bond requirements of straight beam bars passing through ... · 美國混凝土學會(aci) 352...
TRANSCRIPT
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高強度鋼筋混凝土之梁柱接頭設計
李宏仁
高強度鋼筋混凝土(New RC)結構設計與施工技術研討會2016.12.09
國立雲林科技大學營建工程系 副教授營建材料暨技術服務中心主任(TAF認證實驗室主管)
美國混凝土學會(ACI) 352 梁柱接頭委員會 委員
ACI-ASCE Committee 352, "Recommendations for Design of Beam-Column Connections in Monolithic Reinforced Concrete Structures (ACI 352R-02)," American Concrete Institute, Farmington Hills, MI, 2002, pp. 38.
Key reference
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500,000
1,000,000
1,500,000
2,000,000
2,500,000
3,000,000
3,500,000
4,000,000
4,500,000
5,000,000
-
50
100
150
200
250
Usage License by Story, Above 21 story buildings and floor area
Buildings Total floor areas (m²)
2016
(Buildings)(m2)
1995 2005
2
資料來源:內政部統計處核發建築物使用執照按層數別分21層以上棟數及總樓地板面積註:2016年至9月底止227棟今年是歷史新高點….
Background
TaipeiTokyo
集中在新北市、台北市、台中市及高雄市等都會
-
3
New RC 預鑄工法
參考日本都市更新經驗
The Tokyo Towers, 2008年完工時為日本最高(58F, 192m)之New RC住宅
(都市再生開發案)
-
Emulative Precast Beam-Column
Connections
Cast-in-place concrete
Column unit
Grouted coupling sleeve
Beam unit
Grout
Column unit Roughened surface
Beam unit
• 現場只澆置接合部及樓板混凝土• 快速、高品質• “Emulation” of monolithic concrete structures
(亞利預鑄)
-
Advantages
20層樓案例比較
-
ACI 318
Joint Design Problems
1000x1000-mm Column
600-mm beam width (TYP.)
𝑉𝑛 = 𝛾 𝑓𝑐′𝐴𝑗
𝛾 =? 𝛾 =? 𝐴𝑗 =?
(40x48-in.)
(24-in.)
Plan view of connection
-
• Development Length
• Anchorage Length
• Confinement
• Joint Shear Strength
• Mechanical Splices…
Challenge for Connection Design
using SD690 reinforcing steel bars
-
Development length requirement at
interior joint
ACI 318-1420
b
c
d
h
MPa420 20
y
b
cf
d
h ACI 352-02
Zhu and Jirsa (1983) evaluated the
test results of 18 interior beam–
column joints and concluded that a
minimum column depth of 20 to
22𝑑𝑏 is appropriate to avoid bondfailure at an interstory drift of 3%
for Grade 420 bars and a concrete
strength of 28 to 35 MPa.
Code background
-
Laboratory Specimen under Cyclic Deformation Loading
Axial Load
6 m
3.2 m +─ +
─
P
Lateral Load Q
-
Laboratory testing
-
“J” failure versus “B” failure
32/600/
729/103/
30.1/,
bc
yac
nmjh
dh
ff
VV
61/450/
508/61/
95.0/,
bc
yac
nmjh
dh
ff
VV
04.0/ cg fAP 00.0/ cg fAP
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“BJ” failure versus “BJa” failure
25/005/
470/56/
08.1/,
bc
yac
nmjh
dh
ff
VV
19/004/
347/31/
78.0/,
bc
yac
nmjh
dh
ff
VV
06.0/ cg fAP 10.0/ cg fAP
-
13
Video of Specimen EW0 beyond 2% drift
19/004/
347/31/
78.0/,
bc
yac
nmjh
dh
ff
VV
-
Bond failure along beam bars in beam-column joint (BJa failures)
14
G.L
Plastic
Hinge
ch
Bond stress
ch
bd
Pinching effect
Strength and stiffness degradation,
poor hysteresis behavior
Low residual stiffness at small displacement
Unlikely to repair
-
T1= As,topao fy
