Lateral-torsional buckling of haunched members in portal frames : an assessment of BS 5950 : part 1

Junid, SMBS

Abstract

The research described in this thesis, relates mainly to the
current method of design of steel portal frame structures.
The study is divided into two major parts, first being the
full-scale test on a 24 metre span frame and the second
deals with the problems of lateral-torsional buckling in the
haunch region of the frame.
Detailed accounts of the full-scale testing on the 24 metre
span frame and the experimental results are given.
Supplementary tests on beams cut out from the tested frame
in order to establish the strain-hardening factor are also
presented.
A literature survey on the published material pertinent to
the lateral torsional-buckling of a tapered member was
undertaken. Different methods of treatment for the elastic
stability of tapered members and any evidence from previous
research in this area were reviewed.
Details of an appropriate finite element and the
corresponding computer programme are given. This section
describes the assumptions and the Finite Element
formulations adopted in the computer programme. The earlier
work on this analysis dealt only with prismatic members and
this was extended to solve tapered sections. Therefore, a
full calibration of the finite element formulation for a
tapered member was carried out. The stability clauses in BS 5950 are introduced
systematically. Theoretical work which leads to the
formulation of the clauses in Appendix G is also described.
These stability clauses were assessed by the analysis of
selected prismatic and tapered members using the finite
element formulation. From this assessment some modifications
to the clauses are proposed. The results of the modified
clauses are compared with those given by the finite element
analysis and the original clauses. Lastly, the modified
clauses are checked with the results of the portal frame
tested, to confirm its validity.
This study leads to the proposal for some amendments in the
clauses in Appendix G and Clause 5.5.3.5. of BS 5950.

Citation

Junid, S. Lateral-torsional buckling of haunched members in portal frames : an assessment of BS 5950 : part 1. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Aug 18, 2011
• Publicly Available Date: Aug 18, 2011
• Award Date: Jan 1, 1992