Cambridge Community Centre
Instructors: John Straube, Jaliya Fonseka
Team: Mapendo Ngilinga de Carvalho, Dixon Leung, Ivy Mei
Media: Revit, SketchUp, AutoCAD, Enscape, Illustrator & InDesign
Project Status: Community Centre Concept
Spring 2021
Project Background
Cambridge Community Centre is in between the bustling downtown area and vast residential space. The community centre seeks, first and foremost, to create a space that inspires the members of the community to become active participants in the activities of the neighbourhood. The radial program of the building creates a space that surrounds the users with views of nearly all the activities the community centre has to offer. The difference in heights of the lobby and gym gives parents and friends the option to see the gym activity from above while creating an acoustics separation from the gymnasium and the library. Floor-to-ceiling windows in the dining rooms, library and flexible rooms flood the spaces with natural light, contributing to a vibrant environment, animated by the large lobby and generous views to the outdoor spaces.
Gymnasium Illustration (D.Leung)
Gravitational Loads
Focusing on the skeleton of the gymnasium structure, the roofing membrane is being supported by a layer of 76mm steel decking that spans 2.5m. These layers are supported by a series of 1600mm deep OWSJ (Open Web Steel Joists), spanning 32m, spaced out 2m on-center with diagonal bridging between the OWSJ rows every 5m. The diagonal bracing is needed as the span of each joist (32m) exceeds the requirement of 18m. In addition, the open-shaped joists allow for mechanical and electrical systems to pass along the roofs structure. The OWSJ’s sit on a series of horizontal beams, W250x149, that till transfer the dead load from the roof to the W250x89 columns. These columns are spaced around the gym’s perimeter every 7.3m and transfer the roofing loads straight down to the reinforcing foundation walls below.
Bracing Connection
The lateral bracing connection was created using a triple beam brace gusset setup. Each lateral bracing beam connecting to the gusset is bolted onto the angled gusset. The horizontal beams are bolted to the column through a simple endplate. The W250x149 columns were designed to have stiffeners along with the connection for maximum rigidity of load transfer to the column.
Horizontal Buckling
To minimize the chances of buckling, horizontal bracing elements, W250x149, span across the columns and reduce the effective length of the column and allow for a thinner cross-section. The horizontal bracing between the joist fulfills a similar function and contributes to the stiffness of the roof diaphragm.
Lateral Loads
With the gymnasium space having a ceiling height of 10.5m, a lot of lateral bracing will be needed around the perimeter to keep the possibility of the entire structure buckling out of consideration. Since the space created four tall walls, we decided to place lateral resisting members on each of the four walls. The diagonal lateral bracing used around the perimeter is square HSS 152x152x6.4 and collects the lateral loads that are applied onto the exterior face of the gymnasium façade. These lateral loads are then transferred back to the horizontal beams and columns around the gym’s perimeter.
Structural Steel Framing
Building Façade
The principal façade of the community centre is a plain wood façade. The clean line of the wood façade leads us to the unique shape of the exterior of the building. The build-up of white metal serves as an accent on the front and side of the second floor to build the contrast between the brown wood texture as an aesthetic reason.
The main wall assembly is the steel stud wall with rigid insulation outboard of the structure and cavity insulation fill in the structure. The rain-screen is panelized between the plain wood cladding and the rigid insulation. The roof assembly is designed to be an exposed single-ply roof system without ballast. The water membrane is installed over the rigid insulation. Underneath the insulation, the air/vapour barrier is installed over the plywood sheathing. The thermal membrane is intended to be continued to increase the overall performance of the wall assembly on the energy aspect.
Enclosure Build-up (I.Mei)
Mechanical Systems
Given the large size of the multi-purpose room, we wanted the space to feel open and tall, which meant minimizing ceiling depth as much as possible. To this end, we began by opting for a 600mm deep web-steel joist structural system, in contrast with the solid steel I-beams used predominantly in the rest of the community centre. This way, we can pass any of the required services through the openings of the structure, rather than having to allocate space underneath it.
Another important decision was to separate the air handling units servicing the building. Though 1 or 2 central AHU’s could theoretically service the entire community, we decided to split the building into different zones, each with its own rooftop AHU’s. By doing so, we avoid the need to pass large ducts across the ceiling spaces, and it also allows us to exercise finer control over the microclimates within our community centre, ultimately leading to increased occupant comfort and superior energy efficiency. A compact layout of services is also crucial to accomplish narrow ceiling depths. The diagram on the right illustrates how services might be arranged in the floor sandwich of the multipurpose room.
Multi-Purpose Room Mechanical Isometric (M.Carvalho)
Cafe & Lounge (D.Leung)
Library (D.Leung)
Exterior View (D.Leung)