EFFECT OF CROSS-SECTION SHAPES OF PILES ON LATERAL RESISTANCE OF PILE GROUPS IN SANDY SOIL

Superstructures may be subject to lateral load like earthquake, wind, wave impact, and ship ducking. In these cases, engineers prefer to apply piles or pile groups. The exact predictions of the load-deflection response of pile groups under lateral loading have always been a big challenge for engineers due to the many parameters involved. These parameters include soil relative density, type of soil and its classification, water table elevation, length and diameter of pile, type of load, rigidity of pile and pile cap, etc. In this study, some experimental tests were performed to investigate the effect of cross-section shape of pile on lateral resistance of pile group. To consider the quantity of materials used to construct pile for optimum design, four different cross-section shapes of piles with the same surface area were used. The cross-section shapes of piles involved H pile, end closed pipe, square, and fin pile. Different conditions such as pile arrangement, pile spacing, and soil relative density for different cross-section shapes of piles were assessed. A poorly graded sandy soil was used. The lateral load was applied to pile groups using a 2.5 kN capacity jack and the deflection of pile cap was measured by a dial gage with accuracy of 0.01 mm. Results revealed that the ratios of lateral resistance of fin pile, square pile, and H pile groups to that of pipe pile group were 1.4, 1.19 and 0.85, respectively. By increasing the number of piles in group, the average lateral load per pile in the pile group was reduced for all pile shapes. Also, by increasing pile spacing from 3Dp to 6Dp , the lateral resistance of each pile in group and also group efficiency of all pile shapes increased significantly. Although the lateral resistance of pile groups increased upon an increase in the soil relative density, the group efficiency was reduced by 50%.