James Fisher Strainstall (JF Strainstall) have completed a six year monitoring contract on the Burj Khalifa Tower in Dubai - the tallest man-made structure ever built.

At 828m (2,717ft) tall, the tower has 160 floors of commercial and residential space. When fully open its expected capacity is 35,000 people at any one time and standing completely empty it weighs approximately 500,000 tonnes.

JF Strainstall were contracted to undertake monitoring of the preliminary pile tests to ensure the piles could bear the weight of the enormous building. Due to the sheer size of the structure, the bearing pressures applied to the ground, coupled with the soft rock ground conditions present at the site, provided a significant challenge to the design of the footing system. To ensure the building was adequately supported, the foundations comprising 45,000 cubic metres of concrete reinforced with steel, featured 192 piles, each 1.5 metres in diameter and 43 metres long.

JF Strainstall also supplied and installed a structural monitoring system to monitor the structure's performance as construction progressed. Strain gauges were used to monitor the stress distribution during construction and the creep, shrinkage and elastic properties of the concrete, to enable comparison with the modelled predicted stresses.

While most of the construction work is now complete, the structural monitoring system will continue to provide important data on the structural behaviour of the tower and the impact of changing environmental conditions during the initial commissioning period.

As the enormous task of fitting out and furnishing the inside of the tower continues, the strain gauges will continue checking that the structural behaviour remains within the design limits. In the event of any excursion of the stresses over these limits, real-time alarms will be generated enabling structural engineers to investigate and undertake any required remedial works.