Upload
dangkien
View
215
Download
1
Embed Size (px)
Citation preview
Professor Kypros PilakoutasProfessor Peter Waldron, Dr Maurizio Guadagnini
Centre for Cement and ConcreteThe University of Sheffield, UK
Andrew HendersonDirector of World Wide Sales, Concrete Reinforcement Products
ERICO
New Punching Shear Reinforcement for Flat Slabs
Centre for Cement and Concrete
• Problem/Solutions
• Lenton® Shear Fortress
• Experiments
• Results
• Conclusions
OutlineOutline
Shear ReinforcementShear Reinforcement
Conventional Reinforcement Closed
Hoop Sausage Links
Inclined Shear Reinforcement
• Difficult to anchor
• Difficult to install
• Does not facilitate prefabrication
SystemsSystems
Stud-rail Systems
• Priority over flexural re-bar installation• Conceptual issues
•System•Anchorage•Shear design
ΤΤhe he LSF LSF on top of theon top of the uupper pper flexural reinforcementflexural reinforcement
Lenton® Steel FortressLenton® Steel Fortress
s s
depth11””
• Maximum effective depth
• Easy placement/ Adaptability
• Shear design based on Codes (e.g. ACI 318)
• Excellent anchorage
AdvantagesAdvantages
• 1st Series (PSSA-D)• 2nd Series (PSSF-H)• Beam Tests (B1-B10)• Slabs with holes (PSSH1-5)• Slabs with FRP reinforcement• Tests for ICC Certification (California)• Cyclic tests (California)
Testing workTesting work
top #5@8”
bottom #4@8”
links 3#2@20”
Column 4 # 5 8”
6’ 7”
8”
8”
Testing ArrangementTesting Arrangement
Loading Frame
Slab
FLAT SLAB TESTING
Reaction Frame
Load Application
Testing ArrangementTesting Arrangement
Loading Ring Frame
Reaction Ring Frame
Jacks
Column Stub
S1
S2
S3
S4
S5
S6
S7S8S9
S10 S11 S12
D5
D4
D3
D2
D1
D6 D7 D8
R250 mm 10” R400 mm 16”
R600 mm 24” R850 mm 36”
D9
D10
D11
RS5,6
RS3,4
TS1RS7,81
2 RS1TS2
RS2
InstrumentationInstrumentation
Strain gauge location Displacement Measurements
PSSAPSSA
Control Slab PSSAControl Slab PSSA
4685
PSI
0.4511102454PSSAinchesmmKipskN
Maximum DisplacementMaximum LoadSlab
PSSB and PSSCPSSB and PSSC
PSSB,C
PSSB
PSSC
SS1 SS2SS3
SS4
SS5
SS6
SS7
SS8
PSSDPSSD
SS1 SS2
SS3SS4
SS5
SS6
SS7
SS8
PSSD
0
100
200
300
400
500
600
0 5 10 15 20 25
Displacement (mm) at D850
Load
(kN
)
0
20
40
60
80
100
120
PSSA PSSB
PSSC PSSD
Load
Kip
s
Load - DeflectionLoad - Deflection
0
100
200
300
400
500
600
0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000Microstrain in Flexural Bar
Load
(kN
)
PSSA
PSSB
PSSCPSSD
Load - StrainLoad - Strain
0
20
40
60
80
100
120
Load
Kip
s
S1S1
PSSA to PSSDPSSA to PSSD
0.8421126560PSSD
0.9524126560PSSC
1.0025126560PSSB
0.4511102454PSSA
inchesmmKipskN
Maximum Displacement
Maximum Load
Slab
4685
PSI
0
100
200
300
400
500
600
0 500 1000 1500 2000 2500 3000Microstrain on shear reinforcement
Load
(kN
)
PSSB
PSSC
0
20
40
60
80
100
120
Load
Kip
s
PSSB versus PSSCPSSB versus PSSC
SS1 SS6
SS7
SS12
PSSE
PSSEPSSE
0
20
40
60
80
100
120
Load
Kip
s
PSSE versus PSSBPSSE versus PSSBL
oad
(kN
)
0
100
200
300
400
500
600
5 1010 15 20 25 30
PSSEPSSBPSSA
Deflection (mm)
D850
SS1 SS6
SS7 SS12
SS1 SS6
SS7 SS12SS9 SS10
PSSF PSSG
PSSF and PSSGPSSF and PSSG
0
100
200
300
400
500
600
0 5 10 15 20 25Displacement (mm) at D850
Load
(kN
)
PSSE
PSSF
PSSG
PSSA
1.0928133590PSSG
1.1930134598PSSF
1.0326129573PSSE
0.4511102454PSSA
inchesmmKipskN
Maximum Displacement
Maximum Load
Slab
Load - DeflectionLoad - Deflection
0
20
40
60
80
100
120
Load
Kip
s
6342
PSI
0
100
200
300
400
500
600
0 2000 4000 6000 8000 10000 12000Microstrain in the Shear Reinforcement
Load
(kN
)
SS3SS9
PSSE
Load - StrainLoad - Strain
SS1 SS6
SS7
SS12
0
1
2
3
4
5
6
7
8
9
0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000Microstrain on the strip
Load
(kN
)
Cross-section with hole
Cross-section without hole
Strain ReadingsStrain Readings
•Strain normally measured at cross-section without hole to avoid recording stress concentration due to hole
SS1 SS6
SS7 SS12
PSSHPSSH
PSSH
More slabs with holesMore slabs with holes
PSSH Load-DeflectionPSSH Load-Deflection
0
100
200
300
400
500
600
700
0 5 10 15 20 25 30Displacement (mm)
Load
(kN
)
PSSG D11
PSSG D8
PSSH D11PSSH D8
D11
•PSSH capacity increased by more than 100%
0
100
200
300
400
500
600
0 1000 2000 3000 4000 5000 6000 7000 8000
Strain on Strip
Load
(kN
)
SS2SS7
PSSH
PSSH Load-StrainPSSH Load-Strain
The LSF:
• Prevents brittle punching shear failure and leads to ductile behavior
• Fast and easy fixing; placed on top of main reinforcement for max anchorage
• Can be designed as conventional shear reinforcement
• Evidence of LSF yielding
ConclusionsConclusions