Hogg’s Hollow Bridge is the most sensitive segment of Highway 401 and is viewed as the most critical and complex portion of the Ministry’s 401 Strategic Rehabilitation Program.  Just west of Yonge Street, the 378m long bridge is the longest and highest in the Toronto section.  It comprises eight main trussed spans each 42.7m long and two approach spans of concrete slabs on steel beams.

Morrison Hershfield completed two separate assignments involving the following major work items:

• Structural rehabilitation of a total of 12 structures including complete deck replacements at the Hogg’s Hollow Bridge
• Rehabilitation of the pavement structure including concrete base repairs
• Extensive construction staging and traffic management over multiple construction seasons including provision for winter staging and construction shutdown

As lead consultant for this Total Project Management (TPM) Detailed Design assignment, Morrison Hershfield was responsible for:

• Detailed design for all roadwork, structural and electrical components
• Development of construction staging plans for multiple seasons including winter shutdowns
• Preparation of contract package and documents
• Management of subconsultants for geotechnical investigation and pavement design, and environmental approvals 

The impact of delays on passenger and commercial traffic resulting from construction activities and/or construction related collisions on this section of highway would be severe.  Work proceeded in a manner that met the safety needs of the traveling public and workers within the construction zone, with minimal disruption to commuters and commercial carriers.

Morrison Hershfield leveraged its experience with similar freeway improvement projects to ensure a biddable and constructible design.