Effect Of The Horizontal Component Of Earthquake On The Buckling Of Concrete Spherical Shells

The buckling failure of reinforced concrete spherical shell structures under the effect of the horizontal component of earthquake is investigated using a finite element method over a wide range of shell configurations. For this effect, two different loading case scenarios are considered; first, the shell is analyzed under the effects of the vertical seismic component alone. Then, the model is reanalyzed under the same loading conditions plus the horizontal earthquake component, taking into account two different horizontal-to-vertical earthquake spectral ratios. It is concluded that including the horizontal component of earthquake can result in a reduction in the buckling capacity of this type of structure; the impact of which is highly influenced by the horizontal-to-vertical earthquake spectral ratio and the shell geometry. It is also observed that the formulation adopted by ACI slightly overestimates the buckling capacity of spherical shells especially when horizontal seismic effects are included.