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A Comparison Study between Top-down Load Test and Bi-directional Load Test Analysis Method in Rock-socketed Small Size Drilled Shaft  

Song, Myungjun (Hyundai Engineering & Construction Co., Ltd. R&D division)
Song, Younghun (Hyundai Engineering & Construction Co., Ltd. R&D division)
Jung, Minhyung (Hyundai Engineering & Construction Co., Ltd. R&D division)
Park, Youngho (Hyundai Engineering & Construction Co., Ltd. R&D division)
Park, Jaehyun (Korea Institute of Construction Technology Geotechnical Engineering Research Division)
Lee, Juhyung (Korea Institute of Construction Technology Geotechnical Engineering Research Division)
Chung, Moonkyung (Korea Institute of Construction Technology Geotechnical Engineering Research Division)
Publication Information
Journal of the Korean GEO-environmental Society / v.14, no.9, 2013 , pp. 5-12 More about this Journal
Abstract
In this study, each top-down load test and bi-directional load test has been performed on the 480mm diameter of two rock socketed drilled shafts, which are located next to each other, and the results have been compared. The result shows that the settlement from the equivalent load-settlement curve of bi-directional load test is smaller than one from top-down load test, because elastic is not considered in equivalent load-settlement curve of bi-directional load test. Therefore elastic shortening should be considered to obtain appropriate equivalent load-settlement curve. Three existing methods used to obtain equivalent load-settlement curve with consideration of elastic shortening has been compared with the result of top-down load test. The result shows that those existing methods are sufficiently applicable to the design. In addition, result of comparison between top-down load test and bi-directional load test shows that bi-directional load test was found to overestimate bearing capacity because it does not consider pile body failure.
Keywords
Top-down load test; Bi-directional load test; Drilled shaft; Load-settlement curve; Elastic shortening;
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