large volume of marine traffic, a trenchless methodology was chosen. CCI was subcontracted to deliver a detailed engineering design for the HDD crossing.

The proposed pipeline installation consisted of a 940 m long NPS 42 (1,066.8 mm) HDD which required the pipe section to be prepared down a populated street in downtown Victoria, BC.

The narrow street led to an atypical pullback layout, which required extensive analysis including street level lidar scanning and 3D modelling to determine the impact to residents, powerlines, trees, and existing infrastructures. The road was shut down for pipe makeup and preparation.

This paper will discuss the detailed engineering design work completed pre-construction to evaluate the impact that preparing a large diameter pipe section along a densely populated street would impart. Additionally, the detailed pullback model will be compared to the actual implementation, including both the support locations and impacts, as well as the loads experienced during the pipe pullback operations.

Publication Date: 2019

Presented at: 
NASTT’s 2019 No-Dig North Show, Calgary Alberta
October 28-30, 2019
Paper Number: WA-T1-01

For more information on this article, please contact Sam Wilson (sam.wilson@ccisolutions.ca).