Logbook wk02

Week 02 Summary

Construction Systems Enclosure System – protection, shell or envelope of a building, consisting of the roof, exterior walls, windows and doors. (Ching, 2014) Service System – anything providing amenity/essential services to the building; electrical, mechanical, hydraulics.

Structural Systems – frame, column & beam, mass construction.

ESD Strategies ESD – Environmental Sustainable Design Recyclability – reduce, reuse, recycle.

1. Carbon footprint – measure of greenhouse 2. Gases used.

3. Local materials 4. Thermal mass – use of a material to store energy, e.g. concrete slab.

5. Water harvesting – collection and use of rainwater.

6. Insulation 7. Wind energy 8. Solar power 9. Material efficiency 10. Night air purging – bring outside air inside in the evening to remove stable air.

(Newton, Clare, 2014)

Structural Joints Roller Joint – allows horizontal movement; only resists vertical forces.

Pin Joint – allows rotation, resists both vertical and horizontal.

Structural Systems Every load must have a responding force of equal strength.

Solid Structure – early buildings; mud, bricks, stone; Compression architectures, efficient, e.g. Egypt, Great Wall.

Surface Structure – Sydney Opera House Membrane Structure – tension, shade sails, sport stadiums; large area; Cheap.

Hybrid Structure – air integral; particular membrane called ETFE; covering large, expense economically, quickly, e.g. Beijing Olympic swimming cube and bird nest.

Skeletal Structure – common; frame system; very efficient way to transfer loads down through to the ground.

(Newton, Clare, Structural Systems and Forms, 14/03/2014) Consideration

Performance requirements – structural, fire resistance, comfort, protection from elements, compatibility, easy maintenance.

Aesthetic qualities – proportion, color, surface qualities.

Economic efficiencies – budget, affordability(initial cost & maintain cost).

Environmental impacts – embodied energy, constructability efficiency. *EMBODIED ENERGY – how much energy is in the item. Moving it, maintaining it, running it, getting rid of it.

Fixed Joint – Resists vertical, horizontal and rotational forces.

(Cantilever – one point of support, e.g. a tree, wing of a plane)

第 # 期:[日期] Studio Report (Frame)

折页册

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Materials A 600mm x 100mm x 2mm piece of balsa and glue only. Technically the span is easy to be reached since the weight of bridge self is very light due to the characteristic of balsa woods.

However, they are flimsy, easily bent and snapped, the flexibility of balsa increase the difficulty when apply loads on the final stage.

Process & Construction System & Load Path Diagram We planned to cut the balsa into 3 pieces which size is 500mm x 33mm x 2mm each, the totally length after them all be put together would meet the requirement which is 1500mm. Not to be judgmental, but the whole idea had a fundamental bug at this very beginning. We took the 2mm side to face up and down; therefore the bridge floor became too narrow to bear loads. Also, all joints were fixed joint where bending and deflection occurred.

Later when we have done the cutting and stick the wood pieces together. We noticed that we could glue them in two ways, by referring to the diagrams above, the diagram on the right hand side looks more likely to break, but unlike the unpredictable frame on the left, it’s also easier to be strengthened.

2

第 # 期:[日期] Studio Report (Frame)

折页册

In order to strengthen the weak joint, we discussed a various possibilities of collapse; the one most likely to occur has been diagramed on the left, the solid lines represent the original position, and the dotted lines represents the possible condition of collapse. It shows that when loads come from the central, the right end goes down and breaks the stickiness in between.

Therefore we glued two short and narrow balsa pieces to fix the weakness and prevent dislocation. We later placed three pieces of balsa on each side in order to support the narrow balsa above and below, by maximizing tension at a frame like this, the deformation we predicted before doesn’t take place

After fixation on two ends, and applied a square horizontally in the middle to bear the loads. We tested the bridge by stressing it with a heavy fabricconcrete, as shown in the picture an diagram, the bridge twisted obviously immidiately after we applied the load. The bridge continued twisting until the wider side of wood facing up and collapse from one of the very end.

3

第 # 期:[日期] Studio Report (Frame)

折页册

The critical collapse point for this structure is one end of the bridge. As shown on the left, we cut groove on a piece of of balsa and insert the end of the bridge in, technically, it supposed to transfer the loads efficiently to the table. However when we pressed our finger on to hold the bridge, the loads dragged the central of the bridge down and twisted the whole structure, therefore the load paths reversed and eventually collapse the end.

Comparison with Other Group This group built the structure by placing the wider side of the bridge horizontally which made the bridge more stable. On the two ends, unlike ours, they seperated the end into three direction and pinned the woods on a paperboard. This group increase the stability and bearing capicity efficiently. However, they didn’t strengthen the weakness - the joints that linked each piece of woods, by this, the bridge might easily collapse once the bridge approaches certain length or the loads reaches certain weight.