Constructing Environments ENVS10003 Juhyun Son-‐354978 Logbook Interim submission LOGBOOK WEEK1(Page2-‐7) LOGBOOK WEEK2(Page8-‐12) REFERENCE (Page13)
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CONSTRUCTION The meaning of building construction is the process of preparing; planning, design and financing. In the first week, we have studied about materials for the construction, basic structural forces, site analysis, load path diagrams and bluestone that often used in construction in Melbourne. Moreover, we construct a tower by using MDF (Medium Density Fibreboard) to understand the nature and behaviour of modular mass construction and how loads can be transferred through the compression structures.
Figure 1 Construction site
Figure 2 knowledge map of construction
Materials-‐Melbourne’s bluestone Bluestone is the material of cultural or commercial or building stone varieties. It is often used in Melbourne’s construction. Building stone of bluestone is basalt that can easily found in volcanoes around Melbourne area. Basalt is used in construction because it is easy to find near Melbourne, however, sandstone is normally used in Sydney and clay for bricks and limestone is used in Perth. Basalt is commonly dark colouring, therefore, it makes city dark.
Figure 3 bluestones (basalt) with bubbles
Figure 4 knowledge map of Melbourne's bluestone (basalt)
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Basic structural forces The change in the shape or movement of a body can be determined as a Force. Both magnitude and direction need to be considered as a vector function by an arrow whose length is proportional to the magnitude and whose orientation in space represents the direction. In the construction, the force can be divided into tension forces and compression forces.
Figure 5 Force diagram
Figure 6 force diagram with description.
Tension forces Tension force is pulling force. For example, when a structural member is pulled over by an external load, it is moving apart and undergoes tension. It will cause the extension on a member depending on the stiffness of the material, cross sectional area, and the magnitude of the load. Tension can be determined as opposite of compression. Tension force on a structural member is most often used as it can span large distances.
Figure 7 tension force described by green colour
Figure 8 the changes of member shape after applied tension force
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Compression forces Compression forces on a structural member are pressed from each end of a member. It is the opposite effect of a tension force as mentioned above. It will cause the compaction of a member and the material will be shortened by compression force. Compression members are commonly used in columns.
Figure 11 Examples of the load path diagram on a structure
Figure 10 the shape changes after applied compression force
Figure 9 A compression force is pushing outward along the curve
Load path diagram For this part of studies, live load is the only one has to be considered. Live load is an applied load and it has to be considered how it transfers to the ground. When an applied load is placed on the beam, it only transfers to the column and reaction forces from the ground to stable the structure will support it.
Figure 12 Load path diagram of simple structure and description
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Site analysis One of the most important thing in construction is site planning. It includes the boundaries of architecture, landscape architecture, engineering, real-‐estate development, urban planning and economics. There are several points that significantly important for site analysis; location, neighborhood context, site and zoning, legal elements, natural physical features, utilities, human and cultural. Also, the climate is really important issues in construction, therefore, it is considered well by engineer’s site analysis.
Figure 13 Examples of site analysi
Figure 14 Examples of site analysis 2
Studio session-‐Mass Construction Tower (Pavilion) Build a Mass Construction Tower as high as possible using the least amount of MDF. There are two methods of constructing the MDF blocks; Stack Bond and Stretcher Bond. One of these methods has to be decided to construct a tower as high as possible. Our group has chosen the stretcher bond method because the force from upper block can be transferred to two different blocks that placed below. It will make the tower more stable. Furthermore, it will prevent the collapse of the tower even if we remove the blocks in the middle of the construction.
Figure 16 how the load transfer to the ground for each structure method
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Figure 15 Stretcher Bond method
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One side of the tower should be open with the gate to obtain the object the size of 17blocks for the height 11 blocks for the width; however, our group has decided to construct a tower with one side open from the bottom to the top as shown in figure 17. Actually, the first designed tower was with the gate at the bottom. But the purpose of this workshop is to build a tower as high as possible with the least amount of blocks. Therefore, to obtain the object and build a tower as high as possible, the design has been changed as shown in following figures. Furthermore, the rubber band which makes the top of the gate stable makes the tower unstable when it gets higher.
