Effect of Seismic Horizontal Loads on the Structure of the Taj al- Molk Dome in Jameh Mosque of Isfahan

The external forces acting on the structures are divided into two categories based on the direction of application: a. Loads applied in the vertical direction or gravity loads such as: dead loads, live loads, snow load, etc. b. Loads applied in the horizontal direction or lateral loads such as: earthquake load, wind load, etc. Therefore, in this study, the behavior of the northern dome of Isfahan Jameh Mosque (Taj al-Molk dome) was examined under horizontal seismic loads using a finite element three-dimensional model (3D FE) (nonlinear dynamic analysis) with one level of numerical complexity with the aim to cover the structure of the dome, which has a medium to high complexity in operation. The results indicated that the structure of the Taj al-Molk dome is vulnerable to horizontal loads, so that if the residual deformation occurs in the range of 0.4% and 0.8%, it will cause the structure to collapse. On the other hand, geometric features (irregularity in the plan and height of the dome, the presence of large openings, height changes in the cross section as well as the presence of the dome or an internal inclined arch) play an essential role in the seismic performance of the building.