building construction 2 bld 60703 / arc 2513 project 1
skeletal construction: temporary bus shelter group members: lee jun yen rudy irawan shazleen shafiqah wong teck poh yee mae yuen tutor: Mr. mohamed rizal
0324552 0328658 0324367 0327462 0328561
00 / contents
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01 introduction 02 design
2 3-9
3 4-5 6 7-9
design consideration design process materials selection orthographic drawings
03 construction
10-17
10 11-14 15-17
construction components construction details and components construction process
04 analysis
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18-20 21
load and strength studies strength test
05 conclusion 06 references 07 appendix
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01 / introduction In this project, students are required to design a temporary bus shelter that can accommodate at least five to six people with maximum height of 3000mm and base size of 2000mm x 4000mm. To produce a strong and stable structure, we are required to understand and demonstrate the knowledge of skeletal frames and its joints. The model constructed is in a 1:5 scale (800 x 400 x 600mm) and all the joints used should reflect the real joints. 2 forms are chosen which are cuboid and triangular prism to form the basic design of the bus shelter. Construction components such as wall, column, floor and roof is taken into consideration when designing.
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02 / design consideration
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To design a temporary bus shelter that is strong as well as comfortable, certain aspects are taken into account.
weather conditions
The bus shelter should provide the necessary protection for the users from the weather conditions of the site such as rain or harsh sunlight.
accessibility
As the bus shelter is a public structure, access to the structure is carefully thought out.
transparency
spatious capacity
temporality
High visibility level in the structure is important to allow users to notice oncoming buses or traffic. No obstructing structure is situated at the most front of the shelter to reduce conflict of views.
Ample spaces are provided to allow a minimum of 5 people in the structure at a time with enough seating space.
Permanent joints are restrained from being used in the structure so that disassembly of the bus shelter is easier.
02 / design process
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Based on the design consideration, the design of the bus shelter is inspired from leaves. Leaves branches out from a tree to form a canopy that provides shade and protection to those who are under it, a natural shelter of sorts.
design 1: The skeletal frame of the bus shelter seems to branch out from the ground. A tilt is given to the roof to allow proper rain flow of the structure.
design 3: Braces are added to the skeletal frame to provide more support to the structure.
design 2: The folded roof is simplified into one long tilted roof to further aid rain flow. The tilt allows for a bigger surface area to create a bigger shade for the users. More structural support is added to the frame to hold the cantilevered roof.
design 4: The support is simplified into bracers as it will obstruct the circulation of the space.
02 / design process The final design is confirmed and the joints are thought out to form a strong structure.
FINAL DESIGN:
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02 / materials selection
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steel
timber
polycarbonate
Steel is used as our prime material for our flooring. I-beams are used for the ground beam to create a stable base frame. Steel hollow sections are then slotted in to form the floor joists. This creates a strong structure to support the temporary bus shelter.
Timber is our chosen material for the rest of the skeletal frame. The material allows for interesting joints to be used to create a strong skeletal frame for the bus shelter.
Polycarbonate is the material for the roof. It protects the users of the bus shelter from harsh weather conditions. The translucent material will allow sunlight to pass through providing lighting to the space. It is tinted as well so sunlight will be filtered and prevent the space from too heated up.
