Canadian Consulting Engineer

Vancouver East Apron Expansion

ACRES INTERNATIONALOnly a year after completing the International Terminal Building at Vancouver International Airport (YVR) in 1996, the airport authority needed to add a new wing, known as the East ...

March 1, 2000   Canadian Consulting Engineer

ACRES INTERNATIONAL

Only a year after completing the International Terminal Building at Vancouver International Airport (YVR) in 1996, the airport authority needed to add a new wing, known as the East Chevron, to the existing terminal to keep up with increased traffic to the U.S.

To minimize disruption, the apron around the new wing had to be built first. In an area confined on four sides by existing functioning aprons and roads that could not be relocated, Acres International’s design team had to accommodate a larger de-icing area, remote overnight aircraft parking, and dual aircraft taxi lanes.

De-icing and more

The 90,000-m2 expansion to the apron was designed with a horizontal and vertical geometry that allows for multiple uses. The de-icing area provides four B747-400 de-icing positions, but also functions as one of the dual apron taxi lanes and as the remote aircraft parking area at times when de-icing is not going on.

The multi-use approach was done by grading the apron to create two 16,000 m2 de-icing areas that can be used when one of the taxi lanes is closed. The de-icing areas function independently, and both use the storm water system to collect glycol via a simple valve system (the operations had to be simple because staff turnover is high). The fluids are sent to pumping stations and then to a detention lagoon for later disposal.

The new glycol collection system, combined with the installation of dedicated oil-water separators, designed by Associated Engineering, improves the quality of run-off water entering the Fraser River. The same approach is expected to be used in future construction at the airport.

Pavement variations

The pavement structure of the east apron expansion is a combination of portland cement concrete (rigid pavement) and hot-mix asphaltic concrete (flexible structure). In the past, all apron pavements at YVR’s main terminals were rigid and virtually the same everywhere, regardless of the frequency or type of aircraft that might be using the surface.

For the east apron expansion a rigid pavement section was designed for the aircraft stands where heavy channelized loads are imposed and refuelling takes place.

Three main types of flexible pavement were used for the remaining sections. Rather than the rigid structure that would normally have been used for areas experiencing the heaviest loads, a unique “stabilized” flexible pavement was constructed. It combines a flexible asphalt surface that can be recycled in the future, with a subsurface cement-stabilized base course that distributes the heavy wheel loads to the weak Fraser River delta soils of the Sea Island location.

The east apron is separated from public roads by a 300-metre-long blast-deflector fence. In the past, U.S. suppliers usually provided such fences. For this project one was designed that met the criteria but used local materials and cost 50 per cent less than the proprietary version.

Another engineering challenge was having to construct the pavement in staged layers over several years. The drainage system’s manholes and catch basins had to be capable of draining the granular surfaces in the first year, as well as draining the finished pavement when the project was completed. The solution was to design the aircraft load-bearing reinforced concrete lids (including the gratings and structural steel beams) to be lifted to their final elevations and then grouted into place.

The use of flexible and rigid pavement construction saved about 20 per cent in construction costs compared to all-concrete pavement.

The design methods also allowed the airport authority to stage the work to meet their cash-flow requirements. Seven main work phases and three intermediate phases (co-ordinated with the designer of the hydrant refuelling expansion) meant the work was divided into segments, thus keeping airport operations as normal as possible. The overall “project definition” budget was $20.8 million, and the final cost of the east apron expansion was $16 million.CCE

Client: Vancouver International Airport Authority (YVR)

Design engineer, project definition, financing brief and resident inspections: Acres International (George Nowak, P.Eng., Janet Glass, P.Eng., Ken Salmon, P.Eng., Jamie Almeda, James Wynne, Wayne Lozinski, P. Eng.)

Project and construction managers: Pacific Liaicon

Geotechnical: Klohn-Crippen

Drainage modeling and oil/water separators : Associated Engineering (design), Acres International (integration)

Hydrant refuelling system: Colt Engineering (design) /Schroder Engineering

Quality control/assurance: Terra Engineering, Levelton Engineering

Aerial photograph: Jim Jorgensen


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