BUILDING STRUCTURE BLD61003 PROJECT 1 : STRUCTURAL DESIGN POST MORTEM Tutor : Mr Mohamed Rizal
Wong Chee Fon Keshav Seeraz Peh Ellyn Loh Shu Wei Cheong Yen Sin Jovin
0327220 0326598 0326812 0331016 0328050
CONTENT
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1.0
Introduction
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2.0
Abstract
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3.0
Construction System
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3.1 Foundation and Floor System 3.1.1 Definition of Foundation & Floor System 3.1.2 Safety and Strength (Foundation System) 3.1.3 Safety (Floor System) 3.1.4 Strength & Rigidity ( Floor System) 3.1.5 Foundation System Proposed Design 3.1.6 Flooring System Proposed Design
8 9 10 11 12 13 15
3.2 Post and Beam 3.2.1 Definition of post and beam structure 3.2.2 Criteria of post and beam structure 3.2.3 Safety 3.2.4 Stability 3.2.5 Strength & Rigidity 3.2.6 Economy 3.2.7 Feasibility 3.2.8 Optimization 3.2.9 Wall System 3.2.10 Timber Louver 3.2.11 Conclusion
17 18 19 20 22 23 24 25 26 27 30
3.3 Roof System 3.3.1 Definition of Roof System 3.3.2 Criteria of Roof System 3.3.3 Safety 3.3.4 Strength and Rigidity 3.3.5 Stability 3.3.6 Integration 3.3.7 Economy 3.3.8 Optimization 3.3.8 Conclusion
31 32
3.4 Curtain Wall System 3.4.1 Definition of Double Glazing and Curtain Wall 3.4.2 Type of curtain wall system 3.4.3 Original curtain wall structural analysis 3.4.4 Curtain wall amendments and solutions 3.4.5 Safety 3.4.6 Strength 3.4.7 Feasibility 3.4.8 Economy 3.4.9 Sustainable 3.4.10 Conclusion
41 42 43 44 46 48 50 51 52 53 54
33 34 35 36 37 38 39
4.0
Orthographic drawing
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5.0
Conclusion
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6.0
Reference and Appendix
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The interlocking culture is a visitor interpretation center designed to allow visitors to further their knowledge on the culture and common beliefs of Batu Caves. The VIC is located on a flat green land of with an approximate area of 450m2. Structural design is part of the general design problems. In reality, it can be regarded as one of the most important design problems as it deals with life safety of the building occupants.
1.0
INTRODUCTION
The original structure of the VIC mostly make use of timber for the structural member,such as the roof structure, post and beam which is not comparatively unsuitable than the other materials that are available. Besides that, the VIC also utilize timber for the curve roof that are mostly for aesthetically purposes rather than improving the function or durability of the roof.
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THE INTERLOCKING CULTURE
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1.1 // BUILDING INTRODUCTION The design of the VIC started off with the multicultural nature and lifestyle of the people on site. With that in mind, the concept of interlocking the culture was decided. Interlocking the culture and lifestyle of the people is used as a means to bring the people of different race and religion together in order to create a more united and peaceful society. The concept of interlocking the culture is then translated into the form it is now, which is interlocking boxes creating interlocking and exciting in-between spaces. Besides that, the main feature of the VIC is its curved roof and large curtain wall facade as well as the huge overhang roof. The VIC is designed with the surrounding in mind, thus it uses natural and environmental friendly material such as timber for most of its building structure in order to blend in with its surrounding depicting the humble and patient of the mountains and people on site. However, sadly the design of the VIC have not taken the construction feasibility and workability into consideration. Thus, causing the stability, structure, strength, rigidity and feasibility to be at jeopardy.
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The objective of this project is to enhance the understanding the basic structural theory and structural behavior.
2.0
ABSTRACT
The assignment allows and appraise the existing structural design of the proposed building all the while looking for a solution to improve the existing structural design. It also include the modification of the design and the proposal of a new scheme with appropriate system for the building design. The assignment enhance the appraisal on the technical standards as well as structural design codes and loading codes to be applied to the building design. It also focuses on the identification of structural system and forces and the application of structural theory in designing structural elements.
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Lightweight Construction
3.0
CONSTRUCTION SYSTEM
Lightweight construction is a type of construction where the construction materials required are much lower than a heavyweight construction, they are very much favourable due to the lower material costs. Lightweight construction are known to be great at responding to the outdoor temperature where the building can be cooled more rapidly during the night especially in hot climate countries like Malaysia. Lightweight construction system generally have lower site impact and disturbance than heavyweight construction however, it is also less durable and require higher maintenance than heavyweight construction.
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3.1 FOUNDATION AND FLOOR SYSTEM
3.1.1 3.1.2 3.1.3 3.1.4 3.1.5 3.1.6
Definition of Foundation & Floor System Safety and Strength (Foundation System) Safety (Floor System) Strength & Rigidity ( Floor System) Foundation System Proposed Design Flooring System Proposed Design
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3.1 // FOUNDATION AND FLOOR SYSTEM 3.1.1 Definition and Criteria Foundation A foundation is the element of an architectural structure which connects it to the ground, and transfers loads from the structure to the ground. Foundations are generally considered either shallow or deep. Flooring System A slab is a structural element, made of concrete, that is used to create flat horizontal surfaces such as floors, roof decks and ceilings. A slab is generally several inches thick and supported by beams,columns, walls, or the ground.
General Analysis On Building Foundation and Floor System The building has two pad footings foundation, one supporting a timber wall and the other connected to the end of the roof structure and both of them are incorrectly position and do not have other foundation system. The whole weight of the structure is acting on the timber walls. Diagram 3.1.1 Existing foundation of the building.
The building uses timber flooring which is directly in contact with the soil and does not provide any details on the substructure.
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3.1.2 // SAFETY & STRENGTH FOUNDATION : Inaccurate and missing foundation system Problem : Diagram 3.1.1 Existing foundation of the building.
The foundation system of the building consist only two rectangular pad footing, one supporting a timber wall and the second one supporting the end of the roof to the ground and the rest of the foundation system is missing. The building itself is being supported by timber walls with no columns. This will result in the failure and the collapsing of the entire design.
