Knowledge CentreTechnical Resources SearchConference PapersCHIEF PEGUIS TRAIL EXTENSION – ROTHESAY ST. OVERPASS RAPID DESIGN & CONSTRUCTION OF AN INTEGRAL ABUTMENT BRIDGE WITH MSE WALLS & CELLULAR CONCRETE BACKFILL

CHIEF PEGUIS TRAIL EXTENSION – ROTHESAY ST. OVERPASS RAPID DESIGN & CONSTRUCTION OF AN INTEGRAL ABUTMENT BRIDGE WITH MSE WALLS & CELLULAR CONCRETE BACKFILL

Abstract

The Rothesay Street Overpass is one component of a significant Public Private Partnership (P3) project, the Chief Peguis Trail (CPT) Extension, in Winnipeg, Manitoba. Due to changes in the P3 Contractor’s design/construction team, the overpass subcontractor was required to hire a design engineer for the Rothesay Street Overpass, and had less than one year to complete the design and construction of the structure. In the preliminary stages of the CPT project it was decided to raise the overpass 3 m from the original at-grade design in order to eliminate a costly lift station that would have been required for land drainage with a 6 m deep underpass. The overpass is in a congested urban/residential location, and raising the structure required the addition of narrow approach embankments over poor soil conditions between residential housing. The P3 Contractor owns the CPT facility for 30 years, after which ownership reverts back to the City of Winnipeg. As a result, the schedule, cost, constructability, durability, future maintenance and stringent hand-back criteria were critical factors affecting the design and construction. To minimize structure depth, maintenance costs, and increase durability, a two-span precast box girder overpass with integral abutments was selected. Due to the compressed schedule, Mechanically Stabilized Earth (MSE) retaining walls were selected to create the narrow approach embankments, abutment backwalls, and grade changes required to fit the structure into the project’s right-of-way. To compensate for the poor underlying soils and high anticipated settlement, lightweight cellular concrete backfill, up to 5 m in depth, was required. The use of cellular concrete around integral abutments provided unique challenges, and innovative details were developed to allow performance of the integral abutments in a relatively rigid backfill. Preliminary design through to construction completion and overpass opening on December 1, 2011, took approximately 11 months, and the design and construction was completed on budget and on schedule. This project demonstrates that: (1) Construction schedules can be significantly compressed even when utilizing new and innovative materials and designs. (2) The combination of an integral abutment overpass, MSE abutments and retaining walls, and lightweight cellular concrete backfill is a viable alternative when site conditions, the construction schedule, and/or construction costs dictate that a more traditional structure will not achieve the project goals. (3) MSE retaining walls are very quick to erect, and backfill with cellular concrete can accelerate the construction, however, procurement of construction materials can have a significant effect on the schedule. (4) A comprehensive Quality Management Program, including third party reviews, is essential to the success of the design and construction of a P3 project. (5) P3 projects are inherently an economical and cost effective solution for providing new and replacement infrastructure, even if they are not “mega” projects. 6) Selection of an appropriately skilled design-build team is critical to the success of an innovative and fast-track design-build project. 

Conference Paper Details

Session title:
BRIDGES – INNOVATIONS (B)
Author(s):
Eric B. Loewen
Marc Baril
Rados Eric
Topics:
Structures
Year:
2012