ASSESSMENT OF PILE GROUP UNDER SIMULTANEOUS LATERAL STATIC AND INCLINED CYCLIC LOADS IN SANDY SOIL

Abstract

ABSTRACT Pile foundations are often subject to more than one load in nature. Among the common loads that the piles are subjected to are static loads and cyclic loads. The two loadings, when simultaneous, cause a serious problems in the bearing capacity of the piles and the surrounding soil. Therefore, the major objective of this study is to assessment the performance of pile group under inclined cyclic loads simultaneous with static lateral loads in sandy soil with a relative density of 70%. A series of 96 laboratories investigation were conducted to determine the group of pile response when exposed to combined loadings, by measuring the changes in lateral deflection at tip of pile and the bending moment along the pile depth. Numerous factors are investigated and their effect on group of pile performance model (2 2) including: the ratio of spaces between piles (3D, 5D, 7D), influence of inclination angles of cyclic loading ( 0°, 10°, 20°, 30°), the cyclic load ratio ( 20%, 40%, 60% and 80%) and the effect of the presence of a static lateral load on the cyclic load. In light of the findings, the presence of the static load with the inclined lateral cyclic load has a positive effect on the deep foundations where the lateral deflection is reduced by an average of 54% for the three spaces. Also the lateral deflection at combined lateral loading decreases with increasing pile spacing, the percentages of reduction in the lateral deflection compare to pure loading are (16%, 73%, 75% ) for spacing (3D, II 5D, 7D) respectively. It is important to note that the presence of a static horizontal load reduces the maximum bending moments and the number of critical points along the pile. It is significant to mention that the increase in the inclination of the cyclic load reduces the lateral deflection, where the average of decrease in the lateral displacement of the pure and combined loadings about (7%, 26%, 9%) at 10°, (54%, 30%, 12%) at 20° and (183%, 98%, 141%) at 30° for the three spacings (3D, 5D, 7D) respectively compared to the lateral displacement at critical angle ( 0° ) when CLR = 80%.