Canadian Consulting Engineer

Ocean View

Anyone who attends a conference in Vancouver appreciates spending time at the Canada Place convention centre. It's wonderful to step outside onto the quayside and inhale the bracing ocean air. Above, a row of white sail roofs soars upwards,...

August 1, 2009   Canadian Consulting Engineer

Anyone who attends a conference in Vancouver appreciates spending time at the Canada Place convention centre. It’s wonderful to step outside onto the quayside and inhale the bracing ocean air. Above, a row of white sail roofs soars upwards, facing across the water to the towering North Shore mountains.

Now, the 1986 building has a sister a few hundred metres along the shore. Vancouver Convention Centre West opened in April, and it too faces out over the water’s edge in dramatic style. However, instead of soft organic forms and materials, the new structure is glass, steel and wood, with jutting angles that are “folding, sliding and rising from the waterfront and adjacent public park,” say the designers.

The building has already accumulated some history, mostly because of its rising construction costs, which were subjected to a provincial auditor’s report in 2007. The auditor found that the cost escalation from $495 million budgeted in 2004, to the final (and achieved) $883.2 million, was partly due to the fast-track design-build approach, and also partly due to the inflated cost of labour and materials in a city bursting with construction activity for the 2010 Winter Olympics.

The new convention centre will serve as the media centre for the Winter Olympics in February. Rising only to five stories, it has 1.2 million square feet, including exhibition halls (223,000 sq. ft.), meeting rooms (60,000 sq. ft.), retail space (90,000 sq. ft.), ballroom (55,000 sq. ft.) and 400,000 sq. ft. of open public meeting areas, plazas and walkways.

The low roof profile was necessary to allow for view corridors to the mountains, but the designers took advantage of this feature by outfitting it with what’s believed to be the largest green roof in Canada. The roof stretches six acres and is planted with 400,000 indigenous plants. This and other unusual features such as a blackwater (sewage) treatment facility and use of ocean water cooling are intended to earn the building a LEED Gold rating.

The civil and structural engineering were a formidable challenge, not least because two-thirds of the construction was over water. Also, the architecture is irregular (one facade “leans”), there is no basement space for equipment or parking, and there is the ever-present risk of seismic activity in this region.

Some of the engineering challenges in this complex project are described in the articles that follow. — BP

Architects: LMN, Musson Cattell Mackey, DA Stuctural: Glotman Simpson (Robert Simpson, P. Eng., Geoffrey Glotman, P. Eng., Phil Espezel, P. Eng.) Mechanical & project management: Stantec (Blair McCarry, P. Eng., David Walker) Electrical: Schenke/Bawol (Wolf Schenke, P. Eng. Marine/foundation: Worley Parsons/Westmar (Harold Kullmann, P. Eng., Ryan MacPherson, P. Eng., Geoff Harrison, P. Eng., Carol Turner, P. Eng.) Civil: Sandwell. Geotechnical: Golder. Building envelope/wall: Morrison Hershfield. Fire protection: GHL. Lighting: HLB, Schenke/Bawol General contractor: PCL. Owner: PAVCO/VCCEP, BC Pavilion Corporation Supplier: Osram Sylvania (lighting controls and DALI ballasts) Below Water -Foundation & Marine Design

WorleyParsons Westmar

Building on work from other proposed developments at the site, we first conducted an intensive review of historic records to assess the level of risk to the deep foundation components.

We changed the structural supporting system for the foundation from a drilled-shaft (caisson) concept to a high capacity driven piled structure. The new concept is estimated to have saved over $10 million in costs and it removed the high risk of installing deep foundations from the critical path of this fast tracked project.

The elevation of the structure is almost a metre below normal wharf level in order to accommodate existing infrastructure on shore. This meant that the main electrical and mechanical systems tunnel and the truck loading bays were located below high tide.

The final structure included over 900 driven steel pipe piles. It has precast concrete deck beams and girders, a segmental post-tensioned precast concrete utility tunnel, wave impact protection, and three construction tower crane runways.

Among the other challenges facing the design team were the tight schedule, poor ground conditions, and environmental challenges. A unique bolt-on precast concrete marine “habitat skirt” surrounds the perimeter of the foundation creating a critical link between the existing marine habitat on adjacent shorelines and a new reef habitat offshore from the facility. — Richard Malinek

Trusses Floor To Floor -Structural Design

Glotman Simpson Consulting Engineers

With strict zoning restrictions and two thirds of the building hovering over Coal Harbour, this was never going to be a straightforward project. The architectural concept included very large spans, juxtaposed spaces, angular shapes and heavy loads. The superstructure design and construction was complicated by the high seismic zone, sloping columns on the north face, the irregular geometry throughout, and the glass curtain wall.

