[Image above] Macrete crew members supervise installation of a FlexiArch bridge at Pleasington in Northern Ireland. Credit: Emma Martin at Story Contracting Ltd.; Macrete
Engineers at Queen’s University Belfast (Northern Ireland) have developed—and will soon install—the world’s longest self-arching bridge.
The pre-fab concrete bridge is a flat-pack bridge, named for its ability to be transported flat to the installation site. When lifted off a flatbed truck, flat-pack bridges use gravity to self-assemble into an arch.
The latest, and longest, flat-pack bridge consists of 17 one-meter-wide tapered blocks of pre-cast concrete. Each block weighs 16 tons, for a total of 272 tons of bridge-building concrete.
The technology behind this engineering feat is Macrete’s FlexiArch system, which links the top of the concrete blocks together with a bonded flexible membrane. The U.K. now has more than 50 FlexiArch bridges installations.
“This innovative system is exceptional as it is easily transported in flat pack form and then rapidly installed on site,” Macrete project manager Abhey Gupta says in a Queen’s University press release. “It is also unique as its strength does not depend on corrodible reinforcement, thus it should have a lifetime of at least 300 years, whereas conventional bridges seldom achieve their design life of 120 years.”
In comparison to a traditional bridge, the FlexiArch system allows the structure to be built much quicker and cheaper. It also requires little maintenance because the bridge derives its strength from compression, eliminating the need for corrodible rebar—a big concern when it comes to bridge maintenance.
The bridge will be installed near Portsmouth (Northern Ireland) and will span 16 m, the farthest yet for a flat-pack bridge. According to the release, the bridge will be installed in less than a day using a 200–300 ton crane and a specially designed lifting beam.
To see other FlexiArch installations and read more about the technology, head over here.
And if concrete is your jam, be sure to check out Cements 2015 and submit your abstract by March 31.
Credit: newsedge101’s channel; YouTube