T2= As,botao fy
QCc2
Cc1
Cs2= As,topk2ao fy
Cs1= As,botk1ao fy
hcColumn depth
db
Average bond focres
Beam bar diameter
with flange in
compression
Typical As,top As,bot
and then k1 k2
(c)Q
1
221joint
b
ccb
sc
L
L
jd
hLQ
QCCTV
ka
a 14
2
yob
bpcb fd
uhd
bp
yos
bp
yo
b
c
u
fα
u
fα
d
h
a
a
a
k
44
1
Horizontal shear and bond forces acting on the joint concrete
jcjo AfV int
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Comparison of the Overstrength Factors for International Design Criteria
Design codes and standards
Grade Yield strength, min (MPa)
Yield strength, max (MPa)
𝛼𝑜 factor
ACI 318 (2014)(ASTM A706-15)
420550
420550
540675
1.25
AIJ Guideline (1999)(Nishiyama 2009)
390490
590A590B685A685B
390490590590685685
510625675650785755
1.311.281.141.101.141.10
Eurocode 8 (2004) All - - 1.20NS 3101 (2006)(AS/NZS 4671:2001)
300E500E
300500
380600
1.25
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Factor 𝜶𝒔 accounting for the bar stress level developed in the joint
-
bp
yos
b
c
u
fα
d
h
a
a
4
Available bond strength
-
Relative column dimension required by different codes and recommendations (1/2)
-
Relative column dimension required by different codes and recommendations (2/2)
-
Min. Col. Dimensions required by
different codes and recommendations
𝑓𝑐′(MPa) 35 35 35 70 70 70
Design Criteria 𝑓𝑦(MPa) 420 550 690 420 550 690
AIJ Guideline (1999) 29 37 44 18 23 28
Eurocode 8 (2004) 33 42 50 21 26 31
NZS 3101 (2006) 25 32 38 18 23 27
Brooke & Ingham (2013) 26 33 40 18 23 29
Li & Leong (2014) 28 35 43 20 25 31
Proposed Eq. 22 28 34 15 19 24
Kelly et al. (2014) 19 28 37 14 19 26
ACI 352R-02 20 26 33 20 26 33
Note: Reference beam-column joint with a column axial load of
0.2A𝑔𝑓𝑐′; bottom-to-top reinforcement ratio of 0.75; equal diameters for
top and bottom bars.
-
Comparison
• Recommended
cp
yos
b
c
f
fα
d
h
6a
aand 20
Kelly et al. (2014)c
y
b
c
f
f
d
h
3.1)(
4.22
1and 20
(SI unit)
Kelly, D.; Lepage, A.; Mar, D.; Restrepo, J.; Sanders, J.; and Taylor, A., "Use of
High-Strength Reinforcement for Earthquake-Resistant Concrete Structures,"
Tenth US National Conference on Earthquake Engineering, Anchorage, Alaska,
2014.
Lee, H.-J., Chen, H.-C., Tsai, T.-C., (2016), “Minimum column depth for
acceptable bond performance of straight beam bars in beam-column joints,” The
18th Japan-Korea-Taiwan Joint Seminar on Earthquake Engineering for Building
Structures (SEEBUS 2016), Tainan, Taiwan, December 2-3, 2016.
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RC
New RC
Database construction
JP75%
US12%
TW7%
NZ5%
KO1%
• 357 test data published in Japan, US, NZ, and Taiwan
• Unified database for normal-strength and high-strength RC
• Beam-column joints without trans. beams/slabs, eccentricity
Column bar versusyf cf
