Week 4 Anita Nicholls 698556
‘Scale, Annota8on and Working Drawing Conven8ons’ Why and how scale is used for documen3ng building projects? Scale is used for prac8cal reasons and allows building projects to be visually represented on paper. Mul8ple scales are used to convey different informa8on, and the scale that is chosen accommodates the specifics that varying professionals within the construc8on field are interested in. Smaller scaled are used to convey details and small measurements (e.g. of joints) whilst larger scales can convey room dimensions and larger contextual measurements. For example, A scale of: 1:10 enables interior designers to get a view of the inside of a room 1:100 is oQen used in floor plans, and is used by many as a reference guide for example a glazier would be interested in this scale to determine the loca8on of windows 1:1000 is oQen the scale of a large site plan and is commonly used in landscape architecture and urban design The preferred working units for building projects is millimeters. For construc8ng documenta8on, appropriate scales used vary depending on what aspect or detail of a building is being represented. Scales commonly found are 1:5, 1:10, 1:20, 1:50 1:100, 1:200 and 1:1000.
‘Construc3on Documenta3on Tour’ TITLE BLOCK Types of informa8on found in the 8tle block on the floor plan page: -‐Consultants -‐Key plan -‐Client -‐Project -‐Drawing Title -‐Drawing Number -‐Revision Column This informa8on assures that the page is legi8mate and the revision column keeps builders up to date with any status changes. DRAWING CONTENT-‐PLANS -‐The floor plan shows the context of the building -‐The dimensions of the ‘Oval Pavilion floor plan is 1:100, these units are in -‐There is a grid shown on the plan that used a numerical and alphabe8cal system to iden8fy the grid lines. -‐The purpose of the legend is to navigate your way around the building. The main structural layout is also based on the grid. -‐Some parts of the drawing are annotated to label exis8ng components proposed changes. References to other
drawings are shown on the plan using symbols.
Windows and doors are iden8fied by symbols such as Floor levels are noted on the plan
Some areas of the drawing are clouded to indicate areas that have references to zoomed in images DRAWING CONTENT-‐ELEVATIONS Q: What type of informa8on is shown in this eleva8on? How does it differ from the informa8on shown on the plan? A: Building heights. Each eleva8on only shows one side of the building Q: Are dimensions shown? If so, how do they differ from the dimensions on the plan? Provide an example of the dimensions as they relate to the eleva8on. A: Yes, they show the measurements between the references. Q: What types of levels are shown on the eleva8ons? Illustrate how levels are shown in rela8on to the eleva8on. A: Q: Is there a grid? If so how / where is it shown? A: Yes, with a broken line over the drawings Q: What types of informa8on on the eleva8ons are expressed using words? Illustrate how this is done. A: Proposed changes Illustrate how the doors and windows are iden8fied on the eleva8ons. Door number tag with room number, Window number tag with room number 7. Find where this eleva8on is located on the plans. Found.
‘Construc3on Documenta3on Tour’ DRAWING CONTENT-‐ SECTIONS Q: What type of informa8on is shown in this sec8on? How does it differ from the informa8on shown on the plan and eleva8on? A: Internal details are shown which give more informa8on about the usage of space within and around the building. Illustrate how the sec8on drawing differen8ates between elements that are cut through and those that are shown in eleva8on (beyond) Provide examples of how different materials are shown on the sec8ons
DRAWING CONTENT-‐ DETAILS Q: What sort of things are detailed? A: Materials, windows, structural elements, Q: Are the details compressed using break lines? Why? A: Yes, it enables sufficient informa8on to be displayed without the unnecessary use of extra space Provide examples of how different materials are shown on drawings at this scale:
3. The informa8on in the drawing set of the Oval Pavilion conveys much more technical informa8on than is perceived whilst viewing the building at face level. Although the drawings are explicitly made in a smaller scale, and the site plan shows much of the context of the building in comparison to other built and natural forms, it is s8ll not as clear as viewing the site at a 1:1 scale first hand. Much of the structural elements and mechanical systems are expressed in simpler forms on paper however the materials are also simplified, this contrasts viewing the site, as site visits allowed complex details in the materials to be seen and appreciated whilst concealing much of the internal elements. The eleva8on drawings whilst maintaining an accurate scale, allow much more of the building to bee seen without the percep8ve distor8ons of some elements over the other which occurs for example when looking up at a building from below, and things above seem wider and shorter in height than reality. However, some8mes these perceptual understandings help us to understand depth. As cab be seen in the photograph to the right, depth can be observed underneath the roof structure, this was only represented two dimensionally as a drawing. Architectural drawings show the shape, measurements and aesthe8c of the building design whilst structural drawings show the internal func8oning elements within the building for example the workings of a joint connec8on.
