By Hassan Ally, P.Eng., Arup
Bergeron Centre for Engineering Excellence, Engineering HighlightsBuildings
Engineering the new home for engineers at York University involved heavy duty, large-scale testing labs, flexible spaces, environmental chambers and unusual architectural features.
From the January-February print issue.
Arup provided multi-disciplinary engineering consultancy services for the Bergeron Centre for Engineering Excellence at York University in Toronto. Our work included civil, structural, mechanical, electrical, information technology and security engineering, as well as providing initial engineering advice for the facade.
Several engineering challenges were addressed to achieve the university’s vision and objectives for the building, resulting in quite unique solutions.
Structural: foundations, high bay civil lab
The 15,744-sq.m, five storey building is founded on a hybrid system of foundations that include spread footings and deep pile foundations. Crystalline concrete was placed at different locations in the slab-on-grade to provide a waterproofed environment for the basement spaces at level 0. In addition, mass footings were placed underneath sensitive equipment, with neoprene isolation around to minimize the transmission of vibrations.
The building includes a triple-height civil engineering lab which is structurally isolated from the remainder of the building to minimize the transfer of noise and vibrations. It is also equipped with a strong wall/floor to accommodate the forces imposed by the hydraulic test equipment. The equipment is used to test to destruction prototype structural elements and construction materials like concrete and steel. The strong floor is 18 m x 18 m in plan and 1 m thick, while the L-shaped strong wall is 6 m high and 1.5 m thick. These elements incorporate a grid of 75-mm diameter anchor holes through their full depth at 600 mm centres to facilitate fixing of the specialist machinery used for testing.
Other structural highlights include special 800-mm diameter daylighting tubes that were designed to be founded in the level 1 slab to allow natural lighting to enter the workshops and laboratories at level 0.
An underground utility tunnel links the basement level to an adjoining building. It was designed to accommodate heavy traffic and truck loading during the construction phase. A green roof impacted the structural design on both levels 1 and level 5.
Additionally, the structural team addressed special architectural features, such as the feature freestanding stairs that are in plate steel and geometrically unusual. the trapezoidal windows, the irregularly-shaped retaining walls, and the framing for the irregular “cloud” cladding.
The essence of our structural input in this project, however, is appreciating other disciplines’ challenges, anticipating site problems, and working closely with the contractor to respect the aggressive construction schedule without compromising quality and value.
Mechanical: central plant, clean rooms, environmental chambers
The heating requirements for the building are met by the university campus central steam plant, with shell and tube heat exchangers used to generate heating hot water. Heating to the building is provided through terminal devices such as trench heaters under double and triple-height glazing, through radiant ceiling panels within perimeter laboratory and classroom areas, and through the ventilation systems in central areas.
The building’s cooling requirements are served from the campus chilled water central plant which nominally runs from spring through fall. A dry cooler is provided at roof level to meet the cooling requirements for the laboratory process loads and for the 24/7/365 cooling loads associated with the IT and electrical rooms.
The mechanical systems are systematically exposed to become architectural features in themselves and to showcase them for the engineering students and faculty. The energy efficient systems include demand control ventilation, variable speed fans and pumps, and airside energy recovery. The laboratory exhaust system has variable speed highly efficient fans and motors, and it incorporates a heat recovery system that meets 100% of the make-up heating load in winter.
A clean room rated at ISO Class 7 filtration levels is located at level 0 and is provided with its own dedicated air handling plant. In addition three environmental chambers located in the building can each provide individual tight temperature control from 85°C down to -35° C to facilitate experiments.
Another special system is provided for the spray paint booth which is located at roof level for the mechanical engineering department. The booth has a dedicated filtration exhaust and make-up air system.
The building has been designed to meet LEED Silver, certification, while provisions have been made to achieve LEED Gold, including providing cable routes and the structural capacity for a proposed photovoltaic array to generate electricity at roof level.
The building is fully protected with a sprinkler system to NFPA 13 and a standpipe system to NFPA 14.
Electrical and lighting
Power is derived from the campus HV network through a 2MVA unit substation at 13.8kV/600V. The substation can be expanded into a double ended arrangement for future extensions.
Cat 6 cabling supported by a fibre optic backbone meets the IT requirements. Security provisions include IP CCTV cameras on a converged network, with scheduled access control to all laboratories for students and faculty. In addition the public address system uses IP speakers on a converged network.
Emergency power is derived from a new generator installation at an adjoining building.
The lighting controls are a mix of sophisticated central relay based control and local dimming/switching touch screen control. Designed to meet the requirements of ASHRAE-2010, the system will manage light levels in every space based on occupancy, daylight levels and time of day scheduling. The lighting has a sleek look, with slim, sharp linear pendant fixtures which accentuate architectural elements of the building.
A mix of LED and T5 fluorescent technologies will result in energy efficiency surpassing ASHRAE requirements. Direct and indirect lighting allows for comfort and enhanced learning, while dimming capabilities in the presentation and event spaces add ambiance. In the offices, switched receptacles will allow for the automatic shutdown of monitors, desk lamps and other such devices when the room is unoccupied.
Civil: underground sewers and stormwater management ponds
Arup’s civil team developed an early enabling works package to expedite the relocation of deep underground storm and sanitary sewers which service approximately 50% of the campus. The sewers ran through the middle of the proposed footprint of the building and were at between 9 m and 11 m depth. This work meant that construction on the building foundation started early, helping in the constrained construction schedule. In diverting the sewers we had to carefully consider any impacts to adjacent foundations and the building loads. The installation sequence had to minimize service disruptions for the campus.
Arup minimized the footprint of the stormwater management system by designing a two-pond system to offset peak run-off flows from different areas of the site. Each dry pond complements the retaining walls and landscape features and is designed for potential future development in the area. The building’s green roof and underground infiltration chamber system also promote on-site rainfall retention and groundwater recharge, ensuring that the increased imperviousness of the site will not increase stormwater flows to the downstream stormwater management pond, Stong Pond, which is already at maximum capacity.
BIM: 3D modelling and prefabrication
The entire project was developed in BIM. This technology has allowed the design to be developed in 3D and provided early warning for identifying possible clashes. For the underground services installation, for example, the sub-trade contractor was able to take our model and use it to generate off site materials take-off and prefabrication. The prefabricated materials were individually tagged, cut to measure and delivered to the site in packaged crates, which reduced the installation period that would normally take two weeks to three days. The same method is being used for the above ground services, with pipework, ductwork and conduit being prefabricated and installed on frames off site, before being delivered to the building. cce
Hassan Ally, P.Eng., is an associate-principal at Arup in Toronto and the project leader for engineering design of the Bergeron Centre for Engineering Excellence. See credits on page 18 for Arup’s full project team members.