Reliability Based Design of High Capacity Micro-piles May 4th 2006 - - PowerPoint PPT Presentation

Reliability Based Design of High Capacity Micro-piles

Yoshinori Otani ,P.E.ｊp Hirose & Co., Ltd. Masaru Hoshiya Musashi institute of technology May 4th 2006

ISM ’06 Schrobenhausen

Theme

Reliability Based Design

Limit State Design Method Allowable-stress Design Method

High-capacity Micro Pile

Performance Provision Design

Problem of setting up

Limit State Performance function Z Safety Index β

Code Code Calibration Calibration

Vertical Bearing Mechanism

• f HMP

Horizontal Bearing Mechanism

• f HMP

Limit state 1 Limit state 2

Performance function Z i

Horizontal Bearing Vertical Bearing

Computing of the Safety Index β

Coeffcient of variation （Ground condition、Grout material 、Load）

• Monte Carlo simulation method
• FOSM method

43 Design examples

• f HMP

Result of Calculation(1)

5 10 15 1 2 3 4 5 Safety Index βａ Frequency 1.5 1.6 1.7 1.8 1.9 2.0 2 4 6 8 10 12 14 16 1 2 3 4 5 Safety Index β1 Frequency 1.5 1.6 1.7 1.8 1.9 2.0

Figure 1 Histogram of Overall Safety index βa Figure 2 Histogram of Safety Index β1 Figure 4 Histogram of Safety Index β3

2 4 6 8 10 12 14 16 1 2 3 4 5 6 Safety Index β2 Frequency 10.5 11.0 11.5 12.0 12.5 13.0 13.5 5 10 15 20 25 30 1 2 3 4 5 Safety Index β3 Frequency 3.0 3.2 3.4 3.6 3.8 4.0

Figure 3 Histogram of Safety Index β２

Result of Calculation(2)

Frequency Safety Index β１ Safety Index β2

2 4 6 8 10 12 14 16 0.30 0.40 0.50 0.60 0.70 0.80 0.90 5 10 15 20 0 40 0 60 0 80 1 00 1 20 1 40

Frequency

Figure 5 Histogram of Safety Index β1 Figure 6 Histogram of Safety Index β２

Influence of Uncertainty

Uncertainty of Reliability Based Design

• Construction dependency of MP

boring, grouting,

• Ground characteristic

No uniformity, ground water

Summary

the HMP design Optimization Statistical works by accumulating the data

An uncertainty of the ground characteristic and the construction dependency of HMP