Solution :
Figure 3.1.1 Rectangular reinforced pad footing
Diagram 3.1.2 Wide strip reinforced concrete foundation
The first proposed solution is to use concrete foundation, pad foundation system with rectangular pads and reinforced concrete.The arrangement of pad foundations will consist of a series of discrete, well-separated pads. Pad foundation is recommended as considering the load of the superstructure, the type of construction materials, the types of adjoining structure and that it is a low rise building. The second proposed solution is to use of strip footing with reinforced concrete. Strip foundations (or strip footings) are a type of shallow foundation that are used to provide a continuous level strip of support to a linear structure such as a wall or closely-spaced rows of columns built centrally above them. The reason for the use of reinforcement of steel in concrete is that concrete is strong in compression but weak in tension. Strip foundation can be used for most soils and is suited to light structural loadings such as those found in many low-to-medium rise domestic buildings.
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3.1.3 // SAFETY FLOOR SYSTEM : No mention fire safety protection and fungi and insect attack Problem : Figure 3.1.2 Fire damaged timber flooring
The floor system of the building consists of timber flooring without mention of proper fire safety protection of the timber. It is a severe fire hazard to the general public and to the building itself. Since the floor system does not mention any timber preservatives, it is therefore also vulnerable to fungi and insects attack. Solution : It is recommended to use preservative treatment against decay and insect attack. As a fire safety measure, “Fire-retardant-treated wood� (FRTW) will be used. It is a wood which has been impregnated with fire-retardant chemicals in solution under high pressure. It retard the spread of flame and limit smoke production from wood in fire situations.
Diagram 3.1.3 Thermoguard fire varnish
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3.1.4 // STRENGTH & RIGIDITY FLOOR SYSTEM : The building has no floor substructure system Problem :
Figure 3.1.3 Damaged flooring system
The floor system of the building is in direct contact with the soil and has no floor substructure system and no insulator. Without the floor substructure, the floor will crack. It will also affect the timber more quickly as it will absorb moisture from the soil and which will lead to fungi attack. The lifespan of the existing floor structure is really low.
Solution :
Diagram 3.1.4 Steel floor framing system with timber finish flooring
The proposed solution is to have a steel floor framing system with timber finish. Steel has one of the highest strength-to-weight ratios of any construction material. This results in savings in the foundation required and the lightness also makes for easier on-site handling. Because of its strength, steel can span longer lengths, offering larger open spaces and increased design flexibility. Steel’s inherent strength and noncombustible qualities enable light steel frame houses to resist such devastating events as fires, earthquakes, and hurricanes.
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R.C Footing Stump for Column Reinforcement concrete
3.1.5 // PROPOSED FOUNDATION IMPLEMENTATION OF PROPOSED FOUNDATION SYSTEM
600 6nos 38mm⌀
600 2000
900
600
1100
High tensile Anchor Bolt and Nuts
R.C Pile Refer to consultant design
Minimum cover to main reinforcement shall not be less than 50mm on the surface of the contact with the earth face.
2000
2000
Diagram 3.1.5 R.C footing stump for column
Foundation to Steel Column
PAD FOUNDATION GROUND BEAM
STEEL COLUMN
LEVELING BOLT NUTS
STEEL COLUMN BASE PLATE
FULL THREAD ANCHOR BOLTS
BEAM REINFORCEMENT BARS
TIGHTENING BOLT NUTS
STIFFENER PLATES
Diagram 3.1.6 shows steel column section I welded on steel base plate with full penetration butt weld with plate stiffeners
Diagram 3.1.6 Foundation to steel column connection
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3.1.5 // FLOORING SYSTEM IMPLEMENTATION & CONCLUSION OF PROPOSED FOUNDATION SYSTEM
Diagram 3.1.7 Sections with amended pad footings
The original design of the foundation system would not withstand the weight acting on it and would eventually collapse. As a final proposal, rectangular pad footing with reinforced concrete with sloping face is used as foundation. The pad foundation is fixed to steel columns supporting the roof structure. The weight of the building is transferred by the beams and columns to the foundation. Therefore the design is now safer, more structurally rigid and have a longer span. Strip footing as a second proposal will not be used due to cost and labour.
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3.1.6 // PROPOSED FLOORING IMPLEMENTATION OF PROPOSED FLOORING SYSTEM
Diagram 3.1.8 Flooring to steel floor framing system
Joist members are to be simply supported between bearers and should be used with bearers of the same depth. Spans for joist spacings 450mm.
D= 240mm W= 72mm T= 2.4mm
D= 235mm W= 64mm T= 2.4mm L= 16mm
Diagram 3.1.12
Angle brackets will need to be fixed using six 12x20 screws Diagram 3.1.9
The beams and joists are laid out and bolted to the stumps in much the same manner as wooden beams and joists. Steel posts can also be attached to the frame in place of stumps if none are available. Many modular, steel framing elements will interlock with great ease.
Load bearing walls will need to be fixed through the floor lining into the bearer or joist. Diagram 3.1.10
Diagram 3.1.13
Non load bearing walls need only be fixed to the floor lining. Diagram 3.1.11
Diagram 3.1.14
Steel Flooring System are galvanised to minimise corrosion, adequate ventilation should be provided where the system is subjected to humid conditions
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3.1.6 // PROPOSED FLOORING SYSTEM IMPLEMENTATION & CONCLUSION OF PROPOSED FLOORING SYSTEM
Diagram 3.1.15 Floor plan with amended flooring system
From the existing floor system, we can deduct that it would have not last for long due to its materiality and without any floor substructure system. The proposed solution is to have a steel floor framing system with timber finish.Timber preservative is used for treatment against decay and insect attack to prevent any damage to the building, and it also protected as a fire safety measure, “Fire-retardant-treated wood� (FRTW). And steel substructure is galvanized and passive fire protection, such as spray-on fireproofing is used. The flooring system as proposed is now more durable, there is less maintenance and the substructure is rigid and also safer.
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3.2 POST AND BEAM
3.2.1 3.2.2 3.2.3 3.2.4 3.2.5 3.2.6 3.2.7 3.2.8 3.2.9 3.2.10 3.2.11
Definition of post and beam structure Criteria of post and beam structure Safety Stability Strength & Rigidity Economy Feasibility Optimization Wall System Timber Louver Conclusion
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3.2 // POST AND BEAM STRUCTURE 3.2.1 Definition Post and Beam Structural System
Diagram 3.2.1 Post and beam structural system.