Advantages: Sustainable, reusable, aesthetics appeal Advantages: light compared to timber, durable, can be recycled, can withstand extreme forces and weather conditions Disadvantages: high maintenance cost, susceptible to corrosion Action: A layer of finishing is added on top so the steel structure is more resistant from corrosion
Disadvantages: Might face discoloration and forms mould if untreated, will shrink and swell depending on weather conditions such as humidity
Advantages: Blocks UV rays, light-weight, resistant to heat, sunlight and rain, able to withstand force Disadvantages: More expensive than plastic or glass, not scratch resistant, possible denting on surface
02 / orthographic drawings
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roof plan scale 1:25
floor plan scale 1:25
02 / orthographic drawings
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roof level ground level
side elevation scale 1:25
ground level
front elevation scale 1:25
02 / orthographic drawings
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roof level ground level
section scale 1:25
ground level
back elevation scale 1:25
03 / construction components
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polycarbonate tinted hollow sheet screwed with washers to roof joists
timber roof joi sts connected by housing joints and screwed
timber roof beams joined by l-brackets and lap joints
timber secondary column joined by l-brackets and gusset plate
timber braces joined by gusset plate
timber braces
joined by gusset plate
timber main column
screwed to steel square post base in steel joists
timber bench joined by l-brackets
timber flooring screwed with self-driving screw to steel joists
steel square hollow section joined by angle cleats
steel I-beam joined by angle cleats
steel sill plate welded to steel i-beam
concrete footing joined to sill plate by anchor bolt
03 / construction details and components
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flooring The flooring system consists of a steel joists and a timber flooring as the platform for the floor. Steel is used for the flooring system as steel is more resistant to the weather than timber.
125mm x 125mm I-beam Welded to 375mm x 250mm sill plate Connected to 400mm x 500mm concrete footing using anchor bolt
125mm x 125mm steel square hollow section Joined to I-beam with 60mm x 60mm angle cleats to form steel joists
I-beam joined by 60mm x 60mm angle cleats to form ground beam 250mm x 250mm x 125mm steel square post base Welded to 375mm x 375mm sill plate Connected to 500mm x 500mm concrete footing using anchor bolt
03 / construction details and components
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column and beam
100mm x 100mm roof beam is joined to the columns using gusset plate and 25mm x 25mm L-brackets
150mm x 100mm back beams are connected to the column using a lap joint
150mm x 100mm secondary columns are joined to the flooring using 25mm x 25mm L-brackets
03 / construction details and components
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column and beam
Secondary columns are joined to the roof beam using customised gusset plate
Front braces are joined to the columns using customised gusset plate
Back braces are joined to the columns and roof beam using customised gusset plate
03 / construction details and components roof
14 Vertical roof joists are joined to the horizontal joists using housing joints at an interval of 600mm
Roof joists are joined to the roof beam using a series of 25mm x 25mm L-brackets
seating
The bench consists of timber 450mm x 500mm bench leg as support for the 530mm long timber planks
03 / construction process
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The steel joists are made in a metal workshop. Long mild steel pieces are welded to make an I-beam in 1:5 scale.
Mild steel pieces are cut using a steel cutter chop saw at the workshop.
The steel pieces are welded together to form I-beam. The I-beams are connected together to form the frame of the steel joists.
Steel square post base and steel metal base plates are drilled with holes with a bench type drilling machine to enable installation of nuts and bolts.
The steel base frame and joists are then assembled together by welding.
The steel base frame is then coated with paint to prevent corrosion through rusting.
Recycled meranti wood is used for the whole timber superstructure. Mechanical tools were used to cut the wood into desired dimensions.
The timber pieces are then smoothened out with sandpaper.
03 / construction process
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The two main timber columns are slotted into the steel square post base plate.
It is then secured in place with wood screws.
MDF boards are cut into desired dimensions at a workshop with wood edge cutting machine.
MDF boards are then attached to steel base frame with self drilling sheet metal screws to create the timber flooring.
The secondary columns are then attached to the timber flooring with L brackets screwed to timber flooring and steel base frame with self drilling sheet metal screws.
Secondary columns and main column are then secured together with a gusset plate.
Braces are then added and secured with wood screws.
The roof rafters are assembled together with their lap joints placed together and secured with wood screws.
03 / construction process
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The roof rafter is set aside while the roof beam is attached to the main column using gusset plate.
A customised gusset plate was made to achieve the angle we wanted.`
Roof rafters and beams are then attached to the main and secondary columns with L brackets and wood screws.
After assembling the roof frame, a polycarbonate sheet is screwed into place on top of the frame.
Bench seat planks and bench legs are attached together with L brackets and wood screws to form the bench
The bench is then secured to the timber flooring with L brackets and self drilling sheet metal screws to connect to the steel joists.
To connect the structure with its foundation, the steel base plate are secured with bolt and nut and placed into a concrete mixture before it sets.
