PT1.3 - Construction of Bridge

3.1       Design rationale

General design
The design of the bridge is a hybrid between a camelback and a warren bridge with the supports below the bridge instead of above

Warren Bridge

Camelback Bridge

It incorporates the slightly curved truss of a camelback bridge as stress is more evenly distributed on curves than on corners.

 The diagonal design of the links is to spread out the horizontal stress that the bridge will receive. As can be seen in the simulation, the stress is spread out evenly through the use of the diagonal members.

The bridge also has to be symmetrical, so that the stress applied will be evenly distributed.
The black line is the line of symmetry 

The middle of the bridge, where the load is applied, has to be specially re-enforced, as moment there is the highest. Moment is calculated by the Load*Distance.  The X-shaped truss in the middle should increase the bridge's ability to hold weight.

We used triangular trusses as triangles are one of the more stable shapes under stress.

Members of the bridge
The bridge has 3 different kinds of members- Horizontal, Vertical and Diagonal.
 The horizontal members were the ones that provided the most strength in the bridge
The Vertical members linked the truss to the bridge, greatly increasing its strength.
The Diagonal members stabilized the truss and the bridge, preventing premature collapse.

Base of the bridge
As it is a hanging bridge, it does not have a base/bases.
Joints of bridge
The joints of the bridge are
approximately 4cm in length. The rationale for this is that the glue needs a big enough surface area to be able to be sturdy. However, our design calls for the bridge to have trusses, and to ease the constructing of the trusses, we have left gaps in the joints for the trusses to be slotted in.

Before inserting the trusses

After inserting the trusses

After inserting the trusses

3.2       Detailed dimensions

Mass of bridge
124 Grams
Overall length
590 mm
Overall width
20 mm
Overall height
850 mm

3.3       Construction of prototype

Photograph of prototype
 Due to time constraints, we couldn't complete the diagonal trusses.

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