Friction piles behavior in soil base and piles settlement calculation

Subject: friction piles are calculated by the first and second group of limit states. The article describes a new method for friction pile design by the second group (by settlement) of limit state in relation to the pile foundations of buildings and structures in the urban area and in the design of extensions to existing buildings in which the value of settlement is limited or unacceptable. A new method of piles settlement calculation is different from existing method by the Building Code SP 24.13330.2011. The method is based on a new approach of the pile behavior in soil base, which is different from the existing regulations and science papers. Research objectives: the new method of pile settlement calculation is presented with the purpose of clarifying the calculation of pile bearing capacity unlike an existing method in the Building Code (SP 24.13330.2011). The basis of the design is a new idea of the pile behavior in the soil base, which differs from the existing approaches. Materials and methods: the method consists in the formation of the pile settlement only as a result of pile shortening from the compressive force by the deformation of the pile material. Results: the design equation is presented for calculation the pile settlement caused by the pile material deformation. The condition for determining the pile length is presented, which provides the pile settlement only due to the pile material deformation. Conclusion: such approach of the pile settlement calculation is necessary for the design of extensions to existing buildings, as well as new structures near existing buildings, in which the settlement value is already close to the ultimate value of settlement. The article presents the examples of pile settlement calculations obtained by various methods (including the method of the Building Code SP 24.13330.2011) for comparison of the results. The article can be used in the piles design and in the formation of new design standards for pile foundations of structures and machines.