Brief review of building damage by the 2011 Tohoku Japan earthquake and following coping activities

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1 1 Brief review of building damage by the 211 Tohoku Japan earthquake and following coping activities Isao Nishiyama* (BRI), Izuru Okawa (BRI), Hiroshi Fukuyama (BRI) and Yasuo Okuda (NILIM) BRI : Building Research Institute NILIM : National Institute for Land & Infrastructure Management 14 th U.S.-Japan Workshop on Improvement of Structural Design and Construction Practices December 3-5, 212, Makena Beach & Golf Resort

2 1. Introduction 2

3 JMA Seismic Intensity & Hypocentral Region 3 Tohoku earthquake Mw=9. (14:46 JST on March 11, 211) 45km (NS) x 15km (EW)

4 Building and Residential Land Damage by Earthquake Motion and Tsunami BRI and NILIM sent 43 teams for field survey and the following reports are available as of December 2, 212 http://www.kenken.go.

4 4 Building and Residential Land Damage by Earthquake Motion and Tsunami BRI and NILIM sent 43 teams for field survey and the following reports are available as of December 2, ents/publications/data/132/index.html ents/publications/data/135/index.html ents/topics/211311/311report.html ents/publications/data/138/index.html nts/topics/211311/311summaryrepo rt.html

5 2. Recorded Ground and Building Motions 5

6 ' 14 2' 14 4' 14 2' BRI Strong Motion Network ' 139 2' AKT TRO 38 NIG THU, SND NGN MIZ IJMA KSO NGY 35 OSK, SKS YMN SMZ 35 SMS 34 MTS ISK HRH HKD HKU IWK HCN2, HCN TAMA2, MIYA2 MYK HRO KGC 211/3/11 14:46(JST) h=24 km, M9. km 139 4' 139 2' ' 36 2' 36 2' 36 ' 36 ' UTK, NMW, SMD 35 4' 35 4' KDI NKN YYG CGC, CG2, CG3, NDLG, NDLM, NDLA YKH KWS NIT SITA, SIT2 TDS AKB TUF ADC EDG TKD TUS MST ICK MTK 35 2' 35 2' 14 ' FNB ANX, BRI, NCTD TKC YCY CHB km IJMA In 1957, BRI started strong motion network.

Damaged Building in Sendai city Acc (cm/s 2 ) 1 1 1 Acc (cm/s 2 ) 1 4 Disp (cm) Disp (cm) T(s) 4 4 4 2. 1.5 1..5 (a) Acc. in Trans. Dir. (b) Acc. in Long. Dir. (c) Bldg.

) Flexural failure of multi-story shear walls which can absorb large earthquake energy was observed.

7 Damaged Building in Sendai city Acc (cm/s 2 ) Acc (cm/s 2 ) 1 4 Disp (cm) Disp (cm) T(s) (a) Acc. in Trans. Dir. (b) Acc. in Long. Dir. (c) Bldg. Disp. in Trans. Dir. (d) Bldg. Disp. in Long. Dir. (e) Transition of natural periods Time (s) Trans 9F(Trans.) 1F(Trans.) 9F(Long.) 1F(Long.) Flexural failure of multi-story shear walls which can absorb large earthquake energy was observed. Though the building could secure human lives by preventing its collapse as demand of seismic codes, buckling and/or rupture of steel bars and steel plates in the columns and compressive crashing of concrete were observed. Finally, the building was demolished. Long.

8 8 Damaged Building in Sendai city (cont.) (cm/s 2 ) (cm/s 2 ) (cm/s 2 ) (cm/s 2 ) (cm/s 2 ) (cm/s 2 ) (cm/s 2 ) (cm/s 2 ) F (peak: 258 cm/s 2 ) 292-1F (peak:- 23 cm/s 2 ) 22-9F (peak: 14 cm/s 2 ) 292-9F (peak:- 529 cm/s 2 ) Time (s) F (peak:- 333 cm/s 2 ) F (peak: 33 cm/s 2 ) 192-9F (peak: 98 cm/s F (peak: 728 cm/s 2 ) Time (s) 1F(NS) 258 cm/s 2 1F(EW) 23 cm/s 2 9F(NS) 14 cm/s 2 9F(EW) 529 cm/s 2 1F(NS) 333 cm/s 2 1F(EW) 33 cm/s 2 9F(NS) 98 cm/s 2 9F(EW) 728 cm/s 2

9 52+3 story building in Osaka city 9-2 Disp. (cm)2-2 Disp. (cm)2-2 Disp. (cm)2-2 Disp. (cm)2-2 Disp. (cm)2-2 Disp. (cm)2 Displacement 1F SW-NE (peak:- 9.1 cm) 1F NW-SE (peak: 7.8 cm) 52F SW-NE (peak: cm) 52F NW-SE (peak: cm) 52F-1F SW-NE (peak: cm) 52F-1F NW-SE (peak: 84.8 cm) Time (s) Pseudo Vel. Resp.Spectrum (h=5%) 1 The large responses lasted at least 1 minutes in the building in Osaka, 77km from the epicenter. A 137cm maximum displacement occurred on the top floor. Many non-structural interior members such as ceilings, walls, fire doors, sprinklers, etc. were damaged, and even confinements of passengers in elevators occurred. Pseudo Velocity Response (cm/s) (cm) Period (sec) (cm/s/s) 1 SW-NE NW-SE

