wk2

Studio Report

Product

Concept used to build this bridge – Truss A truss is a structural frame based on the geometric rigidity of the triangle and composed of linear members subject only to axial tension or compression.

Different components of a truss.

Tension and compression are present to spread the loads downwards.

Green arrows indicate the load paths of the bridge

In our bridge, we used pinned joints. They could theoretically allow rotation but resist translation in any direction

Real truss bridge in U.S.

The diagram on the left tells the principle of the bridge during the tutorial lesson.

The heel (in red) is the force created by the table to the bridge.

The big blue arrow is the weight of the bridge (gravity force) and the arrows on top of the bridge are the loads.

The compression and the tension both make their roles to spread the load to the table in order to make the bridge stable.

Pinned joints

fixed joints

Roller joints

Roller joints allow rotation but resist translation in a direction perpendicular into or away from their Fixed joints maintain the angular relationship between the joined elements, restrain rotation faces. They are not and translation in any direction and provide both employed in building construction as often force and moment resistance as pinned or fixed connections but they are useful when a joint must allow expansion and contraction of a structural element to occur

Comparison to other groups The other group also use the concept of truss to build their bridge.

The difference between theirs to ours is that their top only consist of one bar, which we had two bars.

If we have to put loads on our bridges, I think the design of ours are better. It is because two bars can separate the load paths and transverse the loads to the table more stable comparing to this bridge.

We could also upside-down our bridge. The loads carried by this side of the bridge was not that bad in fact. This was because the loads could also transverse to the end of the tables effectively.

Exploration of the use of material for bridges Criteria for being a good material for building a bridge

1.Performance requirement – fire resistance, protection from rain, easily maintained 2.Economic efficiencies – initial cost, future performance

Concrete

Bricks

3. Environmental impact Advantage for these materials: • High-strength • Can change to different shape easily • Uniform size • Low cost

Steel

Rusting Iron could never be the built material for bridge. As it is easy to collapse if the structure is rusted.

Aluminum

Learning Loop Arch – is curved structure for spanning an opening designed to support a vertical load primarily by axial compression. They transform the vertical forces of a supported load unto inclined components and transmit them to abutments on either side of the archway.

Shells are thin, curved plate structures typically constructed of reinforced concrete. They are shaped to transmit applied forces by membrane stresses – the compressive tensile and shear stress acting in the plate of their surfaces.

Membranes are thin, flexible surfaces that carry loads primarily through the development of tensile stresses. They maybe suspended or stretched between posts, or be supported by air pressure.

Construction systems: 1. Performance requirement – compatibility, fire resistance, movement from soil 2. Aesthetic qualities – proportion, color, highly polished?

3. Economic efficiencies – affordable? Initial cost and future maintenance cost 4. Environment impact – the effect dealt to the environment