harbour air

This site is of great ecological importance, both aquatic and terrestrial. The site sits along the Fraser River, British Columbia’s longest river. This river is home to some of the worlds largest salmon runs and populations of giant White Sturgeon. Also, this site is a nesting and resting area for migratory birds as it sits along the Pacific Flyway. It is important to consider this site as a small part of a large network of natural systems. 

 
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DESIGN INTENT

The intent of the Harbour Air Seaplanes terminal and hotel redesign is to protect the tidal shelf and reforest the riparian zone along the Fraser river. Due to the concern for ecological and environmental issues related to the site, the goal of all the buildings is to be as ecologically and environmentally sensitive as possible. Cohabitation of humans and animals is essential for this project as it is a very ecologically sensitive and active area for seabirds and salmon. All the buildings aim to be as passive or hybrid as possible by using passive solar heating, natural cross ventilation, solar chimneys, heat recovery ventilation units, geothermal heat pumps, river sourced closed loop geothermal and thermal mass stabilization. 

Float planes are incredible machines. Watching a landing or takeoff is a spectacle. This space exemplifies the spectacle of the float plane through siting the building on the water close to the landing area of the planes. A long, glazed façade allows the noise and power of the planes to permeate into the waiting hall and restaurant to heighten the participants experience. 

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section model 1:50

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section model 1:50

 

 View from inside hotel unit looking past the spa and pool. 

View from inside hotel unit looking past the spa and pool. 

 View from the spa looking out towards the hotel mounds.

View from the spa looking out towards the hotel mounds.

STRUCTURAL STRATEGY

Sea Island is primarily composed of a sandy soil, which is unstable in nature and favours distributed loads, not point loads. Bedrock is approximately 25 meters[1] below the site and makes piles necessary for the hangar/event space.  The small hotel rooms, which are buried in the ground, are built on a floating concrete raft foundation, which distributes the point loads on the unstable soil. The hotel check-in/spa must be built on floating concrete raft foundations as well since it is also built on the dike. 

The Hangar space sits on the water level to allow float planes to easily be maintained and stored. The hangar and event space fall under F2 and A2 occupancies which require a 2-hour fire separation between these spaces. Non-Combustible, sprinklered construction is chosen for the space to meet required NBCC requirements. This space is part of a large, dike rebuilding process that is currently underway by the City of Richmond and the dike authority.  The walls are constructed of thick cast in place concrete walls, as they essentially function as the dike. These walls are shored into the dike to provide which provides lateral stability. End bearing friction piles   anchor the hangar space into the bedrock, and combined with an integrated closed loop geothermal system and ground sourced heat pump to temper the interior environment of the building. Two large (3000mm tall) steel belt trusses are anchored atop the concrete retaining walls. These belt trusses allow the use of a glazed curtain wall system, which in turn allows sunlight to enter the hangar space.  A deep (2500 mm) space frame sits on top of these belt trusses to span across the hangar space.  Both steel structures are coated in intumescent paint to meet required fire ratings. This space frame structure is necessary to support an inhabitable intensive green roof.  The intention of the green roof is to recreate a wide riparian zone that is heavily planted to buffer this proposal from the noise and pollution generated by YVR. 

There is a total of 21 hotel rooms nestled in the forested riparian area to create a rolling hill landscape and area of cohabitation. The soil conditions on site are of sandy, unstable soil composition. The best structural option for constructing the foundations in this situation is a slab on grade with an edge beam. This distributes the loads on a larger surface than piles would have and is less disturbing to the soil. The slab allows the hotel units to float as a unit as the soil shifts. 

The cabin walls and roof are precast concrete construction with exterior insulation. This reduces costs and on site ecological impact due to shorter  on site construction times. The interior spaces are clad in a wood finish with an exposed concrete floor. This C classification space is combustible, non sprinklered construction. 

The hotel units are buried in the ground and use the earth’s thermal mass as a heat sync in summer and winter. This creates a temperate indoor climate and reduces heat loss and gain. The south facing glazing allows the sun enter the units to heat the space and views to the river and seaplanes. Radiant floors are also present to provide additional comfort. These radiant coils get their heating and cooling from geothermal heating coils that run within the dike to the mechanical room in the hotel check-in building.

 

 Sectional Model

Sectional Model

 Departure from the float plane terminal view. 

