Arch Engineers provided comprehensive design and inspection services for the Trans Mountain Expansion Project, focusing on the development of a resilient retaining wall and underpass bridge abutment capable of withstanding substantial passive, live, and dynamic loads. These loads included those from a 40” diameter pipeline, loaded rock trucks, pipelayers, and excavators. Our engineering solution featured Mechanically Stabilized Earth (MSE) lock block retaining walls, tailored to meet stringent specifications and various loading scenarios, including pipe, surcharge, and live loads.
The project involved meticulous analysis of pipe weights and considerations for transportation, incorporating detailed bridge drawings as blueprints to accommodate coated pipes, pipelayer weight, and different loading scenarios involving both empty and water-filled pipes for hydrotesting. Additionally, the scope included the design of an overpass bridge along the right-of-way (ROW) for pipeline welding and eventually feeding a thruster to pass under the Fraser River. This required precise engineering to ensure the structural integrity and functionality of the retaining walls and bridge abutments under diverse loading conditions.
One of the significant project constraints was the construction of two large bridge approaches and two retaining walls designed as abutments for the bridge. These structures allowed over-dimensional traffic to pass under the bridge via an underpass and gain access to the ROW. Initially designed for a 12-month effective life, the project faced delays, necessitating monthly inspections of the footings, walls, and bridge bearings for possible month-by-month extensions. Arch Engineers’ proactive and thorough inspection regime ensured the ongoing safety and stability of the structures, adapting to project extensions and maintaining high standards of engineering excellence throughout the project’s lifecycle.