In Architecture, post and lintel structural system is a simple construction technique also called column and beam. Horizontal member is supported by two vertical posts at either end. A beam is a structural element that is capable of withstanding load primarily by resisting bending. Column is a structural element that transmits through compression, the weight of the structure above to other structural elements below. All structural opening have evolved from this. Post and beam structures either load bearing wall structures or frame structures. A large of spans is also possible depending on the types of elements which are used.
3.2.2 Criteria Generally, beam width should not be more than the width of the column on which it rests, or width of the wall below it so that it can be concealed in the wall. It depends on many aspects including its position in the structure, loads and many other parameters. Having said this minimum depth of beam can be decided based on the deflection requirement that is based on span/depth ratio. The post and beam structural system need to carry the gravity load and lateral load, a good structural system will ensure the building structure is stable and strong. Diagram 3.2.2 Current building structure.
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3.2.3 // SAFETY Material Properties
Figure 3.2.1 Timber structure decay and collapse.
Problem : Used of timber as materials without proper fire safety protection. Wood consists of organic compounds which are composed mainly of carbon and hydrogen. They can combine with oxygen and burns. Because of these properties, wood is classified as a combustible material. Wood is a hygroscopic material. This means that it will adsorb surrounding condensable vapors and loses moisture to air below the fiber saturation point. Like any organic good, wood is a nutritional product for some plants and animals. Insects drill holes and drive lines into wood. Even more dangerously, fungi cause the wood to decay partially and even completely. Post and beam is important structural system, if wood decay will increase collapse probability of timber structure, it may put the safety of building users and general public in a risk. Solution : Replaced additional of passive fire protection steel with timber. Steel can soften and melt with exposure to extremely high temperatures. However, with addition of passive fire protection, such as spray-on fireproofing, buildings built of structural steel can sustain greater temperatures. Steel is durable as it is impervious to fire, termites, rot, splitting and other hazard that will affect any organic materials.
Figure 3.2.2 Steel structural system.
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3.2.4 // STABILITY Proper Load Bearing System
Diagram 3.2.3 Missing column and beam.
Diagram 3.2.4 Location of column and beam.(Section)
Diagram 3.2.5 Location of column and beam. (Floor Plan)
Problem : The overall structure of this building do not have any proper column and beam to resist the lateral and gravity loads causing the structure lack of rigidity and stability. Generally the load of the slab is transferred to the columns or walls through beams, down to the foundation, and then to the supporting soil beneath. A Column transmits the load from ceiling/roof slab and beam, including its own weight to the foundation. Hence it should be realized that the failure of a column results in the collapse of the entire structure. Solution : Beams and columns will be added to the structural design to reinforce the rigidity of the overall structure. This will ensure load distributes evenly to the columns so that columns would not be buckle under extensive load. Determine the location of column and beam based on the maximum span of steel beam. Steel beam members can span up to 18m, but the most usual range of steel beam spans rang from 3m to 9m. In the case of this building structure, 7m as the maximum span of beam is appropriate to carry the load bearing system. According to deflection criteria (Span/Depth ratio), for a simply supported beam, the span to effective depth ratio should be less than 20. (Beam depth> span/20) The rules of thumb for structural steel design defines the criteria for span and depth beam. For girders, calculate 3/4 inch of depth for every foot of span. Maximum Span: 7m (24 feet) Beam Depth: 450mm (18�) According to the available size of steel column and beam in Malaysia, decide the most suitable size for supporting structural system. Beam: 450mm x 200mm (I-Beam) Column: 300mm x 300mm (H-Section)
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3.2.4 // STABILITY Structural Connections
Diagram 3.2.6 Bolted Connection and Welded Connection.
Problem : Structural system is impossible to work regularly without proper connection. Connection failure is one of the main issue for causing building structure collapse and structural system failure. Timber structure system requires a more complex way to connect the structure members together and also crews builders required for timber connection, if install it with improper way, it might cause the failure of connection. Solution : In engineering, a connection serving to join the individual members of a structure, to ensure the reliability of the structure, and provide for functioning of the structure as a whole in accord with the requirements of use and assembly. Connections are also used to join separate structures in order to provide rigidity, spatial distribution of structures, and construction of reinforced building units. In this steel frame structural system, moment connection is appropriate as method of connection. Web of beam is connected to column with bolted angles. Top and bottom flanges of beam are field-welded to column with full penetration weld. Columns is reinforced with plates to carry bending forces from beam flanges to column. This connection transfer gravity loads and bending forces between the members. Beam is restrained from even small rotation termed AISC (American Institute of Steel Construction) Fully Restrained.
Diagram 3.2.7 Moment Connection.
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3.2.5 // STRENGTH AND RIGIDITY Affordability of Load and Stress
Diagram 3.2.8 Axonometric view of location of column and beam.
Problem : Used of timber beam and column. Timber structures are less durable because they have properties to against natural phenomenon.Its lifetime is only between 15 to 20 years. Besides, by increasing the strength and rigidity of timber columns and beams, size of it have to be larger, this will causes the oversizing of timber column and beam that could not fit into the building. Solution : Replacing timber beam and column to steel beam and column. Steel is tensile and has a high strength to weight ratio which means it has high strength per unit mass. Thus, the dead weight of steel structures is relatively small. Steel is a structurally efficient building material and so buildings are lighter and often foundations can be smaller as a result. While it takes longer to work with, steel is stronger and lighter than timber. Its strength means it can cover greater spans than timber. Steel can undergo large plastic deformation before failure, thus providing large reserve strength. Steel structure are more durable than timber because these structures got extra strength which against natural agents such as wind, rain, earthquake etc. The lifetime of steel structures may be up to 50 years.
Diagram 3.2.9 Load stress diagram of column and beam..
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3.2.6 // ECONOMY Advantages and Disadvantages Problem : Timber beam and column take longer time to construct due to the joint and connection problems. The joint between timber piles is weak, so it can not be used effectively in places where long piling is required. Load bearing capacity of timber is comparatively low. Lack of experienced builders and erection crews also become a main issue of timber construction. Timber also need higher maintenance fee for the treatment of insects and rotting. Figure 3.2.3 Timber frame structure.
Figure 3.2.4 Steel frame structure.