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Relations between failure modes, displacement
ductility, and the experimental-to-nominal shear
strength ratio for the 202 interior joints assembled
by Lee and Hwang (2013)
𝑉𝑗ℎ,𝑚𝑉𝑛
Displacement ductility ratio
-
Selected 59+6 = 65 interior joints
• Bar 𝑓𝑦 not less than 400 MPa
• A minimum of two cycles at the limiting drift ratio
• BJ or BJa failure
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Evaluation of the hysteretic behavior at
the limiting drift cycle(>3.5% 2nd or 3rd)
1
19.0PPD EE
10.0)(4
1
s
Deq
E
E
DE
PPE
%33
%36
iKoK
01.0io KK
sE
StrengthStiffnessEnergy dissipation
𝑄 ≥ 0.75𝑄𝑚
𝐾𝑜 ≥ 0.05𝐾𝑖
Τ𝐸𝐷 𝐸𝑃𝑃 ≥ 0.125
ACI 374.1-05
𝜉𝑒𝑞 ≥ 0.125
-
Energy dissipation Index
Provided-to-required development length ratio
cp
yos
b
c
f
f
d
h
6a
aa
cp
yos
b
c
f
f
d
h
6a
aa
𝐸𝐷𝐸𝑃𝑃
𝜉𝑒𝑞
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Strength and stiffness degradation
Provided-to-required development length ratio
cp
yos
b
c
f
f
d
h
6a
aa
cp
yos
b
c
f
f
d
h
6a
aa
mQ
Q
i
o
K
K
-
Performance Evaluation
n
mjh
V
V ,
cp
yos
b
c
f
f
d
h
6a
aaProvided-to-required
development length ratio
-
Final Recommendations
20 and 6
oflarger thecp
yos
b
c
f
fα
d
h
a
a
os
tops
o
sA
A
aaa
11
7.01
,
where
20.10.29.0
cg
PfA
Pa
Brooke and
Ingham (2013)
NZS 3101 (2006)
Omitting tfaa
-
cp
yos
f
f
5a
aa
cp
yos
b
c
f
f
d
h
6a
aa
20 ,
6max
cp
yos
b
c
f
f
d
h
a
aa
n
mjh
V
V ,
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設計手冊𝑓𝑐′ SD420 SD550 SD690
𝑘𝑔𝑓
𝑐𝑚2𝑀𝑃𝑎 α𝑠 =1.80 α𝑠 = 1.56 α𝑠 =1.83 α𝑠 = 1.58 α𝑠 = 1.87 α𝑠 = 1.61
280 28 25 21 32 27 39 34350 35 22 20 28 25 35 30420 42 20 20 26 22 32 27490 49 20 20 24 21 29 25560 56 20 20 22 20 28 24630 63 20 20 21 20 26 22700 70 20 20 20 20 25 21770 77 20 20 20 20 23 20840 84 20 20 20 20 22 20900 90 20 20 20 20 22 20
1000 100 20 20 20 20 21 20
註:本表適用於內柱軸力大於0.15𝐴𝑔𝑓𝑐′。
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Seismic Testing for Interior Beam-
Column Joints500x600-mm Beam6-D32 top and bot.
600x600-mm Col. 16-D32
USD685 bars
-
21 6
cp
yos
b
c
f
fα
d
h
a
a
Test results
𝑓𝑐′ = 100(132) 𝑀𝑃𝑎
𝑓𝑦 = 685(697) 𝑀𝑃𝑎
Design equation
𝑃 = 0.05𝐴𝑔𝑓𝑐′
𝛼𝑜 = 1.15
19 mm 32
mm 600
b
c
d
h
Provided0.88
,
n
mjh
V
V
4%-drift PerformanceRating = 3 Acceptable
-
• Development Length
• Anchorage Length
• Confinement
• Joint Shear Strength
• Mechanical Splices…
Challenge for Connection Design
using SD690 reinforcing steel bars
-
Anchorage Length for Headed Bars
ℓ𝑑𝑡 ≥ 0.192𝑓𝑦𝑑𝑏
𝑓𝑐′
ACI 318-14, 8𝑑𝑏 , 150 𝑚𝑚 (MPa unit)
ℓ𝑑𝑡 ≥ 0.06𝑓𝑦𝑑𝑏
𝑓𝑐′
(kgf/cm2 unit) ℓ𝑑𝑡 ≥ 0.016𝑓𝑦𝑑𝑏
𝑓𝑐′
(psi unit)
(a)value of 𝑓𝑐′ ≤ 6000 psi (42 MPa);
(b)bar specified 𝑓𝑦 ≤ 60 ksi (420 MPa);
(c)bar size ≤ No. 11 (D36);
(d)net bearing area of head 𝐴𝑏𝑟𝑔 ≥ 4𝐴𝑏;
(e)normal-weight concrete;
(f) minimum clear cover of 2𝑑𝑏
(g)minimum clear spacing of 3𝑑𝑏 between bars.
