High-strength aluminum footbridge designed to withstand deep-ocean movement, high wind speeds [BD+C's 2014 Great Solutions Report]

The metal’s flexibility makes the difference in an oil rig footbridge connecting platforms in the West Philippine Sea.

December 29, 2014 |
Photo courtesy MAADI Group

Montreal-based MAADI Group recently designed a 151-foot-long, 6½-foot-wide pedestrian work bridge to connect platforms in the West Philippine Sea. Using high-strength aluminum for the bridge’s material, MAADI designed the bridge with lateral movement capability that could withstand deep-ocean movement and wind gusts up to 200 km/hr (124 mph).

MAADI’s President/CEO, Alexandre de la Chevrotière, says that water and wind movements can cause the platforms to shift by as much as one inch, so the bridge was engineered to account for movement up to one meter. A trolley system at one end of the bridge allows slight back-and-forth movements of the bridge between the platforms. 

The span was built in four sections. Its abutments are unique, according to de la Chevrotière, in that their pin connections rotate on two axes. There’s also a pin connection at the top of the trolley, which allows the bridge to move in several different directions by as much as three degrees to account for ocean movements, he says.  

The 13-ton bridge was built to accommodate up to 80 workers on deck. (The accompanying image shows 8.4 tons of water being used to test the span’s load capacity.) The bridge’s camber was designed to reduce the deflection caused by dead and live loads.

“Aluminum is the material of the future,” says de la Chevrotière. “It doesn’t rust and it’s maintenance free.”

Read about more innovations from BD+C's 2014 Great Solutions Report.

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