Recorded Responses and Performance of Buildings during the 2011 Great East Japan Earthquake

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1 Guest Professorship Presentation, Tongji Univ., Shanghai The 5th Kwang-Hua Forum on Innovations and Implimentations in Earthquake Engineering Research Shanghai, China, 9-1 December 212 Recorded Responses and Performance of Buildings during the 211 Great East Japan Earthquake Kazuhiko Kasai, Professor and Director of SERC Tokyo Institute of Technology, Japan Wuchuan Pu, Associate Professor Wuhan University of Technology, China Guest Professorship Presentation, Tongji Univ., Shanghai

2 Guest Professorship Presentation, Tongji Univ., Shanghai Full-Scale Shake Table Tests for Realistic & Detailed Studies 4-Story Bldg. Tested to Collapse 5-Story Bldg. w/wo Dampers 3-Sory Rocking Frame w. Dampers Guest Professorship Presentation, Tongji Univ., Shanghai

3 Tall Bldgs. in Tokyo Metropolitan Areas New and Old Tall Buildings in Shinjuku District (Sub-Center of Tokyo) Kasai Lab., Structural Engineering Research Center, Tokyo Institute of Technology

4 During the Great East Japan Earthquake, March 11, 211, many instrumented buildings were shaken strongly for the first time to level 1 or higher considered by Japanese seismic design. The records should show true capability of tall buildings, response-controlled buildings, and baseisolated buildings whose performance have not been validated yet. Last year (4th Forum), we evaluated properties and responses of one tall bldg. and three responsecontrolled tall bldgs. by mode-based method utilizing the records. This year (5th Forum), we extend our study to more variety of buildings and methods.

5 Tokyo Institute of Technology, Kasai Lab. Tokyo Institute of Technology, Kasai Lab. Three Different Approaches to Interpret Records Building Monitored Sensor Sensor Sensor T 1, ξ 1 T 2, ξ 2 T 3, ξ 3 ( Member-to-Member Model May Be Created ) Mode-Based Model Shear Beam or Stick Model

6 29-Story Building (No Dampers): Modal Properties in Y-direction 1 Transfer Function F 1F 1 Transfer Function F 1F Frequency (Hz) Y-direc. Output 16F 29F Ave. Natural Frequency (Hz) Damping ratio 1st mode 2nd mode 3rd mode 1st mode 2nd mode 3rd mode Kasai Lab., Structural Engineering Research Center, Tokyo Institute of Technology

7 29-Story Building (No Dampers) Name Kogakuin University Completion 1989 Number of Floors 29 floors above ground 6 floors below ground 1 floor penthouse Aspect Ratio EW(X): 3.73; NS(Y): 5.59 Frame Type Period (s) (obtained by Kasai lab.) Steel frame with brace EW (X): 2.96s, 1.s NS (Y) : 3.9s,.94s Kasai Lab., Structural Engineering Research Center, Tokyo Institute of Technology

8 Acc. of top and base Top acceleration Base acceleration High Frequency Low Frequency Acc. of top floor Mode superposition Actual Acc. Dispt. of top floor Mode superposition Double integral of actual acc. 29-Story (No Dampers), Y-direction Recorded and calculated responses agreed well: Thus, both the records & modes are reliable. Kasai Lab., Structural Engineering Research Center, Tokyo Institute of Technology

9 29-Story Bldg. (No Dampers), Y-direction Modal Contributions to Disp. and Acc. Top Floor Dispt. 1st Top Floor Acc. 3rd 2nd 1st The vibration continued for more than 6 min. The recorded responses are well interpreted using the modes and modal responses. Kasai Lab., Structural Engineering Research Center, Tokyo Institute of Technology

10 21-Story Bldg. with 336 Steel Dampers & 284 Viscous Dampers Y X 21-story Steel Frame Viscous damper (284) Steel damper (336) Kasai Lab., Structural Engineering Research Center, Tokyo Institute of Technology