Conditions
-
Exterior Beam-column Joints
under Cyclic Loading
-
Specimen Design and Details𝑓𝑐′ = 70 𝑀𝑃𝑎𝑓𝑦 = 734 𝑀𝑃𝑎 (𝑆𝐷690) 𝑓𝑦𝑡 = 843 𝑀𝑃𝑎 (𝑆𝐷790)
Varying shear demands and Ash,ratio
ℓ𝑎ℓ𝑑𝑡
≈ 1.0
2𝑑𝑏 𝑐𝑙𝑒𝑎𝑟 𝑠𝑝𝑎𝑐𝑖𝑛𝑔
-
Global and Local Response @ 4% drift
𝑉𝑒𝑥𝑝
𝑉𝑛,𝐴𝐶𝐼= 0.85
𝐴𝑠ℎ𝐴𝑠ℎ,𝐴𝐶𝐼
= 1.00 (1.20)
𝑤𝑖𝑡ℎ 𝑓𝑦𝑡 = 690 (843)𝑀𝑃𝑎
Beam Yielding
-
Global and Local Response @ 6% drift
𝑉𝑒𝑥𝑝
𝑉𝑛,𝐴𝐶𝐼= 0.85
𝐴𝑠ℎ𝐴𝑠ℎ,𝐴𝐶𝐼
= 1.00 (1.20)
𝑤𝑖𝑡ℎ 𝑓𝑦𝑡 = 690 (843)𝑀𝑃𝑎
Followed by Joint Shear Failure
-
𝑉𝑒𝑥𝑝
𝑉𝑛,𝐴𝐶𝐼= 0.85
BJ failure
J failure
𝑉𝑒𝑥𝑝
𝑉𝑛,𝐴𝐶𝐼= 1.29
ℓ𝑎ℓ𝑑𝑡
≈ 1.0
2𝑑𝑏 𝑐𝑙𝑒𝑎𝑟 𝑠𝑝𝑎𝑐𝑖𝑛𝑔
2𝑑𝑏 𝑐𝑙𝑒𝑎𝑟 𝑠𝑝𝑎𝑐𝑖𝑛𝑔
-
𝑉𝑒𝑥𝑝
𝑉𝑛,𝐴𝐶𝐼= 0.68
ℓ𝑎ℓ𝑑𝑡
= 1.6
B failure
2𝑑𝑏 𝑐𝑙𝑒𝑎𝑟 𝑠𝑝𝑎𝑐𝑖𝑛𝑔
𝑓𝑐′ = 119 𝑀𝑃𝑎
𝑓𝑦 = 744 𝑀𝑃𝑎
-
𝑉𝑒𝑥𝑝
𝑉𝑛,𝐴𝐶𝐼= 0.63 BJa failure
ℓ𝑎ℓ𝑑𝑡
= 0.63
𝑓𝑐′ = 44.4 𝑀𝑃𝑎
𝑓𝑦 = 707 𝑀𝑃𝑎 (𝑆𝐷685)
Anchorage Failure!
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Locations of the heads (or hooks)(ACI 352R-02, 4.5.3.2)
-
• Development Length
• Anchorage Length
• Confinement
• Joint Shear Strength
• Mechanical Splices…
Challenge for Connection Design
using SD690 reinforcing steel bars
-
設計公式修訂建議(黃世建等人)
• 橫箍柱 (ACI 318-14)
47
MPaf yt 800≤其中
cg fAP ′3.0>當
或 MPafc 70>′
0 09
max 0 3 1
0.2
c
yt
gsh c
c yt ch
gcf n p
yt ch
f.
f
AA f.
sb f A
Afk k k
f A
放寬使用90°-180°彎鉤並交錯配置,但須提高圍束箍筋量
Required
-
ACI 352R-02 Design Example
-
• 韌性抗彎構架接頭區亦須負責傳遞柱軸力,故需要配置柱箍筋圍束柱核心混凝土。
• 細則比照柱端部(耐震彎鉤、間隔、換端)
• 除非梁構材貫穿接頭且梁寬最少為柱寬度之3/4,視為具有圍束作用時,則在該梁構材構入範圍內,平行該梁構材方向可配置較少之繫筋,每組橫向鋼筋之總斷面積得為柱規定值之半 (Ash,ratio > 0.50)
• 箍筋間距仍不得超過 6𝑑𝑏及15 cm。
接頭箍筋
-
Effect of Ash,ratio on
Joint StrengthJ failure
BJ failure
C3
C5
-
Joint Shear Strength Degradation
Degradation of joint
shear capacity
B-type
BJ-type
Joint shear demand
(proportional to beam flexure capacity)
Jo
int
sh
ea
r fo
rce
Deformation or Drift
2
