양방향말뚝 재하시험을 통한 현장타설말뚝의 연직지지력 설계정수 산정

Abstract

Bi-directional loading test data are available to evaluate the design parameters which reflect the characteristics of a construction method and the variations of ground at the site where drilled shafts are installed. The method to design parameters of a real bridge by bi0directional loading test was introduced. The plans of multi-level testing and installation of measuring instruments should be made according to the rough estimation of axial bearing capacity, the length of pile, and the constructin method. While the relationship between end bearing resistance and displacement was obtained directly from the bi-directional loading test, the relatinship beteween unit side resitance and displacement was calculated through the measuring valures, 1% displacement of pile diameter was adopted as the criteria of failure for ultimate resistance. As the settlement of pile head at the total ultimate bearing capacity obtained from these method was less 1.5% of pile diameter, this method was conservative to use in the field.