1. Musashi Institute of Technology
IWM ’03 Seattle
Application of High-capacity Micro-piles for Seismic Retrofitting of Existing Water Service Tower in Japan
Sep.25th 2003
Yoshinori Otani
Hirose & Co., Ltd.
Masaru Hoshiya
Musashi Institute of Technology

2. Contents HMP Okazaki Example ( RC Water Service Tower )
Preliminary　Survey
Design
Construction
Evaluation of Earthquake Performance of HMP
by Acceleration Seismograph’s Measuring　　　　　　　　　　　　　　　　　　　　　　　　　　　

3. Location Location of the Site Rokku Water Purification Plant
Tokai Plate Boundary Type Earthquake

4. Water Service Tower Constructed in 1933 70 years old
Historic Significance　　　　　　　　
Urban Landscape and
Environment Prize
Functioning for water supply

5. Section Planning S

6. Design Flow Chart Preliminary survey Verification of existing tower
Selection of
retrofitting method
Seismic design (level 1)
Level 1:earthquake motion of
high occurrence probability
Seismic design (level 2)
Level 2:earthquake motion with the strong
　　intensity of low occurrence probability
type Ⅰ:Plate boundary type large-scale earthquake
type Ⅱ:Inland direct strike type earthquake

7. Preliminary Survey Schmidt Hammer Test for Existing Concrete Material
Stress strength kN/m2　　　　　
Degree Investigation of Visual Observation
Corrosion of the steel reinforcement bars , Cracking
Water leakage, Surface deterioration
Diagnosis Conducted to Classify Deterioration

8. Design（１） Verification of existing tower Selection of
retrofitting method
Micro pile 　 Construction limit
(Root pile) Small boring machine　　　　　
HMP Satisfaction of allowable displacement
(Level 2 earthquake motion)
High-capacity

9. Seismic Design Design of pile Verification of pile foundation
Response displacement method
Verification　of
pile foundation
Level１：Allowable bearing capacity
Allowable stress
Level 2：
Allowable ductility factor
Allowable response displacement
Strength
Design Coefficient
Yield of foundation
Yield Coefficient
Response displacement

10. Protection of vegetation
Construction(1)
Protection of vegetation
Excavation of the base
Placing of HMP
Placing of HMP

11. Reinforcing bar arrangement of new footing
Construction(2)
Attachment of
steel pile head
Reinforcing bar
arrangement
Reinforcing bar arrangement of new footing
Pile Head

12. Completed work

13. Disaster Prevention Plan
The central disaster prevention conference
Basic disaster plan
Regional disaster plan
Prime Minister Koizumi
Tokai Earthquake
High probability of occurrence
Large scale earthquake

14. Disaster Strengthening Area
Earthquake Motion of
Seismic Intensity low 6
Tsunami
Disaster Strengthening Area
HMP Examples in Disaster Strengthening Area for Tokai Earthquake

15. Measurement Plan
Bisyamon bridge
Acceleration　Seismographs

16. Purpose of Measurement
Expected vibration behavior of non-reinforced abutment
Seismograph on the ground surface
Comparison
The actual measured values of reinforced abutment
Seismograph on the abutment
Seismic performance of HMP

17. Summary and future plans
HMP Method
( for reinforcing of the existing structures)
respond ・to revisions in the seismic design standard
・to changes in the demands of society
by way of non-detrimental to the landscape
In the future,
confirm ・the actual seismic performance of HMP
by seismograph measurement