Flexural buckling and second-order analysis of pre-stressed steel beams with un-bonded/bonded deviators

Abstract

In-plane bucking and nonlinear elastic theories of PS (Pre-stressed) beams subject to not only compression induced by a tendon cable but also to external forces are newly formulated. The system consists of a simply supported/cantilever steel beam, a straight cable with constant eccentricity, anchorages, and multiple deviators. In particular, the effects of having either un-bonded or bonded deviators on the elastic buckling and nonlinear behavior of the PS beam are rigorously investigated. To achieve this, buckling and second-order analysis theories of PS systems with no deviator, one deviator, and multiple deviators are derived in non-dimensional form. In addition, stability and large displacement problems of the simple/cantilever beam system are analytically solved while considering the effect of deviators. In order to verify the validity of the proposed theories, numerical examples for PS systems are given and the results compared with FE analysis results from ABAQUS models. The results show that deviators restrain flexural deformation of beams that have buckled under the initial tension very strongly so that the system’s buckling strength is greatly improved. Particularly, it is found that the critical buckling loads of simple and cantilever PS systems due to initial tension are equal when the number of deviators is identical.