11 41-Story Bldg. with 688 Oil Dampers Steel Core Frame 41-story Steel Frame + Oil damper (688) ( ) Oil Damper Kasai Lab., Structural Engineering Research Center, Tokyo Institute of Technology

12 54-Story Bldg. Retrofitted by 288 Oil Dampers. 54-story Building: Steel Frame Oil Dampers 42m Y X 63m Oil Damper Kasai Lab., Structural Engineering Research Center, Tokyo Institute of Technology

13 Without damper, the acc. and disp. will increase considerably. Top Floor Acc. Top Floor Disp. Black Line: With damper, actual recorded acc. and disp. (double integration). Gray Line : No damper, modal analysis by assuming 1% damping ratio. Kasai Lab., Structural Engineering Research Center, Tokyo Institute of Technology

14 Floor (& Ceiling) Response Spectra Spa (cm/s 2 ) (a) Bldg. 1 Increased Bldg. Damping (4%) Original Bldg. Damping (2.1%) T(s) Spa (cm/s 2 ) (c) Bldg. 6 Decreased Bldg. Damping (1%) Original Bldg. Damping (3.4%) T(s) Spa (cm/s 2 ) (b) Bldg. 4 Decreased Bldg. Damping (1%) Original Bldg. Damping (3.7%) T(s) Spa (cm/s 2 ) (d) Bldg. 9 Decreased Bldg. Damping (1%) Original Bldg. Damping (3.9%) T(s) Floor response spectra of 4 tall bldgs. (damping ratio=3%) Kasai Lab., Structural Engineering Research Center, Tokyo Institute of Technology

15 Six (Two) Bldgs. in Roppongi Hills, Tokyo The largest private-sector redevelopment in Japan (76,m 2 ). Tokyo cultural center containing offices, residences, retail facilities, cultural facilities, a hotel, a cinema complex, a broadcasting center, and others. It aims to be a disaster prevention city protecting people and assets. Bldg.-6 (54story) Buckling Restrained Brace and Semi-Active Oil Damper Bldg.-1 (8 story) Green Mass Damper Bldg.-2 (18 story) Base-Isolated Bldg.-3 (21 story) Low Yield Point Steel Shear Wall Bldg.-5 (43 story) Viscous Damping Wall Bldg.-4 (29story) Base-Isolated

16 Building 1 of Roppongi Hills GMD R2F Ch.1,11,12 Ch.13,14,15 Top of GMD Ch.7,8,9 R1F 6F 5F Bottom of GMD (bldg. top) 4F 3F Ch.4,5,6 2F 1F B1F Ch.1,2,3 B2F B3F B4F 8-Story + 2-Story Penthouse Foot Area 4,527m 2,Total 23,831 m 2 SRC Frame with Large Span for Theaters etc. Green Mass Damper (GMD) 36,5 kn vs. Bldg. 35, kn 46 Natural Rubber Isolators & 22 Viscous Dampers

17 Bldg. -1 Mode-Based Model Excluding GMD Transfer function fitting [Bottom of GMD (bldg. top)] vs. [B1F level] Curve fitting X Direc. Frequency (Hz) f1 f2 f3 Damping Ratio h1 h2 h3 3F Bldg. top Average Transfer Function Displacements (cm) Building top, X-direction Frequency (Hz) Accelerations (cm/s 2 ) Record Time (s) Modal Analysis

18 Bldg.-1 Shear Beam Model Including GMD GMD Model Building Green Mass Damper (GMD) Building Top Natural Rubber Isolator Nonliner Viscous Damper X Direction The design model was revised. Force (kn) Displacements (cm) Record GMD Model

19 Bldg.-1 Shear Beam Model Including GMD GMD Relative Displacements R2F R1F 6F Bottom of GMD Top of GMD Displacements (cm) 5F 4F Time (s) Absolute Accelerations 3F 2F 1F Accelerations (cm/s 2 ) Record Time (s) Model