3
1J-type
Diagonal strut
mechanism
3
Bond deterioration
Concrete softening
2Truss mechanism
1cc
Yield
penertration
Low Ash,ratio
Degradation ofjoint shear capacity
Deformation or Drift
Jo
int
sh
ea
r c
ap
ac
ity
High
Ash,ratio
Yield
penertration
-
Effect of Ash,ratio on
Drift Capacity
B3
B5
-
• Development Length
• Anchorage Length
• Confinement
• Joint Shear Strength
• Mechanical Splices…
Challenge for Connection Design
using SD690 reinforcing steel bars
-
ACI Code 接頭剪力設計
un VV
接頭標稱剪力強度𝑉𝑛 = 𝛾 𝑓𝑐′𝐴𝑗
接頭配置 𝑉𝑛 for 𝑓𝑐′
in psi
𝑉𝑛 for 𝑓𝑐′ in
MPa
𝑉𝑛 for 𝑓𝑐′ in
Τ𝑘𝑔𝑓 𝑐𝑚2
接頭四面皆受梁圍束
20 𝑓𝑐′𝐴𝑗 1.67 𝑓𝑐
′𝐴𝑗 5.3 𝑓𝑐′𝐴𝑗
接頭三面或一雙對面受梁圍束
15 𝑓𝑐′𝐴𝑗 1.25 𝑓𝑐
′𝐴𝑗 4.0 𝑓𝑐′𝐴𝑗
其他 12 𝑓𝑐′𝐴𝑗 1.00 𝑓𝑐
′𝐴𝑗 3.2 𝑓𝑐′𝐴𝑗
(b) 接頭三面或兩對面有梁束制(a) 接頭四面有梁束制 (c) 其他束制條件者
(b) 接頭三面或兩對面有梁束制(a) 接頭四面有梁束制 (c) 其他束制條件者
(b) 接頭三面或兩對面有梁束制(a) 接頭四面有梁束制 (c) 其他束制條件者
𝑉𝑛 = 0.083𝛾 𝑓𝑐′𝐴𝑗
𝑉𝑛 = 0.265𝛾 𝑓𝑐′𝐴𝑗
xbhbbj 2
b
x
x
h
bj
Joint effective area
(psi)
(MPa)
(kgf/cm2) ACI 318
-
Case study, bj and -value per ACI 318
• Beam width bb= 24 in.• Increasing square column section from 24x24 in. to 48x48 in.
Plan view of connectionBeyond 𝑏𝑐xℎ𝑐 = 32x32,𝑏𝑏
𝑏𝑗< 0.75,both 𝛾 values drop to 12
Trans. beam
Trans. beam
bb=24"24"x24"Column
48"x48"
32"x32"
Loading beam
Loading beam
bb=24"
24"x24"Column
48"x48"
32"x32"
Loading beam
Loading beam
-
Frame subjected to Lateral Loading
Interior joint Exterior joint
Tee joint Knee joint
Interior joint
Exterior joint
-
Code Change Proposal
接頭標稱剪力強度𝑉𝑛 = 𝛾 𝑓𝑐′𝐴𝑗
𝑉𝑛 = 0.083𝛾 𝑓𝑐′𝐴𝑗
𝑉𝑛 = 0.265𝛾 𝑓𝑐′𝐴𝑗
(psi)
(MPa)
(kgf/cm2)
柱連續性 梁連續性 橫向梁圍束 示意圖 𝛾值
連續
連續
兩側皆有 20
任一側無 15
不連續
兩側皆有 15
任一側無 12
垂直剪力方向構入接頭兩側面之橫向梁覆蓋接頭面寬度寬度達3/4以上,則該接頭視為具有橫向梁圍束作用
-
Case study, proposed -value
• Beam width bb= 24 in.• Increasing square column section from 24x24 in. to 48x48 in.