Learning Loop In-‐Situ Concrete: Poured into the framework and cured (process of hydra8on) on site. Process: Fabrica8on and assembly of formwork, the placing of reinforcement, the pouring, vibra8on and curing of the concrete. -‐Mort commonly used for structural purposes, in foo8ngs, retaining walls and all bespoke (non standard) structural elements. -‐some8mes sprayed into place using a pressure hose (shotcrete) Construc8on and control joints are poten8al weak points and considera8on must be made in terms of water and moisture control Precast concrete: Fabricated in a controlled factory environment and then transported to site. +ve: more standardized, higher quality, allows greater efficiency in labour on site -‐ve: limited in size due to the limita8ons of transporta8on, on-‐site changes are restricted Used in various applica8ons that are oQen associated with structure, commonly used in retaining walls, wall systems and columns. In a mul8-‐story building, Floors provide support for the column at each level. As span is the distance between two structural elements (and can be measured between ver8cal or horizontal supports), the column span is the distance between the top of one floor to the underside of the second.
Floor and Framing Systems Dead and live loads are carried from the slab into the beam, then the beam carries the loads to the columns which will transfer the loads down into the founda8on system. Three types of materials considering: concrete, 8mber and steel Concrete system: slabs of various types that span between the structural supports that can be one way or two way (depending on es8mated floor loads, the func8on of the building or cost efficiency). Slab thickness roughly the span of the slab divided by thirty. E.g. 6m spans of slab, then the depth would be about 200mm Structural Steel system: spanning between girders (main beams), steel framing can take several forms (e.g. a web of steel) and can use heavy weight structural steel or light gauge steel framing. OQen a combina8on of member types and material are combined. Steel framing systems are oQen combined with concrete slab systems Timber Systems: tradi8onal system uses a combina8on of bearers (primary beams) and joists (secondary beams). Common in Australia, consists of joists which support the flooring itself (floorboards, decking, ply panels etc.), these joists are supported on bearers. The bearers span on other supports which may be brick peers or concrete stumps. Typically floorboards span 450mm or 600mm.
Concrete is like an ar8ficial stone. Advantages: It is fluid and shapeless before it harden, can be formed and shaped. A common concrete mixture: 1 part cement (Portland or Lime), 2 parts fine aggregate (sand) , 4 parts coarse aggregate (crushed rock) and 0.4-‐0.5 parts water. -‐reaches 75% of its compressive strength within 7 days with tes8ng for its required strength at 28 days. As concrete is very strong in compression but weak in tension. To improve its structural performance, steel (which is very strong in tension) is oQen added in the form of reinforcement (in the form of mesh or bars). Reinforced concrete is very strong in compression and tension. Reinforcement is also used to form a fixed or rigid moment joint (between a slab and a wall). Proper3es: Hard, not very fragile, medium porosity, high density, low conduc8vity for both heat and electricity transfer, very durable, not very easy to recycle and reuse, high embodied energy, long las8ng, cost effec8ve (Depending on the labour) Cau3on: Provision of sufficient cover over the reinforcement to prevent water from seeping in, the iron and steel bars rus8ng and expanding and thus causing the concrete to chip off and expose the reinforcement. Poor vibra8on of the concrete during the pouring process (to get rid of air bubbles) can result in the concrete failing.
GLOSSARY Joist: Structural suppor8ng beams (oQen arranged parallel and with even spacing) that act to support the floor or ceiling Steel decking: light gauge corrugated metal sheets used in construc8ng roods or floors Bearer: A load suppor8ng structural member (bearer goes onto stumps then a joist goes onto a bearer) Girder: The primary horizontal? Beam, it carries loads from other beams and slabs connected to it Concrete Plank: An (oQen pre-‐cast or pre-‐stressed) concrete plank used for floor or roof decking Spacing: The distance between a series of similar elements, and is measured centre-‐line to centre-‐line. It is oQen associated with suppor8ng elements. The spacing of the suppor8ng elements is dependent by the spanning capabili8es of the supported elements.
