This paper is a sequel to recent publications in which a novel method to allow for the P-delta effect of steel sway frames designed by ultimate limit state approaches was proposed. In this paper the new P-delta method is examined by way of a wider parametric study covering various subassemblages and also a full framework. The method does not require the calculation of the effective column lengths and in principle would remain valid where fully plastic analysis is adopted by design Codes. It is concluded that this extremely simple method can lead to savings in material as well as in design time compared with conventional effective length-based procedures.
There are a confusing number of beam-column approaches in present steel and concrete design codes. This paper critically compares uniaxial beamcolumn design provisions in limit state approaches coupled with an elastic structural analysis. Such analysis and design are the most popular in design offices. The aspects of lateral-torsional buckling and local stability (web and flange buckling), are excluded from this study. The object ofthis paper is to make practising engineers aware of the many divergent presentations of such beamcolumn design provisions in current design specifications and to encourage the use of alternative design methods, instead of the common enective iengthbased approaches. One such alternative method, recently developed by myself, is included in this paper for comparison purposes.
The raft analysis and design, site investigation and choice of material parameters were descriptionbed, as well as the subsequent monitoring of its settlement performance. Levelling studs and a magnetic borehole extensometer were installed to monitor raft settlements and compression of particular soil horizons. The maximum settlement measured over five years to April 1988 was 36 mm. The key parameters in raft design were discussed. These included soil parameters, applied loading, contact pressure distribution, stress distribution with depth below the raft, relative raft stiffness and time-dependent settlement.