Pedelta is working as an exclusive design team leader to provide the design coordination and structural engineering services including technical assistance during construction for the winning proposal submitted to Build Toronto in response to the RFP – DB Services Fort York Pedestrian and Cycle Bridges. Pedelta’s proposal includes a unique design for the Fort York Bridges consisting of two tied stainless steel network arch bridges to cross the railway corridors. Each bridge is supported by a single arch rib inclining at 18º to provide a slender, transparent and elegant impression. The two arches tilt in opposite direction, and the overall layout resembles a Yin & Yang shape to emphasize both contrast and continuity, expressing a modern, understated and elegant aesthetic. The innovative bridges are based on the company’s aesthetic philosophy of “Complex Simplicity”.
Pedelta’s proposal includes an unprecedented technical innovation in North America: the use of Duplex Stainless Steel on the entire structure. This pioneering use of a forefront technology will provide premium aesthetics within an unique setting in addition to a safe and durable asset for the community. The structure has an extended life cycle, is more corrosion-resistant and requires less maintenance, reducing its overall cost.
The design has been focused on both structural efficiency and pleasing proportioning of the geometry. Both bridges span the rail corridors almost perpendicularly to minimize the crossing distance, which leads to a 52 m span for the North Bridge and 44.5 m span for the South Bridge. Also, both bridges use trapezoidal cross sections for girders and triangular cross sections for arch ribs. The span-to-rise ratio is around 6 and the span-to-arch-depth ratio is around 100. To accommodate the 5 m elevation difference between the ends of the South Bridge, a curved landing is proposed to gracefully connect the bridge to adjacent paths.
The bridges are designed to add a distinctive visual element with clear vistas to Toronto and its neighborhoods without dominating the city skyline. Both north and south bridge landings propose specific lookouts, out of the traveled zone. The south bridge curved approach ramp provides constantly changing panoramic view perspectives to Garrison Common and Fort York.