Digging deeper

zoom

zoom

THE EARTH MOVES: Taller towers require deeper pilings.

zoom

As the number of high-rises being constructed in the UAE climbs, the piling and foundation process goes deeper to keep buildings standing for years to come, reports Shikha Mishra.

When it comes to buildings, pilings and foundations have a lot to answer for.

The quality of foundations and pilings has given us one of the most beautiful among the Seven Medieval Wonders of the World - The Leaning Tower of Pisa.

The tower was intended to stand vertically, but because of its poorly-laid foundation and loose substrate that allowed the foundation to shift direction, it began to lean towards the south-east soon after its construction began in 1173.

But not all foundation errors end up becoming national treasures. A miscalculation in the most basic of the construction processes - foundation - can lead to horrific mishaps.

Professor Harry Poulos, senior principal of Coffey Geotechnics in Australia, says that the foundation design process in the Middle East - while not different in principle from that in other parts of the world - has to take into account the relatively weak rock and soil deposits on which tall buildings are founded, the relatively small amount of experience of how foundations behave in these deposits and the extraordinary loads that the new super-tall buildings impose on the foundations.

"As a consequence, designers are being forced to use cutting-edge methods of analysis, design and testing to gain an adequate degree of confidence that the foundations will perform as expected.

Because of unprecedented foundation loadings, tests on foundations cannot be carried out in the conventional manner, by applying loads to the pile head. We cannot get enough load on in this way to test the pile adequately," he says.

"Thus, we are using new techniques such as the Osterberg Cell test in order to be able to apply the required test loads to the foundation piles. We are also taking great care to verify the integrity of the foundation piles, which are invariably constructed of concrete.

Integrity testing is vital because the groundwater conditions in the UAE are very conducive to deterioration in the quality of concrete over short periods of time. Any flaws or defects in the concrete piles may compromise their long-term durability."

The biggest cost variable on a construction project is likely to be what is under the ground. According to a study presented in 2005 by the Department of Building and Real Estate, Hong Kong Polytechnic University, Hong Kong, owing to the complexity and the short contract period, foundation projects bear the highest risk and cost among construction stages.

Print | Email | Discuss this article |

USER COMMENTS (0 COMMENTS)

POST A COMMENT

CLICK HERE TO POST A COMMENT

Add your Comment All posts are sent to the administrator for review and are published only after approval. ArabianBusiness.com reserves the right to remove any comment at any time for any reason. Please keep your responses appropriate and on topic.
Name *
Remember me on this computer
Email *	(Your email address will not be published)
City
Country
Subject *
Comment *
Notify me of further comments
Security Code *
Please click post only once - your comment will not be published immediately.