Expanding North America’s Busiest Highway

At 820km, King’s Highway 401 is one of the longest highways in the world and a vital economic corridor across the province of Ontario. However in recent years there has been a significant increase in traffic on this route, making an expansion necessary to ensure the continued rapid transportation of motorists and goods.

Built in the 1960’s, Highway 401 is the primary route across Southern, Central and Eastern Ontario. Originally a convenient bypass, enabling motorists to travel across the province quickly, Highway 401 has evolved and now also represents a vital economic corridor for goods transportation. With certain sections carrying an average of over 420,000 vehicles per day, Highway 401 is North America’s busiest highway and has contributed significantly to Ontario’s prosperity. Due to an increase in use in recent years, the existing highway has struggled to cope with the additional traffic. Therefore, the Ministry of Transportation of Ontario (MTO) has deemed an expansion necessary in order to enable the continued efficient use of this important route. To date, 50% of construction has been completed and the conclusion of the project is expected in August 2013.


Doubling the lanes whilst minimizing motorist inconvenience

This expansion began in August 2009 and will be conducted in various phases, with this particular project encompassing the widening of the Highway 401 interchange at Hurontario Street. To do so, the highway will grow from 6 to 12 lanes with 4km of new collector lanes and 5.2km of pavement, including 12.5km of new sewers, 2 storm management ponds, and all associated traffic signals. Furthermore, the replacement of the Hurontario interchange requires the building of 4km of access ramps, 17 retaining walls, a bridge with steel girders and a concrete deck, and 4 new rigid frame bridges.

The main structural work associated with the project is the demolition of the existing Hurontario Street Bridge over Highway 401, and the construction of a new, longer bridge over the additional lanes. During this entire process the highway itself will continue to be in constant use. To enable the continuation of traffic, the new bridge will be built in two stages. The first half will be built adjacent to the existing bridge. Once this is completed, the traffic will be moved onto the new section of the bridge to enable the demolition of the existing bridge and the construction of the second half of the new bridge.

 


Why Holcim?

The project was put out to tender by the MTO in May 2009 and the construction work contract was then awarded to the lowest bidder at CAD 102 million, Dufferin Construction (DCC). DCC is a division of Holcim Canada and worked in cooperation with other divisions of Holcim Canada on the implementation of this project. This low bid was supported by the suggested use of Portland Cement Concrete Paving (PCCP), generating a saving of CAD 1.2 million over the alternative asphalt option.  Having worked with DCC on previous projects, the MOT had been extremely satisfied with the work done and awarded DCC an average CPI rating of 80. The CPI assesses quality (60%), safety (15%), timeliness (15%), and contract administration (10%) and gives the contractor a rating out of 100. As stated by Mike S. Chan, Area Contracts Engineer for the MTO, “I am always very happy to work on projects with DCC”. This proven track record for excellence therefore provided the MTO with the confidence that the project would be completed to a high standard.



Holcim’s scope of work

Having been selected as the general contractor, Dufferin Construction (DCC) is responsible for the structural work (including demolition), excavation, earth works, and concrete and asphalt paving. To produce the total volume of PCCP needed, DCC have installed a portable wet batch concrete plant on-site. Plant capacity is 160 m3/h, and on paving days 1,000 m3 per day is produced. Due to the limited capacity of the mixer trucks the PCCP is discharged using dump trucks, with a fast delivery time of only 30 minutes to the paver made possible as a result of having an unagitated mix.

Dufferin Concrete, another division of Holcim Canada, provides the 22,500 mRMX for all structural works (bridges) from 3 plants within a 15 minute distance. For the roadway section of the project 50,000 m3 of PCCP is required. The pavement structure also includes an Open Graded Drainage Layer (OGDL) under the PCCP requiring 19,300 mof concrete, whilst the access ramps are paved using Hot Mix Asphalt (HMA). Including recycled aggregates, granulars for the base of the road and the sewers amount to 710,000 tons.

All the aggregates and the cement needed for the different RMX’s are delivered by Dufferin Aggregates and Holcim Canada, respectively.  Over 80% of the asphalt needed is supplied from DCC’s Bronte asphalt plant, 20% (approximately 20,000 tons) of which is recycled, and the remaining volume is then covered by a third party supplier.  The cement, meanwhile, is delivered from a silo approximately 20 km away.

 


New techniques

Bridge deck

In order to build the 186 m bridge deck, a special technique with a sliding form was used. After first building the walls, the 28 m deck sections were casted and cured. The form was then lowered on jacks and pushed forward to the next section. This is the first time such a technique has been employed in the construction of an MTO structure; previously it was only utilized in the construction of floors for high rise buildings. This technique saves both time and money, but is only possible in specific cases where the bridge being constructed is a certain length and has walls on each side.

