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Foundation analysis and design
01 Jan 1968-
TL;DR: In this paper, Fondation de soutenagement et al. presented a reference record for Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08.
Abstract: Keywords: Fondation ; Mur de soutenement ; Pieux ; Capacite portante ; Ancrage ; Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08
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01 Jan 2009
22 Mar 2016
01 Jan 2013
TL;DR: In this paper, three different design methodologies were adopted and compared with field load test values to assess, which best simulate the realistic conditions, and the most appropriate method of calculating soil skin friction is O'Neil & Reese method in local context compared to other two methods.
Abstract: Cast in-situ Bored (CIB) piles in Sri Lanka are very often designed considering only the end bearing capacity, neglecting the soil and rock skin friction. This causes foundations to become very uneconomical. The study presented here was done as a case study, where the subsurface does not contain any compressible soil layers, which subsequently cause to buildup negative friction forces on piles during its consolidation process. Three different design methodologies were adopted and compared with field load test values to assess, which best simulate the realistic conditions. The Burland method, ICTAD method and O'Neil & Reese method were used to calculate the theoretical soil skin friction levels, whilst Williams and Pells method was used to calculate the skin friction in the rock socket. Both High Strain Dynamic Test (using Pile Dynamic Analyzer (PDA)) and Static Load Test (SLT) results were used to interpret the actual field skin friction values, keeping in mind about the relative merits and demerits of these techniques. It was revealed that the results obtained during field load tests are substantially higher when compared to the theoretical results obtained through all three methods. However, O'Neil & Reese method in combination with Williams and Pells method provides substantially higher values compared to other two, which are the most widely used methods in local pile design practice. Hence the most appropriate method of calculating soil skin friction is O'Neil & Reese method in local context compared to other two methods. The reason behind the large discrepancy between theoretical values and field load test values may be due to two reasons, viz., (a) soil parameters obtained from in-situ test results with the help of standard charts and tables do underestimate local subsurface conditions and (b) the methods used to calculate the rock socket friction highly underestimate the locally available high grade- high strength metamorphic bedrock conditions.