BIRT IWMB Replacement Study

The Burrard Inlet Rapid Transit (BIRT) Ironworkers Memorial Bridge (IWMB) Replacement Study is a high-level planning project commissioned by The District of North Vancouver. The study, conducted by Spannovation Consulting Limited, aims to develop optimal bridge crossing options for the Second Narrows, with a focus on carrying transit lanes across the Burrard Inlet. The project reviews the condition and deficiencies of the existing IWMB, a critical link along Highway 1. The primary goal is to address key challenges and regional objectives related to connectivity and resiliency while integrating general-purpose traffic with rapid transit and active transportation.

The IWMB serves as a major route structure with a daily traffic volume of approximately 125,000 vehicles per day. It is crucial for both regional and national goods movement and is considered a Priority 1 Major Route structure in the regional transportation network. However, it has vulnerabilities related to seismic activity, ship collision, wind, and fatigue, and the existing structure cannot be made to comply with current bridge codes through retrofit. Therefore, the study prioritizes measures to achieve a crossing that can withstand extreme events and continue to serve as a lifeline for the region.

The proposed solutions aim to integrate transit, highway, and active transport lanes in a phased construction approach. The first phase includes two eastbound collector-distributor lanes, two transit lanes, and two active transport lanes. The second phase replaces the existing IWMB carrying six highway lanes of general-purpose traffic. Bridge solutions proposed include twin bridge and stacked bridge concepts. The study, completed with limited funds, recommends further option generation and evaluation work, especially regarding foundations and tie-ins, to better evaluate impacts on private property and other constraints.