US-Japan Collaborative Study on Seismic Damage of Buildings and their Mechanism Japanese PI: Hitoshi Shiohara, The University of Tokyo Counterpart PI: John W. Wallace, UCLA Objective: To collect and recording of the the data on structural damage of engineered buildings as well as to investigate the factor which caused each structural damage, carried out as a joint effort of Japan (AIJ) and US (EERI). Major Outcomes 1) Joint reconnaissance efforts of building damage by Japanese and US researchers 2) Jointly participated and presented at International Symposium of JAEE in March 2012, Tokyo 3) Presentation at special session of 11WCEE 4) Contribution to the publication of reconnaissance report from AIJ in 2013
Publication: Reconnaissance Report (by AIJ) PREFACE springer.com Devastating damage in the Tohoku region of Edited by the Architectural Institute of Japan Preliminary Reconnaissance Japan occurred during and after the earthquake off the Pacific coast of Tohoku Report of the 2011 Tohoku-Chiho earthquake on March 11, 2011. Taiheiyo-Oki Earthquake Geotechnical, Geological and Earthquake Engineering series The report summarizes damage associated with ground failures including landslide and liquefaction as well as non-structural 7 The only o ffi cial reconnaissance report of the Architectural damages such as to equipment and Institute of Japan 7 Full of concrete information on facilities, partitioning walls and ceilings, and building damages in the Tohoku and Kanto regions functional failures in skyscrapers . Also 7 Mainly consists of field information in the damaged areas without brief description of the Japanese Seismic detailed analysis Design Code will be provided in the Appendix. A proposed scheme of anti- E U D R E B M E T P E S tsunami design for buildings is also 2012 included.
Second Phase: 2010 ～ A C B D
A C B D
A B C D A B C D
Beam-column joint: Full Scale Shaking Table Test at E-Defense in 2010
E-Defense test on RC Building in December 2010 X Y 20 m 15 m E-Defense 3D Shaking Table Four Storied Wall-Frame RC Structure
List of Column List of Girder C1 C2 G1 Location End Center End Section Section 4Fl. RFl. B x D 500 x 500 500 x 500 3Fl. B x D 300 x 600 4Fl. Rebar 8-D22 10-D22 Top 4-D22 3-D22 4-D22 Hoop 2,2-D10@100 2,2-D10@100 Bottom 3-D22 3-D22 3-D22 Joint 2,2-D10@140 2,2-D10@140 Web 4-D10 Stirrup 2-D10@200 Section Section 2Fl. B x D 500 x 500 500 x 500 Rebar 8-D22 10-D22 3Fl. B x D 300 x 600 Hoop 2,3-D10@100 2,4-D10@100 Top 5-D22 3-D22 5-D22 Joint 2,2-D10@140 2,2-D10@140 Bottom 3-D22 3-D22 3-D22 Web 4-D10 Top Stirrup 2-D10@200 Section B x D 500 x 500 Section Rebar 8-D22 Hoop 2,3-D10@100 B x D 300 x 600 2Fl. Joint 2,2-D10@140 Top 6-D22 3-D22 6-D22 1Fl. Bottom 3-D22 3-D22 3-D22 Bottom Web 4-D10 Section Stirrup 2-D10@200 B x D 500 x 500 500 x 500 Rebar 10-D22 10-D22 Hoop 3,4-D10@100 3,4-D10@100 Joint 2,2-D10@140 2,2-D10@140
Margin of joint shear capacity Joint shear / Nominal joint shear capacity
Column-to-beam strength ratio Column-to-beam strength ratios
JMA Kobe 50%
JMA Kobe 50%
JMA Kobe 100%
JMA Kobe 100%
3D Full Scale RC Frame Structure Shaking Table Test at E-Defense in 2010 • Four-story full scale RC frame structures were tested, - The building structure was designed and constructed such that it conforms to current seismic provisions in Japan and the US. • Shear failure of lightly reinforced beam-column joints were confirmed, - BC joints with column-to-beam strength ratio between 1.0 showed joint shear failure. - Vulnerabilities of frame structure with lightly BC joint has been demonstrated. 17
SEISMIC DAMAGE OF A NINE-STORY RC RESIDENTIAL BUILDING IN SENDAI DESIGNED BY OLD SEISMIC CODES
Nagamachi - Dwelling Complex
Brief History of RC buildings and Seismic Codes in Japan 8 1 8 1 5 1 0 6 7 7 8 9 1 0 9 9 9 9 9 0 0 1 1 1 1 1 2 2 1968 Tokachi-oki Earthquake *BSL : Building Standard Law Amendment of BSL Enforcement Order ( Prevention of column shear failure ) 1978 Miyagiken-oki Earthquake Amendment of BSL Enforcement Order ( The “shin-taishin”, new standard ) 1995 Hyogo-ken Nambu Earthquake ( Effectiveness of the 1981 revision was confirmed ) Act on Promotion of Seismic Retrofitting of Existing Buildings ( To urge building owners to retrofit existing vulnerable buildings ) Amendment of BSL Enforcement Order ( Performance based criteria introduced ) I II III ～ 1971 ～ 1981 1981 ～ 2011 Tohoku-chiho Taiheiyo-oki Earthqukae
