Effects of un-bonded deviators on the out-of-plane buckling of steel H-beams pre-stressed by a straight tendon cable

The out-of-plane buckling characteristics of a pre-stressed (PS) system that consists of a steel H-beam, rectilinear tendon cable, anchorages and deviators is newly reported, in which the girder is subjected to combined compressive force and bending moment introduced by the tendon. For this, new lateral-torsional buckling theories were analytically formulated and solved for the PS system having no deviator, one intermediate deviator, two deviators at regular intervals and multiple deviators. In order to verify the validity of the proposed theories, numerical examples for the PS system are given and compared with the analysis results by ABAQUS models, which are composed of thin-walled beam, rigid beam and truss cable elements. The results showed that unbonded deviators installed externally restrain lateral and torsional buckling strength.