The present paper discusses on ultimate strength of a shallow reinforced concrete dome supported at four corners, the peripheries of which are stiffened by edge beams of a relatively large depth. The loads for investigation are not only dead load but also approximate earthquake loads considering horizontal earthquake forces together with anti-symmetrical vertical component caused by horizontal earthquake motions. The method is based on an elastic-plastic geometrically nonlinear analysis considering both effects of initial geometric imperfections and tensile strength of concrete. Based on the results, several important structural features are revealed. The geometric imperfection distribution similar to those caused by dead load reduces the ultimate strength, and the strength is also much reduced if no tensile strength is assumed for concrete, while the inverse imperfections much increase the strength. The ultimate strength interaction between dead load and earthquake loads shows the importance in design to include the anti-symmetrical load components of earthquake loads. Finally, the importance of stiffeners at free edges is confirmed and shell geometries of bending moment-free are suggested for increasing strength.
