Lessons learned from ICE’s LEGO bridge – and its destruction

In April 2017 ICE invited students from Shenfield High School to its Bridge Engineering exhibition in London to discover how bridges are built. They also had an exclusive chance to participate in testing the record-breaking LEGO suspension bridge to destruction.

See the LEGO bridge reach its point of no return
See the LEGO bridge reach its point of no return

ICE invited the Shenfield students after a request by the mother of Jacob Franklin, grandson of the late John Mitchell, who is commemorated by ICE's annual John Mitchell Medal award for geotechnical engineering.

The Year 7 and 8 pupils had an afternoon of educational presentations and activities on civil engineering at ICE, culminating in a 'failure test' of the 30m long, 3m tall LEGO bridge.

A track was added across the length of the bridge to allow a train to run across, with the weight increased incrementally until the bridge collapsed.

How the ICE LEGO Bridge was built

Formerly the centrepiece of ICE's Bridge Engineering exhibition, which showcased civil engineers who have created some of the world's greatest bridges, the LEGO bridge spanned the equivalent of three London Routemaster buses parked end to end. It weighed 0.75 tonnes and made from more than 200,000 plastic bricks.

It was designed by world-renowned bridge engineer and ICE Gold Medallist Dr Robin Sham, of infrastructure services firm AECOM, and constructed by Ed Diment and his team at Bright Bricks,. Financial support was provided by exhibition sponsors COWI, CEMAR and Tony Gee and Partners.

How does a suspension bridge work?

A suspension bridge is a type of bridge in which the deck (the load-bearing portion) is hung below suspension cables on vertical suspenders.

Queen Mary II bridge.
Queen Mary II bridge.

Towers support the majority of the weight as compression pushes down on the suspension bridge's deck and then travels up the cables, ropes or chains to transfer compression to the towers. The towers then dissipate the compression directly into the earth. The key term is the principle of 'tension' and 'compression'.

Testing the bridge to destruction

The event was an opportunity to demonstrate what civil engineers do, using experiments and activities to gain a real sense of what the students could achieve and accomplish from a career in civil engineering.

Clare Taylor, Bridge Engineer, COWI, described the general principles of bridge engineering and her journey to becoming an engineer from school and university. She explained how she now travelled the world working on some of the world's most recognisable structures but also how her projects had changed the lives of communities in the developing world.

Ed Diment, Director, Bright Bricks also explained to students how the LEGO bridge was constructed and how it achieved its Guinness World Record. Students were given the opportunity to build their own suspension bridge structure and test how it could withstand increasing weights and the principles of tension and compression.

The event culminated in a failure test of the LEGO suspension bridge.

Aftermath of the bridge demonstration
Aftermath of the bridge demonstration

What did the students learn?

Shenfield High School students at the exhibition
Shenfield High School students at the exhibition

Jacob Franklin, said:

"I really enjoyed the day and learning more about how bridges work. I'm glad I got to see the LEGO bridge coming down! It's definitely made me want to become a civil engineer."

Making way for the next ICE exhibition…. Tunnels and tunnelling

The LEGO bridge is to be rebuilt at a new home. The ILH is now hosting the next exhibition, Tunnel Engineering. Supported by Ferrovial Agroman, together with UNPS, Topcon and CEMAR, Tunnel Engineering opens on 15 May at the Institution of Civil Engineers, One Great George Street, Westminster, London, SW1P 3AA.

The free exhibition is open Mondays to Fridays, 10am to 5pm, until mid-November 2017.

If you are a school party and interested in attending a future exhibition at ICE, please contact Debra Francis, Visitor Experience Coordinator at: debra.francis@ice.org.uk.

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