Solution : Replace timber with steel beam and column to increase the construction speed. While steel beam and column can erect rapidly as this results in quicker economic payoff. Steel does not need much maintenance. Using steel material less waste in terms of environmental issue. They can be constructed off-site by professional steel fabricators and then assembled on site. Steel is durable as high strength structure.
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3.2.7 // FEASIBILITY Proper structural system
Diagram 3.2.10 Axonometric view of load stress diagram of column and beam.
Problem : The original building structure mainly design for aesthetics purpose without proper structural system. Timber structural system are not suitable in this complex building structure because its strength not enough to support stably. Part of space volume exceed three stories height but lack of sufficient column and beam. Load bearing capacity of timber is comparatively low, it means the span will be shorter. This results will need amount of timber and extend the construction duration. The joint between timber piles is weak, some parts of this complex building structure connects together by blocks, it may be not stable or more stabilize connections needed. Crews builder and proper connection are required in timber construction, if structure system be installed improperly and it may cause the building structure temporarily exists. Solution : To remain the aesthetic design of the whole structure, using steel frame structure with timber finishes. Propose steel structure as supporting system because steel structures have a good load carrying capacity and it also has a high strength to weight ratio. Steel beams and columns have capability to carry load with a long span, which usually used in high-rise building. While steel structure system is build in a more simple way and faster comparing with timber structure but still can support the loads.
Diagram 3.2.11 Axonometric view of column and beam.
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3.2.8 // OPTIMIZATION Structural system and Aesthetics
Figure 3.2.5 Fully timber structure.
Rendering timber and steel facade
Problem : Original building structure is using timber as frame structure and wall. It is used for aesthetics purpose as well, make the whole structure having a better look with timber. Timber framing may not be optimise to use it as construction. Solution : A whole new structural design will be added to the building while maintaining the initial outlook of the building. Change timber material to steel frame structure with timber finishing to balance between aesthetics and safety. High strength of steel frame structure is the main reason for being used in this building structure. Steel is a highly durable metal, it can withstand a considerable amount of external pressure. Thickness of columns and beams may also be related to aesthetics requirement. Steel beams and columns can resist the loads with comparatively small dimension with timber.
Figure 3.2.6 Steel structure with timber finishes.
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3.2.9 // WALL SYSTEM Insulation
Steel Frame
Problem : Timber frame for walls was the initial design for the building. As timber wall frame is having more disadvantage and also high maintenance. Disadvantages such as deterioration of timber are due to biotic agent and abiotic agent. Biotic agent include decay and mold fungi, bacteria and insects, while abiotic agent include sun, wind, water, certain chemical and fire. High maintenance on the treatment of timber preservations and also remedial treatment. Solution : Replace timber frame with steel frame. Steel frame is used to erect the wall with proper insulation installation. Then plaster board as the outer layer and use timber finishes to complete the walls. As steel frame is more durable compare with timber frame, it resist fire, termites, rot and any number of hazard which can affect any kind of organic materials. Beside steel frame are predictable and affordable, it is definitely straight and slight expensive than wood but with better quality. Steel frame are also lightweight comparing with timber which is suitable in lightweight structures.
Timber Finishes
Plaster Board
Diagram 3.2.12 Materials layer of wall.
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3.2.10 // TIMBER LOUVER
Problem : Timber louvers is the original design in the building, but the louvers are not connected to any supporting structure that are standing by itself which is technically could not be build. Solution : Timber louvers design are remaining in the design but adding supporting structures like steel structure that connect both end of the timber louvers to make sure the louvers can stand and build. Besides, steel structure is used as other part of structure systems are using steel as well. Besides, as this steel structure is exposing to the weather, so it must undergo galvanization process which is metal has been coated with a thin layer of zinc to protect it from corrosion.
Figure 3.2.7 Timber louvers connected to steel structure.
Diagram 3.2.13 Location of timber louvers.
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Ground Floor Plan (Before) Scale 1: NTS
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Rearrange the floor plan according to the location of columns and beams, include adjust the length and position.
Extend the Length
Maximum span: 7m Beam: 450mm x 200mm (I-Beam) Column: 300mm x 300mm (H-Section)
Move the position of Curtain Wall Extend the Length Adjust the Position
Ground Floor Plan with proposed location of column and beam Scale 1: NTS
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3.2.11 // CONCLUSION The original structural system are lacking of proper supporting structure system which causes the building could not be build in terms of stability, feasibility, strength and rigidity. Besides, the original building design did not considerate of materials in terms of stability, safety, economy and optimization. New structural system that added into the building are design to hold the load of roof and also the load of the building to make sure that the building can is strong and stable. Consideration material in the design is taken note by replacing timber structure to steel structure as steel are more suitable to fit in this building. Even though timber structure was replaced with steel structure but the timber finished looking was remained in this building for the aesthetic purpose.
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3.3 ROOF STRUCTURE
3.3.1 3.3.2 3.3.3 3.3.4 3.3.5 3.3.6 3.3.7 3.3.8 3.3.9
Definition of Roof System Criteria of Roof System Safety Strength and Rigidity Stability Integration Economy Optimization Conclusion
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3.4 // ROOF STRUCTURE 3.4.1 Definition and Criteria Roof Structural Frame The roof rafters,beams and trusses are what forms the roof structural frame.They are the most important components that makes up the roof to stand strong and still.They also gives the shape of the roof and maintains it whether it is in a geometric or organic form acting as a skeletal.Every roof must have these components in order to meet the criteria of constructing a roofing structure. Fig 3.3.1 DIagram Of Roof Structure
Roof Sheathing,Insulation,Membrane and Covering Roof sheathing is the material that goes on top of roofing structure,that the roofing system is constructed on.The sheathing is applied so the actual underlayment and roof covering can be applied.Roof insulator helps reduce heat transferred while membranes prevents water into the interior.The covers provides protection and finishes.
General Analysis On Building Roof Structure
Diagram 3.3.1 Location Of Roof
The roof structure of a building is just a single slab that has no structural support,layers or sufficient thickness (Roof thickness:100mm).The openings on the roof are covered with glass panels which interrupts the structural support of the roof as it is located not at the edges but at the middle.
