Tallest Flagpole In The World
The Jeddah Flagpole has been officially recognised by The Guinness Book of World Records as the world’s tallest, at 171 m high.
t is located on the Tariq Ben Zayed Roundabout in central Jeddah, Kingdom of Saudi Arabia and carries a flag approximately 30 x 60 m weighing up to 1 tonne.
Byrne Looby Partners have been involved on this landmark project from start to finish. Employed by the design and build contractor, Al Babtain LeBLANC Technologies FZCO, Byrne Looby planned and supervised the initial site investigation, designed the piling and foundations and provided site supervision throughout the construction.
The Byrne Looby project team consisted of John Byrne leading the geotechnical input, Richard Thiemann heading the structural element, Sam Peet undertaking all the computer modelling while Ian Pearcy and Aidan Commerford were responsible for the drafting. Byrne Looby had three people on site throughout the different stages of the project.
The ground comprised coralline limestone over sandstones, siltstones and mudstones and it required sixteen piles 25 m long and 1200 mm in diameter to support the foundation block. The foundations include 95 t of rebar and 450 m³ of concrete.
Massive reinforcement of foundation and dynamic testing prior into installing the flag pole.
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As well as resisting the high moments and shear from wind loads on the flagpole the foundations needed to provide sufficient stiffness to avoid build-up of resonant vibrations. The foundation comprised an octagonal reinforced concrete base 16 m across and 2 m deep with a 2.5 m high plinth on top.
To resist the very high oscillating loads under the flagpole base a C45/55 concrete was specified for the plinth whilst the base was reduced to C32/40. Despite the high concrete strengths the base was tanked to provide adequate durability against the aggressive soils.
The high concrete strengths meant high potential temperature during curing of the concrete. Careful design of the mix was required together with batching using iced water and cooling of the aggregate.
To ensure the precautions were adequate a 2 x 2 m test cube was poured and temperatures monitored. The foundation was poured in two sections, the base and the plinth.
The flagpole is a tubular steel structure tapering from 5 m diameter at its base to 2 m at the top. It encloses an access stair and the flag raising mechanism. The flagpole was erected in segments and bolted to the foundation with 168 pretensioned bolts fixed to a double anchor ring within the base.
Byrne Looby staff were resident on site throughout the works to confirm that works were constructed in accordance with specifications and to provide full records of the works carried out.