Joint Effect of the Nonlinearity of Elastic Foundations and the Variation of the Inertia Ratio on Buckling Behavior of Prismatic and Nonprismatic Columns Using a GDQ Method

Table 5

Nondimensional critical buckling loads of nonuniform columns without elastic foundations with parabolically varying stiffness distributions .

Boundary conditions	Buckling load
	Bleich [47]	Singh and Li [11]	Rosa and Franciosi [50]	Eisenberger [49]	Huang and Luo [51]	Present proposed technique (N = 15)
Simple-simple	20.7923	20.791633301	21.21653	20.792288456	20.7922884552	20.7922891004959
Clamped-clamped	—	82.228445608	—	81.923363881	81.9233636440	81.9233426420278
Clamped-simple	—	42.313450996	—	42.109176122	42.1091761225	42.1091391192221