Departure from the float plane terminal view. 

ENVIRONMENTAL CONTROLS

The building is built within the dike so the earth that surrounds the building acts as thermal mass to regulate temperatures. Radiant in dock heating from geothermal provides localized heat for workers.  

The wide opening that allows seaplanes to enter and exit the building is the main form of ventilation for the building. When the seaplanes get fired up in the hangar for repairs, a CO2 sensor will detect the increase in toxic fumes turning on the fans within the solar stack chimneys on the roof. This will aid in the additional ventilation required within the hangar when seaplanes are running.

The majority of environmental systems and controls in this project focus on the restaurant and waiting hall/terminal building that is situated on a floating, concrete raft foundation on the Moray Channel. Airport terminals are designed as indoor spaces but the majority of people using the facility are transient. This makes environmental controls of the space challenging; keeping the indoor climate comfortable for temporary occupants (passengers) and comfortable for long-term terminal staff. A number of factors such a clothing insulation, activity levels of the various occupants, sedentary time, and overall comfort expectations must be taken into consideration along with environmental controls. Having the building situated on the Moray Channel allows for the body of water to be used for climate controls. 

Winter Heating/ Summer Cooling:
 
To reiterate, the restaurant and waiting hall building is situated on a floating, concrete raft foundation on the Moray Channel. The building is orientated with glazing along its long edge, the south façade. The roof is angled at 15° to permit passive solar gains to the building that are desirable at nearly all times on site (See Figure 1 and 2). There are virtually no days where solar gain is not beneficial to the building. However, the basic dimensions of the building was input into the Instantaneous Energy Calculator (see Appendix A) and contradicting results were given. On the most extreme case in the summer, the summer solstice (June 21), the restaurant and waiting hall has a net energy flow of approximately +17,000W and +25,000W. This means the building needs to be cooled. In the winter (using January 21 because the winter solstice generally has not as cold temperatures as later months), Instantaneous Energy Calculator estimated that the net energy flow for the restaurant is -4,012W and the net energy flow for the waiting hall is  -49,813W. The calculator does not take into consideration the various ways the spaces are conditioned. To aid in conditioning the interior spaces, a concrete radiant thermal wall is used. The wall runs through the centre of the building, and divides private and public functions, while providing heat and cooling to each side of the space. This system is coupled with a closed loop heat pump system that is fully integrated into concrete raft foundation. A loop of coils heat exchanges with a water based heat exchange field. The temperature of the Moray Channel at this location is quite stable and will help to stabilize interior temperatures with the aid of a heat pump. Average monthly temperatures range from 7°C in January to 20° C in June. The heat pump system will aid the boiler in heating the building in winter months through using compression and expansion to upgrade the energy from the heat sink, further reducing environmental impacts. To cool the interior spaces, the heat pump system is run in reverse. 

Water Collection:
 
The wall that runs through the building like a spin collects all the rainwater off the roof, which mitigates the impact on Vancouver’s water treatment system. Water falling onto the roof of this structure, by code must not be directly discharged into the Fraser river.  The water is collected and stored inside the insulated thermal wall awaiting filtration. When potable water is demanded to refill toilets, and provide water for washroom taps, an inline UV filtration system purifies the water before delivery. The restaurant can collect approximately 50 000L of water per month and the waiting hall can collect approximately 107 000L per month (see Appendix B for calculations). The roof is a steel roofing system, which is a major contributor to the buildings environmental embodied energy impact (see Appendix C for details). Although the focus of the project is to be ecological and environmentally sensitive, to be able to provide the building with clean and useable water, a steel roofing system is ideal. Also steel roofs are fully recyclable, durable, and reduces the amount of pipes that must run in the water to land in order to get filtered water.   
 
Ventilation:
 
These spaces are directly adjacent to the docking area for a total of 11 De Havilland Otters. These machines create excessive amounts of noise, and air pollution. Therefore, natural ventilation of the adjacent space is not favourable, nor is it permissible. ASHRAE has noted minimum ventilation rates for the restaurant and waiting hall (see Figure 3). A high efficiency HRV system is employed to deliver fresh air to the interior. This system recovers heat from the main air returns in each space and recovers up to 85% of the energy from exhaust air. The air intake is positioned on the opposite side of the plane docking area to minimize pollutants.