The effect of spacing between geogrid and footing length on rectangular footing under eccentric load

Designing a foundation needs to be done carefully because of its important function to support the upper structure, including the soil condition. The soil must be able to withstand the load which applied above it. Recently, a lot of construction was built in areas with an insufficient bearing capacity of soil due to the limitation of the area. Therefore, It is needed to reinforce the soil and improve the bearing capacity by adding synthetic materials, such as geogrid. In this study, sand soil with a relative density of 80% will be tested under several variations in the length of the foundation (L) and vertical spacing between geogrid layers (h). The tests were carried out in the laboratory using rectangular footing with 10×12 cm, 10×14 cm, 10×16 cm in sizes and vertical spacing between geogrid layers 1 cm, 2 cm, 3 cm. The loading test was carried out using hydraulic jack and load cell on the model with eccentricity (e) 1 cm and the number of geogrid reinforcement (n) 3 layers. To observe the settlement that occurs, the value of the digital dial gauge was read every 50 kilos. The reinforced models, both L and h variation, showing the greater value of bearing capacity than the unreinforced model. Based on the analysis results, the test model produces the maximum of Bearing Capacity Ratio (BCR) 1.75 when the dimension of the rectangular footing is 10×12 cm and vertical spacing between geogrid layers is 3 cm.