Scott Munter Scott Munter –– Steel Reinforcement Institute ...
Transcript of Scott Munter Scott Munter –– Steel Reinforcement Institute ...
Scott Munter Scott Munter –– Steel Reinforcement Institute of AustraliaSteel Reinforcement Institute of AustraliaMarkMark PatrickPatrick –– MP EngineersMP EngineersMark Mark Patrick Patrick –– MP EngineersMP Engineers
Vijay Rangan Vijay Rangan –– Curtin University of TechnologyCurtin University of Technology
New Design Rules in AS 3600 2009Overview
New Design Rules in AS 3600–2009 Straight D500N bars Tensile development lengths Tensile lap lengthsp g
Recent Australian Bond Test Series University of New South Wales University of Queensland Curtin University of Technology (SRIA)
A t li B d T t R lt Australian Bond Test Results
New Design Rules in AS 3600–2009 D500N Bars to AS/NZS 4671
Stress
Tensile Strength fu(Onset of Necking)Tensile-to-yield-stress
ratio fu /fsyStress u sy
Yieldstress
Uniformstrain
stress fsy Fracture
u
Strain
New Design Rules in AS 3600–2009 D500N Bars to AS/NZS 4671
Property D500N
D500N Bars to AS/NZS 4671
Nominal diameter (mm) 10 to 40
Characteristic yield stress (MPa)Characteristic yield stress (MPa)
lower 500
upper 650
Tensile-to-yield-stress ratio min 1 08Tensile-to-yield-stress ratio, min. 1.08
Uniform strain (%) , min. 5.0 DUCTILITY
PARAMETERS
Estimate upper characteristic tensile strength = 1.15x650 = 750 MPa = 1.5fsy
Basic Tensile Development Length:New Design Rules in AS 3600–2009
1 d b b sy b50 1.0 0.15( /29
k c d d f dL k d
Basic Tensile Development Length:
c2
sy.tb 1 b
b c
29(132 )
L k dd f
acd = min. (c1, c2, a/2)
and db cd 3db c1
R fi d T il D l t L thRefined Tensile Development Length:
3 sy.t tr tr.min s p sy.tb sy.tb[1.0 ( ) / ] [1.0 0.04 ] (0.7/ )L K A A A L k L3 sy.t tr tr.min s p sy.tb sy.tb
Transverse reinforcement Transverse pressureterm, k4 term, k5
Basic Tensile Lap Length:New Design Rules in AS 3600–2009
1 d b b sy b50 1.0 0.15( /29
k c d d f dL k k d
Basic Tensile Lap Length:
a c2
7
sy.tb.lap 1 b
b c
29(132 )
L k k dd f
cd = min. (c1, c2, a/2)and db cd 3db c1
R fi d T il L L thRefined Tensile Lap Length: sy.t.lap tr tr.min s p sy.tb.lap 3 sy.tb.lap 1 b[1.0 ( ) / ] [1.0 0.04 ] max.[(0.7/ ) ,29 ]L K A A A L k L k d sy.t.lap tr tr.min s p sy.tb.lap 3 sy.tb.lap 1 b
Transverse reinforcement Transverse pressureterm, k4 term, k5
New Design Rules in AS 3600–2009
What minimum tensile stress should anchored or spliced bars be capable ofanchored or spliced bars be capable of
reaching before failure occurs?
In design it is assumed that the nominalIn design, it is assumed that the nominal yield stress, fsy=500 MPa, will be reached b f th h li f ilbefore the anchorage or splice fails…....
but what about in the real structure?
New Design Rules in AS 3600–2009
Clause 13.2.6 Welded or mechanical splices
“Welded or mechanical splices formed between Class N reinforcing bars shouldbetween Class N reinforcing bars should
not fail prematurely in tension or compression before the reinforcing barscompression before the reinforcing bars, unless it can be shown that the strength
d d tilit f th t b tand ductility of the concrete member meet the design requirements.”
