Installation of approximately 7 kilometres of sulphate-resistant RCP
under 401 median.
New special provisions in the Ministry of
Transportation Ontario (MTO) contracts for
major highways address the long-overdue quality
standards for the acceptance of drainage product
specifications. As a minimum quality control procedure
for pipe products, the contractor must now inspect the pipe
received at the job site and complete a comprehensive
checklist that includes a letter signed by a professional
engineer that states that all pipe supplied to the contract
complies with the contract documents.
Highway 401 widening between Regional Road 97 and
Homer Watson Boulevard in the Regional Municipality of
Waterloo was the first contract that specified reinforced
concrete pipe (RCP) for median drainage. AECON worked
with Delcan (contract administrator) and Con Cast Pipe to
ensure that the quality of the installation matched the quality
of the product shipped to the site.
The contract called for the widening of Highway 401
from four lanes to six, over a distance of 7.8 km from 2.0
km west of Cedar Creek Road (Regional Road 97) to 1.3
km west of Homer Watson Boulevard (Regional Road 28).
Included in the contract was the construction of a concrete
median barrier, the reconstruction of the eastbound ramps
of the Cedar Creek Road interchange and improvements to
the horizontal curve west of Roseville Road (Regional
Road 46). AECON’s five crews, who worked simultaneously
about 750 metres to one kilometre apart, installed
approximately 7 km of the sulphate-resistant RCP median
storm sewer. Shipped to the project were:
61 metres of 1050 mm diameter (50D) RCP;
293 metres of 600 mm diameter (50D) RCP;
435 metres of 525 mm diameter (50D) RCP;
1,944 metres of 450 mm diameter (50D) RCP;
2,454 metres of 375 mm diameter (50D) RCP; and,
1,597 metres of 300 mm diameter (50D) RCP.
Pipe supplied to the project is considered small diameter,
suggesting that applications for this range of concrete
pipe are not limited to alternate products such as high-density
polyethylene conduit or corrugated metal pipe. Since
400 series highways are managed during winter conditions
with periodic applications of sand and salt mixes, the pipe
design had to withstand any potential corrosion from road
salts. Today’s standard concrete pipe design accounts for
harsh environments such as road salts in stormwater and
snowmelt by testing for concrete density and appropriate
placement of steel reinforcement before product is shipped
to projects.
At the beginning of Stage 2 of the contract, AECON
received approximately 35 loads of RCP for immediate
installation by its crews. Key to the safety of the job site
and movement of product into the site was the maintenance
of a haul road for deliveries and movement of equipment.
All construction had to take place without significantly
interrupting the flow of traffic on Highway 401 since it
connects major urban centres in Ontario with Québec and
the US.
Proper scheduling and no delays in delivery of product
were critical considerations of the contractor in accepting
the specification for concrete pipe. Because quality product
was delivered on site when required and soil conditions
were favourable, the crews discovered that working with
concrete pipe did not cause any delays in constructing the
storm sewer. With the right equipment and experienced
pipe installation crews on site, any misconceptions about
difficulties in laying concrete pipe due to lengths, weights
and durability were soon left behind. The pipe-laying phase
of the project was completed within the scheduled time.
Changes introduced to MTO’s contracts are monumental
in terms of recognizing the inconsistency of contract
specifications with respect to quality assurance and quality
control. Situations where there may be lack of uniformity
and supporting logic for the specification of gravity
pipe are beginning to fade. Design guidelines used by
MTO incorporate life cycle costing and cost/benefit
methodologies into the selection process of pipe materials
used for drainage installations. In addition, other risk factors
such as corrosion and abrasion are incorporated into
the selection process to assist designers in specifying the
most appropriate, cost-effective pipe material for environmental
conditions encountered.
Reinforced concrete pipe has long been excluded from
use as a product for storm sewers under the concrete barriers
of 400 series highway medians. MTO’s special provisions
have opened new opportunities for Ontario’s traveling
public and taxpayers to enjoy the benefits of reinforced
concrete pipelines. MTO is monitoring the success of the
Highway 401/Regional Road 97 project as it issues the special
provisions for gravity drainage products on other highway
projects.
