SC and WG meetings in conjunction with ISO/TC 59 Plenary in Tokyo, Japan, 15 Oct. 2012 Industry/ ISO session Lessons Learned from the Building Damage by the 2011 Great East Japan Earthquake Masanori TANI Research Engineer, Dept. of Structural Engineering, Building Research Institute (BRI), JAPAN 1
Contents 1. Detail of the 2011 Great East Japan E.Q. 2. Building damage caused by Ground motion Outline of damage New findings & lessons learned 3. Building damage caused by Tsunami Outline of damage New findings & lessons learned 2
1. Detail of the 2011 Great East Japan E.Q. 3
2011 Great East Japan E.Q. JMA (Japan Meteorological Agency) Seismic Intensity which is different from the Modified Mercalli Intensity Scale (MM) This magnitude was 4 th largest one in the world since 1900 6~7 in JMA SI IX in MM SI Mw=9.0 (March 11, 2011, 14:46) Hypocentral Region 450km in NS direction, 150km in EW direction 4
2011 Great East Japan E.Q. Casualties Statistical Data Deaths 15,871 1923 Kanto EQ (142,807 Deaths) 1995 Kobe EQ (6,434 Deaths) Missing 2,778 Damage to buildings Total collapse 129,582 Partial collapse 265,980 Source: National Police Agency, as of 10 October 2012 2011 Great East Japan E.Q. 10 EQs in last 100 years caused more than 1,000 deaths Nat. Res. Inst. Earth Science Disaster Prevention M>=7 EQs 101 EQs in last 100 years Magnitude 5
Locations of field surveyed cities and towns <Objectives> Classification and characterization of damage Iwate Miyagi Damage by tsunami Damage by E.Q. motions Investigate building damage in the urban area where JMA seismic intensity of 6 or more recorded Fukushima Tochigi BRI Ibaraki Tokyo Chiba Fukushima Daiichi Nuclear Plant Damage by liquefaction 6
2. Building damage caused by Ground motion 7
Damage to buildings caused by seismic motion <Summary> Damage to buildings is not so severe whereas the seismic intensities were high and the disaster areas were extended to extremely large Timber Structure:Typical seismic damage was observed RC Structure, Steel Structure:Significant difference appears between before and after the new seismic design code (1981). Typical seismic damage was observed Non structural Elements:Fall of suspended ceilings in largescale spaces, exterior walls, and interior materials were observed Residential Land:Damage to developed grounds and sloping for residential houses were observed. Severe liquefaction damage occurred in very wide areas. 8
Typical seismic damage to Timber structures Damage of houses with store (Inclination of 1 st story) Damage due to Bio deterioration Collapse of 1 st story Collapse of 2 nd story Damage of Dozo (Japanese traditional wood storehouse coated with clay and plaster finish) 9
Typical seismic damage to RC structures Collapse of soft 1 st story by shear failure of columns Shear failure of non structural walls Pullout of anchor bolts of the exposed type SRC column base Shear failure of coupling beams Shear failure due to opening of shear walls 10
Typical seismic damage to steel structures Buckling of brace Rupture of horizontal brace Spalling of concrete at joint コンクリート剥落 Rupture of brace at joint Buckling of diagonal member of latticed column Dropping of extensive ceiling materials and exterior finish materials 11
Typical damage to nonstructural elements Cracking and spalling of tile Failure of glass Fall of exterior wall panels Damage and fall of suspended ceiling
Typical seismic damage to residential land Tilted 3 degrees Large scale liquefaction and settled or tilted structures Sand boiling and tilting of house Failure of footing caused by the ground damage Land sliding on the slope of the developing hill Damage of retaining wall and house movement 13
New findings and lessons learned from the observed damage and coping activities Most of the damage classified were observed in the previous earthquakes. Previous revising of codes (or handbook) are effective for preventing the damage. <Under discussion> Fell down of ceilings, escalator Discussion on new regulation Liquefaction Discussion on performance indication of buildings Long term E.Q. ground motion Discussion on evaluation procedure of high rise buildings and/or isolated buildings <Completion> Tsunami Structural design method for Tsunami Evacuation Buildings 14
