Abstract
This study investigates the behavior of ring footing erected on gypseous soil and compares it with the circular footing, including conducting (24) experiments of loading ring footings, where the inner and external diameter ratio was (Din./Dout. = 0, 0.2, 0.3 and 0.4), resting on two types of Gypseous soil, for the circular footing the external diameter was (150mm) and thickness (15mm) made from solid steel. The results for study showed the ring footings were best than the circular footings. The ratio (Din./Dout. = 0.4) was beast for all ratios of (Df/D). Capacity of bearing increased when the ratio (Df/D) increase. Bearing capacity for high-gypsum content soil showed good results compared to the low-gypsum content soil. The first was high content of gypsum (63.42%) obtained from the Tikrit University, and the second was low content of gypsum (8.15%) from the Baiji area. The tests were doing inside box have dimensions (900×900×700 mm). The experiments were divided into twelve tests for dry gypsum soil condition with high gypsum content using density of (13.76 kN/m3), and twelve tests for dry soil with low gypsum content using density of (14.87 kN/m3). Experiments were conducted for different ratios (Df/D=0, 0.5, and 1).