 

PLC Pavement for green award

With the special permission of the MTO, this project was also used to test a new type of concrete pavement on one 100m strip. This concrete made from Portland Limestone Cement (PLC) contains 15% limestone and 5% recycled cement kiln dust, thereby reducing energy demand in the cement production process.  This new and more environmentally friendly type of concrete pavement has also been submitted by DCC with the Ontario Road Builders Association as a candidate for green award. 

 

New specifications for sewer pipes  

To reduce costs, polymer laminated steel pipes were suggested in the tender for use in the sewerage system. Although cheaper than concrete, these thinly walled pipes require very careful handling to escape deflection and damage. To avoid the penalties which would have been imposed by the MTO should such damage occur, a premium cost solution for DCC was chosen. This involved the use of a coated strap rather than chains when maneuvering the pipes, and High Performance Bedding (HPB) when laying them. This HPB was comprised of a very fine stone rather than the usual aggregates so that compaction around the pipes was unnecessary. Due to their more delicate nature, workers were also trained on how to handle the pipes without damaging them.

 

Holcim quality and service: Rising to the challenges

Safety

Given the risks posed by the continued use of the highway by motorists while under construction, health and safety is paramount on-site to ensure zero harm to traffic and workers. Each week a 30 minute occupational health and safety (OH&S) meeting is held in order to uphold good practice on-site. A joint OH&S committee has also been set up in which the safety advisor regularly participates, plus there are regular formal internal audits which are conducted by a safety advisor. The taking of active measures such as the building of a fence to separate the old and new bridge structures have also helped to enhance safety. To date, there has been no lost time due to injury, and the most recent safety audit in November 2011 awarded the site a 98% compliance rating.      

 


Timeliness

On a site already under tight time constraints due to the political commitment given by the MTO to the public, this continuance of traffic also poses further challenges. Strict limits regarding lane and highway closures are stipulated in the project contract, with the closure of one lane being permitted for a maximum of 7 hours and two lanes for 5 hours per night. A single Saturday night was scheduled for the demolition of the Hurontario Street Bridge, and 2 Saturday nights were given over to the construction of the new underpass structure. Penalties have been put in place for early or late lane closure or delays in the completion of work, but to date no payment has been necessary.

As this project is heavily-staged, falling behind on a single aspect will result in delays to the entire construction work. Close management of the site and subcontractors is therefore vital to ensure that deadlines are met, with weekly meetings being held to allocate resources (equipment, crews) according to needs. The vertical integration of Holcim Canada into DCC has assisted in securing the on-time supply of materials and any shortage is supplemented by Dufferin Aggregates, improving on-site flexibility.  Lane and highway closures are communicated to the public in advance, and timelines are assigned to critical tasks. According to Chan, communication is one of the company’s greatest assets: “They are always willing to sit down and talk to us about how to solve any problems that may come up”. Owner induced delays are caught up on with support from the contractor, offering extended working hours, Saturday work, or by working through the winter. In this way then, Holcim is operating to ensure that the project progresses with minimal delays.    

Quality

MTO specifications for the smoothness of the pavement allowed a tough tolerance of just 5 mm to design elevation. Therefore, in order to guarantee optimum smoothness and fulfil these requirements, graders and bulldozers are guided by GPS. Road smoothness is further ensured by the experience and skills of Holcim employees and high standards in equipment quality. For mass pours (e.g., one deck of 800 m3) temperature is controlled using ice in the summer and hot water for structural concrete in the winter. Thanks to pay adjustment factors based on performance Holcim is currently on a 5% bonus due to the quality finish of the pavement surfaces, despite the fact that PCCP is more difficult to work with than asphalt due their being fewer options to correct any mistakes or unevenness.


A road towards environmental and economic sustainability

When complete, the expansion of the Highway 401 interchange at Hurontario Street will result in improved traffic flow and an increase in the speed at which people and goods can be transported across the province of Ontario.  Furthermore, the project will require a total of over 500,000 man hours to complete, generating income for local workers. Almost 20%, or 20,000 tons, of the asphalt is recycled, thereby reducing resource and energy use. What is more, this project was used as an opportunity to explore the potential of developing and using a more environmentally friendly type of cement. In testing the suitability of this contender for the Ontario Road Builders Association green award for future use, Holcim is also paving the way towards a more sustainable future for road construction as a whole.