Addi8onal Terminology
Girder: A main beam Beams: Horizontal Structural element. Loads are carried along the length of the beam and transferred to ver8cal supports. Beams can be supported at both ends, at various parts along the beam, at points away from the end of the beam or only at one end (these beams are called can8levers) Can3levers: A structural element only supported at one end (or the overhanging of one element is significant). Loads are carried along the length of the member and transferred to the support. They can be ver8cal, angled or horizontal. Formwork: The temporary support or moulds used to hold the liquid concrete in place un8l it becomes hard. It can be built at the building site (in-‐situ) or in a factory (pre-‐cast) out of a range of materials (8mber, metal, plas8c, formply etc.). Formwork is oQen removed, stored and reused or it may stay in place forever (Sacrificial formwork) (IN SITU CONCRETE) • Construc8on Joints: Used to segment parts of the construc8on work into more manageable sec8ons • Control Joints: Absorb the expansions and contrac8ons caused by thermal varia8on and to account for the shrinkage of concrete over 8me (PRE-‐CAST CONCRETE) • Construc8on Joints: Occur when one precast element meets another • Control Joints: The type and performance of the structural joins are cri8cal to the overall performance of the building
Construc8ng Workshop Week 4
ACTIVITY: ‘CONSTRUCTION PHASE’
Materials: 1200 X 3.2 X90mm Ply X2 Task: Construct a beam with a span of 1m, u8lising the materials to its best abili8es. 1200 X 35 X 35mm Pine X2 36 Nails Equipment used: Hammer, Western Saw, Bench hook Our group had 2x ply and 2x pine wood. Ini8ally we thought of stacking two beams with the beam containing a material deficiency (small chip that we decided to work with) on top, sandwiched between two planks. We altered our design to incorporate 4 equally sized and spaced wooden blocks between the two beams.
Load path diagram showing the distribu8on of the load through the four middle blocks down to the bopom beam.
Trying to limit the amount of joins created (weakness points), we nailed the exterior side planks onto the two strips with four equally spaced sawed off blocks placed in the middle. We appropriately chose our nail size to be smaller (but s8ll effec8ve) causing a smaller hole to be pushed through the wood meaning there would be less of a suscep8bility of weakness caused by altera8ons in the material. There was only one middle join through the horizontal central axis on either side of the structure going through the centre of each of the four the interior blocks
Using efficient labour processes by sharing the workload across all four team members, everyone was working on a task at the same 8me.
ACTIVITY: ‘CONSTRUCTION PHASE’ We noted that the top of our structure would be subject to compression, so we placed a greater number of nails on the top side in order to prevent the slices of wood from buckling off under compression.
This side view shows that the two exterior pieces of 8mber are used with an emphasis on the materials compressive ability based upon shape, increasing the rigidity of the design.
ACTIVITY: ‘DESTRUCTIVE TESTING PHASE’
The greater the deflec8on, the more distributed a load is through a structure. Our structure was quite rigid and would probably have undertaken more compressive forces if we did not have a natural fault in our material. A rigid structure generally resists the compressive forces and fails with a large impact rather than a more flexible structure that undergoes deforma8on for a longer period before finally breaking. Our structure failed at the base which was expected as we had very strong compressive force resistance but not as much resistance towards tensile forces at the bopom, this combined with a weakness in one of our 8mber pieces lead to breakage.
Maximum weight reached on recording: 313kg Star8ng deflec8on: 147 End deflec8on:190
Comparisons
The group managed to nail down their top beam within the last minute allocated for construc8on, and showed great teamwork and labour efficiency during this 8me.
Maximum weight reached on recording: 356kg Star8ng deflec8on: 134 End deflec8on:200 Failure occurred at t he fixing for this group, Their structure had not been completed as were missing some wooden blocks that were supposed to have run evenly throughout the middle. As can be seen in the photo to the leQ, the buckling of nails and subsequent wobble in this structure is caused by the increasing amount of compression that the top of a beam undergoes when an increasing amount of force is applied. This would have happened to our structure, however we took preventa8ve ac8ons and placed more nails at the top to resist the compressive forces tearing the structure apart.