Effect of incident directionality on seismic behaviors of single-layer cylindrical reticulated shells

Multi-dimensional ground motions have a significant uncertainty in the angle of seismic incidence (ASI) on structures, which is an unfavorable factor in terms of seismic design of structures. This study numerically investigates the effect of incident directionality on seismic safety of single-layer cylindrical reticulated shells (SCRSs). Twenty far-field ground motions are selected based on a multi-directional selection criterion and utilized to excite SCRSs at 24 ASIs. The results show that the incident directionality has a remarkable and unfavorable impact on the seismic responses (especially peak resultant displacement (PRD)), plasticity depth, damage state, bearing capacity (BC), and collapse time of SCRS. The traditional excitation method (TEM), having confidence levels of 50 % and 57 % for PRD and BC, respectively, cannot ensure the multi-directional seismic safety, and thus the response amplification factor and BC reduction factor models are proposed to address it. Moreover, extensive parametric analyses are performed on the multi-directional seismic behaviors of SCRSs with different structural and loading parameters, indicating that the span, rise-to-span ratio, and live load pattern may need to be considered in the multi-directional seismic design of SCRS. Finally, the multi-directional seismic responses of base-isolated SCRCs are discussed, suggesting that the base-isolated system can substantially reduce SCRS response as well as the response variability with ASI, i.e., mitigating the multi-directional seismic risk.