St. Patrick's Island Pedestrian Bridge
Located in the City of Calgary, near the south entrance of the Calgary Zoo, the St. Patrick’s Island Pedestrian Bridge is an important connection to both sides of the Bow River.
Consisting of a continuous posttensioned cast-in-place concrete deck and three steel arch spans, the bridge was designed to evoke the image of a stone skipping across the River.
As Construction Engineer, ISL designed the temporary support bridges to span the Bow River and to support the cast-in-place walkway along the segmental pieces of the arch as they were erected into place. ISL also provided the first order precision survey services throughout the project.
The construction of the bridge was planned to be completed within a 20 month timeframe and would require the bridge deck to be completed prior to the winter season, with the arch segments being erected in the late winter and early spring.
Adapting to Change
In June 2013, the City suffered the largest flood event of its recent history. The St. Patrick’s Bridge was mere months away from completion when excessive water caused the loss of temporary supports under the deck. The team decided to demolish the deck and alter the sequence of construction. ISL and Graham Construction & Engineering collaborated on the redesign of the temporary arch supports and ISL created updated modelling for the erection of the remaining south arches and final load transfer. The work was completed in May 2014.