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WEAK POINTS OF THE ROOF
3.3.3 // SAFETY Collapsing and Cracking LACK OF COLUMN
Diagram 3.3.2 Roof Vulnerable to Collapsing
Problem: The roof component of the building is very thin and fragile due very minimal support with the obviously missing structural frame which makes it very vulnerable to collapsing and cracking.There’s not enough beams and columns to support the roof slab which also contributes to roof collapsing.Collapsing of roof can cause other structural components of the building to be damaged and crushed.Most importantly the occupants of the buildings will be in risk of danger and may lead to fatal injuries. Solution: The roof structure definitely must have a complete structural support.The roof frame structure is the most important component of structure that should be presence together with sufficient number of post and beams as support throughout the span of the roof to ensure no accidents occur.
Fig 3.3.2 Roof Collapsing
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3.3.4 // STRENGTH AND RIGIDITY Roof Vulnerable to Bending Problem:
Diagram 3.3.3 Points that are Vulnerable to Bending
Due to missing of the skeletal frame support for the roofing,its strength is definitely missing and bending will most likely occur especially when the roof has such a huge span of length.The openings on the roof also further removes its strength as it decreases in volume encouraging it to be more flimsy and even more vulnerable to bending.Its rigidity of course is low which means it can be affected if there is a wind load which builds up positive pressure.The overhang part of the roof has the least strength and rigidity. Solution:
Diagram 3.3.3 Steel Structural Frame
Diagram 3.3.4 Steel Roof Truss Support
The roof structure requires a structural frame which includes the roof beam,truss and rafters that supports it throughout its span.Openings on the roof should be shifted to the edge of the roofing or perhaps avoid having them.Steel roof truss should be applied and acts as a roof beam that supports the roof increasing its strength in resisting any load and also preventing it from bending.
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3.3.5 // STABILITY Unable to Stay in Shape and Resist Load Problem:
Diagram 3.3.4 Thin Roof Unable to Resist Loads
The roof cannot stay in shape and cracking,bending and collapsing will occur.Resistivity of the roof to any load is very low as there’s no skeletal frame support.The roof to post and beam connection is very weak as there’s no proper roof beam or rafter to connect.The organic form of the roof makes it even harder to stay in shape as the stability at different point is different.The overhang roof of 6 meters is most likely to collapse first as it has the weakest stability point.
Solution: Roof skeletal frame system must be integrated with strong steel joints that will not allow the structure to be flimsy.Nuts and bolts or welding method are very strong connection methods that can preserve the shape of structure well.A strong connection between the roof and the post and beams must be done to allow support and transmit the load into the ground.
Fig 3.3.5 and 3.3.6 Nuts and Bolts And Welding Joint Method
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3.3.6// INTEGRATION Integration of Insulation and Gutter Problem:
Diagram 3.3.5 No integration of systems on the roof
The existing roofing did not have any integration in its roof which is a waste as it is a long span and all of its spaces are covered with roofing.The roofing only has one functions which is only to protect from climatic exposure but gains a lot of heat which then is transmitted into the interior. The roof also does not help in channelling the water properly which means when during rainy days the water will flow straight downfall from the roof to the ground. Wiring and piping system is also not integrated in the roof.
Solution: INSULATION LAYER
GUTTER
FIg 3.3.7 Diagram of roof integration
A insulation layer should be sandwiched underneath the zinc roofing.The insulation layer creates a barrier over the roof which reduces the amount of heat entering the interior.This helps to save cost from using extra active cooling features. Installing gutter at the edge of the roof allows the water to flow down to it and able to channel it to the drainage on the ground.This promotes better rainwater management in the building service.
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3.3.7// ECONOMY Expensive Timber Roofing Covering Problem: Almost the entire roof covering is made from timber planks which is expensive making it a very ubiquitous and ambitious choice of material.The roofing does not requires timber material for covering as it is less appreciated as it lays on top compared to the form of the roof which is aesthetically beneficial instead.Timber coverings requires maintenance
Solution: Fig 3.3.8 Zinc roofing
A cheaper,lighter and able to be flexible in shape to fulfill the structural efficiency,strength,rigidity,stability and a more affordable installation and material rate.Zinc roofing would be more suitable and easier to maintain as it is extremely corrosion resistant which protects it from any climatic exposure.
Fig 3.3.9 Zinc roofing details
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3.3.8// OPTIMIZATION ZINC ROOFING TO REPLACE TIMBER Problem:
Fig 3.3.10 TImber roofing
Timber roofing brings better aesthetics to the overall look of the roof but it might not be optimise to use it as it sacrifice the structural strength and better integration with other structural system as timber roofing requires more skills and time to construct. Solution: Zinc roofing as an alternative brings the advantage of being more flexible in shape as it is more easier to shape compared to timber roofing.This gives them the advantage to be structurally more flexible to support with and less concerned on problems such as collapsing or cracking.The method of welding also gives a major boost in terms of joint strength and also saves more time.Steel framing promotes better integration to all parts of the construction system.
Fig 3.3.11 Zinc roofing
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3.4.9 // CONCLUSION The original construction of the roof will not be able to stay in shape,resist loads,vulnerable to cracking and collapsing,parts of the roof will bend and there is no integration of services as it does not have a structural system that acts as a skeletal frame for it to connect to the column and beams which is also lacking.The timber material of the roof also contributes problems in the economy and optimization aspect. Bad integration of roof to column and the number of columns supporting the roof is lacking.
Roof lacking skeletal frame support making it having many weak points.
No integration of roof insulation and gutter.
Diagram 3.3.6 Sections without admentmends of roof
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The new proposed design integrates a roof beam and truss into it to keep it in shape, and also increasing its structural strength and rigidity.More columns are added to support the roof and helps distribute loads into the ground.Insulation and gutter in integrated into the roof.zinc roofing is used for roof covering.The new proposed design of structural integration brings an overall safety and balance to the structural system.
INSULATION
Zinc Roofing
Steel column to beam connection.
GUTTER
Roof Beam and truss.
Integration of gutter and insulation.
