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The Structural Engineer, Volume 50, Issue 3, 1972
In this paper is presented a study on dynamic stability of thin-walled bars with open cross-section, subjected to compression by an axial force, composed from a static component and a variable one. The case of non-symmetric profiles is analysed in the first instance, to obtain general equations of vibratory motions; these are then particularized for profiles with an axis of symmetry, currently used in construction.
A computerized finite difference method is presented for the analysis of slender reinforced concrete columns. The method is developed in detail for the particular case of columns fixed at the base and prevented from deflecting laterally at the top as compressive loading is applied. Symmetric bending is assumed. The columns may have a cross-section varying along the length. The effects of cracking of the concrete, initial lack of straightness, and of initial deflexion of the top of the column by cantilever action are allowed for. Reduction in the capacity of the column arising from creep of the concrete is examined. The method presented may be adapted to suit end conditions other than fixed base pinned top. Flow diagrams for the computer analysis are given.
The President: This must have been a most exciting job with many problems to overcome. It was a congested site, with restrictions of allowable pressures on the ground. The factors which influence the engineering design are quite amazing; I think you said that it was imperative to obtain a uniform pressure on the ground and that that particular restriction to some extent led you to adopt the curve columns.