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

2. 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.

3. 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

4. High-Capacity Micro Pile
Core Reinforcing Bar

5. 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

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

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

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

9. Limit State #1
Limit State #2

10. Sensitivity Coefficients
Limit State #1

11. Limit State #2

12. Partial Factor Design Method
Target Safety Factor
Standard Design Equation

13. Standard Design Equation
Target Safety Index
Standard Design Equation

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

15. Limit Sate #2
Limit State #1

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

17. 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.