Joint venture scores twice on
highway twinning project

By Andy Bateman, Engineering Editor

Hitachi EX1100, fitted with a mass excavation bucket, loads a pair of Cat 773D trucks. The EX1100 is the joint venture's largest machine on site.

   Two veteran Ontario roadbuilders, two northern highway contracts and a number of innovative techniques are adding up to success for the provincial Ministry of Transportation's Highway 11 twinning program.
     Joint venture partners, Aecon Construction and Materials Ltd., Brampton, Ont. and Leo Alarie and Sons Ltd., Timmins, Ont. began work on the Trout Creek Bypass, 45 km south of North Bay, in July 2000. Valued at $46.2 million, MTO Contract 2000-0261 includes 8 km of all new construction and five structures. This spring, the joint venture also began work on the South River contract, MTO 2001- 5106, which ties in with the south end of the Trout Creek Bypass and extends the twinned highway a further 10 km south towards Huntsville. This contract is valued at $24 million, including one structure and the construction of an east service road.
     JV project manager Bryon Kmith told Aggregates & Roadbuilding during a recent site visit, that good progress is being made on both projects. "The challenge here is dealing with natural ground conditions that range from swamp and earth to Laurentian Shield granite. The bypass contract is all new highway, while most of existing highway will become the northbound lanes of the completed South River contract. Extensive swamp excavation and surcharging of rock fills has been required on the bypass in order to obtain proper settlement of the swamplands. The bypass is on track for completion this fall, while the South River contract is in its early stages after a mid-May start."

Trout Creek Bypass
     Steve Amer, superintendent on the bypass contract, explains that the new alignment required the excavation of 1 million m3 of swamp and dirt as well as nearly 1 million m3 of rock. After excavating the swampy material, a lift of backfill, typically 2 m thick, was placed to bring the surface level approximately back to the original subgrade level. The fill material consisted of rock or excavated earth Selected Subgrade Material or SSM. Numerous wick drains, consisting of fibre-wrapped plastic sections some 100 mm by 6 mm wide, were installed at the same time to assist water movement up through the fill and accelerate the settling process. The fill on the road platform, bridge approaches and access ramps then received a surcharge (preloading) of a 3 m lift of Granular B to make sure that settlement would be complete before final paving.

Hitachi EX300LC loads one of the project's three Volvo A35C articulated dump trucks.

     The one-year pick up on the bypass schedule was achieved by working right through the winter of 2001/2002 when, despite frigid conditions, up to 10 000 m3 per day of fill was placed.
     Equipment to gauge settling of fill areas, up to 500 mm in places, included piezometers to monitor the water pressure under the fill and inclinometers to measure its lateral displacement. After settling, most of the Granular B surcharge was then removed to leave a permanent lift in place as part of the final platform. Road base construction was completed by the addition of a 150 mm lift of Granular A that also provided a running surface during construction. Base material quantities totalled 600 000 tonnes of Granular B and 150 000 tonnes of Granular A. Paving this summer will involve three lifts of HL4 asphalt including two 40 mm lifts and a final 50 mm lift. In addition to the mainline paving, the bypass will have paved shoulders on both sides with a 1.5 m wide shoulder on the median and a 3 m wide shoulder on the outside lane.

South River contract
    South River project superintendent Don Laforest explains that work here is focusing on the first 6 km section this construction season, with excavation quantities including 1.7 million m3 of earth and 225 000 m3 of rock excavation. Cut and fill quantities are about balanced, with the subgrade fill material and granular base materials sourced mainly from within the road alignment. As with the bypass contract, excavated earth fill is utilised as selected subgrade material to backfill excavated swampy areas. Here, the SSM will receive a lift of modified Granular B Type 1 material, varying in thickness from 600 mm to 750 mm depending on location, followed by 150 mm of Granular A to complete roadbase construction. Asphalt paving will begin next year.

Smooth rock cuts were obtained through experience with the Laurentian Shield granite.

     Not surprisingly, most of the joint venture's extensive earthmoving fleet is currently concentrated on the South River contract, transferring material from excavation to fill areas. No less than eight excavators, 12 rigid-body haul trucks, three articulated dump trucks and six dozers are at work supported by compactors and graders, as well as a number of smaller support and rental units. The excavator fleet includes a Hitachi EX 1100, an Hitachi EX 750, a Caterpillar 350, two Caterpillar 345Bs and two Caterpillar 330s, a Hitachi EX 300 LC and a Komatsu PC 200LC for fine grade work. The larger excavators are teamed with a haul truck fleet that includes eight Caterpillar 773Ds, three Caterpillar 769s and three Volvo A35C articulated dump trucks.
     After dumping, fill materials are levelled by a Caterpillar dozer fleet consisting of two D8Ns, two D6s, a wide-track D6 and a wide-track D5. Three of these dozers, the two D8Ns and one of the D6s, are fitted with a satellite guidance system to accelerate the levelling process.
     Behind the dozers, the compactor fleet includes two Bomag BW211D-3 compactors as well as Superpac 8400 rental machines. Additional support equipment includes a Caterpillar 16G grader on haul road maintenance, a Caterpillar 950 wheel loader and four hired tri-axle haulers.

Environmental Protection
     A number of measures have been taken to protect any watercourses that cross the road alignment. During the construction of the Trout Creek bridges, these measures included shock treatment to stun the fish while the existing streambed was cleaned and lined with riprap on its side slopes. Root wads were added to encourage fish spawning. Creek work on the South River contract involves extensive aquatic habitat work combined with staged diversions, all in the spawning window of the fish.

Stringent conditions are laid out for the
protection of aquatic habitats.

     Existing channels are surveyed to facilitate mirroring in the diversions. This is accomplished through the construction of cascades, rocky ramps, vortex rock weirs, rock protection, live willow stakes, large woody material and the planting of 400 trees on the new slopes. Detailed cross section surveys, pebble substrate count, photographs from set vantage points and the installation of erosion pins are some of the requirements that must be monitored over time to ensure the aquatic habitat is maintained, and are all part of stringent MTO conditions for fisheries preservation.

Quality procedures
     Plan administrator Ed Baran explains that the contract is working under a self-regulated quality compliance procedure. Under the procedure, the contractor is required to follow an accepted core quality control plan and job specific quality control appendix. The implementation and adherence to the quality control plan is paramount and both quality control personnel and workers ensure compliance with the items set out in the plan.

Structures
     The Trout Creek Bypass incorporates two separate structures carrying the north and southbound lanes over Trout Creek and, at nearly 300 m long, these five span structures are reportedly the longest span bridges in the MTO's North Eastern Region. In addition to their impressive size, the bridge design incorporates both a 3 per cent grade (longitudinal slope) as well as a 4.5 per cent superelevation (cross slope) to align with the road profile at this location.
     Concrete volumes on the bypass contract totalled some 6 300 m3 of 50 MPa high performance concrete as well as 1 800 m3 of 30 MPa concrete, supplied by Rainbow Concrete Industries Ltd.
     Asphalt aggregates for both contracts are being provided by E & E Seegmiller's portable spread which is set up in the nearby Marshall pit.
     Consulting engineers for both contracts are URS Cole Sherman.

September-October 2002 issue

Aggregates and Roadbuilding Magazine
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