20 Performance of Bldg.-1 (Shear Beam Model): Comparison with fixed GMD Case Max Relative Displacements Max Absolute Accelerations Floor Floor Theater Without GMD Displacements (cm) Accelerations (cm/s 2 ) With GMD Record Without GMD With GMD Record

21 Building 6 of Roppongi Hills Ch.31,32,33 Ch.22,23,24 Ch.13,14,15 54-Story + Penthouse 2-Story Foot Area 16,281m 2 Total Area 38,15m 2 CFT Columns, Steel Beams 192 Buckling-Restrained Braces, 356 Semi-Active Oil Dampers Ch.4,5,6 Ch.1,2,3 Semi-active oil dampers are designed to provide more efficient control than passive dampers for moderate earthquakes and winds. During March 11 event, the recording accidentally stopped after 18 sec. So, we constructed the ground acc. data from 18 to 5 sec., based on the records obtained at the neighboring bldgs., as will be explained.

22 Bldg.-6 (Mode-Based Model): Created by using records up to 18 sec. Curve fitting for 3 modes Y Direction Curve fitting for 5 modes Accelerations (cm/s 2 ) Displacements (cm) Transfer Function Transfer Function Frequency (Hz) Frequency (Hz) Time (s) Time (s) Accelerations (cm/s 2 ) Displacements (cm) Time (s) Time (s) Record Modal Analysis Record Modal Analysis

23 Compared ground level acc. records of four buildings, by rotating coordinates and shifting time records. Bldg.-6 Bldg.-1 Bldg.-2 Bldg.-5 Bldg.-6 Bldg.-5 Accelerations (cm/s2) Bldg.-1 Time (s) Bldg.-2

24 Copied ground level acc. records of the closest bldg.-1 (after 18 secs.), and performed Y Direction Bldg.-6 に一番近い Bldg.-1 の加速度を 18 秒以降に加えた 上部構造の挙動はモード重合法により再現した Accelerations (cm/s 2 ) Displacements (cm) Time (s) Record Modal Analysis Accelerations (cm/s 2 ) Time (s) Bldg.-1 Bldg.-6

25 Bldg.-6 (Mode-Based Model): Compared w. assumed low damping cases Building Top(52F), Y Direction Accelerations (cm/s 2 ) Displacements (cm) Time (s) Modal Analysis (Original Damping) Modal Analysis (1% Damping) Building Top(52F) Y Direction Maximum Square-Root of Sum of Squares Relative Displacement Absolute Acceleration Original Damping 3.33 (1.) 7.94 (1.) 1% Damping (1.45) 16.6 (1.79) 2% Damping (1.16) (1.41) Original Damping (1.) 17.1 (1.) 1% Damping (2.3) 3.36 (2.2) 2% Damping (1.57) (1.53) *()= comparison with original damping case

26 Sendai City Hall, Miyagi Prefecture, Retrofitted by Toggle System & Viscous Damper

27 Mechanism of Toggle-Type Control Brace Story drift Arm Viscous Damper Amplified Disp. Arm Amplification てこ の増幅作用を応用したトグル mechanism by leverage principle was adopted 機構を採用 Seismic 地震時に生じる層間変形を Energy is absorbed effectively because damper deformation 2~3 is 倍に増幅してダンパーに伝え 効 amplified by 2 to 3 times of story drift. 率よくエネルギーを吸収する制震工法

28 Configuration of Toggle-Type Control Brace Frame 4 Frame D Total Number of Dampers X-Direction 88 Y-Direction m 28.35m FrameD X Y Frame m 6th Floor

29 Toggle-Type Control Brace

30 Sendai City Hall (Mode-Based Model) Frequency (Hz) Damping Ratio 1st 2nd 3rd 1st 2nd 3rd Curve-fitting of transfer function (X-Dir. 8F / 1F) Obtained from recorded data Curve-fitted ideal curve 1 Amplitude 1 1 Phase Angle (rad) Frequency (Hz)

