Hi, well it's not about buildings, it's about how to build them now, this is interesting, worth the read, enjoy:
Top piling company breaks new ground
A Bahrain-based German ground engineering and piling contractor has introduced a new piling technology for the construction of the country's first private power station. The BD1 million piling contract is being carried out by German geotechnical contractor, Keller Grundbau GmbH, which has an office in Manama.
The Al Ezzel Combined Cycle Power Plant has been designed to add 950mw of electrical generating capacity to meet the future needs of Bahrain.
The main contractor for the project is Siemens AG Power Generation.
"Our work involves the improvement of the soils under the power station buildings by installing more than 70km of what are called Vibro-replacement stone columns," said Keller Grundbau branch manager Imtiaz Ahmed Syed.
"Keller has already carried out piling work for the two existing power plants in Hidd but for this particular contract, we have introduced a technique new to Bahrain," he told the GDN.
"With the new technique, stone columns are being installed by the so-called 'dry' method with a purpose-built Vibrocat rig."
Two methods of installation namely the 'wet' and 'dry' methods are available for the installation of the columns.
In the wet method, water jets are used to create the hole and assist in penetration.
In the dry method, the hole is created by the vibratory energy and a pulldown force.
"Vibro replacement is a technique used to improve sandy soils with high fines contents more than 15 per cent and cohesive soil such as silt and clay," explained Mr Syed.
In this method, columns made up of stones are installed in the soft ground using the depth vibrator.
The vibrator is used to first create a hole in the ground which is then filled with stone during withdrawal of the vibrator.
The stone is then laterally displaced into the soil following re-penetration of the vibrator.
In this manner, a column made up of well-compacted stone fill with diameters typically ranging between 700mm and 1,100mm is installed in the ground.
The Vibro replacement technique provides an economic and flexible solution, which easily adapts to varying ground conditions, said Mr Syed.
Using Vibro replacement, the following geotechnical improvements are achievable:
Compaction of the subsoil and increase in density;
Improvement in the stiffness of the subsoil to decrease excessive settlements;
Improvement in the shear strength of the subsoil to decrease the risk of failure;
Increase in the mass of the subsoil to reduce the effect of ground vibrations;
Rapid consolidation of the subsoil.
The 'dry' process will satisfy the high environmental standards required for the project in Bahrain, said Keller technical manager-Gulf, Brian Pickering.
"This technique eliminates the need for water to assist the vibrator to be driven into the ground," said Mr Syed.
"This method of installation is particularly suitable for sites where the creation of mud must be avoided or where water is not readily available."
Additionally, the 'dry' method has the same benefit as the 'wet' method, which has been in use in Bahrain since 1976. They use stones from local quarries and thus reduce dependency on imported materials.
Mr Syed said the first phase of the piling work would be completed next month.
"A short second phase work will start in January next year and will be completed in two months," he added.