By Dillon Consulting
AWARD OF EXCELLENCE / TRANSPORTATION Winnipeg’s Southwest TransitwayCompanies & People Transportation Transportation Infrastructure
“This is a complex engineering project that is the first leg of a busway network. It will move Winnipeg significantly towards a sustainable transportation system, bringing major social and environmental benefits.”
The City of Winnipeg engaged
Dillon Consulting for the design and construction management of its first rapid transit corridor – the Southwest Transitway.
The transitway is a key component of Winnipeg’s transportation master plan and consists of a high-speed busway that is physically separated from the regular street system. The intent of the project is to increase transit ridership, reduce traffic congestion and support the city’s growth.
The transitway was built within an existing dense urban environment on an alignment in immediate proximity to a CN mainline and the Red River. It is also near to a Manitoba Hydro substation, major arterial roads, multiple underground utilities, and several private properties. The tight site created complexity in both design and construction.
Using a fast-track approach that involved seven tendered contracts, Dillon delivered the complex project over a three-year construction period, on time and on budget. Rapid transit service commenced on April 8, 2012.
The project included the grade-separated busway, stations, a tunnel beneath a CN railway mainline, a bridge with an enclosed station over a major arterial roadway, and bike paths. Also, portions of two major arterial roadways had to be relocated to create space for the transitway. A complex construction staging plan was employed to minimize traffic disruptions.
Tunnel below a railway
Below the active CN railway line the tunnel was built in two phases. It is a 200-metre cast-in-place concrete structure with an additional 150 metres of retaining/wing walls.
A complex shoring system was used to eliminate vertical obstacles, allow continuous unobstructed work, and increase safety. It consisted of sheet piling on three sides of the tunnel structure and struts that spanned between the sheet piles.
The tunnel needed to be constructed at a very obtuse angle to the railway tracks to accommodate the roadway geometry and minimize land impacts. It was also designed to accommodate conversion to light rail transit (LRT) in the future.
Osborne station on a bridge
Osborne Station, the transitway’s showpiece, is located atop a new bridge that spans a busy road. The bridge and station building had to be built at a skew angle in relation to the street beneath. The site constraints required the termination of exterior girders at the west pier. To mimic the profile of continuous girders, innovative methods of analysis were used to generate a design that cast the terminated girders into the pier. A very shallow bridge girder was designed to provide sufficient roadway clearance and accommodate the necessary vertical curvature of the transitway on the bridge.
To sustain the potential LRT loadings, thick member sizes and tight girder spacings were used. Also, expansion and contraction effects due to temperature variations had to be considered in the design for both the bridge and the station superstructure as the station is not completely enclosed and heated. Because the fixed points of the bridge and building superstructure are different, the superstructure could not be braced to the bridge and therefore is an independent structure.
A new pumping station and land drainage system, installed using tunnel boring technology, services the transitway as well as the CN mainline, tunnel and an adjacent development. Also, special design approaches were implemented to protect two 69-kilovolt lines located beneath a 300-metre length of the transitway.
The transitway has improved access to downtown and has already stimulated new development, including a community of 900 dwellings adjacent to Fort Rouge Station and a mixed-used tower at Osborne Station. cce
Winnipeg’s First Rapid
Transit Corridor – Southwest Transitway
Award-winning firm/prime consultant:
Dillon Consulting (Dave Krahn, P.Eng.;
Bill Menzies; Robert Taylor, P.Eng.;
Jeff Short, P.Eng.; Taran Peters, P.Eng.;
Rick Pidsadny, C.Tech.;
Tracey Kucheravy, CET)
City of Winnipeg, Transit Dept.
Other key players:
AECOM (geotechnical, rail engineering); GPP architecture
(station architect); McGowan Russell
Group (aesthetics and landscape)