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 4

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

Boundary conditions	Buckling load
	Bert [36]	Singh and Li [11]	Rosa and Franciosi [50]	Eisenberger [49]	Huang and Luo [51]	Present proposed technique (N = 15)
Simple-simple	15.31	14.505200922	14.58426	14.511249540	14.5112495395	14.5112495409638
Clamped-clamped	—	57.445246088	—	57.393956136	57.3939561351	57.3939565758955
Clamped-simple	—	29.495964646	—	29.448962806	29.4489628062	29.4489634582706