Diagram 3.3.7 Sections with amendment of roof
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3.4 DOUBLE GLAZED CURTAIN WALL
3.4.1 Definition of Double Glazing and Curtain Wall 3.4.2 Type of curtain wall system 3.4.3 Original curtain wall structural analysis 3.4.4 Curtain wall amendments and solutions 3.4.5 Safety 3.4.6 Strength 3.4.7 Feasibility 3.4.8 Economy 3.4.9 Sustainable 3.4.10 Conclusion
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3.4 // DOUBLE GLAZED CURTAIN WALL 3.4.1 Definition and Criteria Double Glazed Insulating Glass Insulated glass unit (IGU), more commonly known as double glazing combines multiple glass panes separated by a vacuum or gas filled space that reduces heat transfer into the building interior. Insulating glass units (IGUs) mostly are manufactured with the thickness that range from 3mm to 10mm. Laminated or tempered glass are also used as part of the construction. Interior 10mm single glazed unit Cavity - Gas infill
Curtain Wall Curtain wall system are non-load bearing cladding system for external walls. The curtain wall systems does not carry any structural load from the building other than its own dead load and also loads imposed on them such as wind and seismic loads, which they are able to transfer the load to the main building structure through connections at floors and columns of the building. Curtain wall systems differ from storefront systems as they are able to span up to multiple floors, with the design requirements such as thermal efficiency, building movement, water diversion, thermal expansion and contractions.
Exterior 10mm single glazed unit Desiccant Secondary (structural) seal
Diagram 3.4.1 Double Glazed Curtain Wall Section
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Mullions Transom
Double glazing panel
3.4.2 Type of Curtain Wall System Stick System
Building Structure
Anchors
Stick curtain walling (SWC) is a type of system where the mullions and transoms are factory cut and transported to site as loose sticks and bars. The transported loose bars and sticks are then able to be assembled into a ladder frame which is also known as the ladders for faster site erection. The advantages of a stick curtain walling system is its flexibility where the production of the sticks and bars can be customized for both angular and complex facades.
Modular (Unitised) System
Double glazing panel
Diagram 3.4.2 Stick system curtain wall
Diagram 3.4.3 Unitised system curtain wall
Modular curtain wall system range from vertical and horizontal mullion framing. All of the systems and applications of the system use the same 52mm wide extruded aluminium frames with different depths to form the horizontal and vertical structural section. The system is often filled with a vulcanized EPDM gasket to insure waterproofing in between the glazing units.
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3.4.3 // Double Glazed Curtain Wall Analysis The building uses curtain wall as an opening for natural lighting for the space as a mean for sustainability and energy cost saving solution. However the structure of the designated curtain wall of the building consists of several problems that affects the structural stability and feasibility of the curtain wall. Firstly, the curtain wall does not have sufficient support for the curtain wall. The original design of the curtain wall only have supports at its two end connecting it to the columns of the building. However, the span of the curtain wall designed for the building is too wide and tall to support its own weight without sufficient structural support.
Diagram 3.4.4 Placement of Curtain Wall
Besides that, The original design of the building structural system does consists of beams connecting the columns. The lack of beams made it impossible to add additional anchors to support the curtain wall. This problem is mostly directed at the largest curtain wall facade which is located at the entrance hall with a triple volume ceiling height, making it impossibly unstable without structural support.
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7.4m 1.2m
Absence of structural member for connections and anchors installation.
2.7m
8.4m
Weak stability of mullions due to the lack of beams.
Diagram 3.4.7
THE INTERLOCKING CULTURE Original design of double glazed curtain wall before amendment
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3.4.4 // Curtain Wall Structural Amendments Problem : Support failure. The designated curtain wall only have support at its two sides connecting it to the column of the building which is insufficient for the large span and height of the curtain wall.
Diagram 3.4.5 Curtain wall section before amendment
Solution : Add beams across columns. Connecting the columns with beams not only allow extra structural support for the building but also add extra support to anchor the curtain wall to the building structure.
Diagram 3.4.6 Curtain wall section after amendment
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3.4.4 // Curtain Wall Structural Amendments
Diagram 3.4.8 Curtain wall mullions before amendment
Problem : Connection failure The original design of the building structural system does not consists of beams connecting the column making impossible to add additional anchors to connect the mullion and transom to the beam for extra support. Another problem after connecting the beams and columns is that the mullions does not meet the height of the beam making it impossible to anchor the mullions to the beams. Solution : Adjust curtain wall mullions Beams are aligned to the floor slab of the second level, however the height of the beam does not meet the original height of the mullions. The height and the number of mullions are needed to be adjusted in order to allow the mullions to be anchored to the building structure.
Diagram 3.4.9 Curtain wall mullions after amendment
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3.4.5 // SAFETY Theft Problem : The usage of standard glass. Annealed glass are standard glass that have not gone through treatments, making it weaker and easier to break compared to treated glass.
No applied load
Bending load applied
Annealed glass
Tempered glass
Annealed glass
Solution : Replace standard glass to tempered glass. Standard glass are easier to break compared to tempered glass which is stronger in comparison as it is processed by controlled thermal and chemical treatments. The outer surface of the tempered glass are changed into compression while the interior are changed into tension. Thus making it safer from burglary break ins.
Tempered glass
Diagram 3.4.10 Standard and Tempered glass load stress diagram
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3.4.2 // SAFETY Fire Safety Problem : The usage of standard glass.
Fig 3.4.11 Shattered Standard glass https://wallpaperscraft.com/download/broken_glass_cracks_textu re_82465/3840x2400
Solution : Replace standard glass to safety glass (tempered glass). On occasions, it is required to knock out glazing panels for emergency access and ventilation from the exterior. Standard glass are shaped with wounding sharp edges when broken which can be dangerous for access while tempered glass breaks into smaller pieces with less sharp edges, providing a safer access in case of emergency.
Problem : The usage of curtain wall system. Curtain wall is a system where only the framing and mullions are attached to the structure, thus leaving gaps in between levels, causing the fire and smoke to spread through the levels with no resistance. Solution : Apply fire safing and smoke seals Applying fire safing and smoke seal at gaps between the structure slab and the curtain walls helps compartmentalize the levels and thus helps slowing down the spreading of fire and smoke throughout the building. Fig 3.4.12 Shattered Tempered glass https://depositphotos.com/12893010/stock-photo-reinforcementmetal-framework-for-concrete.html
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3.4.6 // STRENGTH Problem : The usage of standard glass. Standard glass is weaker in comparison to tempered glass. Standard glass are weak and are only able to withstand its own dead load, Standard glass bends when is under a certain level of load and stress. Once a standard glass starts cracking under a certain level of stress, the crack will disseminate throughout the glass as there are no structure within the glass to hold and support it. Fig 3.4.11 Shattered Standard glass https://wallpaperscraft.com/download/broken_glass_cracks_textu re_82465/3840x2400
Solution : Replace standard glass to tempered glass. Tempered glass are processed by controlled thermal and chemical treatments making it four to five times stronger than standard glass, thus making it harder to break. Tempered glass are also able to resist their own dead load and imposed live load such as wind load and seismic load. Tempered glass are also less likely to experience thermal break compared to standard glass.
