punching shear strength of transversely prestressed concrete decks
DESCRIPTION
Presentation at Structural Faults & Repair - 2012, EdinburghTRANSCRIPT
1Titel van de presentatie
Punching Shear Strength of Transversely Prestressed Concrete Decks
Sana Amir
04-07-2012
Prof. Dr. ir. J. C. Walraven, Dr. ir. C. van der VeenStructural Engineering / Concrete Structures
2Titel van de presentatie
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
3Titel van de presentatie
IntroductionCompressive 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).
4Titel van de presentatie
• 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.
IntroductionCompressive Membrane Action
?
5Titel van de presentatie
Past Research
Provided the limitations are satisfied, charts from OHBDC (1979), NZ Code can be used for strength assessment.
Kirkpatrick, Rankin, Long, TaylorUK HIGHWAY AGENCY STANDARD BD 81/02
/ 0.251.52( ) (100 )p c eP d d f Q Hewitt & Batchelor Model
6Titel van de presentatie
• 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.
Mikael Hallgren Model
Limitation:
Analysis of symmetric punching of reinforced slabs without shear reinforcement – Open to further development.
7Titel van de presentatie
Punching Shear Failure Transversely Prestressed Concrete Decks
• Provisional of additional in-plane forces due to
prestressing
• Improved punching shear capacity
• Improved serviceability
8Titel van de presentatie
Engineering Method
ps pee s
y
f
f
Charts from OHBDC or NZ code may be used to estimate the ultimate capacity.
Analysis MethodsModified Hallgren Model
where Fb = η Fb(max) and Mb = η Mb(max)
9Titel van de presentatie
Capacity predictions for reinforced concrete decks by UK Highway BD81/02 and
modified Hallgren model.
Tests by Kirkpatrick et al (1984)
10Titel van de presentatie
Application to Experimental Data
R² = 0.8233
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 1 2 3 4 5 6
η
TPL (MPa)
η - TPL relationship
Savides (1989), He (1992)
Tests in Queen’s University, Kingston, Canada
40
50
60
70
80
90
100
0 1 2 3 4 5
Pu
nch
ing
Loa
d (k
N)
TPL (MPa)
TPL ~ Punching Load
Pt
Pmh
Ph&b
PNZ
Variable Restraint Factor
Method of superposition
11Titel van de presentatie
FUTURE TESTS
Transverse Prestress Level
1.25 MPa 2.5 MPa
6400
12Titel van de presentatie
Main Parameters:
Transverse Prestress Level
Skewness of the joints
Loading position
CMA
13Titel van de presentatie
• 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.
Conclusions
14Titel van de presentatie
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.
15Titel van de presentatie
Thank you