Detailed analysis can cut piling costs by almost 20%

Piling cost can be reduced by almost 20 per cent provided proper studies are undertaken to determine the ground condition and its influence on foundation.

Geological and structural engineers who had gathered during the two-day "Piling and foundation forum" being organised by Fleming Gulf stressed on the need for re-categorisation of the ground stratigraphy in Dubai to better understand what lies beneath the sand.

Asim Guba, Director, Arup, said the benefits of a detailed study of mineralogy would include saving time, adding to the safety level of the structure and reducing waste.

"It is very important to conduct a detailed study on risk assessment and safety and the existing ground condition and its influence on foundation. An SEM [scanning electro microscopic] study is essential to understand the mineralogy of the soil that will help design deep foundation of high-rise buildings. There needs to be a categorisation of the design based on ground geology and stratigraphy. Each location is different and would require a different design," said Guba.

According to him, it is a matter of dealing with uncertainty and that uncertainty can be dealt with through greater understanding of the ground. "Every project needs to look at what is available to people looking at the project, to see how much risk there is on the ground. If there is not much information available, there needs to be more prudent, more conservative approach that needs to be taken. The more information and understanding there is, the greater the mitigation of the risk," said Guba.

Yasser El Mossallamy, Associate Professor, Geotechnical Engineering at Ain Shams University in Cairo, said there is increasing demand in Gulf countries for more and more highrise building with underground basements. Stressing on the need for pile-raft foundation, he said the combination of pile and raft system can reduce the settlement and tilting to a much greater extent.

According to Mark Newton, Director of Operations at Dutch Foundations, the construction industry, since 2003, especially in Dubai, has experienced a hugely accelerated change in terms of working environment.

"Construction techniques, had to change, awareness and appliance of safety regulations has gone from one extreme to another," he said.

"In 2005, when I came to Dubai safety enforcement on sites, especially by piling contractors was almost zero. With certain events that happened in late 2005 the authorities reacted very quickly and realised that something has to be done about the loss of productivity."

According to him, the scenario has changed and there is a detailed safety code and as a self-initiative, companies have gone ahead with introducing training methods and are getting accredited by international safety organisations.

Also discussed during the conference was the impact of wind, earthquake and sea-wave loading on piles and the seismic risk in the UAE and the effects on the foundation design. According to experts, the UAE has been following more stringent earthquake resistance design requirements as compared to other countries in the region.