A comparative study on the stability of double-curvature and conventional cable domes

• Four cable domes with different curvature are developed and optimized. • The ultimate stability loads are calculated using nonlinear Arc-Length method. • Geometric and material imperfections and initial defects are considered. • Local buckling of struts is also considered by modeling them as beam elements. • Negative-curvature domes are more stable than positive- and zero-curvature domes. Cable domes are lightweight structures used for covering large areas such as arenas and stadiums. The aesthetic view and versatile forms of cable domes attracted many designers to develop new forms with better stability and rigidity. The roof curvature has crucial effect on the stability performance of cable domes. Compared to the traditional forms of cable domes with positive-Gaussian curvature, a newly developed double-curvature cable dome is intended to have better stability and rigidity due to the saddle roof surface. To investigate this, this study compares the stability performance of four cases of cable domes of Geiger type: a positive-, zero, and two negative-Gaussian curvature cable domes with different sag values of the saddle surface. The four case studies have the same cable-struts arrangement and dimensions in plan, the same length of struts and mid-point height above the lowest point in the roof. The domes are designed and optimized under external loading 1.0 kN/m 2 . The external loads are then increased incrementally to 10.0 kN/m 2 using Arc-Length method and the total deformation and stresses in all elements are monitored and compared for all cases. Geometric and material nonlinearities and the initial defect are considered. Struts are modeled using beam elements to consider the flexural rigidity of struts with the aim to investigate the effect of local buckling instability of struts on the ultimate stability load of cable domes. The load-carrying capacity is obtained, and the comparison shows that negative-curvature domes are more stable than zero- and positive-curvature domes. However, more attention is required when designing the outermost struts in negative-curvature domes to increase dome's stability. Moreover, considering the local imperfection in negative-curvature domes decreases the ultimate stability load by approximately 7.5 % and as such considering the flexural rigidity of struts is recommended when investigating the ultimate stability load in this type of domes.