Q. A pipe or groups of bars be adopted as load carrying element of min-piles?

The design of mini-piles someway differs from other traditional pile types. For example the design of most common pile types is controlled by external carrying capacity. Though due to the small cross sectional area, design of mini-piles is limited by internal carrying capacity. Henceforth the choice of suitable load carrying element is of paramount importance in the design of mini-piles. 

For steel pipes used as load carrying element, it's of circular cross section with a high radius of gyration. Furthermore it possesses a constant section of modulus in every direction, it serves the properties of excellent column. Bars are suitable when pure axial loading is needed in confined situation.