Seismic Performance of High-rise RC Wall-type Buildings in Korea

Transcription

1 Seismic Performance of High-rise RC Wall-type Buildings in Korea December 2 th, 24 Han Seon Lee Professor, Korea University, Seoul, Korea Structural Concrete Engineering Lab.

2 Ratio of Apartments / Total (%) Introduction Year 2 Total No. of housing units: 4,,49 Total No. of apartment units: 8,6, Year National Census 2

3 Introduction A C D E B A. Jamsil Els Apt. in Seoul (4-story) B. Banpo Samsung Raemian Firstige Apt. in Seoul (2-story) C. Yongsan City Park in Seoul (-story) D. Haeundae I Park in Busan (2-story) E. We ve the Zenith in Busan (8-story)

4 Problems Mock-up test of special shear wall (-story residential building in Daegu, Korea) Coupling beam Special boundary element for shear wall 4

5 2 Chile Earthquake (M w 8.8)

6 Spalling and crushing of concrete Creagh, A., Acevedo, C., Moehle, J., Hassan, W., & Tanyeri, A. C, Seismic performance of concrete special boundary element, 2 PEER Internship Program & NEES Grand Challenge Project PEER Laboratory at UC Berkeley, 2 S S2 Compression 6 kips kips S Tension S Comp S2 Comp - 8 kips

7 Spalling and crushing of concrete Yuniarsyah, E., Taleb, R., Kono, S., & Tani, M., An experimental study on confined RC wall boundary regions under uniaxial monotonic and cyclic reversal loadings, SEEBUS, 24 Long: -D (ρ g =.8%) Trans: -D4@8 (ρ w =.2%).m/m 9.MPa.4m/m.MPa

8 Earthquake simulation test To clarify the seismic response characteristics of the RC high-rise residential building model by performing earthquake-simulation tests on the small-scale models. : scale -story RC wall-type building model 2 : scale 9-story RC piloti-type building model 2 : scale 2-story RC flat-plate core-wall building model 22 8

9 Procedure of this study. : scale -story RC wall-type building model 2. Calibration of analytical model using PERFORM-D through comparison with shake-table results (Distorted model). Evaluation of reliability of analysis (True replica model) 4. Effect of foundation flexibility. Effect of coupling beams and slabs 6. Evaluation of -story RC wall building structure according to the analytical results 9

10 Prototype structures Elevation Base shear coefficient, Fundamental period, Base shear, C S S = ( R / I Plan D E ) T a =.2 (X - dir.) and Design code: AIK2 Height: 2m(-story) Weight: 2,2 kn Wall thick: 8/6mm Slab thick: 2mm A w /A f (X-dir.) = 2.% A w /A f (Y-dir.) = 4.% f c = 24 MPa f y = 4 MPa SDS.8 (Y - dir.) R / I T a = C t (h n ) /4 =.86sec (X-dir.) and.8sec (Y-dir.) V = C s W =,kn (X-dir.) and 2,kN (Y-dir.) E =. W: weight, S D, S DS : spectral accelerations at period sec and.2sec, respectively (.24,.49), R: response modification factor (4.), I E : importance factor (.2), C t =. (X-dir.): RC moment resisting frame (MRF), C t =.49 (Y-dir.): other structures, h n : height of structure (2m).

11 Accel. (g) Accel. (g) Accel. (g) : scale experimental model PGA =.6g Original Taft N2E (X-dir.) 4.4 sec PGA =.6g True Replica Model (: scale) 24. sec sec PGA =.g Time / Accel. Distorted Model (: scale) Time / Accel Items (unit: kn) Total Weight Self Weight Added Weight Prototype 2, 8,2, True Replica Model (:) Distorted Model (:) 8 4 / * Maximum pay-load capacity of the shaking table = 6kN