Fig 3.4.11 Shattered Standard glass https://wallpaperscraft.com/download/broken_glass_cracks_textu re_82465/3840x2400
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3.4.7 // FEASIBILITY Anchor Angle clip bolted to spandrel beam
Problem : Connection Failure The curtain wall system of the building exceeded well over 8m which is higher than the criteria height of a curtain wall and also the usual manufactured height of glass. Besides that, the surface of the the facade wall does not have any structure to connect the wide span curtain wall system to the building structure.
Structural steel beam
Solution : Add beams across the curtain wall. Adjoin horizontal elements across the columns to ensure a more stable structure frame as well as to allow foot hold for connections between the curtain wall and the building structure. The curtain wall system spans up to 7m, thus it need extra connectors between the facade wall and building structure to ensure the stability of the curtain wall and to resists impost load on the facade better.
Diagram 3.4.11 Curtain wall section after amendment
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3.4.8 // ECONOMY Problem : Usage of modular system curtain wall. Unitised system curtain wall requires higher field labour which have higher pay than standard labour. Solution : Replace modular system to stick system. Stick system are more economic friendly compare to modular system as it has lower requirement volume at the same time it does not require higher field labour that requires more pay.
Transmitted Solar Radiation 83% Radiation of absorbed heat (inside) 6%
Reflected Heat (outside) 8% Absorption Radiation of absorbed heat (outside) 3%
Diagram 3.4.12 Double glazed curtain wall heat transmission diagram
Problem : Use of single glazed curtain wall Single glazed curtain wall allows light to penetrate further into the building, however it also allow more heat to penetrate into the space, thus it requires more air conditioning to cool down the spaces. Solution : Replace single glazed curtain wall to double glazed curtain wall. Double glazed curtain wall may have cost more than single glazed curtain wall during the initial construction, however double glazed curtain helps reduce the heat of the atmospheric air from penetrating into the interior spaces thus reducing the usage of air conditioning which then reduce the energy costs needed to support the excessive use of air conditioning.
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3.4.9 // SUSTAINABLE Heat Loss 45%
Problem : Usage of single glazed curtain wall. Single glazed curtain wall does not help maintain the thermal comfort of the interior spaces thus requiring the usage of air conditioning to maintain the quality of the indoor air. Solution : Replace single glazed to double glazed curtain wall Double glazed curtain wall consists of a glazing pocket which helps reducing the amount of heat penetrating into the space which in turn reduce the usage of air conditioning that is harmful to the environment.
Diagram 3.4.13 Single glazed curtain wall heat transmission diagram
Heat Lost (55%- 77%) Radiation of absorbed heat (inside) 6%
Reflected Heat (outside) 8% Absorption Radiation of absorbed heat (outside) 3%
Diagram 3.4.14 Double glazed curtain wall heat transmission diagram
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3.4.10 // CONCLUSION The original design of the curtain wall consists of many mistakes in terms of structural, safety, strength, feasibility and stability. The structural system of the curtain wall have been amended to support its own dead load as well as imposed loads such as wind and seismic load, by strengthening the connection to the building structure. Besides that, the curtain wall design and also structural system of the building have been altered in order to accommodate the connection anchor between the curtain wall and the beam structure. Moreover, the design of the curtain wall have also been altered to be more strong, sustainable and economic by changing the materials used. Tempered glass have been suggested as a solution to solve the problem of heat gain through the large glass opening as tempered glass is stronger and is able to reflect part of the heat directed into the space back to the environment.
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7m
1.8m
2.7m
Beams added in order to install anchors for connection between curtain wall and building structure.
8.4m
Additional mullions for extra support of curtain wall
Diagram 3.4.15
THE INTERLOCKING CULTURE Double glazed curtain wall revised design
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4.0
ORTHOGRAPHICS DRAWINGS
5.1 5.2
Before Readjustment After Readjustment
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4.1
ORTHOGRAPHICS DRAWINGS BEFORE AMENDMENTS
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4.2
ORTHOGRAPHICS DRAWINGS AFTER AMENDMENTS
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5.0
CONCLUSION
The initial design of the building consists of many problems regarding the structure and construction systems. However, we have provided several proposals and solution that is able to modify and strengthen the structure of the building. In conclusion, we are able to identify the problems on the building structure and provide solutions to amend it without affecting or changing much of the design and aesthetics.
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6.0
REFERENCE & APPENDIX
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Reference 3.1
3.3
Roof System En.wikipedia.org. (2018). Domestic roof construction. [online] Available at: https://en.wikipedia.org/wiki/Domestic_roof_construction [Accessed 2 Oct. 2018].
Foundation and Floor System
Gupta (2018). Steel roof trusses. [online] Slideshare.net. Available at: https://www.slideshare.net/Dudesid1/steel-roof-trusses [Accessed 2 Oct. 2018].
CWC. (2018). Fire-Retardant-Treated Wood - CWC. [online] Available at: http://cwc.ca/wood-products/treated-wood/fire-retardant-treated-wood/ [Accessed 1 Oct. 2018].
Understand Building Construction. (2018). Steel Frame Structures | Steel Framing | Steel Structures. [online] Available at: http://www.understandconstruction.com/steel-frame-structures.html [Accessed 2 Oct. 2018].
