11-04-2021

Historic Success During A Pandemic

The Mackinac Deck Study

Historic photograph of the Mackinac deck construction
Historic photograph of the Mackinac deck construction

On July 8, 2021, we presented the bridge deck preservation and deck replacement study report to the Mackinac Bridge Authority (MBA) Board of Directors at a public meeting held on Mackinac Island, marking a significant milestone for both us and MBA. The report defines a 17-year capital program that will culminate in the completion of the full deck replacement for this 5-mile-long bridge crossing over the Strait of Mackinac. This will be the largest capital project ever undertaken by MBA since the bridge opened in the fall of 1957.

We were tasked with the deck preservation and replacement study early in 2020, just as the coronavirus pandemic was causing turmoil in project execution around the world. Our team undertook the most comprehensive condition inspection ever completed at the bridge and executed a plan to complete the multidisciplinary study—all while working remotely. Remote over-the-shoulder progress review meetings were also scheduled with MBA staff, a technique that benefited the effectiveness of the project workflow.

3D model printed in-house at Parsons and now on display at MBA’s main office in Saint Ignace, Michigan
3D model printed in-house at Parsons and now on display at MBA’s main office in Saint Ignace, Michigan

The study included field condition inspection, material sampling and laboratory analysis, service-life modeling, load rating, alternatives development, 3D computer modeling and wind tunnel testing, construction cost estimates, safety- and accident-history review, benchmarking against similar bridges, 3D-model printing, and alternatives analysis. The latter is an application of AltEval, a multicriteria decision algorithm written by a Parsons Fellow for complex decision-making situations such as this.

At the completion of the above-noted board meeting, the chairman complimented our team on the thoroughness of each aspect of this study report and the resulting presentation. The entire team’s dedication to the project and commitment to collaboration are what defined and successfully delivered this complex project during the most unusual of times.

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