This paper examines the elastic and inelastic seismic behaviour of single layer steel cylindrical lattice shells. The main dynamic characteristics for this form of structure are firstly examined through a parametric assessment, which also leads to proposed expressions for estimating the fundamental period and mode of vibration. The seismic response of five typical shell configurations, representing a wide range of rise to span ratios, is then assessed within the linear elastic range under selected earthquake excitations. Particular focus is given to the relative influence of the horizontal and vertical seismic components on the internal actions. In order to provide a means for evaluating the underlying inelastic behaviour, a simple pushover approach, which is suitable for this structural form, is suggested using the forces obtained from the fundamental mode shape. The peak angle change is proposed as a damage parameter within the nonlinear analysis for characterising the inelastic global and local demands in shells of different geometries. Incremental dynamic analysis is subsequently carried out in order to evaluate the detailed nonlinear time history response. The results provide detailed insights into the influence of the horizontal and vertical excitations on the nonlinear seismic response, and illustrate the suitability of the peak angle change as an inelastic deformation measure for shells of different geometric configurations. The main findings from the linear and nonlinear assessments are highlighted within the discussions, with a view to providing guidance for performance based assessment procedures as well as simplified design approaches.

No abstract

Cylindrical lattice shell structures are commonly used in many applications such as in train stations, gymnasia, and sports halls. In comparison with their behaviour and design under gravity loading, their behaviour under seismic loading has received less attention, particularly in terms of the development of practical design procedures. Current European codes of practice lack specific guidance on the seismic design of these shells. In this paper, the salient considerations influencing the seismic response of single layer cylindrical lattice shells are examined. The effect of key geometric parameters such as the rise to span ratio, length to span ratio, inter-element angles, as well as the structural mass, on the characteristic natural periods and corresponding vibration modes are investigated using the finite element program OpenSees for two typical situations of boundary conditions. The influence of these parameters on the axial forces and bending moments in the members when subjected to the horizontal and vertical components of an earthquake is also assessed. The response is evaluated in the linear and nonlinear ranges, including representative time history analyses, with due consideration of both material and geometric nonlinearities. The results provide an insight into the main factors that govern the seismic behaviour of single layer cylindrical lattice shells, with a view to supporting the development of practical design and assessment procedures for this structural form.