Fell down of ceilings Ceilings fell down in 2000 buildings 5 casualties 72 injuries Gymnasium Music hall 15
Fell down of escalator Support length Backup system Fixed support Unfixed support 16
Liquefaction Pile foundation Spread foundation Settlement about 35cm About 30cm Difference in damage between support mechanisms 17
Long term E.Q. ground motion observed in a high rise building in Tokyo (cm/s 2 ) Acc. (cm/s 2 ) RC structure 37 stories 200 0 200 200 0 200 200 0 200 最大 98 cm/s 2 最大 141 cm/s 2 最大 198 cm/s 2 1F Max. 98 cm/s 2 18F Max. 141 cm/s 2 37F Max. 198 cm/s 2 0 50 100 150 200 250 300 350 400 秒 Time (s) 18
Long term E.Q. ground motion observed in a high rise building in Osaka Velo. (cm) (cm/s) 150 0 Max. 7 cm 最大 7cm 1F 1F 150 150 0 Max. 29 cm 最大 29 cm 18F 150 150 0 Max. 85 cm 最大 85 cm 38F 38F 150 150 Max. 136 cm 52F 52F Steel structure 55 stories 0 150 0 100 200 300 400 500 600 Time (s) 19
Damage to damper of base isolated buildings Lead damper Steel damper Cracking Deflection Loosening of bolts 20
3. Building damage caused by Tsunami 21
Most of the RC buildings were survived without any structural damage Rikuzentakada City However, severe damage were observed in a part of RC Buildings 22
Damage to RC buildings by Tsunami (1) Total collapse 23
Damage to RC buildings by Tsunami (2) Collapse of 1 st story Tsunami Tsunami Tsunami pressure pressure pressure 2F(wall) 2F(wall) column column 1F 1F column column 24
Damage to RC buildings by Tsunami (3) Overturn Climb over a fence Cold storage warehouse (with a few small openings) 25
Damage to RC buildings by Tsunami (4) Failure of walls Sewage treatment plant (Wall height: 12 meters) 26
Damage to RC buildings by Tsunami (5) Scouring & Tilting Very high stream with whirl dig a hole in the ground 27
Damage to RC buildings by Tsunami (6) Sliding Tsunami pressure 28
Damage to RC buildings by Tsunami (7) Debris impact 29
Damage to Steel buildings by Tsunami (1) Swept away of structure Column bases Failure of exposed columns Failure of column top connection 30
Damage to Steel buildings by Tsunami (2) Overturning Exterior finishing was survived Large tsunami load and buoyancy occurred 31
Damage to Steel buildings by Tsunami (3) Washed away of finishing (4) Large residual deflection 32
Damage to Timber buildings by Tsunami (1) Swept away of entire buildings 33
Some timber buildings located just behind a relative large building were survived because the tsunami pressure was mitigated. 5 stories RC building Tsunami direction (Provided by the Geospatial Information Authority of Japan) 34
Tsunami evacuation buildings Evacuation to a high ground is a basic principle when tsunamis occur If there is no high ground to evacuate to, a tsunami evacuation building will protect human lives instead of high ground Tsunami evacuation building should be prepared for quick evacuation in coastal area 35
Structural design requirement on the tsunami evacuation buildings Design target 1) Not to collapse 2) Not to overturn 3) Not to slide The walls and columns, for the tsunami contact side shouldn t be destroyed by the wave pressure
1 2 3 Structural design requirement on the tsunami evacuation buildings Calculate tsunami pressure Calculate tsunami load Calculate story shear force Design flow 4 Calculate buoyancy a) Buoyancy for design of superstructure b)buoyancy for design of foundation 5 6 7 Design of exterior elements Design for debris impact Design for scouring 8 Design for collapse prevention 9 Design for overturning prevention 10 Design for drifting prevention 11 Design of foundation beam 37
Design of tsunami evacuation building Design tsunami force is capable of over seismic force in case inundation depth is larger than 10m High capacity buildings required thicker wall, much steel bigger, longer piles available with conventional techniques 38
Thank you for your attention BRI Japan 39