New Design Rules in AS 3600–2009
A f f li d b t th Any form of splice can reduce bar strength
New Design Rules in AS 3600–2009700
600
700
Diameter f u uMPa %
400
500
Pa)
Diameter f u u
Control 664 10.015.1 620 4.514 8 607 3 5
MPa %
300
400
Stre
ss (M
P 14.8 607 3.514.5 590 2.013.9 550 0.8
200
S 13.9mm notch diameter14.5mm notch diameter14.8mm notch diameter15.1mm notch diameter
0
100
0 2 4 6 8 10 12 14
Control Bar – N16
0 2 4 6 8 10 12 14
Strain (%)
700Design principles
600
400
500
MPa
) ACI 318 – 08 Non-seismic1.25 x 500 = 625 MPa
300
Stre
ss (M 1.25 x 500 625 MPa
100
200
0
100
0 1 2 3 4 50 1 2 3 4 5
Strain (%)
Recent Australian Bond Test Series
U i it f N S th W l University of New South Wales
• 10 conventional slabs in flexure
• Small diameter, widely-spaced D500N12 or N16 barsD500N12 or N16 bars representative of slabs or walls (min. clear distance 157 mm)
• No staggering
• No transverse reinforcement
• Short lap length (max. approx. 18db) for bond failure
Recent Australian Bond Test Series
U i it f Q l d University of Queensland
U ti l ll t t t• Unconventional pull-out tests,
without flexure to cause bar
prying, etc.
• Small diameter D500N16 bars• Small diameter, D500N16 bars
representative of slabs or walls
• Contact lap splices
• No staggering• No staggering
• Transverse bars present in 3 of
these tests, but presence should
be ignored in design since onbe ignored in design since on
wrong side of main bars
Recent Australian Bond Test Series
C ti U i it f T h l SRIA t t Curtin University of Technology – SRIA tests
200TYPICAL
138TYPICAL
300
62
N24
900
4 N24 contact lap spliceswithout transverse reinforcement
Recent Australian Bond Test Series
C ti U i it f T h l SRIA t t Curtin University of Technology – SRIA tests
4500
125TYPICAL 1375
900
300
1500
Test lap length =900 mm, while AS 3600–2009 design L 930 if i l f' d k 1 0Lsy.tb.lap = 930 mm if use nominal f'c and k7=1.0
Recent Australian Bond Test Series
C ti U i it f T h l SRIA t t Curtin University of Technology – SRIA tests
Recent Australian Bond Test Series
C ti U i it f T h l SRIA t t Curtin University of Technology – SRIA tests
Face splitting & Edge side splittingFace splitting & Edge side splitting
Recent Australian Bond Test Series
C ti U i it f T h l SRIA t t Curtin University of Technology – SRIA tests
Recent Australian Bond Test Series
C ti U i it f T h l SRIA t t Curtin University of Technology – SRIA tests
150TYPICAL
75TYPICAL
30051 TYPICAL
N24
900
62
6 N24 contact lap spliceswithout transverse reinforcement
Recent Australian Bond Test Series
C ti U i it f T h l SRIA t t Curtin University of Technology – SRIA tests
Recent Australian Bond Test Series
C ti U i it f T h l SRIA t t Curtin University of Technology – SRIA tests
Side splitting
Recent Australian Bond Test Series
C ti U i it f T h l SRIA t t Curtin University of Technology – SRIA tests
Bar prying
Australian Bond Test Results
A i C t I tit t (ACI) D t b American Concrete Institute (ACI) Database3.0
ss -08
2.5
mat
e B
ond
Stre
s
5 f sy
