Week 4: FLOOR SYSTEMS AND HORIZONTAL ELEMENTS Floor systems: 1. Span Define: distance between 2 structural supports (Ching, 2008) Measured: vertical supports (for ) Horizontal support (for ) ** Not necessarily same long as a member ** 2. Spacing Define: repeating distance between series of similar elements. (Ching, 2008) Associated with supporting elements Measured: center line – centerline = *SPACING of supporting elements depended on SPANNING capabilities of supported elements. (Ching, 2008) 3. Strut Held in compression 4. Retaining wall
Materials and their systems: 1. CONCRETE SYSTEM: 2 directions Or 1 direction Measuring depth of slab: span (m) x 30 Eg) Diagram on reinforcements for concrete beams Footing: part of building that transfers the super system load to the ground Foundations: supports the footings. Is the soil = not man made 2. STEEL SYSTEM: Heavy gauge: structural steel, large joists between main girders. (Ching, 2008) Light gauge: steel web joists Can combine with concrete:
3. TIMBER SYSTEM: Joists – support secondary flooring Bearers-‐ span between stumps and piers Can be closely spaced for thinner timber, wider apart for thicker timber Parts of floor system: BEAMS: horizontal structural element Function: carry loads along the length of beam + transfer to vertical supports. CANTILEVERS: supported at only one end Function: transfer load to main support system INSITUE CONCRETE: Joints: construction – used in small and manageable places Control – absorb expansions PRE-‐CAST CONCRETE: - Standardized outcome - Controlled process - Increased quality - Faster construction process Joints: construction and structural
WEEK 4: ‘SCALE, ANNOTATED AND WORKING DRAWINGS CONVENTIONS’ Scale: Why: to represent the building in a smaller view that is an exact representation of the building. Allows clients, builders, and architects to work, modify and present the design in a clear and manageable way. How: scale is reduced used a ratio that equally represents life size to smaller size. Drawing to life size: time the length of member by the units in the scale bar. How does the information in the drawing set compare to what you observed in last weeks site visit? The information gives a clear structure of what was seen in the site visit. Although specific element within the drawings are not recognizable base construction isn’t that far ahead. Smaller details such as box guttering can not be seen because fascia is covering it. How does the scale of the building compare to scale of the drawing? The scale of the drawing is a lot smaller compared to the building. Scale 1:1, so every 1cm = 1m. How do architectural and structural drawings differ? Structural drawings are primary based on the details of how the building is constructed, such as joints and footings as well as loads. Including design, location and dimensions. Where as architectural drawings show the overall picture of the building, including landscaping and aesthetics. Both drawings can show elevation, sections.
CONSTRUSCTION DOCUMENTATION TOUR:
Week 5: COLUNMS, GRIDS, WALL SYSTEMS Columns: - Vertical structural members designed to transfer axial compressive loads. - Considered slender members - Short or long Comparison of short + long columns: EL: effective length CD: smallest y set dimension
JOINING OF COLUMNS: Fixed joint – pin joint: contriflexture 1/3, 0.3 = 0.75 of original length is lost. Fixed – fixed: 0.5 contriflexture = length is halved Pin – pin – pin: contriflexture halved. Middle column effectively makes 1 into 2 = reducing likely hood of buckling. LOAD BEARING WALLS: 1. Concrete: insitu or precast Panels: provide support for spandrel panels 2. Reinforced masonry: either core filed hollow concrete blocks or grout filled cavity masonry. Bond beams: used over openings. Special concrete blocks, alternate to steel/concrete lintels. (Ching, 2008) 3. Solid masonry: single/multiple skins, concrete or clay brick Joined: brick/wall ties 4. Cavity masonry: 2skin Advantages: o Increased thermal performance o Opportunity for insulation o Better waterproofing o Run services Recognizable: damp proof course + weep holes (Ching, 2008) eg) Melbourne university swimming complex
STUD FRAMING: 1. Metal and timber: smaller sections of framing or light gauge steel Smaller sections: o Repeated @ smaller intervals o Require restraining à noggins: prevents long thin members buckling Consists of: BRICK VENEER CONSTRUCTION: 1 skin non-‐structural masonry + 1 skin structural frame wall. Used for aesthetic appeal. Walls Uses: structure system and enclosure systems Systems: 1. Structural frames o Concrete frames eg) large scale city building o Steel frames eg) industrial building o Post-‐beam eg) sloping site 2. Load bearing walls o Concrete eg) new apartment buildings o Masonry
3. Stud walls o Light gauge steel framing o Timber framings eg) Z or C section
STURCTURAL FRAMES 1. Concrete frames: using a grid of columns w connecting beams. Square column + Circle column: spiraling reinforcements o Moment joint: beam interconnected into column. (Ching, 2008) 2. Steel framing: grid, connected to girders and beams.