𝑏𝑏,𝑡𝑟
ℎ𝑐< 0.75,𝛾 value drop down one category Plan view of connection
Trans. beam
Trans. beam
bb=24"24"x24"Column
48"x48"
32"x32"
Loading beam
Loading beam
bb=24"
24"x24"Column
48"x48"
32"x32"
Loading beam
Loading beam
-
b
x2
x1
hj=hcol
bj
Joint effective area
jjj hbA
(a)梁主筋貫穿梁柱接頭, hj=hcol (b)梁主筋錨定於接頭內, hj=ldt
b
x2
x1
hj=ldt
bj
Joint effective area
𝑏𝑗 = 𝑏 + 𝑥1 + 𝑥2 ≤ 𝑏𝑐𝑜𝑙
其中𝑥1及𝑥2分別為梁兩邊至柱邊之距離(圖6.3),代入上式計算時,𝑥1或𝑥2值不得超過 Τℎ𝑐𝑜𝑙 4。[黃世建等人(2014)]
Effective Joint Area
除非梁主筋之錨定長度皆超過3/4柱深度以上,接頭有效深度ℎ𝑗得為柱深度ℎ𝑐𝑜𝑙
(設計手冊)
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第六章 梁柱接頭相關規定
本章建議鋼筋混凝土梁柱構架接頭設計及細部配置之相關規定,係以符合韌性抗彎構架接頭之強度及韌性要求來撰寫。除非另有規定,本章之相關規定僅適用於梁柱接頭• 常重混凝土𝑓𝑐
′ ≤100 MPa (1000 kgf/cm2)• 縱向鋼筋 𝑓𝑦 ≤690 MPa (7000 kgf/cm
2 )
• 橫向鋼筋 𝑓𝑦𝑡 ≤790 MPa (8000 kgf/cm2 )
6.1 剪力強度
6.2 接頭箍筋
6.3 接頭鋼筋伸展及錨定
𝑉𝑛 = 𝛾 𝑓𝑐′𝐴𝑗
𝐴𝑠ℎ
20) and 6
max( cp
yos
b
c
f
fα
d
h
a
a
(SI unit)ℓ𝑑𝑡 ≥ 0.192𝑓𝑦𝑑𝑏
𝑓𝑐′
𝑀𝑖𝑛𝑖𝑚𝑢𝑚 2𝑑𝑏 𝑐𝑙𝑒𝑎𝑟 𝑠𝑝𝑎𝑐𝑖𝑛𝑔
(SI unit)
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References
李宏仁、張又仁、張家榮、黃世建,(2014) 「高強度鋼筋混凝土梁柱接頭剪力強度測試」,國家地震工程研究中心報告,NCREE-14-008。
李宏仁、徐富威、陳盈璋、黃世建(2016),高強度鋼筋混凝土五螺箍柱及預鑄梁柱接頭耐震性能測試,國家地震工程研究中心報告, NCREE-16-002。
李宏仁、柳文皓、陳惠雅、黃世建(2016),具橫向梁及版之RC梁柱接頭耐震性能研究及資料庫建構,國家地震工程研究中心報告, NCREE-16-010。
李宏仁、黃柏嘉、黃世建(2016),具橫向梁及版之新高強度鋼筋混凝土外部接頭耐震性能測試,國家地震工程研究中心報告, NCREE-16-012。
• Brooke, N. J.; and Ingham, J. M., "Seismic Design Criteria for Reinforcement Anchorages at
Interior RC Beam-Column Joints," Journal of Structural Engineering, V. 139, No. 11. 2013,
pp. 1895-1905.
• Kang, T. H. K.; Shin, M.; Mitra, N.; and Bonacci, J. F., "Seismic Design of Reinforced
Concrete Beam-Column Joints with Headed Bars," ACI Structural Journal, V. 106, No. 6,
Nov-Dec. 2009, pp. 868-877.
• Lee, H.-J.; and Hwang, S.-J., "High-strength concrete and reinforcing steel in beam-column
connections," Structures Congress 2013, Pittsburgh, PA, 2013, pp. 1606-1615.
• Watanabe, K.; Kiyohara, T.; Tasai, A.; and Hasegawa, Y., "Deformation Capacity of High
Strength RC Exterior Beam Column Joint with Beam Main Bars Anchored Mechanically,"
Proceedings of the Japan Concrete Institute, V. 26, No. 2. 2004, pp. 481-486.
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李宏仁等人 (NCREE-16-002)62
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ACE JOINT
續接器
Be a m unit Be a m unit
Column unit
Groute d Coupling S le e ve
Ca s t-in-pla ce concre teGrout
Lb = 6 m
Lc = 3.2 m
TOPS JOINT
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預鑄柱頭續接
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20 ~ 22
17 ~ 19
17 20
18 21
19 22
S
N
W E W E
柱續接鋼筋之應變
• 接頭上下端柱筋皆可達到降伏• 上柱續接器端無明顯損壞
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S
S
W E S N
E
E 23 ~ 28
23 24 25 26 27 28
梁續接鋼筋之應變
• 梁柱交接面鋼筋可達降伏強度• 接頭區應變梯度明顯• 能充分續接鋼筋貫穿接頭區
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67BOLTOPS 在預鑄梁之應用
預鑄柱 + 預鑄梁下半部及接頭 BOLTOPS套管續接避開梁塑鉸區