A common method to improve the behavior of the footing is to reinforce the soil by geosynthetics. One of the defects of geosynthetics is that these materials disrupt the soil on both sides of them and reduce shear strength of the soil. In order to arrest the lateral spreading of the soil, we can use the new tubular geosynthetics named braid. The main purpose of this study is to evaluate the efficiency of braid elements on the bearing capacity of the footings resting on reinforced sand. The parameters which are investigated in this dissertation are the effect of the depth of the first reinforcement layer, the vertical space between the reinforcement layers, number of reinforcement layers, length of reinforcement layers, the relative density of the sand, the width of he footing, the diameter size of braid elements, the effect of type and shape of the reinforcement elements and the effect of covering the braids with adhesive resin. The model tests are built in a steel box with the dimensions of 100 40 70 cm. The results of the tests showed that, using single layer of reinforcement in a distance equal to 0.5B from bottom of the footing increase the bearing capacity 1.56 times. Besides, decreasing the vertical space between reinforcement layers up to 0.6B and increasing the number of layers, cause an increase in the bearing capacity and decrease in the settlement ratio. Also, with increasing the wide of braid layers the bearing capacity increased while settlement decreased. Increasing the braid diameters and relative density of the soil has indicated that the bearing capacity and bearing capacity ratio increase up to the optimum value. Increase in the width of the footing from 8cm to 10cm and then from 10cm to 12cm, cause decrese in BCR equal to 8% and 3%, respectively. For the tubular shape of braid and geogrid layers, the bearing capacity experiences significant increase in comparison to palannar shape of these reinforcement layers. Also, the results indicated that covering the reinforcement with adhesive resin enhance interface properties between the soil and braid elements and increase the bearing capacity and beraing capacity ratio. Key Words Bearing capacity, strip footing, braid, settlement ratio
