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Title: Design of unbraced multi-storey steel frames
Author: Lok, Tat Seng
ISNI:       0000 0001 3612 2665
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 1984
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The thesis examines the behaviour and design of unbraced rigid-jointed multi-storey steel frameworks subjected to combined vertical and horizontal loading. Design charts are presented which enable guidance to be given on whether the serviceability limit on sway or ultimate limit state under combined loading will be critical for the choice of sections in preliminary design. Parametric studies on forty-three multi-storey, multi-bay rectangular frameworks provide the verification of the Merchant-Rankine formula for the design of such frames. An alternative semi-empirical expression based on the study of the deterioration of overall frame stiffness has been developed. Comparison with the parametric study indicated a significant improvement on the Merchant-Rankine approach to estimate the failure load of frameworks. The expression has then been used as the basis of an approximate optimization procedure for the design of frames to satisfy ultimate strength under combined loading. An approximate hand method to trace the formation of plastic hinges has been developed. The method is applicable to single bay frames, and has also been extended to multi-bay frames. The latter are transformed into equivalent single bay frames. A computer analysis program for semi-rigid connections has been presented using the matrix displacement method. The technique is reduced to an analysis of a rigid-jointed framework by repeated modification of the load vector alone. The analysis program has been used to investigate the sway deflection of unbraced frames and the determination of the effective length of braced columns.
Supervisor: Not available Sponsor: Science and Engineering Research Council ; Building Research Establishment
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TA Engineering (General). Civil engineering (General)