DETERMINATION OF TENDON SPACING FOR PRESTRESSED COLUMN CASING STRUCTURES

Excessive axial moment would be induced and circumferential cracks would appear during tensioning of column casing structures if the prestressing force P and tendon's spacing s were not properly designed. Based on elastic mechanics theories, the formulas for calculating axial moment M, shear force Q, radial displacement w and angle deformation θ are discussed in the paper. A set of superposition formulas for determining the prestressed force P and tendon's spacing s are derived and demonstrated with the field test. It is shown that theoretical results given by superposition formulas are in very good agreement with that of field test, the relative error between them being smaller than 5%. The superposition formulas presented in the paper can be used to determine the prestressing force and tendon's spacing with satisfactory accuracy.