12 Experimental setup LVDTs Steel blocks Steel blocks LVDTs D,D6,D29 A A2 A Accelerometer A4 D, D2 D,D8 A A4 A A6 D, D4 D9,D2 A A6 A A8 D, D6 D2,D22,D2 D2,D24 D D2,D26 A A9 A A8 A A2 D28 Shaking Table Independent Post Reference Frame View A A9 A2 Loadcell A2 Shaking Table View B A2 A22 A24 D, D8 D9, D D D, D2 D4 Independent Post Reference Frame Displacement transducers and accelerometers Wall D2 D4 Footings and load cells at base D2 D6 D2 D8 mm x mm Plate Footing 22mm Thread Bolt Load Cell 2mm bolt Base Plate LC Type I LC Type II LC Type III 2

13 Spectra acceleration (S a ) Earthquake simulation test Test designation Taft N2E (X-dir.) Taft S69E (Y-dir.) KBC2 (DE) Output (Taft.4g X-dir.) Output (Taft.4g Y-dir.) KBC2 (MCE) Output (Taft.6g X-dir.) Output (Taft.6g Y-dir.) MCE DE (R=., I E =.) Period (sec) Intended PGA(g) Measured PGA(g) Return period in Korea (year) X-dir. Y-dir. X-dir. Y-dir..4X YY X Design Earthquake.4XY (DE).6X.6.2.6XY (MCE)

14 Earthquake simulation test 4

15 Acceleration (g) Acceleration (g) Acceleration (g) Acceleration (g) Acceleration (g) Acceleration (g) Acceleration (g) Nonlinear dynamic time history analysis Y-dir. (+) X-dir.(+) Recorded table excitations used for analysis 92 Taft EQ. for distorted model (test, analysis) g.4g.8g.4g.6g Taft N2E, X-dir. (Distorted model) Duration: sec.g.4g.8g.g Taft S69E, Y-dir. (Distorted model) Duration: sec.g.4g.8g.4g.6g Taft EQ. for true replica model (analysis) Taft N2E, X-dir. (True replica model).g Duration: sec 2 Concepcion EQ. for true replica model (analysis) Taft S69E, Y-dir. (True replica model) Duration: sec -.2.g.g.4g.8g g g Longitudinal component, X-dir. Transversal component, Y-dir..4.4 Vertical component, Z-dir..4 (Duration: 6.6 sec) (Duration: 6.6 sec) (Duration: 6.6 sec) Ground acceleration Ground acceleration Ground acceleration -.4 recorded in Conception, 2 recorded in Conception, g recorded in Conception, Time (s) Time (s) Time (s)

16 Shear stress (MPa) Stress (MPa) Stress (MPa) Analytical modeling Wall - E c = 2,MPa -2 Thorenfeldt model - f' c = 2.MPa Perform-D model Strain (mm/mm) f y, ϕ2 = 42MPa f y, D = 489MPa E s = 2,MPa -4 ϕ2 D Strain (mm/mm) Concrete Steel Concrete Shear v n = 2.49MPa G c =.4E c = 9,49MPa v n =.2 MPa G eff =.G c = 4,MPa ASCE/SEI 4-6 Analytical model.2v n....2 Shear strain (mm/mm) Inelastic Shear Wall element Conc. Steel Concrete Shear Others (elastic) Fiber sections : Axial and in-plane bending behaviors in the longitudinal direction : Inelastic shear behaviors : Transverse in-plane bending behavior Shear Wall Ele. 4 nodes (24 d.o.f.) 6

17 Analytical modeling Slab & Coupling beam Slab and Coupling beam : Inelastic beam elements Stiff end zone Plastic hinge (M-ϕ) Shear hinge Stiff end zone Plastic hinge (M-ϕ) Elastic section Imbedded column (rigid zone)

