Encasing a cylindrical granular column with tensile resistant material is proven an effective practice to improve granular column strength. Laboratory triaxial compression tests were conducted on encased granular columns to study the tensile resistant material reinforcing effects. This study explores the behavior of geosynthetic-encased sand columns using a converted approach to reduce laborious efforts. The encased column behavior is simulated by applying persistently increased chamber pressure to unreinforced sand column specimens. Three column specimen diameters, 5, 7 and 10 cm, were employed to study the scale effect. The test results indicate that the converted approach simulates larger diameter encased column well.