COMPARISON & PREDICTING OF PILE AXIAL LOAD CARRYING CAPACITY BASED ON SPT, STATIC PILE LOAD TEST AND SIMPLIFIED SOIL MECHANICS FORMULA (THE CASE STUDY OF SILE RIVER BRIDGE FOUNDATION)

Abstract

The need for deep foundations or piles arises when the soil at shallow depths from the ground level are not competent enough to support shallow foundations such as footings and rafts. Among different pile types Bored caste-in-place piles are commonly used as load carrying pile in view of low vibration, low noise, and flexibility of sizes to suit different subsoil and loading conditions, and it's the main focus area of this paper. Bored caste-in-place piles formed by boring or grabbing and subsequently filling the hole with concrete Pile load carrying capacity commonly estimated using the soil investigation by standard penetration test (SPT) and pile load test settlement versus load curve data especially in the case of Bored caste-in-place piles. Via the actual field data of Sile River Bridge Pile Foundation work; SPT, pile load test and by laboratory tests identifying engineering characteristics the soil samples which got from SPT then Compare & Predict Pile Axial Load Carrying Capacity Based on SPT, Static Pile Load Test and Simplified Soil Mechanics Formula; and. of course the pile load test is the most reliable one. The underneath soil of the study are comprising dominantly of sandy covers the top part of the boreholes up to a maximum depth of 5.00m and there is dark brown soft to stiff, moist clayey silt covers up to the final boring depth 30.00m. Based on USCS soil classification system, the soil type categorized SW, ML, MH and SC type. Based on the soil category the load carrying capacity of the studied pile by Soil Mechanics Formulas & SPT N Value found that SPT N Value method result is as high as 184%, and in all case it is result is higher than Soil Mechanics Formulas whereas Pile Load Test method result gives the higher pile capacity. From the findings that the results are big variation among the three approaches as much as 600% and relatively lesser variation among the different method used Min variation of 103%. Using the three approach (Soil Mechanics Formulas, SPT N Values and Pile Load Test), the pile load test method gives the highest and the soil mechanics formulas methods gives the lowest value, which implies the Soil Mechanics Formulas method is more conservative than the Pile Load Test method and evidently the Pile Load Test method is the most reliable result than two methods.