Once the concrete has cured, the model is now finished.
04 / load and strength studies A structural frame works together with the foundation to provide strength and stability to the overall structure. The framing transfers all types of load to the foundation: i.e. gravity, uplift, and lateral loads.
Vertical load is transferred onto the foundation evenly through the two main columns. The single pitched roof is supported by slanting secondary columns to distribute the load from the main column. Bracing is added to further assist the compressive members and prevent buckling.
The connection between the seating bench and the structural frame increases the surface area in contact with the ground, thus increasing the stability of the structure as well. Weight of the seated users will be transferred through the connection to the structural frame and thus to the ground.
LOAD PATH Roof joists > Beams > Braces > Columns > Floor joists > Foundation > Ground
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04 / load and strength studies
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A typical structural frame is needed to support the static load and the live load. The bus shelter is made sure to be able to withstand both types of load.
Static load or dead load refers to the weight that a structure has to bear due to its permanent elements and structural components.
Live load is the weight created by non-permanent actions on the structure such as rain or human occupancy. This type of load will vary throughout the structure’s livespan.
04 / load and strength studies
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The bus shelter is also designed in respond to the weather especially during rain or windy days considering the forces that would be acted upon the structure.
As an open structure, wind can flow through the structure with ease. This allows for an equal air pressure above and below the roof, reducing the uplift force acting on the angled roof.
Accumulation of rain water on the roof is prevented as the roof is tilted at an angle. Amount of load on the roof is significantly reduced.
04 / strength test
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Test subject : 6 water bottles (0.5 kg each) Total: 3kg
Test subject : 6 textbooks (3 kg) Total: 18kg
Test subject : 4 textbooks (3 kg) Total: 12kg
3 water bottles were tied to the roof and 3 other to the back. This represents live load acting on the structure. The result is successful.
6 textbooks are placed on the timber flooring. This represents live load acting on the structure. The result is successful. The flooring system is able to withstand the load.
4 textbooks are placed on the timber bench. This represents live load acting on the structure. The result is successful. The seating is able to withstand the load.
05 / conclusion
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Through this project we get the chance to apply the knowledge of a skeletal structure into the temporary bus shelter. We learnt to explore on how every single joint connects. We also get to understand how skeletal structure reacts under load and learn how load transfers work in a structure. Although only two materials (timber and steel) are allowed, we get to realize the importance of materiality in these structures and a different material will produce very different results. All in all we understood the importance of each individual connection and one without the other will result in a structure that fails inevitably.
06 / references 1.
Lyons, A. (2015). Materials for architects and builders. London: Routledge, Taylor & Francis Group.
2.
Simmons, H. (2012). Olin’s Construction: Principles, Materials, and Methods, 9th Edition. 9th ed. Hoboken, New Jersey: John Wiley & Sons.
3. Howstuffcompares.com. (2017). Sheet Metal Screw Versus Wood Screw. [online] Available at: http://www.howstuffcompares.com/doc/s/sheet-metal-screw-vs-wood-screw.htm [Accessed 11 Oct. 2017]. 4. Store.curiousinventor.com. (2017). Tutorial on Choosing Screw Type, Size Strength. [online] Available at: http://store.curiousinventor.com/guides/ Metal_Working/Screws [Accessed 11 Oct. 2017]. 5. WOOD Magazine. (2017). Half-lap joints. [online] Available at: http://www.woodmagazine.com/woodworking-tips/techniques/joinery/half-lap-joints [Accessed 11 Oct. 2017]. 6. Doityourself.com. (2017). Cutting Lap Joints in Wood | DoItYourself.com. [online] Available at: http://www.doityourself.com/stry/cutting-lap-jointsin-wood [Accessed 11 Oct. 2017]. 7. Boltdepot.com. (2017). Bolt Depot - How to Identify Nuts, Bolts, and Screws. [online] Available at: https://www.boltdepot.com/fastener-information/ identifying-fasteners.aspx [Accessed 11 Oct. 2017].
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07 / appendix
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Sketches for the temporary bus shelter.