Seismic Retrofit of Ductile Concrete Moment Frames with Innovative Pin-Supported Walls Hiroyasu Sakata Zhe Qu Saburoh Midorikawa Akira Wada Tokyo Institute of Technology 14th U.S.-Japan Workshop on the Improvement of Structural Design and Construction Practices
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Seismic Retrofit of Ductile Concrete Moment Frames with ... Retrofit of Ductile Concrete Moment Frames with Innovative Pin-Supported Walls ... RC frame after 2008 Wenchuan EQ Shearwall
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Seismic Retrofit of Ductile Concrete Moment Frames with Innovative Pin-Supported Walls
Hiroyasu SakataZhe QuSaburoh MidorikawaAkira Wada
Tokyo Institute of Technology
14th U.S.-Japan Workshop on the Improvement of Structural Design and Construction Practices
Kobe city hall after 1995 Kobe EQ
RC frame after 2008 Wenchuan EQShearwall damage in 2010 Chili EQ
(EERI, 2010)
Moment Frame Shearwall
Pin-Supported Wall-Frame System
Background
Pin-Supported Walls
Weak story(Soft story) Strengthening Coordinator
Hinge
FEQ,i
V
V
FEQ,j
Vj
Vi
EQ,j j
EQ,i i
Mw
Pin-Supported Walls
Post-tensioned wall (1~11F)
Bottom hinge
Steel damper (2~9F)
Connector (1~11F)
SRC frame
Transverse shearwall (1~9F)xz
y
After– 2010.3
During – 2009.12
Before– 2008.10
G3 Building in Tokyo Tech
Existing columnRocking wall
Existing beams
Horizontal truss
Shear key
2004501180
4300
Post-tensioned tendon 30- 12.7 (SWPR7B)
Steel rib-22
Steel web-12CL
Lateral rebar 13@200
Longi. rebar D29
Pcon= 0.68Py
cp ≈ 7 MPa
Post-Tensioned Wall and Connector
Steel Damper
xz
1170 kN
585 kN
779 kN
Weight: 2500 kN
∑ dy
wall7.5
∑ dy
wall4.6
Window
SRC
Col
umn
PT W
all
Damper
Stiffener
Rocking wallExisting column
Anchor bolt
Stud
Web
Rib
H
L
Web: PL-6, SLY225Flange: PL-19, SN400BRib: PL-6, SS400 at 250mm spacing
Web height H = 312mmTotal length L = 750~1500mm
Steel Damper
SRC Column PT Wall
Steel Damper
Plan ViewTwo sets of fasteners to make dampers replaceable
Bottom Hinge
0
2
4
6
8
10
12
0 0.005 0.01 0.015 0.02
IDR
Stor
y
Median84th percentile
0
2
4
6
8
10
12
0 0.005 0.01 0.015 0.02IDR
Stor
y
Median84th percentile
(a) (b)
Before After
Story drift ratio Story drift ratio
Numerical Evaluation
• Nonlinear Time History Analysis• Fiber-sectioned beam elements in ABAQUS• 22 Ground Motions (scaled to PGV = 50 cm/s)
Numerical Evaluation
Pre-TensionedCracking
OrdinaryCracking
Nominal shearstrength of
bottom hinge
Moment (kNm) Shear force (kN)
Longi (x) Trans (y)
X PGA: 67.3 cm/s2 and PGV: 14.4 cm/sY PGA: 52.8 cm/s2 and PGV: 12.7 cm/s
Diagonal cracks on transverse shear walls during 2011 Tohoku EQ
Diagonal ruston steel damper
Protective coating peeled off at bottom hinge
Thanks for your attentions!
14th U.S.-Japan Workshop on the Improvement of Structural Design and Construction Practices