[WO2] THEORY
* Membrane - e.g sail on a boat
S T R U C T U R A L LOADS & FORCES [e-Learning]: Structural Systems: * Solid - stone - brick - compression = main action
* Hybrid - e.g skeletal & surface Construction Systems: * Enclosure system * Structural system * Service/Mechanical system
Environmentally Sustainabile Design (ESD): * Local Materials * Material Efficiency * Thermal mass * Solar panels (Energy & Hot Water) * Night air purging * Ventilation * Water Harvesting Structural Joints: * Roller Joint - resists vertical movement
* Pin Joints - resists vert. & hori. * Surface - e.g Opera House
* Fixed Joints - resists vert, hori & rotate
* Skeletal/frame - more common today - effecient transfer of loads Considerations in construction * Performance requirements * Asthetic qualities * Economic efficiencies * Environmental impacts
Analysing Form: * Column & Wall - e.g. Arcade --> Foundling Hospital * Point & Plane
[WO2] STUDIO
In order for the bridge to span across the 1.5m gap, we dividede the sheet of wood lengthways, using three 600mm beams to constuct the main structure of the bridge.
LOADS IN FRAME S T R U C T U R E S
[Bridge building exercise]: To do this activity, we were given 1 sheet of balsa wood (600mm x 100mm x 5mm).
Whilst we were still set on replicating the beam-like structure, we noticed that the joints along the bridge would be weak, and therefore would be likely Structurally, we considered replicating to break when a loads is exerted on the the shape of a steel beam as we all recogstructure. To eliminate this problem, we nised it as being sturdy and durable, in reinforced each join with small sections terms of being able to absorb and disperse of balsa wood that would act as a brace loads. around the main structure.
As the brdige began to form, spanning 1.8m, to structure was quite flimsy and suseptible to a lot of bending and rotating. We hoped that by adding the two flanges on the top and bottom of the structure it would become more stable.
[WO2] STUDIO LOADS IN FRAME S T R U C T U R E S The bottom flange was first stuck down with glue in order to make sure it was centred
Due to time constraints, we were unable to mount the second flange to our bridge. We recognised that this will drastically influence how well the structure performs when a load is applied, as the web (centre spine of a beam) is directly exposed to the load. We suspected that due to the web being the weakest component of the beam, this would be the first area that breaks under the force from the load.
Pins were then added along the spine to add strength to the joinery.
In terms of fixing the brdige to the table, we built up a couple of blocks on each side of the beam, this was to prevent the likelihood of rotation occuring through the structure.
Now that the bridge was fixed to the table and successfuly spanned across the 1.5m gap, it was time to test how well it help up when a load was applied to the centre of the strucutre.
[WO2] STUDIO LOADS IN FRAME S T R U C T U R E S As soon as the load was applied, we saw signs of significant reotation throughout the entire strucutre.
[Key Terms]:
Structural Joint A connection, whether it be a roller, pin or fixed, that joins to components together within a particular strucure. (see theory notes for images of each joint) Frame A construction technique whereby vertical structural members, known as studs, are used As the load increased, the brdige was un- to support timber (or dergoing severe rotation and bending. The steel)frames to make centre of the bridge then broke under the them stable. force. Bracing Bracing refers to the act of using structural components in order to hold another component in place, usually through preventing horizontal, vertical or even rotational movement.
BEFORE
Although the second flange would have added some rigidity to the brdige, it was the table joints that required bracing to counteract the rotation.
AFTER Column Vertical structural component that is used to transfer loads due to compression (see previous entry for image) Tension a loads that pull on a structural member, causing the particles to stretch and elongate. (see previous entry for diagram) Span the distance that a component has to reach within a structure. Steel can span a long distance and remain strong.