Observed Response of Seismically Isolated Buildings during the 2016 Kumamoto Earthquake Mineo Takayama Fukuoka University
Outline 1. Applications of Seismic Isolation Technology in Japan 2. Damages of Conventional Buildings during 2016 Kumamoto Earthquake 3. Response of Seismically Isolated Buildings in Kumamoto Area 4. Conclusions
Number of SI buildings in Japan 1995 Kobe Earthquake 2011 Tohoku Earthquake 1982 Yachiyo-dai
2011 Tohoku Earthquake Story 3 2 1 Fukushima Dai-ichi 1/4 NS-dir. EW-dir. 0 0 200 400 600 800 Max. Acceleration (gal) Emergency Operation Center at Fukushima NPP Story Isolation System: NRB + LRB + Oil Damper 3 2 1 Fukushima Dai-ni 1/2 NS-dir. EW-dir. 0 0 200 400 600 800 Max. Acceleration (gal)
Amplification Factor of Observed Acceleration Amplification of Acceleration 1995 Kobe 2004 Niigata 2005 Fukuoka 2.5 2.0 1.5 1.0 0.5 2011 Tohoku (1FL/BASE) 2011 Tohoku (ROOF/BASE) 0.0 0 200 400 600 800 Max. Acceleration at BASE (gal)
2016 Kumamoto Earthquake Two large earthquakes has occurred consecutively in 28 hours. 50 people died. 8,373 houses collapsed. Fukuoka
Fault cracks appeared on the ground investigated by the Geospatial Information Authority of Japan Aso Volcano Minami-Aso 16th, 01:25 Kumamoto M7.5 Mashiki Nishihara 14th, 21:26 M6.5
Acceleration (gal) 3000 2000 1000 Earthquake Response KMM005EW_acc Spectra 3000 h= 0.050 (Main Shock, EW-dir) 2000 KMM006EW_acc Kumamoto h= 0.050 h= 0.100 h= 0.200 h= 0.300 Acceleration (gal) 1000 Ozu h= 0.100 h= 0.200 h= 0.300 0 0.1 1 10 Period(s) Acceleration (gal) 3000 2000 1000 KMM004EW_acc h= 0.050 h= 0.100 h= 0.200 h= 0.300 Ichinomiya 0 0.1 1 10 Period(s) 0 0.1 1 10 Period(s) Futagawa Fault Acceleration (gal) 3000 2000 1000 Uto KMM008EW_acc h= 0.050 h= 0.100 h= 0.200 h= 0.300 0 0.1 1 10 Period(s) Acceleration (gal) 3000 2000 Hinagu 1000Fault KMMH16EW_acc Mashiki h= 0.050 h= 0.100 h= 0.200 h= 0.300 0 0.1 1 10 Period(s) Acceleration(gal) 3000 2000 1000 Q4160124EW_acc Nishihara h= 0.050 h= 0.100 h= 0.200 h= 0.300 0 0.1 1 10 Period(s)
Damage of Expansion Joints Many damages occurred even in relatively new reinforced concrete apartments. Collapse of old reinforced concrete building Seismic reinforcement of old buildings is urgent.
Relatively new wooden houses were also collapsed in Mashiki town
Damage of City Hall Base Isolated Hospital without damage Damage of the city hall Facilities that become disaster bases are required to have higher earthquake resistance and function maintenance. In the seismic isolation hospital, the function is maintained after the earthquake without damage, and medical practice can continue
Summary of Seismically Isolated Buildings in Kumamoto Pref. 24 Seismically Isolated Buildings including 4 under construction Uses Story Location (City) Apartment 12 1 4F 3 Kumamoto 18 Hospital 7 5F 10F 6 Yatsushiro, Yamaga 4 Office, Warehouse 5 11F 15F 15 Other 2
Location of Seismically Isolated Buildings and Max. Deformation (Deformation shows a double amplitude) 16 18cm A-Hospital B-Office 50cm 60 70cm 90cm M-Hospital 19cm
A-Hospital (2 buildings) LRB Inpatient Ward Outpatient Clinic NRB Steel Damper
Inpatients Ward Outpatient Clinic
Outpatient Clinic Inpatient Ward Max. Deformation:40cm Shear Strain:235% Max. Deformation:36.5cm Shear Strain:230%
After Foreshock April 15, 2016 After Main Shock Just After Main Shock April 29, 2016 April 16, 2016 Damage of Hand rail
B-Office Building NRB, SnRB Steel Damper
Scratch Plate of B40cm Office Building W N S E W 72 cm E S N Orbit
M-hospital NRB LRB
Plan of M-Hospital Expansion Joint Conventional Building Seismically Isolated Building
Movement Trace of M-hospital N 50 半径 46cm 40 30 N-S direction(cm) 20 10 0-10 -20-30 W E -40 S -50-50 -40-30 -20-10 0 10 20 30 40 50 E-W direction(cm) Max. Deformation 46cm (shear strain 330%)
Conventional building Seismically isolated building Conventional building Seismically isolated building Damage of Expansion Joint
Conclusions All seismically isolated buildings worked very well. Health Monitoring All of building owners for Isolation are satisfied System with the performance of the seismically isolated building. Lack of consideration to detail made some damages such as expansion joints. It is very useful to record the earthquake responses of seismically isolated buildings in order to evaluate the effectiveness of seismic isolation system. Scratch Plate
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