Response of a Strand to Axial and Torsional Displacements

Abstract

Taking advantage of geometric considerations the authors give explicit expressions for the determination of axial force, bending and twisting moments in the helical wires, and for the axial force and twisting moment in the core of a 7-wire strand subjected to axial and torsional displacements. The equations given are linear, could be similarly developed for strands of any number of wires or for strands subjected to large displacements, and should be found practical by designers. Measurements on oversize epoxy models of the strand show good correlation with the theory and support the observation that axial load has no effect on the effective torsional rigidity of the strand. Results of experimental strain analyses on steel strands and on models of strands, as well as other theoretical studies on helices and strands, will be published in other papers.