Challenge 4: Bridge Design

Introduction

Cambridge and Anglia Council have commissioned the design of a state-of-the-art bridge over the river Cam. This new bridge will welcome millions of visitors to Cambridge each year and so its design will need to combine Cambridge's reputation for world-class engineering and inspirational architecture. The bridge will also need to 'open' to allow large river traffic to pass, and so an innovative engineering design is required.

Your task, working via the internet in a virtual learning environment (VLE) with all the other members of your team with an assigned member of the Cambridge University Engineering Department (CUED) acting as an adviser, is to design/draw that bridge, using the computer-aided design (CAD) packages specified. You and your team will then come to Cambridge for a day to build and test a working model of the design with the components/materials supplied/made by the CUED workshops.

Design Requirements

• Your bridge must be manufactured entirely from materials in the specified Kit List
• The opening/closing of the bridge must be actuated using either the electric motors or the pneumatic actuators specified.
• The model bridge must be of a single-span design and span a gap of 0.84 m – see the Loading Specification for more details.
• The decking/roadway of the model bridge must be no less than 0.15 m wide and no more than 0.25 m wide.
• It must be able to withstand without significant (visible) deflection a load of 3.5 kN – see the Loading Specification for more details.
• In its "open" position the model bridge must allow model vessels 0.5 m wide and 0.4 m higher than the banks to pass when travelling down the centre of the river.
• In its "closed" position the decking/roadway of the model bridge must be horizontal and no more than 0.05 m above the level of the banks.

Getting Started

We have assembled a range of support materials in the VLE to help your team undertake this challenge. The amount of information may seem overwhelming at first. Therefore we would suggest that you focus initially on learning about Project Management and the Engineering Design Process.

There are several aspects of the design you will then need to consider including:

• The bridge's load-bearing capacity
• How the bridge will open and close
• The bridge's aesthetic appeal
• The bridge's cost – according to the defined cost model

The document Practical Guidelines for Mechanical Design and Manufacture may well prove a source of useful advice on basic mechanical design.

We have also provided a range of information to support the detailed design of your bridge. Real-world engineering project teams are usually multidisciplinary with engineers with different areas of expertise (Mechanical Engineers, Structural Engineers etc.) contributing to the design process. Rather than expecting every member of your team to take in all the information provided, you may find it more effective to allocate responsibility for different aspects of your design to individual team members.

The materials and standard components you have to work with are detailed in the Kit List.

Submission of Drawings

As part of this challenge your team has to produce manufacturing drawings for your design using the CAD packages provided. These drawings have to be submitted to us by 9 March 2007 accompanied by a short document explaining how your design is intended to work to help us interpret the drawings.

We will provide feedback on your design by 19 March 2007. You will then have the opportunity to modify your design in the light of this feedback. Final CAD drawings for your design have to be submitted by 30 March 2007.

Manufacture of Components

Using the drawings you have submitted our technicians will manufacture the metal components in your design in our workshops. Alternatively, if you have access to suitable workshop facilities at school/college or at home, you can opt to manufacture some or all of these components yourself. If you do opt to make components yourself, please remember to bring them with you when you come to Cambridge for the finale.

Finale

In the finale of this challenge you will come to CUED on 21 April 2007 to meet the rest of your team and your adviser face-to-face, to assemble and fine-tune your design, and then formally test it. The timetable for the day is:

10.00 Arrival and registration

10.15 Teams assemble, test and fine-tune designs

13.15 Lunch break

14.00 Tinkering time

15.30 Formal tests of each design

17.00 Participants depart

Post-mortem

After the finales we will assess your designs through discussion (to which all can contribute) in the VLE. The aspects of the designs to be considered will include ingenuity, aesthetics, factors contributing to success or failure of the design structurally and mechanically, and scalability of the design.

Summary of Challenge Calendar

22 January 2007: Teams announced, challenge starts

9 March 2007: Deadline for submitting initial design drawings

19 March 2007: Feedback on designs

30 March 2007: Deadline for submission of final design drawings

2 to 20 April 2007: Manufacture of components

21 April 2007: Challenge Finale in Cambridge