Bridge building exercise 1

Learning objective

To develop students' knowledge of structures by:

• investigating bridge structures
• using their D&T skills and knowledge to build a bridge that supports a load

Design Brief

Design and make a model bridge that will replace a shelf in the Design and Technology display cabinet. When completed, the bridge will be used to support small products made by students in D&T lessons.

Specification The bridge must have a deck truss or deck arch truss structure. The bridge must support D&T products that will be placed on it. The bridge frame structure must be made from 4mm x 4mm lengths of pine. The deck must be made from flexible sheet material such as card. The bridge must stand on two battens fixed to the sides of the D&T display cabinet.

Assignment Guidance

• Measure the internal width of your D&T display cabinet. Your bridge must span the width of the cabinet precisely.
• Study the bridges animation and photographs of bridges, especially those bridges with a frame structure, i.e. truss bridges. 
• You may also find it useful to study the animations of frame structures, forces, support and reinforcement of structures.
• Use your knowledge of frame structures to design a bridge that will fit precisely between the sides of the D&T display case and that will support various D&T products.
• Draw your design.
• Make your design from the 4mm x 4mm lengths of pine. The pine rods should be long enough to form an arch that will span the width of the display cabinet. Use a glue gun to join the various parts or use PVA to glue thin card reinforcement pieces at the joints.
• Work in pairs to make one bridge.
• You should have your own copy of the designs.
• You should use a digital camera to photograph your finished bridge.
• Test your bridge to check that it will safely support the loads it was intended to support.
• Write an evaluation of your bridge. Include a photograph of your bridge with your evaluation.