Constructing Journal Week 7 We went for an off campus site visit during the studio of this week. The construction site we visited stands on 587 Victoria Street, it is a 9 storeys apartment builds for students. The building is mainly built with the structure of concrete and some steel at the top part of it. It is now about 75% finished in process. We started the visit at the ground floor. The main component here is the precast panel. Water pipes are exposed at the ceiling and connect to the whole building. They are made in copper and PVT which conduct all water from roof/ toilet.
It can be seen that the wall is made up of concrete masonry unit, also called concrete block. This block is precast concrete with hollow centres to reduce the weight and improve the insulation. It is a very common material for load bearing wall which can be built with both vertical and horizontal reinforcement,
Up to the first floor, coloured plate boards are used as walls. They are heat-insulative fire-proof colour steel composite plate which can substitute bricks, tiles and precast slabs. The board comprises three layers, the outer layer is the colour steel plate, the middle is a heat-insulative layer, and the inner layer is an incombustible fire-proof plate. This kind of board has the advantages of variety of colour, light weight, heat preservation and insulation, artistic outlook, high assembly, convenient, rapid installation and low cost. For the window, aluminium frame is used with rubber seal.
Passing through the corridor, there is glass and some spacing on the wall. As a consequence, light can enter the apartment. This can reduce the energy and electricity used for lighting.
Next is the top floor of the building. The top of the apartment is made by the use of truss. This allows loads transfer to the main structure of the building and avoid collapse. Also, universal beams are used at the ceiling and some of the columns. The pipe for air conditioning is wrapped up with good insulation at the ceiling. Governized steel is applied for purlin or ceiling. In the space between the building, there is a deck to the ground floor. Moreover, metal clip is used for the connection of walls. Screw joint can also be observed.
(The use of truss)
(pipes for air conditioning)
(Metal clip)
Looking to the outer surface of the building, there is the gutter (might not be seen in the photo), it is connected to a small box with hole and the down pipe to collect water and act as the drainage. The hole on the small box is used as a second exist of water when there is an overflow of water.
(Gutter, small box and downpipe for drainage)
(Casting plate board)
At this floor, the columns are constructed of steel; this is because the top floor of the apartment supports lighter loads than the lower part of the apartment. As a result, only the top uses the steel columns while the lower part uses the concrete columns. Furthermore, steel columns are light than the concrete ones, therefore, it is placed on the top. For the ceiling, except the steel beams, there are steel bar bracings. The function of these bracings is to hold the shape of the roof and avoid the collapsion. It is a kind of reinforce building structure with diagonals support intersect. Moreover, it can withstand seismic forces from an earthquake and efficiently transfer the forces to the main structure of the building.
(Steel columns and universal beams)
(Steel bar bracing)
The floor here is the concrete floor. However, there is a part on the floor that is obviously a few centre meters lower than the normal floor level. This area is for the toilet. The reason why it is lower is that the builder will place a layer of bricks at this area to form the floor. Once the bricks are placed, the floor level should be the same as the normal level. Between the columns, there are some spaces that doors would be built. At the top of the door frame, lintel is applied. Lintel is a kind of load bearing component. Vertical loads that act on it are collected and transfer to both sides of the wall as horizontal loads and then to the ground.
(Toilet area)
(Lintel)
This is one of the floors of the apartment. The ceiling here is constructed of plywood joining together with the use of concrete (the lines). The slabs used in this building are the post tension slabs with 200mm thick and it is two direction slabs.
(Plywood ceiling) Lastly, at the roof, there is a rigid steel frame. The roof is a skilion roof with slope of 1 to 2 degree. There is the parapet on the sides of the roof. Parapet is a barrier and extension of the wall at the edge of roof which is usually wrapped up with a layer of waterproof membrane.
Steel sheet is used for covering the roof. This metal roof decking is corrugated to increase its stiffness and the ability to span across open web steel joints or steel beams, also serve as the base for thermal insulation and membrane roofing (Ching, F.D.K 2008, building construction illustrated 4th ed., John Wiley & Sons Inc., New Jersey). At this level of the apartment, it is easier to see the joints connecting the roof, rafters, beams and walls such as the screw joints.
(Skilion roof)
(Joints of roof, rafters, beams and walls)