Barnett Highway Bridges - Seismic Assessment & Renewal Options

Due to the Evergreen Line Skytrain construction and removal of at-grade crossings, Port Moody relies on three grade separated crossing points over the SkyTrain/CPR lines. The Barnet Highway CPR Westbound and Eastbound bridges are vital for the city's infrastructure, carrying a key MRN road over the CPR right-of-way. Understanding seismic behavior, damage, and service limitations of these bridges is crucial, given their increased significance and potential seismic events. Retrofit solutions are necessary to maintain functionality, considering the varying seismic hazards in Metro Vancouver.

City of Port Moody selected Spannovation to evaluate the seismic performance of the Barnet Highway CP Rail Westbound and Eastbound Bridges, considering retrofit solutions and costs for three seismic performance levels. The westbound bridge, constructed in the 1950s, consists of a cast-in-place concrete 3-span beam bridge with a central drop in span. The eastbound bridge, built in the 1970s, is a pre-cast, pre-stressed I-girder 3-span bridge. Both bridges are positioned at a high, 45-degree skew angle. Our analysis included response spectrum and pushover analyses on 3D models, incorporating soil-structure interaction. Bi-directional pushovers were conducted to account for skewness and capture pier column biaxial demands. We developed practical and cost-effective retrofit concepts to address on-site construction challenges. To assess seismic resiliency, a probabilistic decision analysis-based methodology was employed, considering uncertainties and risks associated with seismicity levels, damage states, direct and indirect costs, and repair and recovery timelines.