diagonal direction have been studied. The structural effect of wooden ties has been investigated. Three spans of 2.5 m, 4.5 m and 6.5 m, three pier heights of 3.5 m, 5 m and 6.5 m, and three pier widths of 1.5 m, 2.5 m and 3.5 m have been considered for the vaults. Non-linear behaviour has been assumed for the brick masonry material. Three-dimensional finite element analysis has been performed by the ANSYS code. The Willam-Warnke failure criterion has been used for brick masonry.
All the vaults have been intact against main and diagonal horizontal earthquakes.
Maximum horizontal displacement under earthquake in the main direction is for the semi-circular by 0.574 mm and for diagonal direction is for raised pointed by 0.724 mm.
The maximum horizontal displacement of the vault in 85.71% of the models is under earthquake in the main direction, more than the earthquake in the diagonal direction.
The average tensile and compressive stresses to their corresponding strengths under earthquake in the main direction are 35% and 11% respectively and for an the diagonal direction earthquake, these ratios are 20% and 3.5%, respectively. Therefore, earthquake actions in the main direction have a greater impact on the domical vault. The use of wooden ties between the bases of the vault, in different earthquakes, with a 41% increase in horizontal displacement, has been improved vault performance.