Effect of support flexibility on seismic responses of a reticulated dome under spatially correlated and coherent excitations

• Investigated the effect of support flexibility on the seismic responses of a dome.
• Estimated statistics of seismic responses due to spatially correlated and coherent excitations.
• Results showed a flexible substructure system for the dome acts as a “base isolation” system.
• Use of uniform instead of spatial varying excitations can largely underestimate responses.

Reticulated domes with substructure system are affected by multiple-support seismic excitations that are spatially correlated and coherent. The influence of the coherency on the seismic responses of such a structure has been investigated but the effect of the spatial correlation and coherency on the responses for the system with different flexibility of the substructure has not been studied. A parametric investigation is carried out to address this issue for a single-layer reticulated dome. For the analysis, sets of records for multiple-support are simulated and used for time history analysis. The statistics of the responses of the dome with substructures of varying degree of flexibility are extracted from analysis, and compared with those obtained under uniform excitations. The results show the importance of considering spatially correlated and coherent excitations, especially as the stiffness of the substructure system increases. They also show that a flexible substructure system for the dome acts as a “base isolation” system for the dome under spatially correlated and coherent multiple-support excitations, and reduces the potential yielding and damage of the structure under large earthquakes. As the stiffness of the substructure system increases the consideration of uniform excitations instead of spatially correlated and coherent excitations can underestimate the seismic load effect by more than 25% for structural members in the reticulated dome and by more than 100% for the columns.