Engineering team builds best balsa bridge

A 76.9 gram balsa-wood bridge which held more than 27 kilograms won the Knights of the Phoenix Bridge Building Competition at the University of Southern Queensland (USQ) recently.

Competing against 11 other bridges constructed by on-campus Toowoomba and Springfield students, the ‘Big W' bridge won with a strength factor of 352; 33 points ahead of the closest competitor.

Senior Lecturer in Mechanical & Mechatronic Engineering Selvan Pather said the competition was part of the assessment for the Introduction to Engineering Design course, a core first-year subject for Engineering students.

'Students were required to design, build and test a bridge within set constraints,' Dr Pather said.

'Although the students haven't learnt the theoretical calculations or failure analysis behind bridge design, most of the teams built exceptionally strong bridges.

'We expect them to use their design creativity, some basic research into load bearing structures, and their ability to build balsa wood models to design and construct their bridges.

'They were supplied with two sheets of balsa wood and the glue, and they are not allowed to use anything else to build a bridge that spanned a gap of 750mm.'

The bridges were tested to destruction; with the strength factor being calculated from the ratio of the load carried to the weight of the bridge.

Two of the four winning team members, David Vandersee and David Casey, completed the course as part of the University's Head Start program.

Under the Head Start program high school students who successfully complete a university course can gain academic credit and entry into a USQ program.

Mr Vandersee said the team tested a couple of prototype bridges from materials they purchased themselves.

'We probably spent three weeks designing it and about three and a half hours building it.'

This course is Mr Vandersee's second under USQ's Headstart program.

'I did Engineering Materials in Year 11, he said.

'I thought it would be good to take some load off by doing it while I'm at school.

'It's a bit hard doing it outside school but I figure in my final semester when I'm doing uni I will have two less subjects to do. It's a good thing to do.

'I'm going to study mechanical engineering at USQ. I've got a cadetship with Russell Minerals so I will work full time for them and do two subjects at USQ each semester.'

Media Contact: Jane Urquhart USQ Media +61 7 4631 2559