ABSRTACT

Dynamic behaviour of single-layer lattice domes is complicated and fundamentally differs from conventional building structures. Their response to dynamic excitation is characterised by the contribution of several vibration modes throughout a wide range of frequencies. Furthermore, due to large deformations associated with a possible development of plasticity within the structure, seismic response of single-layer lattice domes to severe earthquakes is normally highly nonlinear. So far, in the absence of a practical equivalent static seismic loading scheme, realistic seismic response evaluation of single-layer lattice domes still relies on nonlinear dynamic time-history analysis.

Herein, a new analytical method for estimating the nonlinear seismic response of different types of single-layer lattice domes is presented, as the main contribution of this research. The method is based on ‘Modal Pushover Analysis’ (MPA) concept which conveniently accounts for the participation of higher vibration modes in the seismic response, and is consistent with the inherent dynamic characteristics of single-layer lattice domes. The efficiency and accuracy of the proposed method is verified through comparison between the MPA results and those obtained from a full geometrically and materially nonlinear time-history dynamic analysis. It is shown that the proposed method yields accurate results for all types of single-layer lattice domes with different geometrical properties, and effectively removes the necessity of performing nonlinear time-history earthquake response analysis.

Moreover, dynamic characteristics of single-layer lattice domes is sensitive to the geometrical particulars of the structural system. Accordingly, the importance of various geometrical particulars of single-layer lattice domes on their dynamic characteristics has been carried out by means of parametric studies, as the other contribution of this research. The particulars studied include ‘span’, ‘rise-to-span-ratio’, ‘pattern of the configuration’, and ‘relative stiffness of the supports’. It is concluded that ‘rise-to-span-ratio’ and ‘relative stiffness of the supports’ are two important parameters which significantly influence the dynamic behaviour, the effects of other properties on dynamic characteristics of single-layer lattice domes are less important.