AC
I 318
-
1.5
2.0
009
Des
ign
Ulti
m
ACI 408
1.2
1.5fsy bar fracture
1.0
ess
/ AS
3600
-20
1.25 fsy AS 3600-2009
0.5
timat
e B
ond
Stre
0.00.0 0.5 1.0 1.5 2.0 2.5 3.0
Ult
Ultimate Bond Stress / ACI 318-08 Design Ultimate Bond Stress
Australian Bond Test Results
A i C t I tit t (ACI) D t b American Concrete Institute (ACI) Database
90
ACI DATA BASE ‐ BOTTOM BARS, NO TRANSVERSE REINFORCEMENT
70
80
600-
2009
1.5fsy bar fracture
50
60
ency
1.25
f sy
AS
36 1.5fsy bar fracture
30
40
Freq
ue 1
5% Failure Rate
10
20
5% Failure Rate
0
0.063 0.188 0.313 0.438 0.563 0.688 0.813 0.938 1.063 1.188 1.313 1.438 1.563 1.688 1.813 1.938 2.063 2.188 2.313 2.438 2.563 2.688 2.813 2.938 More
Ultimate Bond Stress / AS 3600‐2009 Design Ultimate Bond Stress
Australian Bond Test Results
U i it f N S th W l University of New South Wales3.0
ss -08
2.5
mat
e B
ond
Stre
s
25 f s
yA
CI 3
18 1.5fsy bar fracture
1.5
2.0
009
Des
ign
Ulti
m
ACI 408
1.2
1.0
ress
/ AS
360
0-20
UNSW
1.25 fsy AS 3600-2009
0.5
timat
e B
ond
Str
0.00.0 0.5 1.0 1.5 2.0 2.5 3.0
Ult
Ultimate Bond Stress / ACI 318-08 Design Ultimate Bond Stress
Australian Bond Test Results
U i it f Q l d University of Queensland3.0
s -08
2.5
mat
e B
ond
Stre
s
5 f sy
AC
I 318
-
1.5fsy bar fracture
1.5
2.0
009
Des
ign
Ulti
m
ACI 408
1.25
1.0
ess
/ AS
3600
-20
UNSW
UQ
1.25 fsy AS 3600-2009
0.5
imat
e B
ond
Stre
0.00.0 0.5 1.0 1.5 2.0 2.5 3.0
Ulti
Ultimate Bond Stress / ACI 318-08 Design Ultimate Bond Stress
Australian Bond Test Results
C ti U i it f T h l SRIA t t Curtin University of Technology – SRIA tests3.0
ess
8-08
2 0
2.5
mat
e B
ond
Stre
ACI 40825 f s
yA
CI 3
18
1.5
2.0
2009
Des
ign
Ulti ACI 408
UNSW
1 25 f AS 3600 2009
1.2
1.0
ress
/ AS
360
0-2
UQ
CUT - SRIA (4 bars)
1.25 fsy AS 3600-2009
0.5
ltim
ate
Bon
d St
CUT - SRIA (6 bars)
0.00.0 0.5 1.0 1.5 2.0 2.5 3.0
U
Ultimate Bond Stress / ACI 318-08 Design Ultimate Bond Stress
Bond Test Results & Conclusions
UNSW & UQ tests were designed to replicate slabs & walls incorporating small diameter bars (D500N12 & 16)
Results of UNSW and UQ tests on small diameter (N12 & Results of UNSW and UQ tests on small diameter (N12 & N16) bars, with very high mean AS 3600–2009 test/design ratios of 2.1fsy and 1.8fsy,respectively, indicate that factor k =(132 d )/100 could possibly be increasedk2=(132-db)/100 could possibly be increased
SRIA tests on beams with D500N24 bars performed by Curtin University also indicate 1.25fsy is more realisticsy
ACI database shows that 1.25fsy is a much more realistic target achieved using AS 3600–2009 under non-seismic conditions which serves as a ductility criterion for splicedconditions, which serves as a ductility criterion for spliced D500N bars generally
Scott Munter Scott Munter –– Steel Reinforcement Institute of AustraliaSteel Reinforcement Institute of AustraliaMarkMark PatrickPatrick –– MP EngineersMP EngineersMark Mark Patrick Patrick –– MP EngineersMP Engineers
Vijay Rangan Vijay Rangan –– Curtin University of TechnologyCurtin University of Technology