Hogg’s Hollow Highway 401 Bridge Widening, Toronto, Canada

ABSTRACT: Highway 401 stretches in Ontario, Canada, from Windsor (at Michigan, U.S.A. boarder) to Quebec border. Part of Highway 401 is presently the busiest highway in North America, carrying about a half million vehicles per day along its sixteen lanes (core-collector system) in the Yonge Street and the central Toronto area. In the early 2000’s the Ministry Transportation of Ontario (MTO) decided to widen the existing east-bound collector lanes of Highway 401 at Yonge Street over the Hogg’s Hollow Valley in Toronto. The Hogg’s Hollow is an approximately 500m long, 40m deep valley, incised by the West Don River, prior to its joining the East Don River further south and forming the Don Valley. This paper describes the geology of the site along a summary of the available geotechnical and structural information. The selection of the most suitable widening alternative and its implementation are also discussed.