3. Post and beam: grid, connected to beams. Bracing between bays or at corners and junctions.
ENGINEERED TIMBER PRODUCTS: 1. I beams: timber LVL/ plywood OSB Use: floor joists and rafters 2. Box beams: timber LVL/ 2 plywood OSB Uses: decorative, joists, rafters 3. Timber flanged steel web joists: light tubes, solid rounds, corrugated sheets Uses: floor joists, rafters FRAMING + EFFECTS OF LOADS 1. Fixed frame: (rigid frame) o Resistant to deflection o Sensitive to support settlements of thermal expansion + contraction 2. Hinged frame (rigid, pin joint frame) o Able to rotate as a unit when stressed 3. Three hinged frame o Sensitive to deflection
WEEK 5: ACTIVITY Aim: to re building in a scaled model a certain section of the oval pavilion Assigned section: left hand half of the oval pavilion canopy/cantilever. Elements forming part of structural system Structural elements: structural steel, reinforced concrete columns What the materials are used for: Structural steel-‐ strong in compression. Used as to transfer load to the main reinforced concrete columns. Steel used to create angles for aesthetic appeal and support external cladding. Reinforced concrete columns-‐ part of footings to transfer the loads to foundations of building and to support the large canopy overhead. Structural joints: between structural steel there is fixed joints. You want the canopy to be rigid and avoid any movement within this element. Fixings: bolted, concrete pad footings. Categories Foundations and footings: reinforced concrete columns Vertical/horizontal primary structure: horizontal structural beams. Connecting to the main steel column. Vertical/horizontal secondary structure: horizontal beams, smaller in size connecting from the primary horizontal beams to the canopy’s corners. These beams are load bearing but do not take the same magnitude of force as the primary ones. Materials used: 3x 60cm balsa wood square columns Recycled cardboard 2 x 60 x 10cm balsa wood sheets Pins, sticky tape
Problems: the limited amount of materials brought to class limited the quality of our design and its stability. This caused future problems when analyzing the structure because the fixings and structural element weren’t correct and present. Method: Our group worked on our structure by working upside down, we used the external cladding (which is not part of the structural system), however provided as with a base to work from. Photographic sequence: Joining of two pieces of board together with tape: the canopy roof. Problems: not enough cardboard to create the structure to scale. Solution: scavenged for more cardboard.
Three main structural columns for transferring loads to foundations. Noting: the columns are all the right of the canopy. Architectural decision for aesthetics. Joints: fixed
Developing the primary and secondary horizontal structure. Each beam connecting to canopy corners.
Final completion of case study. You can see in the photo that the structural system is very precise design, for maximum aesthetic appeal to allow for a concealed structure.
Load paths: Key elements identified in the making: Reinforced steel concrete beams continue all the way to the basement footings. Meaning the canopy needs most structural support. Achieved through long columns reaching to foundations.
Comparison to other groups:
This groups worked is evidently of higher quality and provides a much easier model to determine load paths and structural properties. In comparison within the primary structural beams there is secondary vertical framework. This framework is creating a rigid structure, to minimize the movement and deflection of the main beams. Conclusion: from this activity it is evident that the canopy has needed a lot of reinforcement and structural support in order to achieve the large span of distance that the outreach part, without the support of a column. This has been achieved through the three main columns in close in proximity, which are connected down to basement footings and foundations. This spreads the load over a wider area to compensate for the over hang canopy.
WEEK 6: SPACING AND ENCLOSURE SYSTEM ROOFING: Primary sheltering for internal space Collect rainwater Influence appearance Define plates: rigid, planar, monolithic structure that holds diverse loads in multidirectional pattern. Load follows shortest routes. (Ching, 2008) Grids: framework of spaced bars that are parallel to or cross each other. Systems: 1. Flat roof: o Pitch 1-‐3 degrees o Ponding occurs if flat – increase load, leakage 2. Pitched and slopping roof: > 3 degrees TYPES: 1. Concrete roofs: o Flat plates of reinforced concrete o Slopes towards drains o Waterproofing membranes Used: car parks, fire-‐rating requirements, rooftop gardens
v Support of masonry load bearing frames à columns à foundations
2. Structural steel framed roofs Flat – primary/secondary support. Includes: beams, meat decking, concrete, roof beams and purlins. Sloping – light sheet metal Includes: roof beams and purlins Portal frames – braced grid frames (2x columns, beams) Includes: purlins, grids for walls, columns and beams are fixed joints, sheet metal, c, z sections. Leaved off beams below. 3. Truss roofing Define truss: fabricated steel bolted or welded at structural angles and tees to form a triangulated framework. (Ching, 2008) When: shaped roof system, curved Why: slenderness provides a more open roof cavity, aesthetics, bracing and structural strength. o Open web elements o Steel or timber = spans long distances o Efficient, high strength: material ratio 4. Space framing o 3D plate type-‐ long spanning in two directions o Linear steel section: welded, bolted, and threaded. o Used: where glazing is required
Made from: - Circular hollow sections - Pipes - Rectangular hollow section - Square tubes - T-‐section - I beam = allow for large spans
5. Light framed roofs Gable: vertical, triangular section Includes: common rafter, ridge beams, ceiling joists, bird mouthed over beams, outriggers used. Materials: timber, cold-‐formed steel sections Hip: vertical, triangular section Includes: common rafters, hip rafters, Vally rafters, ridge beams, ceiling joists. Materials: timber, cold-‐ formed sections. METALS *refer to back section on materials** - Malleable, ductile, not brittle - Ferrous/non-‐ferrous (increased quality) - Alloys-‐ 2 or more metals. Types: Ferrous magnetic, chemically reactive, compressive strength Non-‐ferrous: greater variety Considerations: - Water damage: Oxidation/corrosion = rusting - Reducing corrosion: Avoid prolonged exposure eg) crevices Seal against moisture eg) enamel, paint Chemical treatment eg) galvanized steel