Pinched within the confines of two immovable limits — the harbour high tide mark and an existing city street — the structure spanning above the expansive exhibition hall on the lowest level could be no deeper than 600 mm to allow for the 9-m clear height required for a world-class exhibition space. Fortunately a few columns could be permitted in the exhibition hall in 27.4 by 36.6-m bays. However, the meeting rooms, ballroom and foyer had to be clear span.

The key solution for planning the structure turned out to be steel trusses the full depth of floor levels — and in a number of cases, multiple floor levels. The special configuration of deep trusses allowed for door openings through the truss walls as required by the architectural layout.

Dozens of large-format wall trusses, scattered eccentric braced bays and floor beams take lateral loads. Trusses over 22 metres deep in the ballroom receive the roof framing supporting a green living roof that spans 55 metres. The multitude of eccentric braced bays help to widely distribute seismic systems to give excellent redundancy and sequential yielding. They also distribute load onto the marine deck over the ocean.

The sloping columns of the north face that lean over the bikeway and open water place a lateral push on the building that the structure needs to resist. We had to find a system that would resolve the forces and still allow the building to go through reverse cyclic yielding, so we used a series of diagonal tensioned braces with disk springs. The spring is tensioned to match the diagonal push of the gravity force of the leaning column. When balanced, the spring frees the seismic system of the lateral loads so it can oscillate through yield excursions without leaning excessively in just one direction.

Building Information Modeling (BIM) transformed the design process and enhanced the construction. Glotman Simpson proposed BIM for this project, and we also took full advantage of electronic communications for 3D modeling, design, presentation and document delivery.

The architectural design used Revit 3D modeling for massing, layout and design. Glotman Simpson implemented steel detailing software Tekla together with SAP2000 and Revit Structure to provide the structural modeling at the design developme
nt stage. By employing Tekla early in the project, the structural design information became the springboard for the shop drawings and foreshortened the tendering and shop drawing period considerably.

As an example, 3D conceptualization allowed us to approximate and shortcut methods to estimate preliminary steel quantities within 5% of the final built configuration on this highly complex and challenging building. — Robert Simpson, P. Eng.

Cooling With Sea Water -Mechanical Design

Stantec Consulting

The 111,000-m2 Vancouver Convention Centre Expansion project set an early target of LEED Gold certification in sustainable design.

Built over the harbour, a sea water heat pump/chiller arrangement was chosen for its lower operating cost and reduced greenhouse gas emissions. The temperature of the sea water allows the system to extract heat from the ocean or reject heat into it. Two heat pump chillers and one variable speed cooling-only chiller meet the heating and cooling demands. A steam back-up from Central Steam, a utility company in Vancouver, is provided for reliability and for the kitchen services.

The sea water is pumped from an intake chamber located just outside the structure’s marine habit skirt to heat exchangers in the chiller room. The heat exchangers provide a separation between the chillers and the sea water, since sea water is very corrosive for mechanical equipment. Also, there are self-cleaning backwash strainers to ensure small particles do not get into the heat exchangers. High density plastic pipe was used since steel pipe would rust out in a very short time between the pumps and the heat exchangers.

With the parking area located within the structural truss space of the exhibit hall, the duct space allowance at the ceiling level in the exhibit hall is small and could not accommodate conventional size ductwork. Two-thirds of the cooling load in this space is met by the ventilation system, while a radiant ceiling provides additional cooling, giving both lower first and operating costs.

The perimeter pre-function spaces with full glazing use radiant floors for heating and cooling, with a demand-controlled air supply system to suit the occupancy. Some pre-function areas can use natural ventilation during times of low occupancy. The Signature ballroom to the North, which has full glazing for views of the harbour and mountains, also has a radiant floor for comfort heating.

The meeting rooms have individual controls, with allowance made for different partition positions. They turn on and off according to the function schedule, or a local operator can override them using a PDA.

Since the 26,000-m2 green roof was deemed a “DMZ -delete mechanical zone,” all the mechanical equipment is within the building enclosure with louvers on the exterior only. With the use of sea water for rejecting the heat from the chillers, the need to have cooling towers on the roof was eliminated.

Sewage treatment on-site

A membrane bioreactor sewage treatment system treats the building sewage on site. It produces clean, reclaimed water for flushing toilets and irrigating the green roof and landscaping. Located in the northeast corner on the lowest floor of the building, the treatment system has a capacity of 20,000 gpd. Thanks to the water treatment, the building achieves a 70% reduction in potable water use (excluding kitchen use).

