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An investigation on spacing of cracks and maximum crackwidth in reinforced concrete flexural members

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Abstract

A method is proposed to determine the crack spacing and maximum crackwidth in reinforced concrete flexural members. The constants appearing in the proposed method are determined from a statistical analysis of the the test results of Hognestad, Clark and Baseet al. Experimental crackwidth values are compared with the crackwidth values computed from the equations given by CP110, Model Code, Gergely and Lutz and the proposed method and the results are discussed.

Résumé

On propose une méthode de détermination de l'espacement des fissures et de leur largeur maximale dans des éléments de béton armé travaillant en flexion. On détermine les constantes de la méthode proposée à partir d'une analyse statistique des résultats d'essai de Hognestad, Clark et Baseet al. On compare les valeurs expérimentales de largeur des fissures d'après les équations fournies par CP 110, le Code Modèle, Gergely et Lutz, on discute la méthode proposée et les résultats.

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Abbreviations

A :

area of concrete surrounding one bar

A ct :

effective concrete area in tension

A s :

area of tension reinforcement

a′:

distance from the compression face to the point at which crackwidth is being calculated

b :

width of section

a c :

average spacing of cracks

a cr :

distance from point of measurement of crack to the surface of the nearest longitudinal bar

a m :

average spacing of cracks when they have just formed (i.e., atM=M cr for a flexural specimen)

c b :

bottom cover measured from the centre of lower bar

c e :

effective cover

c min :

minimum cover to the reinforcement

c s :

side cover measured from the centre of outer bar

d :

effective depth of tension reinforcement

d n :

distance of neutral axis above the bottom for a gross transformed section

E s :

modulus of elasticity of steel

E c :

modulus of elasticity of concrete

f bu :

ultimate bond strength

f ct :

tensile strength of concrete

f y :

characteristic strength of reinforcement

h :

overall depth of cross section

k 1 :

denotes a coefficient which characterises the bond properties of the bars.k 1=0.4 for high bond bars,k 1=0.8 for plain bars

k 2 :

denotes a coefficient representing the influence of the form of the stress diagramsk 2=0.125 for bending

k b :

factor giving average bond stress

k t :

factor giving average tensile stress

l 1 :

distance of sectionxx from an already formed—crack

M :

bending moment

M cr :

moment at cracking

M u :

ultimate moment

s :

spacing of reinforcement

W as :

average crackwidth at the level of steel

W d :

design surface crackwidth

W k :

characteristic crackwidth

W m :

mean crackwidth

W bt :

maximum crackwidth at the lower extreme tensile fibre

W calc :

calculated crackwidth

W exp :

experimental crackwidth

W ms :

maximum crackwidth at the level of steel

x :

neutral axis depth of a cracked section

β1 :

denotes a coefficient which characterises the bond properties of the bars. β1=1/(2.5k 1)

β2 :

denotes a coefficient representing the influence of the duration of the application or repetition of the loads. β2=1 at the first loading, β2=0.5 for loads applied in a sustained manner or for a larger number of load cycles

γ:

a constant

ε1 :

strain at the level considered, calculated ignoring the stiffening effect of concrete in the tension zone

ε m :

average strain at the level where cracking is being considered, calculated allowing for the stiffening effect of concrete in tension zone

ε sm :

strain in reinforcement, σ s /E s

ε sm :

mean steel strain

σ bs :

maximum bond stress

σ s :

stress in steel

σ tx :

maximum tensile stress in the effective concrete at sectionxx

σ sr :

steel stress at first cracking

ρ r :

effective reinforcement ratio,A s /A ct

φ:

diameter of bar

References

  1. Desayi P.—Cracking of reinforced and prestressed concrete members. Parts 1 and 2, The Indian Concrete Journal, Vol. 50, May 1976, pp. 146–150 and 187–190.

    Google Scholar 

  2. Desayi P.—Determination of maximum crackwidth in reinforced concrete members. Journal of the American Concrete Institute, Proc. Vol. 73, August 1976, pp. 473–477.

    Google Scholar 

  3. Desayi P., Ganesan N.—Estimation of maximum crackwidth in reinforced concrete flexural members. The Indian Concrete Journal, Vol. 54, April 1980, pp. 106–112.

    Google Scholar 

  4. Hognestad E.—High strength bars as concrete reinforcement. Part 2,Control of flexural cracking. Journal of the PCA Research and Development Laboratories, Vol. 4, January 1962, pp. 46–63.

    Google Scholar 

  5. Clark A. P.—Cracking in reinforced concrete flexural members. Journal of the American Concrete Institute, Proc. Vol. 52, April 1956, pp. 851–862.

    Google Scholar 

  6. Base G. D., Read, J. B., Beeby A. W., Taylor H. P. J. —An investigation of the crack control characteristics of various types of bar in teinforced concrete beams. Parts 1, 2 and 3. Research Report 41.018, Cement and Concrete Association. Wexham Springs, Slough England, December 1966.

    Google Scholar 

  7. The Code of Practice for the Structural use of Concrete. CP110. Part 1: 1972. Bristish Standards Institution, London.

  8. CEB/FIP,Model Code for Concrete Structures. April 1978, pp. 151–164.

  9. Gergely P., Lutz L. A.—Maximum crackwidth in reinforced concrete flexural members. Causes, mechanism and control of cracking in concrete. ACI Special Publication, SP-20, American Concrete Institute, Detroit, Michigan, 48219, USA, 1968, pp. 87–117.

    Google Scholar 

  10. Desayi P., Ganesan N.—Determination of maximum crackwidth in ferrocement flexural elements of channel cross section. International Journal of Cement Composites and Lightweight Concrete (UK), Vol. 6, August 1984, pp. 169–177.

    Article  Google Scholar 

  11. Bhasin P. C., Chakrabarti S. P.—Design specifications for limit state of crackwidth in flexure. Panel discussion at the 40 th Annual session of the Indian Roads Congress held at Jaipur, India, on 6th February 1980.

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Author notes

  1. N. Ganesan (Lecturer, Research Scholar)

    Present address: Civil Engineering Department, Indian Institute of Science, Bangalore, India

Authors and Affiliations

  1. Civil Engineering Department, Indian Institute of Science, Bangalore, India

    P. Desayi (Professor of Civil Engineering)

  2. Regional Engineering College, Calicut, India

    N. Ganesan (Lecturer, Research Scholar)

Authors
  1. P. Desayi
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  2. N. Ganesan
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Desayi, P., Ganesan, N. An investigation on spacing of cracks and maximum crackwidth in reinforced concrete flexural members. Materials and Structures 18, 123–133 (1985). https://doi.org/10.1007/BF02473379

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