First ever built composite bridge turns 25

A celebrant, the Aberfeldy Footbridge across the river Tay in Perthshire, Scotland, had previously a title of the longest FRP span bridge in the world. The bridge designer is Dundee University Professor Bill Harvey, who developed the project commissioned by the local golf club.

Since the 18th-century stone bridge across the river was too narrow to carry golfers and their equipment, the club turned to the professor for the affordable solution with a fast construction period. Professor Harvey assembled a team comprised of designer Maunsell Structural Plastics and several final-year university students who worked during their summer vacation.

In September 1992 the 112-meter bridge was opened.

The deck and towers were made of interlocking cellular GFRP pultrusions and cables from Kevlar.  Tower legs were bonded together onsite and erected to the foundation without cranes, using only a telescopic forklift truck. This construction process was made possible by the extreme light weight of the bridge. This lack of weight, in fact, posed something of a problem: it is set into vibration or undulation at certain frequencies.  To improve its vibrational damping, concrete was added to some deck cells. The bridge has survived severe flooding and 140 km/hr winds, and is considered aerodynamically stable.

Golf carts have damaged the bridge deck in various ways over the years.  A small tractor was allowed to cross the bridge towing a trailer of sand, and the weight damaging the deck, cracking some planks.  In response, the bridge was strengthened in1997 with GFRP pultruded plates.

The experts called this groundbreaking design the Linksleader Project. Now, this bridge became the source of invaluable data for composite structures designers due to its long, compared with other composite bridges, operating life. In 2012, Dr. Tim Stratford of the School of Engineering, University of Edinburgh published a condition survey of the bridge as 20 years, based on inspections performed in 2004, 2008, 2010, and 2011.

The final statement is that the bridge deck has a smooth curve and there is no evidence of movement of the towers, deck, foundations or abutments. There are no slack cables, and there is no sign that the cables have pulled out from their anchorages. Find more detailed information here.



Industries: Construction

Terms: Composite materials

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