In terms of its energy use, the building is projected to achieve the highest LEED energy points and may exceed its LEED Gold target. Greenhouse gas emissions are projected to be very low at 15 kg/m2 or about one-sixth those of the existing convention centre. — Blair McCarry, P. Eng.

The Utilidor -Electrical Design

Schenke / Bawol Engineering

There are many unique electrical features in the Vancouver Convention Centre expansion, but one of the most innovative is the Utilidor.

Located below the floor of the exhibition hall, the utilidor is a long service space or tunnel. It runs east-west below the floor and on the centre line of the exhibition hall for the entire length of the hall, some 225 metres. The utilidor is approximately 3 metres high and 3 metres wide and is continuous except for a 3.5-m gap in the centre of the run where it crosses the main building expansion joint.

All services for the exhibition hall floor run from the utilidor. It contains two 2000A -600V bus ducts, one from the west electrical room and one from the east room, each running to the centre of the hall. These busses are tied through the floor expansion joint section, with a tie breaker on the east side providing some redundancy for the exhibition hall power.

Connected to the bus duct, a series of 300 kVA transformers is located along the length of the utilidor, which provides 120/208V power to the floor ports. The utilidor also contains voice/data racks and cable trays. It is organized so that all of the power elements are along one wall, and the voice/data/systems equipment and cable trays are run on the opposite side to reduce possible electromagnetic interference (EMI).

The 21,000-m2 exhibition hall includes a series of floor ports based on a 9.1 m x 9.1m grid, the standard for convention centres. The floor ports are large boxes with highway-rated lids, each containing 100A three phase receptacles and other receptacles, as well as voice/data access points. The floor port system is connected to the utilidor with conduits run in the concrete floor. The organization of the floor ports provides low tension conduits into one side and line voltage into the opposite side of each box in such a way that these conduits never cross in the floor slab, again reducing the possibility of EMI.

Running in the floor, radiating out of the utilidor in line with the floor port rows, are empty cable chases to allow temporary connections on a per show basis. The chase rows alternate between an empty 100-mm conduit and a 100-mm x 300-mm raceway. In designated rows, the larger chases are extended beyond the exhibition hall out to the loading dock, allowing temporary cables to connect the loading dock to the utilidor and, via the utilidor, to any of the floor ports. This allows cables from temporary facilities such as broadcast service trailers access to any location on the floor. The whole system is designed for maximum flexibility as the convention floor needs to deal with many different configurations and events. — Wolf Schenke, P. Eng.

Fire Protection, Security And Lighting

The building’s fire protection design took advantage of the flexibility of a performance, or “objective-based” approach, as is provided in Canada’s National Building Code.

Fire Protection Using Objective Codes

Ron Beaton, project architect with DA/MCM, explains that for example the building’s sprinkler system has multiple connections to the city water supply. In case these fail, there is a secondary salt-water intake from the ocean. There is also an overlapping dual sprinkler system in certain areas.

With this redundancy in the fire protection, the designers were able to leave the steel structure in the exhibition hall exposed, rather than cover it with a sprayed fire protective coating as would be normally required.

The designers also did extensive computer modeling of fires and smoke management. This approach enabled them to have a totally interconnected public space of three stories in the lobby (see photo page 16).

Security

For the 2010 Olympics security will be at a premium and special measures will be put in place. For now, though, Beaton says that the security infrastructure in the new building is fairly standard. There are door access controls and a network of CCTV pan and tilt cameras, which serve both for security and life safety. The entire system is monitored in a cwentral control room and connected to Canada Place to the east.

Lighting -Bringing
It All Alive

Perhaps the building’s most striking architectural lighting feature is the flood of indirect lighting onto the Douglas Fir and Hemlock wood slatted panels that line the main lobby and prefunction areas. Lit up at night, the panels make a rich and dramatic play behind the building’s lead- free clear glass walls. (See photo page 14).

The meeting rooms have T5 fluorescent lamps with network addressable DALI dimming ballasts that allow each individual luminaire to be controllable. In the ballroom are metal halide, T8 fluorescent and tungsten halogen lamps in a series of pendants that provide both direct and indirect illumination. In the exhibition hall, the lighting includes both metal halide and high lumen package, fluorescent luminaires, which have networked addressable ballasts and relay-controlled multi-level switching.

Some LED lighting is used to illuminate artwork in the building, and also to light 15-m high signage systems. On the exterior walkways, “dark sky” lighting fixtures confine the light downward to prevent light pollution.

HLB of California were the lighting designers, except for in the main exhibition hall where the lighting was designed by Schenke/Bawol. — BP


Print this page

Related Stories

Leave a Reply

Your email address will not be published. Required fields are marked *

*