Highway 1 Lynn Creek Bridge Renewal

2017-2021 | North Vancouver, British Columbia

McElhanney was retained by the Ministry of Transportation and Transit as prime consultant for the $98M Highway 1 at Keith / Seymour Interchange & Lynn Connectivity project. This high-profile project, one of the largest traditionally procured highway infrastructure upgrades in the Lower Mainland, connected the Mountain Highway and Keith / Seymour Interchanges, provided better east-west municipal connectivity, improved safety, and reduced congestion on Highway 1. McElhanney’s multi-disciplinary team designed complicated interchange geometrics with ramp and intersection reconstruction, realignment of Keith Creek, and new Lynn Creek bridge crossings within a constrained and congested corridor.

A key part of the assignment was upgrades to the existing Lynn Creek Bridge which was constructed circa 1960 and consists of a 72.3m long tied arch span. Our scope included a targeted load evaluation of the arches, development of strengthening concepts, and detailed design for the renewal of the bridge. The load rating evaluation was conducted using a three-dimensional finite element model of the bridge with the arch geometry determined using a three-dimensional terrestrial scanner, which recorded the geometry of the unloaded arches during night-time traffic closures. By modeling the as-built arch geometry and completing a second-order analysis which considers the non-linear behaviour of the arch geometry, we were able to remove conservatism associated with the use of an additional moment application factor required for first order analysis based on the design shape. McElhanney also completed in-situ vibration and deflection monitoring to calibrate the load rating model.

Renewal considerations included bearing and deck joint replacement, steel recoating, fibre-reinforced concrete overlay, structural steel repairs, and a TL-5 barrier system. Key challenges included balancing structural options with tight geometric constraints, reducing traffic impacts during and after construction, addressing environmental and permitting considerations for Lynn Creek, and supporting trail connections beneath the bridge.