Presentation at Structural Faults & Repair - 2012, Edinburgh

1. Punching Shear Strength of Transversely
Prestressed Concrete Decks
Sana Amir
04-07-2012
Prof. Dr. ir. J. C. Walraven, Dr. ir. C. van der Veen
Structural Engineering / Concrete Structures van de presentatie
Titel 1

2. Contents
1: Introduction: Compressive Membrane Action
2: Past Research: Existing methods
3: Punching Shear in Transversely Prestressed Concrete Decks: Analysis
methods
4. Future experiments
5. Conclusions
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3. Introduction
Compressive Membrane Action
CMA is a phenomenon that occurs in slabs whose edges are
restrained against lateral movement by stiff boundary elements.
This restraint induces compressive membrane forces in the
plane of the slab (Park and Gamble, 1980).
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4. Introduction
Compressive Membrane Action
• Bridges are traditionally designed to carry the wheel load entirely in
flexure.
ASSUMPTION: Adequate shear capacity.
• A bridge deck slab designed for bending tends to fail in the punching
shear mode at a load much higher than that based on flexure.
?
• Prestressing provides additional in-plane forces. Therefore, there is a
need to investigate the use of transverse prestressing in bridge decks
considering CMA.
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5. Past Research
/
Hewitt & Batchelor Model Pp = 1.52(φ + d )d f c (100Qe )0.25
Kirkpatrick, Rankin, Long, Taylor
Provided the limitations are satisfied, charts from UK HIGHWAY AGENCY STANDARD BD 81/02
OHBDC (1979), NZ Code can be used for strength
assessment.
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6. Mikael Hallgren Model
• Modified form of Kinnunen – Nylander Model.
• Difference is in the failure criterion
• Slope of the shear crack is not constant but varies with the
geometry and the material properties of the slab.
Limitation:
Analysis of symmetric punching of reinforced
slabs without shear reinforcement – Open to
further development.
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7. Punching Shear Failure
Transversely Prestressed Concrete Decks
• Provisional of additional in-plane forces due to prestressing
• Improved punching shear capacity
• Improved serviceability
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8. Analysis Methods
Engineering Method Modified Hallgren Model
ρps f pe
ρe = ρs +
fy
Charts from OHBDC or NZ code may be
used to estimate the ultimate capacity.
where Fb = η Fb(max) and Mb = η Mb(max)
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9. Tests by Kirkpatrick et al (1984)
Capacity predictions for reinforced concrete decks by UK Highway BD81/02 and
modified Hallgren model.
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10. Application to Experimental Data
TPL ~ Punching Load
100
Pt
90
η - TPL relationship Pmh
80
0.8 Ph&b
70
0.7
PNZ
0.6 60
R² = 0.8233
0.5
50
0.4
η
N
L
P
k
d
h
n
u
a
o
g
c
)
(
i
0.3 40
0 1 2 3 4 5
0.2
TPL (MPa)
0.1
0 Method of superposition
0 1 2 3 4 5 6
TPL (MPa)
Variable Restraint Factor
Savides (1989), He (1992)
Tests in Queen’s University, Kingston, Canada
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11. FUTURE TESTS
Transverse Prestress Level
1.25 MPa 2.5 MPa
6400
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12. Main Parameters:
Transverse Prestress Level
Skewness of the joints
Loading position
CMA
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13. Conclusions
• Deck slabs exhibit high punching strength in the presence of CMA resulting from lateral restraint and transverse
prestressing.
• Since the TPL directly determined the degree of CMA, the punching strength is highly dependent on TPL.
• Modified Hallgren model effectively predicts the punching strength of prestressed bridge decks.
• Tests are required on prestressed decks to gain better understanding of the effect of compressive membrane action
and transverse prestressing on punching strength.
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14. REFERENCES
• Brotchie, J. F. and Holley, M. J. (1971), “Membrane Action in Slabs” ACI Special
Publication, SP – 30, pp 345-377.
• Hallgren, M. (1996), “Punching Shear Capacity of Reinforced High Strength Concrete
Slabs,”Ph.D Thesis, Royal Institute of Technology, S-11 44 Stockholm, Sweden.
• Harris, A. J. (1957), Proceedings of Institution of Civil Engineers, V. 6, pp. 45-66.
• Hewitt, B. E., and Batchelor, B. deV. (1975), “Punching Shear Strength of Restrained Slabs,
ASCE J. of Structural Engineering, V. 101, ST9, pp. 1837-1853.
• Kinnunen, S., and Nylander, H. (1960), Trans. Royal Inst. Technology, Stockholm, No. 158.
• Kirkpatrick, J., Rankin, G. I. B., and Long, A. E. (1984), “Strength of Evaluation of M-Beam
Bridge Deck Slabs,” Structural Engineer, V. 62b, No. 3, pp. 60-68.
• Ockleston, A. J. (1955), “Load Tests on a Three Storey Reinforced Concrete Building in
Johannesburg,” The Structural Engineer, V. 33, pp. 304-322.
• Ontario Ministry of Transport and Communications: Ontario Highway Bridge Design Code
(OHBDC), (1979, amended 1983 & 1992), Toronto, Ontario.
• Park, R. and Gamble, P. (1980), “Reinforced Concrete Slabs”, John Wiley & Sons, UK.
• Rankin, G. I. B. (1982), “Punching failure and compressive membrane action in reinforced
concrete slabs”, Ph.D. Thesis, Department of Civil Engineering, Queen’s University of
Belfast.
• Rankin, G. I. B. and Long, A. E. (1997), “Arching Action Strength Enhancement in Laterally
Restrained Slab Strips,” ICE Proceedings – Struc. & Buildings, No. 122, pp. 46-467.
• Savides, P. (1989), “Punching shtength of transeversely prestressed deck slabs of composite I-
beam bridges”, M.Sc. Thesis, Queen’s University Kingston, Canada.
• Taylor, S. E., Rankin, G. I. B., and Cleland, D. J. (2002), “Guide to Compressive Membrane
Action in Bridge Deck Slabs,” Technical Paper 3, UK Concrete Bridge Development
Group/British Cement Association, pp. 18-21.
• Transit New Zealand Ararau Aotearoa, New Zealand Bridge Manual, 2nd edition, (2003).
• UK Highway Agency (2002), “BD 81/02: Use of Compressive Membrane Action in bridge
decks,” Design Manual for Roads and Bridges, V. 3, Section 4, part 20.
• Weishe, He. (1992), “Punching Behaviour of Composite Bridge Decks with Transverse
Prestressing,” Ph.D. Thesis, Queen’s University, Kingston, Canada.
• Wood, R. H. (1961), ‘Plastic and Elastic Design of Slabs and Plates”, Ronald, New York.
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15. Thank you
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