18 OTM (knm) OTM (knm) Design Earthquake (DE) in Korea OTM (knm) Roof drift (%) Roof drift (%) V/W Maximum Considered Earthquake (MCE) in Korea OTM (knm) Roof drift (%) Roof drift (%) V/W V/W V/W Calibration of Analytical Model Base shear / Building weight, V/W (X-dir.) EXP. Anal. Base shear 2 / Building4 weight, V/W 6 (Y-dir.) 8 EXP. Anal. Roof drift 2(X-dir.) EXP. Anal. Roof drift 2(Y-dir.) EXP. Anal. Overturning 2 moment 4in X-dir. 6 8 EXP. Anal. Overturning 2 moment 4in Y-dir. 6 8 EXP. Anal Base shear / Building weight, V/W (X-dir.) EXP. Anal. Base shear 2 / Building4 weight, V/W 6 (Y-dir.) 8 EXP. Anal. Roof drift 2(X-dir.) EXP. Anal. Roof drift 2(Y-dir.) EXP. Anal. Overturning 2 moment 4in X-dir. 6 8 EXP. Anal. Overturning 2 moment 4in Y-dir. 6 8 EXP. Anal

19 Calibration of Analytical Model Distorted model (EXP: gray, ANAL: orange) vs. True replica model (black) SLE DE MCE 9

20 Analytical modeling foundation flexibility Axial Stiffness of Load cells Soil-Structural Interaction Class C: very dense soil and soft rock v s : shear wave velocity (m/s), G : initial soil shear modulus ( MPa), ν: Poisson ratio (. for sand). ρ s : soil mass density (2kN/m /g) ASCE 4- G = αg = αv s2 ρ s = MPa Type of load cell Axial stiffness (kn/mm) Tension Compression LC Type I 69 8 LC Type II,6,26 LC Type III,,6 K end =,8kN/mm (LC )

21 V/W V/W V/W V/W V/W V/W Effect of foundation flexibility (blue-line) vs. (black-line) DE in Korea MCE in Korea Concepcion EQ..4.2 X-dir. DE in Korea.4.2 X-dir. MCE in Korea.4.2 X-dir. Concepcion EQ Roof drift (%) Roof drift (%) Roof drift (%).4.2 Y-dir. DE in Korea.4.2 Y-dir. MCE in Korea.4.2 Y-dir. Concepcion EQ Roof drift (%) Roof drift (%) Roof drift (%) 2

22 Interstory drift Floor Floor Floor Floor Lateral deflection Floor Floor Floor Floor Effect of foundation flexibility drift (solid-line) vs. (dotted-line) MCE in Korea 2 Concepcion EQ. Roof -.8. Roof Roof -..2 Roof Flexiblebase Fixedbase MCE in Korea Footing (X-dir.) Rotation Drift (%) Flexiblebase Fixedbase MCE in Korea Footing (Y-dir.) Rotation Drift (%) Concepcion EQ. (X-dir.) Flexiblebase Fixedbase Footing Rotation Drift (%) Flexiblebase Fixedbase Concepcion EQ. Footing (Y-dir.) Rotation Drift (%) Roof MCE in Korea 9 (X-dir.) Roof MCE 9 in Korea (Y-dir.) Flexiblebase Fixedbase Flexiblebase Fixedbase Roof Concepcion EQ. 9 (X-dir.) Flexible- Roof Concepcion base EQ. Fixedbase 9 (Y-dir.) Flexiblebase Fixedbase Drift (%) Drift (%) Drift (%) Drift (%) 22

23 Y-dir. Story Story Story Story X-dir. Story Story Story Story Effect of foundation flexibility drift vs. models MCE in Korea 2 Concepcion EQ MCE in Korea at max. base shear (X-dir.) Total Por. +6 Por Por Shear force (kn) MCE in Korea at max. base shear (Y-dir.) Total Por. +6 Por Por Shear force (kn) MCE in Korea at max. base shear (X-dir.) Total Por. +6 Por Por Shear force (kn) MCE in Korea at max. base shear (Y-dir.) Total Por. +6 Por Por Shear force (kn) MCE in Korea at max. base shear (X-dir.) - - Shear force (kn) MCE in Korea at max. base shear (Y-dir.) Total Por. +6 Por Por Total Por. +6 Por Por Shear force (kn) MCE in Korea at max. base shear (X-dir.) Total Por. +6 Por Por Shear force (kn) MCE in Korea at max. base shear (Y-dir.) Total Por. +6 Por Por Shear force (kn) 2

