IDYLWYLD DRIVE OVERPASS AT RUTH STREET REHABILITATION

ISL was retained to perform initial baseline testing and inspection on Idylwyld Drive Overpass to determine the extent of deterioration and offer recommendations for rehabilitation.

Client: City of Saskatoon

Location: Saskatoon, Saskatchewan

Project Type: Structures

About This Project

In 2013, the City of Saskatoon commissioned ISL Engineering and Land Services (ISL) to perform initial baseline testing and inspection on Idylwyld Drive Overpass to determine the extent of deterioration and offer recommendations for rehabilitation. ISL recommended a traditional deck rehabilitation where the top 100 mm of concrete would be removed and replaced. Since bridge deck continuity would be compromised during repairs, shoring would be required. Additionally, though the preference was to eliminate the joint via a semi-integral abutment, the length of the bridge made this impossible. Instead, ISL recommended the removal and replacement of the expansion joint seal.

In 2014, the City reengaged ISL to conduct detailed testing to determine the best strategy and to design the rehabilitation. Seeking the most cost effective solution and aiming to reduce or eliminate costly shoring, ISL modelled and evaluated several options. The evaluation pinpointed two potential solutions: staged concrete removals to replace the top 100 mm of the deck (Option A); and spot repairs combined with an impressed current cathodic protection (Option B).

Since the bridge components were built decades ago, their location and condition could only beassumed until construction. Understanding this uncertainty, ISL designed both options to provide flexibility once the true condition of the bridge was revealed. Option A was later selected, saving the City approximately $600,000.

Additionally, upon further investigation during the 2014 predesign, ISL discovered a way to eliminate the joint from the overpass, implementing a unique semi-integral abutment approach to protect from further deterioration.

By intervening at an opportune time, providing cost effective rehabilitation recommendations focused on the underlying deterioration issues at the site, thoroughly reviewing all potential alternatives and delivering innovation to achieve the desired 50 year service life extension of the overpass, ISL successfully met the needs of the City and ensured that the project aligned with its Core Bridge Strategy and Strategic Goals of Asset and Financial Sustainability, Quality of Life and Moving Around.