Stratco.com.au. (2018). Stratco. [online] Available at: https://www.stratco.com.au/siteassets/pdfs/steel_framing_tuffloor.pdf. Stratco.com.au. (2018). Stratco. [online] Available at: https://www.stratco.com.au/products/building-construction/probeam-flooring/ [Accessed 1 Oct. 2018]. Civil Construction Tips (2018). Wide strip foundation | Civil Construction Tips. [online] Available at: http://civilconstructiontips.blogspot.com/2011/06/wide-strip-foundation.html [Accessed 29 Sep. 2018]. Structural Detail (2018). Steel column footing foundation detail. [online] Available at: https://www.structuraldetails.civilworx.com/shop/steel-frame-details/steel-column-f ooting-foundation-detail/ [Accessed 29 Sep. 2018)
3.2
Post and Beams Lyons_Comparative(2018). A comparative analysis between steel, mansory and timber frame construction in residential housing[online] Available at: https://repository.up.ac.za/bitstream/handle/2263/14400/Lyons_Comparative%28 2009%29.pdf?sequence=1 Steel-vs-concrete and timber. (2018). Advantages and disadvantages of steel as structural design material[online] Available at: https://www.slideshare.net/sheerazgulabro/aquib-steelvsconcrete Standard size of column in building. (2018). What is the standard size of column in building[online] Available at: https://www.quora.com/What-is-the-standard-size-of-a-column-for-building Metric size| Logamatic. (2018). Metric size of universal beams and columns[online] Available at: http://www.logamatic.com.my/universal-beam-column/metric-size/
3.4
Curtain Wall System 3rdreality.me. (2018). Incredible Unitized Curtain Wall Details Unitized Curtain Wall Cad Details – 3rdreality.me. [online] Available at: http://3rdreality.me/unitized-curtain-wall-details/incredible-unitized-curtain-wall-details-unitize d-curtain-wall-cad-details/ [Accessed 25 Sep. 2018]. Allard Double Glazing. (2018). Double vs Triple Glazing - The Differences. [online] Available at: https://www.allarddoubleglazing.co.uk/blog/faq/double-vs-triple-glazing/ [Accessed 25 Sep. 2018]. En.wikipedia.org. (2018). Insulated glazing. [online] Available at: https://en.wikipedia.org/wiki/Insulated_glazing [Accessed 25 Sep. 2018]. Replacementwindowsfordummies.com. (2018). Double Glazed Windows: Advantages and Disadvantages | Replacement Windows for Dummies. [online] Available at: http://www.replacementwindowsfordummies.com/articles/double-glazed-windows-ad vantages-and-disadvantages [Accessed 25 Sep. 2018]. W&W Glass, LLC. (2018). Should I Use a Unitized Curtain Wall or Stick-Built System? | W&W Glass, LLC. [online] Available at: http://www.wwglass.com/blog/post/unitized-curtain-wall-or-stick-built-system/ [Accessed 25 Sep. 2018]. Wbdg.org. (2018). Curtain Walls | WBDG Whole Building Design Guide. [online] Available at: https://www.wbdg.org/guides-specifications/building-envelope-design-guide/fenestrati on-systems/curtain-walls [Accessed 25 Sep. 2018].
Steel connections. (2018). Seminar on connections in steel structures[online] Available at: https://www.slideshare.net/babunaveen/steel-connections Load transfer from beam to column. (2018). How are loads transferred from beam to column[online] Available at: https://www.quora.com/How-are-loads-transferred-from-beams-to-columns
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Appendix 3.1
Foundation and Floor System
3.2
Post and Beams
Figure:
Figure :
3.1.1 Rectangular reinforced pad footing 3.1.2 Fire damaged timber flooring 3.1.3 Damaged flooring system
3.2.1 Timber structure decay and collapse. 3.2.2 Steel structural system. 3.2.3 Timber frame structure. 3.2.4 Steel frame structure. 3.2.5 Fully timber structure. 3.2.6 Steel structure with timber finishes. 3.2.7 Timber louvers connected to steel structure.
Diagram: 3.1.1 Existing foundation of the building. 3.1.2 Wide strip reinforced concrete foundation 3.1.3 Thermoguard fire varnish 3.1.4 Steel floor framing system with timber finish flooring 3.1.5 R.C footing stump for column 3.1.6 Foundation to steel column connection 3.1.7 Sections with amended pad footings 3.1.8 Steel frame flooring system 3.1.9 Steel frame to timber finish 3.1.10 Load bearing to steel frame 3.1.11 Non load bearing to steel frame 3.1.12 Dimension of Joist and Bearer 3.1.13 Bearer and joist connection 3.1.14 Bearer and joist to column connection 3.1.15 Floor plan of amended flooring system
Diagram : 3.2.1 Post and beam structural system. 3.2.2 Current building structure. 3.2.3 Missing column and beam. 3.2.4 Location of column and beam.(Section) 3.2.5 Location of column and beam. (Floor Plan) 3.2.6 Bolted Connection and Welded Connection. 3.2.7 Moment Connection. 3.2.8 Axonometric view of location of column and beam. 3.2.9 Load stress diagram of column and beam.. 3.2.10 Load stress diagram of column and beam.(Axonometric) 3.2.11 Axonometric view of column and beam. 3.2.12 Materials layer of wall. 3.2.13 Location of timber louvers.
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Appendix 3.3
Roof System Diagram: 3.3.1 Location of roof 3.3.2 Roof Vulnerable to Collapsing 3.3.3 Points that are Vulnerable to Bending 3.3.4 Thin Roof Unable to Resist Loads 3.3.5 No integration of systems on the roof 3.3.6 Sections without admentmends of roof 3.3.7 Sections with amendment of roof Figure: 3.3.1 DIagram Of Roof Structure 3.3.2 Roof Collapsing 3.3.3 Steel Structural Frame 3.3.4 Steel Roof Truss Support 3.3.5 Nuts and Bolts And Welding Joint Method 3.3.6 Nuts and Bolts And Welding Joint Method 3.3.7 Diagram of roof integration 3.3.8 Zinc roofing 3.3.9 Zinc roofing details 3.3.10 TImber roofing 3.3.11 Zinc roofing
3.4
Curtain Wall System Figure : 3.4.1 Shattered Standard Glass 3.4.2 Shattered Tempered Glass 3.4.3 Curtain Wall Anchor Diagram : 3.4.1 Double Glazed Curtain Wall Section 3.4.2 Stick Curtain Wall System 3.4.3 Modular Curtain Wall System 3.4.4 Placement of Curtain Wall on Plan 3.4.5 Curtain wall section before amendment 3.4.6 Curtain wall section after amendment 3.4.7 Original design of curtain wall before amendment 3.4.8 Curtain wall mullions before amendment 3.4.9 Curtain wall mullions after amendment 3.4.10 Standard and Tempered glass load stress diagram 3.4.11 Curtain wall section after amendment 3.4.12 Double glazed curtain wall heat transmission diagram 3.4.13 Single glazed curtain wall heat transmission diagram 3.4.14 Double glazed curtain wall heat transmission diagram 3.4.15 Double glazed curtain wall revised design
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