24 Damage Pattern of the Wall and Slab in Experiment Third Floor upper side Third Floor lower side 24

25 Damage Pattern of the Wall A B C D E D E A B C 2

26 Base shear / Building weight Base shear / Building weight Effects of Slabs and Coupling Beams To investigate the influence of the slab and coupling beam, the models with/without slabs (Models SB/NS) are also modeled. Flexiblebase Fixedbase Flexiblebase Fixedbase X-dir. SB NS Period.4s.2s K initial Period.s.88s K initial..6 Y-dir. SB NS Period.284s.s K initial Period.62s.2s K initial Unit of K initial : kn/mm X-dir. (+) Roof drift (ratio) Y-dir. (+) Roof drift (ratio) SB, flexible-base SB, fixed-base NS, flexible-base NS, fixed-base Steel, ε =.2m/m Concrete, ε =.2m/m Concrete, ε c,ult =.6m/m Shear stress degradation in wall, ε =.m/m SB, flexible-base SB, fixed-base NS, flexible-base NS, fixed-base Steel, ε =.2m/m Concrete, ε =.2m/m Concrete, ε c,ult =.6m/m Shear stress degradation in wall, ε =.m/m 26

27 Contribution of Slabs and Coupling Beams Maximum overturning moment, OTM (unit: knm) F j h j = M i + P i l i Pl i i Degree of coupling (d.o.c) = F h Model SB Model NS True replica model Flexiblebase Fixedbase Flexiblebase Fixedbase Table excitation j j F j h j : external overturning moment M i : the sum of the base moments P i l i : the sum of the values of the axial force multiplied by the arm length Total OTM ( F j h j ) OTM due to T/C coupling ( P i l i ) d.o.c ( P i l i / F j h j ) Taft.8XY (DE) % Taft.XY (MCE) % Concepcion EQ % Taft.8XY 9 44.% Taft.XY (MCE) % Concepcion EQ % Taft.8XY (DE) % Taft.XY (MCE) % Concepcion EQ % Taft.8XY (DE) % Taft.XY (MCE) 9 9.% Concepcion EQ % 2

28 model under MCE in Korea Stress (MPa) Stress (MPa) OTM (knm) model under MCE in Korea Stress (MPa) Stress (MPa) OTM (knm) Drift (%) Drift (%) Time histories (MCE): Roof drift (X-dir.) OTM (X-dir.) Axial strain (LW, RW) MCE in Korea Model Roof drift (X-dir.) SB Rotation of footing (X-dir.) (.%) (48.%) Total OTM (X-dir.) -6 - OTM due to T/C coupling LW RW LW MCE in Korea Model SB Roof drift (X-dir.) (.2%) -24 (.%) Total OTM (X-dir.) - OTM due to T/C coupling LW RW RW Y Y2 Y Y4Y Y6 Y Y8Y9 Y X6 X X4 X X2 X F 2F F Plastic hinge LW RW LW RW LW RW

29 model under Concepcion EQ. Stress (MPa) Stress (MPa) Stress (MPa) Stress (MPa) OTM (knm) Drift (%) model under Concepcion EQ. OTM (knm) Drift (%) Time histories (C.E.): Roof drift (X-dir.) OTM (X-dir.) Axial strain (LW, RW) 4 Concepcion EQ Model Roof drift (X-dir.) SB -2. Rotation of footing (X-dir.) (.4%) -6-2 (2.%) Total OTM (X-dir.) -2-8 OTM due to T/C coupling LW RW LW 4 2 RW Y Y2 Y Y4Y Y6 Y Y8Y9 Y X6 X X4 X X2 X F 2F F Plastic hinge.6 LW RW Concepcion EQ. -2 Model -. SB Roof drift (X-dir.) (4.%) -6-4 (46.%) Total OTM (X-dir.) -2-8 OTM due to T/C coupling LW RW LW RW LW RW

