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Steel pipe stacks, which are most common, are simple to drive and can be used as permanent piles in smaller sized diameters and as short-lived caisson or casement for big diameters. Steel follow this link heaps are preferred as end-bearing stacks due to their ability to be driven in deep strata due to small cross-sectional location, lessening dirt resistance. An additional element is their weldability to give longer extensions when required. By taking out the steel casing, a bond zone is developed in between the surrounding bedrock or dirt as well as the cementitious cement.