STUDY ON TWO-PARAMETER CRITERION OF RETICULATED SHELL STRUCTURES UNDER EARTHQUAKE ACTION BASED ON PARK-ANG DAMAGE MODEL

The performance-based seismic design method requires explicit categorization of performance levels of structures, as well as reasonable definition of corresponding performance indicators. Based on the Park-Ang damage model and the response characteristics of displacement and energy dissipation of reticulated shells under earthquake action, a two-parameter model is proposed which is a non-linear combination of two dimensional parameters: maximum deformation and plastic energy dissipation. According to China's seismic code, characteristics of reticulated shells and existing research results, four performance points (LS-1, LS-2, LS-3, and LS-4) are used to classify the performance of reticulated shells into five levels: intact, slightly damaged, moderately damaged, severely damaged, and collapsed. Through 216 groups of comprehensive calculation examples considering different spans, rise-span ratios, roof loads, member sizes and seismic effects, the pending parameter values of the model are fitted. And then a two-parameter criterion suitable for reticulated shell structures is proposed. The corresponding index values (D) at

the four performance points (LS-1, LS-2, LS-3, and LS-4) are 0.3, 0.6, 1.0, and ∞, respectively. The effectiveness and universality of the criterion are verified by shaking table tests of two large-scale reticulated shell. The results show that the two-parameter criterion and the values of performance points proposed in this paper can reflect the performance levels of reticulated shell structures, and have good effectiveness and universality. This criterion can be used for the performance-based seismic design and seismic risk assessment of reticulated shell structures.