30 Floor Stress (MPa) Floor Stress (MPa) Maximum axial strain demand (MCE in Korea) Roof MCE in Korea 9 (X6Y) (X6Y) (X6Y) (X6Y) Axial Roof MCE in Korea 9 (XY6) (X6Y6) (XY6) (X6Y6) Axial X6Y X6Y X6Y X6Y6 Y Y2 Y Y4Y Y6 Y Y8Y9 Y X6 X X4 X X2 X

31 Floor Stress (MPa) Floor Stress (MPa) Maximum axial strain demand (Concepcion EQ.) Roof Concepcion EQ. 9 (X6Y) (X6Y) (X6Y) (X6Y) Axial Roof Concepcion EQ. 9 (XY6) (X6Y6) (XY6) (X6Y6) Axial X6Y X6Y X6Y X6Y6 Y Y2 Y Y4Y Y6 Y Y8Y9 Y X6 X X4 X X2 X

32 Floor Floor Stress (MPa) Stress (MPa) Plastic hinges and axial strain in Frame X4 at instant max. roof drift (-X) Model SB, Instant: 2.s (max. roof drift (-X)) under MCE in Korea MCE in Korea Model SB, Instant: 2.28s (max. roof drift (-X)) under MCE in Korea X6 X X4 X Y Y2 Y Y4Y Y6Y Y8Y9 Y X2 X Y Y2Y Y4Y Y6Y Y8Y9 Y Y Y2Y Y4Y Y6 Y Y8Y9 Y 4 2 MCE in Korea (2.s) Y2 Y4 Y Y Axial 4 2 MCE in Korea (2.28s) -.89 Y2 Y4 Y Y Axial X4Y X4Y

33 Floor Floor Stress (MPa) Stress (MPa) Plastic hinges and axial strain in Frame X4 at instant max. roof drift (-X) Model SB, Instant:.8s (max. roof drift (-X)) under 2 Concepcion earthquake 2 Concepcion EQ. Model SB, Instant:.s (max. roof drift (-X)) under 2 Concepcion earthquake X6 X X4 X Y Y2 Y Y4Y Y6Y Y8Y9 Y X2 X Y Y2 Y Y4Y Y6Y Y8Y9 Y Y Y2Y Y4Y Y6Y Y8 Y9 Y 4 2 Concepcion EQ. (.8s) Y2 Y4 Y Y Axial 4 2 Concepcion EQ. (.s) -.8 Y2 Y4 Y Y Axial X4Y X4Y

34 Conclusions (/2) Effect of foundation flexibility The flexible foundation significantly decreases the initial stiffness with lengthening the fundamental period. The maximum roof drift of the flexible-base model is larger than that of the fixed-base model, whereas the maximum base shear of the flexiblebase model are similar to that of the fixed-base model. The interstory drifts under MCE in Korea within.6%, which satisfy the allowable interstory drift limit,.%, defined by KBC 29 (IBC 26). The maximum interstory drifts in flexible-base model are.~2. times larger than those in fixed-base model. In particular, the translational behavior in the Y direction (the ratio of wall cross sectional area to building floor plan area, A w /A f = 4.%) is more sensitive to the motion of foundation rocking than that in the X direction (A w /A f = 2.6%). 4

35 Conclusions (2/2) Effect of coupling beams and slabs In the models without slab and coupling elements, the natural period, initial stiffness, and maximum strength representing the global responses are considerably lower than those of the model with slab and coupling beam elements. For the design, therefore, the analytical model of the box-type wall building structure ignoring the flexural rigidity of the slab and coupling beam could provide the erroneous information for design. Models with and without slab elements are governed by the membrane actions due to the coupling effect of the web wall to the flange wall. In the analytical model with slabs, the coupling behavior of walls covers approximately 4~% of the total overturning moment, with that in the model without slabs resisting about 2~% of the total. Therefore, the membrane action due to the slab and coupling beam contribution can increase significantly the demand of the overturning moment.

36 Thank you for your attention! The research presented herein was supported by the National Research Foundation of Korea (NRF-29-8) and Architecture & Urban Development Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government (AUDP-B668-). The writers are grateful for this support. 6