Probability Study for a High-Capacity Micropile Horizontal Bearing Mechanism Osamu Maruyama & Masaru Hoshiya Musashi Institute of Technology Yoshinori Otani Hirose & Co., Ltd.

Objectives This paper examines applications of the Partial Factor Design Method to the design and engineering of the horizontal bearing capacity of the HMP based on probability theory.

A reliability analysis is carry out on an actual HMP that was designed based on the Current Design Guideline(proposed)． Design standard is introduced for Partial Factor Design and determine partial factors in compliance with the reliability levels. A comparison is made with regard to the safety of the HMP between the Current Design Code and Partial Factor Design

High-Capacity Micro Pile Core Reinforcing Bar

Analysis of safety index 43 examples of HMPs designed according to the Current Design Guidelines(proposed) Computation of sensitivity coefficients for horizontal bearing capacity. safety index

Failure Mode H ｙ ｘ δa δ Limit State #1 Limit State #2

Limit State Functions for Design Limit State 1 Deformation Limit State 2 Bending Moment

Nature of Probability values Characteristic Value Nature of Probability values Oil-Well Pipe Outside Diameter 17.8(cm) Thickness 1.143(cm) Mean and Standard Dev. Of G and J is obtained by MCF method

Limit State #1 Limit State #2

Sensitivity Coefficients Limit State #1

Limit State #2

Partial Factor Design Method Target Safety Factor Standard Design Equation

Standard Design Equation Target Safety Index Standard Design Equation

Partial Factors Standard Design Equation Design Variable :Outside diameter ｄ Thickness:1.265(cm)

Limit Sate #2 Limit State #1

Safety Index DESIGN#1：Current Design Method DESIGN#2：Partial Safety Factor Method

Conclusions This paper examines the horizontal bearing capacities of the HMP under the two separate critical conditions. It should be considered that both push-in bearing capacity (previously presented) and horizontal bearing capacity for reliability design.