8/12/2019 '13 IISEE
1/31
Seismic Design of Reinforced
Concrete Beam-Column Joints :
byHitoshi Shiohara, Ph. D, Fellow of ACI
Professor
Dept. of Architectural Engineering,
The University of Tokyo
1
Beam-column Joint & Collapse of RC Buildings
Turkey 2011
2
Turkey 2011
Turkey 2011 Turkey 2011
Beam-column Joint & Collapse of RC Buildings
Kobe 1995Kobe 1995
Turkey 1999
3
Turkey 1999
Beam-column Joint & Collapse of Structures
EarthquakeEnineerin esearchnstitute
:
- , ,
.
.
Close Ups of Joint Failure: 1989 Loma Prieta EarthquakeOct. 17
EarthquakeEn ineerin esearch nstitute
:
- .
:
- .
8/12/2019 '13 IISEE
2/31
Beam-column Joint Failure
Royal Palm Hotel Damage at masonry in-fill stair enclosure.: 1993 Guam Earthquake Aug. 8
k
. .
Beam-column Joint & Collapse of Buildings
6
The Pyne Gould Corp. building collapsed when the magnitude 6.3 earthquake struck Christchurch, New Zealand
in 2011. It was built in the 1960s, before the adoption of modern seismic standards for concrete buildings
Background and
Introduction
7
Research and Development : RC Beam-Column joint
1955 The first seismic tests of RC BC joints (Tsuboi and Tomii, Japan)
1965 The first proposal of joint shear strength for RC B-C joints (Endo, Japan)
1967 The first seismic tests of RC BC joints (Hanson et al., USA)
1971 Proposal of joint shear strength for RC BC joints (Koreishi, Japan)
1975 Proposal of joint shear strength for RC BC joints (Kamimura, Japan)
1976 ACI-ASCE352 proposed seismic provisions for BC joints
1976 Paulay (NZ) proposed BC joint mechanism of Strut action and Truss action
1981 Tests on RC BC joint (Meiheit, Jirsa et al. USA)
1982 NZS3101adopted seismic provisions for RC BC joints
1985 ACI318-85adopted seismic provisions for RC BC joints
1991AIJ Guidelinesfor Seismic Design of RC Buildings adopted seismic provisions for RC BC
joints
8
History of the development of beam-column joint seismic design :
8/12/2019 '13 IISEE
3/31
Joint Shear in Beam-column Joints
Vj= Ts + Cs + Cc Vc = Ts + Ts Vc = ats+ atsVc
Vc
Vj
Ts
Dc
T's
'Cc
C's
CcCs
Vc
Vj
Ts
Dc
CcCs
column column
beam
interior beam-column joint exterior beam-column joint
beam
9
Vj < Joint shear Capacity :Joint shear
Design Requirement prevent from joint shear failure
Joint shear
Joint shear Joint shear
BC joint mechanism of Strut action and Truss action
T
c
Vcol
Vcol
hc
hc
Vb
Vb
Cc
Cs
Cc
Cs
T
hb
Paulay (1976 ) Joint shear is resisted by strut action and truss action
Strut action Truss action
Model of statics : only equilibrium is considered
Column-to-Beam Strength Ratio
M
1
M
3
M
4
M
2
M
1
M
2
M
3
Interior
Column
Column
Beam
Beam
Exterior
Column
Beam
11
Column-to-beam strength ratio > 1.0 : Beam-hinge Mechanism
Column-to-beam strength ratio < 1.0 : Column-hinge Mechanism
Column-to-beam strength ratio Column-to-beam strength ratio
Introduction
Current seismic codes protect RC beam-column (BC) joints by
requiring that;
- Joint shear not exceeding joint shear capacity
- where, the design equation for the joint shear capacity are empirical.
But this requirement may have overlooked significant deficiency in
BC joint because;
- The experimental assessments of joint shear capacity have been over-
emphasized, thus tests were focused only to joints with excessive reinforcement
in both beam and column,
- Test dataset are biased in column-to-beam strength ratio
- Obvious lack of tests on BC joints particularly with low column-to-beam strength
ratio (1.0 - 1.5), which is obvious choice of structural engineer to optimize for
stress by seismic load and week beam mechanism,
12
8/12/2019 '13 IISEE
4/31
0
10
20
30
40
50
60
NumberofSpecimens
1.0- 2.0- 3.0- 4.0-
Column-to-Beam Strength Ratio
Interior
Failure ModeBeam (or Column) 92
Beam and Joint 162
Joint 71
Exhaustive list of interior B-C joint specimens
13
0
10
20
30
40
50
60
NumberofSpecimens
1.0- 2.0- 3.0- 4.0-
Column-to-Beam Strength Ratio
Failure ModeBeam (or Column) 92
Beam and Joint 162
Joint 71
standard rangein practice
unrealistic
speicmens
14
Interior
0
10
20
30
40
50
60
NumberofSpecimens
1.0- 2.0- 3.0- 4.0
Top Related