An accurate strength amplification factor for the design of SDOF systems with P–Δ effects
Article first published online: 13 SEP 2013
Copyright © 2013 John Wiley & Sons, Ltd.
Earthquake Engineering & Structural Dynamics
Volume 43, Issue 4, pages 589–611, 10 April 2014
How to Cite
Amara, F., Bosco, M., Marino, E. M. and Rossi, P. P. (2014), An accurate strength amplification factor for the design of SDOF systems with P–Δ effects. Earthquake Engng. Struct. Dyn., 43: 589–611. doi: 10.1002/eqe.2361
- Issue published online: 4 MAR 2014
- Article first published online: 13 SEP 2013
- Manuscript Accepted: 9 AUG 2013
- Manuscript Revised: 5 JUL 2013
- Manuscript Received: 15 MAY 2013
- seismic actions;
- P–Δ effects;
- SDOF system;
- design provisions
The response of structures subjected to seismic actions is always influenced by P–Δ effects. The importance of this effect is generally modest for structures experiencing an elastic response but often relevant for structures responding well within the inelastic range of behaviour. Seismic codes indicate that P–Δ effects may be counterbalanced through an increase in the structural strength required by a first order analysis. This increase is calculated by means of a strength amplification factor. The expressions suggested in codes for this factor are simplistic and often criticized by researchers.
In this paper, the effectiveness of some of the provisions reported in the literature or suggested in seismic codes is evaluated on single degree of freedom systems with different periods of vibration. As suggested by past studies, attention is focused on the influence of the interstorey drift sensitivity coefficient, significant duration of the ground motion, class of the site soil, displacement ductility and equivalent viscous damping ratio of the system. Finally, an accurate expression of the strength amplification factor is proposed. Copyright © 2013 John Wiley & Sons, Ltd.