"Well maybe not the longest truss ever, I think Lord Norman Foster might have something to say about that, but certainly the longest truss from standard production industry equipment," says Chris Cronin, the head of Total Solutions Group (TSG) who supplied the truss.
"We have a well established relationship with Staras, Turkey's leading sound and lighting company," continues Cronin. "And we've worked on many a project together since they purchased their first sticks of truss 20 years ago. Even so when they called me and described their intention to span 77m - basically across the football field - and hang a very large three dimensional video screen from it, I let out an audible gasp. It was an ambitious project from an engineering perspective, but what took my breath away was the fact that it was scheduled for just ten days time."
The stadium opening ceremony for which this structure would be installed was scheduled for 16 January 2011; in ten short days Cronin formulated a composite truss solution, "effectively you create a giant truss structure using existing trusses to form the chords of a super truss". Assisted by Malcolm Richards, TSG's long serving independent structural engineer, the two men assessed the contents of the Staras truss inventory and then crunched the numbers. "Staras own a substantial stock of our Serious HD truss, this formed the four horizontal chords, while 18" Tower truss would make the verticals. Diagonal bracing would be made using 22mm diameter wire rope."
Fevzi Co?kun headed up the project for Staras. "The TSG designed structure proved very easy to construct", he said, "we had just 12 hours on the new turf before the cover sheets had to be lifted in anticipation of the opening match. It proved remarkably stable under load; the hexagonal projection surface hung from it was effectively a huge sail so I was expecting much more lateral deflection."
Co?kun also oversaw a sizable installation of sound and lights, with speakers and lights all around the football pitch perimeter. "I have to say I was most impressed by Fevzi and his technical team," said Cronin. "I see things like this all the time and from my perspective this was no different from a big stadium show at Wembley, and very professionally executed."
(Jim Evans)