31 Shear Model Rigid floor 剛床 Oil damper オイルダンパー ( マクスウェルモデル (Maxwell Model) ) Axial stiffness of column 柱軸剛性 Arm トグル腕 Gap ギャップ 柱軸剛性 Arm トグル腕 Slip Model スリップモデル

32 Hysteretic Curves of Frame, Damper, and System 1st Floor, X-Direction 8 6 Q f1x [tonf] 8 6 Q f1x [tonf] Frame Damper System 8 6 Q f1x [tonf] 4 2 1x [rad.] x [rad.] x [rad.] st Floor, Y-Direction Q f1y [tonf] Q f1y [tonf] 8 8 Frame Damper System Q f1y [tonf] 4 2 1y [rad.] y [rad.] y [rad.]

33 Recorded Data v.s. Two Analyses Shear Beam Model Relative Disp. of Top Floor Abs. Acc. of Top Floor Mode-Based Model Relative Disp. of Top Floor Abs. Acc. of Top Floor [cm] [gal] [cm] [gal] Record Record Analysis of Shear Model 12 Time [s] 12 Time [s] Modal Superposition Analysis 12 Time [s] 12 Time [s]

34 Sendai City Hall (Mode-Based Model) Damped Case vs. Undamped Case Modal Superposition Analysis Damped case Un-damped case (h=.1) Relative Disp. of Top Floor 3 [cm] Time [s] 25 [gal] Abs. Acc. of Top Floor Time [s]

35 Effect of Response Control 1/4 Reinforced Case (Record) Non-reinforced Case (Analysis) PH3 11 PH2 1 X-Direc. PH3 11 PH2 1 Y-Direc. PH1 9 8 PH / Floor 階 6 5 1/61 Floor 階 Design Target (1/15) 1/2 1/1 3/2 1/5 Story Drift Angle 層間変形角 (rad) 1 1/2 1/1 3/2 1/5 Story Drift Angle 層間変形角 (rad) Seismic retrofitting was enough to accomplish design target. If this building was not reinforced, it had large deformation. Design Target (1/15)

36 Responses of Base-Isolated Buildings in Tokyo during the 211 Great East Japan Earthquake Tokyo Tech. 2-Story Base-Isolated Building J2-bldg : Base-isolated tall building Floor number : 2-story Structure:Hybrid structure with steel beams and CFT columns Building area : 1,742m 2 Total floor area : 15,747m 2 Construction Year : 25 Detail of structure BI. floor: Rubber bearing (φ11 x 12, φ12 x 4) U-shape steel damper (NSUD55 x 14) Oil damper(1kn x 2) Super Strct:Mega brace(4-story is 1 unit) Structural Engineering Research Center, Tokyo Institute of Technology 36/1

37 Responses of Base-Isolated Buildings in Tokyo during the 211 Great East Japan Earthquake Tokyo Tech. 2-Story Base-Isolated Building J2-bldg : Base-isolated tall building Elevation Floor number : 2-story Structure:Hybrid structure with steel beams and CFT columns Building area : 1,742m 2 Total floor area : 15,747m 2 Construction Year : J3-bldg (under const.) Detail of structure Z Z BI. floor: Rubber bearing (φ11 x 12, φ12 x 4) U-shape steel damper (NSUD55 x 14) Oil damper(1kn x 2) Super Strct:Mega brace(4-story is 1 unit) Y BI Floor X Y X Plan of BI Floor Structural Engineering Research Center, Tokyo Institute of Technology 37/1

38 Responses of Base-Isolated Buildings in Tokyo during the 211 Great East Japan Earthquake Tokyo Tech. Building Measurement Scheme Configuration of acceleration sensor (27ch) Detail of trace recorder & wire type disp. sensor Target (fixed to superstructure) 2F 14F measuring system 1Analog data By trace recorder 2Digital data By wire type disp. sensor Wire Trace recorder Metal plate Rigid support Wire type disp. sensor (fixed to isolation floor) 7F Z X Y W 2F BI-F 1F N S E Z X Y Trace recorder & disp. sensor Center Strain & stroke of oil damper Measurement detail of BI-Floor (18ch) Structural Engineering Research Center, Tokyo Institute of Technology 38/1

