PRECAST PRE-STRESSED CENTRIFUGAL CONCRETE PILES
Why PHC Piles?
PHC Piles have an extremely high tensile strength which avoid cracks occurring in the pile structure before and during installation (transportation and driving stages) and after installation (service loads and ground movement).
Transportation of piles as well as the tensions created during pile driving is the main cause of tensile stress. Due to the innate weakness of concrete against tensile stress, cracks typically occur in ordinary reinforced concrete pile sections.
In traditional piles, tensile strength is provided by steel rebar. Unfortunately, the reinforcing bars deform longitudinally during transport and installation and consequently sectional cracks are created in concrete.
In corrosive environments, these cracks lead to damage to steel and concrete by penetration of chlorine ion, Sulphates, alkaline reactions, etc. To complicate matters more, inspection and evaluation of integrity of traditional concrete piles after installation are challenging as these elements are not accessible by visual inspection.
Some consultants mainly focus on the superstructure and calculate pile structural strength and resistance, whereas serviceability load during transportation, erection and installation must also be calculated.
In section 3, Australian Standard Piling – Design and installation AS2159 emphasizes the requirements and procedures of considering serviceability loads in pile design. If superstructure loads, transportation and installation influences, seismic loads, ground movements, adhesion of soils and parameters of durability and design life mentioned in section 6 of Australian Standard AS2159 are considered, the parameters of pile design, in corrosive environments, traditional non-prestressed piles must be excluded as an option.
Centrifugally manufactured concrete creates a higher density, hardened concrete compared to cast-in-place method making sure that no cracks are created along the shaft of the pile when pre-stressing is added. This means no damage to the piles during transportation and installation.
To summarize, prestressed manufactured piles results in very high strength concrete guaranteeing the durability and design life of piles after installation.
Our spun piles and poles are manufactured centrifugally and steam cured at controlled pressure and temperature. Compared to traditional piles, the lower weight and higher strength of our piles make them more cost effective to transport and reduce the time of handling and installation.
Embedded flanges in spun piles can be welded easily to join pile sections making installation of multiple sections more efficient and less time consuming.
The strong bond between the pre-tensioned steel elements and the concrete counteracts the tendency for pile head breaking during installation.
Cutting, if needed, is possible at any height.
Connecting the pile head to the foundation is done according to the international standards and instructions by the embedded reinforced bars resulting in easy and rapid execution, lower expenditure and stronger protection of the pile structure during pile connection to foundation.
1. Caging cutting pre-tensioned PC Bar – Cage welding
2. Concrete Feeding Concrete admixture – Concrete pouring – Pre-tensioning
3. Centrifugal Procedure Concrete Initial Curing
4. Steam Curing Concrete steam curing
5. Final actions Demolding and water curing
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