Ing the shaft capacity of DCIS piles which are only 50% of those recommended for preformed driven piles. Although DCIS piles have been used extensively in many countries throughout the world over the past 60 years or so, the. 07/10/09 Rev 4 Enlarged Head By utilising a specially adapted head former our driven cast-in-situ piles can be formed with integral enlarged heads giving savings to the client in pile trimming and floor slab costs. Driven Precast Piles. This type has the advantages and disadvantages of both the driven and the cast-in-situ piles. The procedure of installing a driven and cast-in-situ pile is as follows: A steel shell is driven into the ground with the aid of a mandrel inserted. Franki Driven Cast-in-Situ Piles (DCIS) Franki Forum Bored Piles Full Displacement Screwpiles Micropiles Oscillator Piles Precast Piles Rotapiles Underslurry Piles Lateral Support Concrete Soldier Piles Contiguous and Secant. Franki Pile - Al- Saba Concrete Piles Co. Ltd. The Franki pile, known and used worldwide, was developed at the turn of the century by the Belgian engineer Frankignoul. It is a cast- in- situ concrete pile with an enlarged base and a cylindrical shaft which, due to its powerful driving method during installation, can penetrate stiff soils and reach large depths. By expulsion of a dry concrete plug, the soil surrounding the pile base is improved and thus the initial soil bearing capacity can be increased significantly. In North America, the Franki system is known as pressure injected footing. Maximum lengths are of the order of 2. The Franki pile may be vertical or raked and its bearing capacity varies with the diameter of the pile base and the driving tube being used, which can be changed to suitable loads specified. It requires only a minimum of site preparation and in some particular cases, e. Such a cased shaft eliminates the curing time required for the concrete precast pile. Execution of a Franki pile. Construction of the Franki plug with gravel. Bottom driving with an internal hammer. This operation causes compression of the soil by lateral displacement. Expulsion of the plug and starting to form the Franki base. Formation of the Franki base and anchoring of the reinforcement. Concreting of the shaft. Successive charges of zero slump concrete are rammed into the soil, simultaneously withdrawing the tube. A driven cast- in- situ pile with a cast- in- situ pressure injected base. Driving of the casing. A thick- walled steel casing is placed vertically on the ground. A special concrete bucket is used to pour a certain amount of nearly dry concrete into the bottom of the driving tube. The concrete is rammed with a 2 to 4 ton hammer while the tube is kept in position by steel cables. This hammer can be dropped from a height of several meters. Under its impact the concrete forms a plug at the bottom of the casing which penetrates slightly into the soil. Due to the compression of the concrete plug, a water- tight bottom plug is created which prevents soil or water from entering the casing. In that case, the driving casing must be provided with a lost bottom plate. The casing can also be installed using a large- stem auger (VB- pile). Enlarged . The plug is then expelled by heavy blows of the hammer, making sure that a certain amount of rammed concrete remains in the casing in order to prevent any seepage of water or soil into the pile shaft. This operation is checked with marks made on the driving cable of the hammer and on the lifting cables. The expanded base of the pile is then formed by adding as much dry concrete as necessary to achieve a pre- determined . An enlarged concrete bulb, serving as a pile base is thus formed in the soil, which is heavily compressed and densities and an average diameter of the enlarged bass is about (7. The hammer displaces the concrete laterally into the soil previously compressed by the driving of the tube. Due to the ramming process, the concrete is in close contact with the soil and in this way a cylindrical shaft is obtained, which is resting on an enlarged base, formed to refusal in the bearing layer. The pile shaft can also be made of . This process is similar to ordinary driven cast- in- situ piles. Alternatively, a pre- fabricated pile shaft can be used. The reinforced concrete pile. When Franki piles have to withstand important transversal forces or are subjected to pulling forces, they must be reinforced over their whole length or in part, by means of steel cages consisting of at least 6. The reinforcing bars are tied by 5- 8 mm spirals at the pitch of 1. The outside diameter of the cage varies according to the size of the tube being used. For piles subject to uplift forces, the reinforcement is anchored in the enlarged base, thus providing high pull- out resistance. Depending on the equipment and depths to be reached, the leads can be tilted from 1. The raked shafts are always reinforced over their whole length. They can withstand dynamic stresses and are particularly suitable foundations for structures containing machines and subject to dynamic forces. The composite Franki pile is installed when it is difficult or not suitable to cast the pile shaft in situ. In that case, a pre- fabricated shaft (steel or concrete) is installed after the expanded base has been constructed in the ordinary way. The composite Franki pile is installed in the following way: 1. A driving tube is sunk into the soil down to the required depth. An enlarged base is then concreted by ramming to refusal. An octagonal or circular pile, made of precast reinforced concrete or pre stressed concrete, is sunk into the tube and securely anchored on the base by means of some blows the hammer. The driving tube is withdrawn. This pile offers the following advantages: . By adopting some additional measures, the effects of negative friction may be cancelled. This negative friction is sometimes encountered in non- compressible soils. Franki Piles is a driven, enlarged base, cast in- situ pile that can be constructed in practically all soil conditions. The construction of each Franki Pile is molded to the ground conditions at each pile location, and can safely withstand very high compressive and tensile forces and substantial horizontal loads. Compacting the 'plug' into the tube. Bottom drive the tube to the required depth. Forming the enlarged base. Installing the reinforcing cage. Extracting the tube, during or after concreting of the shaft. Cast in situ Pile. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy. 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