Nagamachi - Dwelling Complex • RC/SRC 9 floors. • Completed in 1969 • No seismic retrofit • Survived major earthquakes in 1978, 2003 and 2005. • Fc 210 & 180 • Grade SD35 rebars
Taihaku ward, Sendai City JR Sendai Station Izumi ward Port of Sendai Aoba ward Miyagino ward Taihaku ward Wakabayashi Pacific Ocean ward Site of the building City of Sendai
1st floor plan and damage rate west Y 5 O O II III s II s O IV s III s II II s II s III II s II Y 4 O I s O O II III I I I s Medical Service II s I s Y 3 O I s I s II s I s II IV s O Entrance south north V s Y 2 O III O O I s I s III O O IV Municipal offices see Fig. 7 Y 1 V V I O IV II III I Y 0 V V III s III III s III s III s II s east X 0 X 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8
2nd floor plan and damage rate west I s Y 5 O O I O O O I I I Y 4 O I s O I O I O I s II II s I s V s II s II s Y 3 O O O O O II II I s I s Municipal offices south north Y 2 I s I s I I s O I I s O I I s I Y 1 O III III I O I III s I I I s Y 0 III O I I O O O I X 0 X 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 east
3rd floor plan and damage rate west RC non-structural partition I s Y 5 O O I O O O I I I Y 4 Y 4 IV s IV s O I s O I O I O I s II II s I s V s II s II s Y 3 Y 3 O O O O O II II I s I s Corridor I s I s I s I s I s I s I s south north Y 2 Y 2 I s I s I I s O I I s O I III s I s I Y 1 Y 1 O III III I O I III s I IV s IV s II s II s I I s Y 0 III X 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 O I I O O O I Apartment X 0 X 1 X 2 X 3 X 4 X 5 X 6 X 7 X 8 east units
Damage Grading Criteria of RC Members Damage grade Damage grade Criteria 0 No damage No damage I Slight Structural concrete cracking of width less than 0.2mm Structural concrete cracking of width larger than II Minor 0.2mm and less than 1.0mm. Structural concrete cracking of width larger than III Moderate 1.0mm and less than 2.0mm. Structural concrete cracking of width larger than IV Major 2.0mm, with cover concrete spalling and visible reinforcement Cover concrete spalling o ff , with some concrete V Severe crushes and longitudinal reinforcement buckling
Residual Lateral Capacity of RC Structural Member Remained Deteriorate d Lost Lateral Load Remained � � � � � Lost Vertical Load Damage Class Load Carrying Capacity Compression failure Yielding of of concrete starts tensile rebars Buckling of rebars and Cracking falling of covering concrete Deflection (a) Ductile member
Elevation of Y 4 frame in longitudinal direction PHRFL 36,150 Shear failure of columns shear crack on beam-column joint RFL 26,150 9FL 23,350 see Fig. 10 8FL 20,750 7FL 18,150 6FL 15,550 IV s 5FL 12,850 Latice steel IV s IV s IV s 4FL 10,150 IV s IV s 3FL 7,400 O O O I I s II I I s O 2FL 4,100 III I s I I II s II II O II s O I s O 1FL 500 GL 5 400 8 = 43 200 Unit in mm X 8 X 7 X 6 X 5 X 4 X 3 X 2 X 0 X 1
Failure of Beam-column Joints
Failure of Beam-column Joints
Elevation of X 1 frame in longitudinal direction steel shape in concrete III III III II s I s see Fig. 7 O III s I I s I s O shear cracks on coupling beams V III O II V O IV III 4 500 6 000 6 000 6 000 4 500 unit in mm Y 0 Y 1 Y 2 Y 3 Y 4 Y 5
Elevation of X 1 frame in longitudinal direction steel shape in concrete III flexural failure and III buckling of rebars at the III bottom of column II s I s see Fig. 7 O III s I I s I s O V III O II V O IV III 4 500 6 000 6 000 6 000 4 500 unit in mm Y 0 Y 1 Y 2 Y 3 Y 4 Y 5
Values of Seismic Index I s Longitudinal Transverse Story direction direction 9 0.37 1.49 8 0.27 1.04 7 0.23 0.82 no good correlation 6 0.20 0.70 5 0.21 0.62 4 0.19 0.51 3 0.20 0.71 2 0.44 0.44 good correlation 1 0.62 0.39 Seismic Evaluation Standards by JBDPA
Beam-column Joints in Y 4 frame 4-D22 4-D19 unit in mm 1250 1150 4-D22+6-D19 600 10-D19 hoop φ 9@250 450 hoop φ 9@250 220 3-D19 4-D22 220 750 750 220 220 600 450 horizontal section vertical section horizontal section vertical section of column of beam of column of beam (a) Beam-column joint at 7F (X 5 -Y 4 ) (b) Beam-column joint at 5F (X 5 -Y 4 )
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