Figure 17 A tower with whole side open
Figure 18 original design of our tower
The material that we used in this workshop is MDF (Medium-‐density fibreboard). The material is very strong and much more dense that particle board, therefore, it is often used as a building material similar in application to plywood. To test the stability of the tower, the blocks in the middle of the tower had been removed. The construction method was stretcher bond; therefore, the tower was really stable even if many blocks were removed in the middle. (Shown in the following figures)
Figure 19 The stability of the tower when the blocks are removed in the middle
Figure 20 Load path diagram shows the stability of the tower by transffering the load through the hole
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LOGBOOK By comparing the project with other group, the tower that we constructed was the highest and used the least amount of blocks. Nevertheless, all other groups had the gate at the bottom or in the middle of the tower. It causes other groups to take more time to get higher towers. Our group has chosen not to have a gate at the front, but the purpose of the constructing mass tower was to build a tower as high as possible by using the least amount of blocks.
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Structural Loads and Forces To understand the structural loads and forces, we have studied structural systems & forms, construction systems, ESD (Environmentally Sustainable Design) considerations &selecting materials, structural connections and a framework for analyzing form. For the workshop, we construct a skeletal structure to understand how the structure can be stable by connecting the frame, bracing and column.
Figure 21 Examples of skeletal structure
Figure 23 Examples of several structural systems
Figure 22 knowledge maps of structural loads & forces
Structural systems & Forms There are several different ways of structural systems & forms; solid systems, shallow surface systems, frame systems (skeletal system), Membrane system and Hybrid systems. In this week’s activity, we use balsa wood to construct a stable tower by using frame system (skeletal system).
Figure 24 Knowledge map of structural systems & forms
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Construction systems Construction systems include structural system, enclosure system, Mechanical system (service system). During the construction, there are significant issues that we need to consider about; Performance requirements, Aesthetic qualities, Economic Efficiencies and Environmental impacts.
Figure 26 Examples of Construction system
Figure 25 knowledge map of construction system
ESD and Selecting Materials Nowadays, construction must consider the impact on environmental issue. In addition, selecting material for the construction should be really important issues to consider about ESD (environmentally sustainable design). When the material is selected for the construction, life cycle needs to be considered as well. Because, the extraction of raw materials from the earth and ends with the disposal of waste products back to the earth or it can be recycled into other products.
Figure 28 knowledge map of life cycle analysis
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Figure 27 life cycle analyses for ESD
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Structural Connections There are 3 basic connections that engineers need to consider about. These are roller joints, pin joints and fixed joints. These 3 different joints are used in different structure. In this week’s study, we have to construct a frame structure. To construct this, we must use truss and bracing to make the structure stable. For this kind of structure, we use pinned joints by connecting them with truss and bracing.
Figure 29 Truss (triangular shape) in frame structure
Figure 30 symbols of joints
A Framework for Analyzing Form A framework can be simply supported by two columns is not strong enough to prevent collapsing by lateral forces unless it is braced. Therefore, wall and a column on the other side can support a framework. There are also several frameworks for the structure; fixed frame, hinged frame and three-‐hinged frame. These frameworks have their own advantages and it will be chosen and used by considering climate issues, the place to built and etc.
Figure 31 Example of framework
Figure 32 how truss system transfer the force into the ground
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ACTIVITY: FRAME The material that we used in this activity is balsa wood. To understand the nature and behavior of frame construction, a tall stable tower need to be constructed by cut balsa wood strings. The purpose of this construction is the same as previous workshop. A stable skeletal construction should be built as high as possible. To make the construction stable, the truss and bracing might be used between columns. Figure 34 Designed frame structure
Figure 33 Frame structure with triangular base
The diagonal string that connects column and the base was too long. The basic concept that our group has designed was not correct. The column should be trussed to each base to make it more stable. Also, the length of the column is too long; therefore the structure wasn’t standing properly. When the construction gets higher, our group realizes that the column should not be that long. Furthermore, our structure needs more trusses to make it stabilize.
Figure 35 zoomed in the column and truss
Figure 36 designed developed in 2-‐D plane
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LOGBOOK The group next us have reached the ceiling. Their column was also long but they have more trusses system at each columns and bases. It makes the structure more stable and their structure may even hold the textbook. At certain weight point, their structure also collapsed, however, their structure was stable enough to carry some amount of weights and it also reached the ceiling. It is showing that their structure was connected well and their truss system could transfer the force to the ground safely.
Figure 38 the best stable tower in the studio session
Figure 37 Best designed 2-‐D plane including load path diagram and reaction forces acting on
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Reference http://en.wikipedia.org Building Construction illustrated Forth Edition. Francis D.K. CHING
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