10 3. Building and Residential Land Damage 1

11 Field surveyed area by BRI and NILIM teams 11

12 Earthquake Motion Damage 12 Courtesy to the Japan MLIT

13 Earthquake Motion Damage (cont.) 13

14 Tsunami Damage 14

15 4. Coping Activities on Selected Issues 15

16 System to Revise Building Structural Codes 16 NILIM Building Structural Code Committee proposal MLIT Building Structural Code WG Long-duration longperiod earthquake ground motions TG Ceiling design method, etc. Private BRI R & D by self-budget technical advice On Building Structural Codes, * Proposal * Public comments * Technical information

17 1. Digital data by BRI strong motion network 2. Long-duration and long-period ground motion, structural performance under multiple cycles of loadings 3. Higher level of PBD, functional after earthquake 4. Fall down of ceilings in spatial structures and escalators in shopping centers 5. Fractured lead damper in seismically isolated buildings 6. Inclination due to liquefaction in residential houses 7. Evaluation of tsunami force 8. etc. 17

18 Long-duration and long-period ground motion prediction method based on observation at about 16 stations ORIGINAL EVALUATION MODEL 18 MLIT PROPOSAL FOR DESIGN MOTION CALL FOR PUBLIC COMMENTS, Tohoku EQ. Revision of the model Philippine Sea plate Pacific plate Long-duration and long-period motion properties Spectral amplitudes from large earthquakes Duration of motions with each frequency band earthquake magnitude distance site specific coefficients (additional factors) Epicenters + Paths Earthquakes used in the analyses Revised evaluation method

36 36 19 Long-duration and long-period ground motion prediction method based on observation at about 16 stations (cont.

CAO, AIJ, etc. MLIT is going to propose a design long-duration and long-period motions and is funding project for the purpose.

19 Long-duration and long-period ground motion prediction method based on observation at about 16 stations (cont.) Long-duration and long-period motions were evaluated for major urban areas with two-, three- connected earthquakes, by HERP, CAO, AIJ, etc. MLIT is going to propose a design long-duration and long-period motions and is funding project for the purpose. HERP Nankai-trough three-connected earthquake model with revised model for major areas Nankai 32 km CAO Mw9 model Osaka Nagoya Tokyo

research cooperation between the BRI and

20 Structural performance against long-duration and long-period ground motions (full-scale) 2 These large-size experiments are carried out under the research cooperation between the BRI and the institutions headed by Obayashi, Kajima and Taisei Co.

21 Fall down of ceilings in spatial structures After Geiyo earthquake (21), a technical advice was issued to recommend putting diagonal braces on ceiling rods, and keep clearance around suspended ceiling. (see left figure) Construction companies reported nearly 2, cases of fall down of ceilings during Tohoku earthquake. Examples with/without injury are compared. (see right figure) 21 Frequently observed damage by earthquake Recommended method in an MLIT technical advice Mass and height of ceiling damaged by earthquake

22 22 Fall down of ceilings in spatial structures (cont.) (Tentative) Allowable Stress Design for probable earthquake + safety margin Scope of regulation Ceiling height > 6m Ceiling area > 2m 2 Unit weight of ceiling > 2kg/m 2 Safety margin Vertical strength Clearance around ceiling

23 23 Fall down of escalators in shopping centers (Tentative) Requirement from H/1 (current) to H/4 (Tentative) Exceptional relaxation to H/1 in case of fall prevention device Roller overlapped Escalator truss Fixed H H/1 Escalator truss Floor Girder Connector Joint cover Fall prevention

24 24 Liquefaction Liquefaction evaluation was made by F L - method at 112 sites in Kanto area, the results were compared with observations. Liquefied sites ( ) are all predicted (F L 1) but many non-liquefied sites are cautioned ( ). Improvement of evaluation accuracy is in need. F L -method requires following information. N-value by standard penetration test (SPT) fine fraction content water level maximum design horizontal acceleration at surface earthquake magnitude F L >1 Liquefied sites Non-liquefied sites F L

25 25 Liquefaction (cont.) Japan s Building Standard Law does not require structural calculation for detached residence (residential land) Liquefaction risk is not evaluated Liquefaction measures are not required Show menus and leave selection to owners Development of affordable liquefaction evaluation method for residential land BRI tries possibility of SWS (Swedish weight sounding test), plus water level and soil judgment Development of practical techniques for residential land Applicability to existing house Prediction of subsidence

26 Tsunami wave force - Tentative guidelines for tsunami evacuation buildings - 26 Previous guidelines Partially relaxed current guidelines (tentative guidelines) Observed results by Tohoku Japan earthquake

tsunami pressure on buildings. Improved CFD technique will be applied to evaluate the effects of openings, water infiltration, etc.

27 Tsunami wave force (cont.) - Tentative guidelines for tsunami evacuation buildings - BRI, Kajima Co. and U. of Tokyo have carried out waterway experiments in order to develop (improve) CFD (Computational Fluid Dynamics) technique for evaluation of tsunami pressure on buildings. Improved CFD technique will be applied to evaluate the effects of openings, water infiltration, etc. AIJ discusses adding new chapter of tsunami loads on buildings into (Revised) Recommendations for Loads on Buildings in Waterway experiment Numerical simulation of Tsunami over seawall

28 Thank you for your kind attention. 28

SAFETY EVALUATION OF SEISMICALLY ISOLATED HOUSES WITH DISPLACEMENT RESTRAINT DEVICES UNDER SEVERE EARTHQUAKE MOTIONS

SAFETY EVALUATION OF SEISMICALLY ISOLATED HOUSES WITH DISPLACEMENT RESTRAINT DEVICES UNDER SEVERE EARTHQUAKE MOTIONS M. Iiba, T.Hanai, M. Midorikawa, T. Azuhata 4 and N. Inoue 5 Director, Structural Engineering