39 Responses of Base-Isolated Buildings in Tokyo during the 211 Great East Japan Earthquake System Identification by Transfer Function 1. System ID of Superstructure + BI Floor X-Direction Y-Direction 2. System ID of Superstructure X-Direction Y-Direction 1st 2nd 3rd 1st 2nd 3rd 1st 2nd 3rd 1st 2nd 3rd Period (s) Damping F 8 高さ (m) 8 高さ (m) 8 高さ (m) 8 高さ (m) F F F BI Floor Modal Participation Function Modal Participation Function Modal Participation Function Modal Participation Function Structural Engineering Research Center, Tokyo Institute of Technology 39/1

40 JSSI s Investigations on Recorded Responses of Advanced Seismic Protection Systems 15th WORLD CONFERENCE ON EARTHQUAKE ENGINEERING SEPTEMBER , LISBON - PORTUGAL 15WCEE Special Session 27.3 Sep. 27 (Thurs.), 17:15-19:15, Room A II Significant Building Responses Recorded During the 211 Great East Japan Earthquake Moderators: Kazuhiko Kasai, Director of SERC, Tokyo Tech. Toshihide Kashima, Senior Research Engineer, BRI KASAI, K., Structural Engineering Research Center, Tokyo Institute of Technology 4/1

41 Introduction: Kazuhiko Kasai (Please download from JAEE or Kasai Lab.) 1. Dr. Kashima, Building Research Institute (BRI), Japan. BRI and NIED Strong Motion Network 2. Prof. Motosaka, Tohoku University, Japan. Long term Monitoring of a Damaged Bldg., Shaking/Damage of Sendai Area 3. Prof. Xie, Tongji University, China. A Bldg. with Oil Damper Damaged: Dynamic Analysis and Retrofit, Sendai 4. Prof. Funaki, Tohoku Institute of Technology, Japan. School Bldgs. of Tohoku Institute of Technology, Sendai. 5. Prof. Hisada, Kogakuin University, Japan. High Rise Bldgs., Tokyo 6 Prof. Kasai, Tokyo Institute of Technology, Japan. JSSI s Investigations on Base Isolated Bldgs. and Damped Bldgs., Sendai & Tokyo 7. Prof. Pu, Wuhan University of Technology, China. Conventional Seismic Resistant Bldgs., Tokyo 8. Prof. Matsuda, Tokyo Institute of Technology, Japan. A Tall Base Isolated Bldg., Tokyo 9. Mr. Goto, NTT Facilities Inc. Damped High Rise Bldg., Sendai 1. Dr. Yamamoto, Shimizu Construction Company, Japan. Several Base Isolated Bldgs., Tokyo 11. Dr. Nagashima, Technology Center, Taisei Corporation, Japan. Semi Active Base Isolated Bldg. and Retrofitted Damped Bldg., Tokyo 12. Mr. Harada, Nikken Sekkei Design Incorporated, Japan. A Damped Bldg., Tokyo

42 Recorded Responses and Performance of Buildings during the 211 Great East Japan Earthquake Conclusive Remarks Responses and performance of major buildings during the 211 Great East Japan Earthquake are discussed, based on the strong motions recorded. Using a mode-based model constructed from the records, contributions of vibration modes were analyzed, and various shaking phenomena in tall buildings that had not been experienced are clarified. When non-proportional damping and/or nonlinear response are prominent, a shear beam model was constructed on a trial-and-error basis. It simulates hysteretic curves story-by-story, clarifying effects of localized high damping in base-isolated bldg. or heavy tuned-mass damper, as well as distributed damping in yielding frames. Using the models, merits of damping technology for structures, occupants, and non-structural components in the tall building are explained.