Flange Strain Measurement in Shear Critical RC T-Beams

Abstract

This paper provides an analysis of the strain measurements and distributions obtained from testing two reinforced concrete T-beam specimens for the purpose of assessing the contribution of the flange to the shear strength. The specimens were instrumented throughout the flange and the compressive zone of the web region in order to obtain comprehensive data required for the understanding of shear resistance mechanisms and quantification of the flange contribution to the shear resistance of reinforced concrete T-beams. It was found that the formation of shear cracking results in significant redistributions of strain through the measured region. Redistributions of compressive strains transversely away from the web region and vertically away from the top surface of the flange were observed. The resulting distributions throughout the specimen were highly nonlinear. In light of the results of this investigation, the assumptions made in the application of existing methods available for prediction of the shear resistance of reinforced concrete T-beams are discussed, and proposed improvements to these methods are also discussed.

Keywords

shear flange flexure failure mechanisms reinforced concrete T-beams strain redistribution flange contribution

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References

Al-Alusi

A. F.

(1957). “Diagonal tension strength of reinforced concrete T-beams with varying shear span”, ACI Journal, Vol. 53, pp. 1067–1077.

ASCE-ACI Committee 445 (1998). “Recent approaches to shear design of structural concrete”, Journal of Structural Engineering, ASCE, Vol. 124, No. 12, pp. 1375–1417.

AS3600 (2001). Concrete Structures, Standards Australia, Sydney.

Brendel

(1964). “Strength of the compression slab of T-beams subject to simple bending”, Journal of the American Concrete Institute, Vol. 61, No. 1, pp. 57–75.

CEB-FIP (1993). CEB-FIP Model Code 1990, Comite Euro-International du Beton.

Chong

O. Y.

(1980). Ultimate Shear Strength of Uniformly Loaded Reinforced Concrete Tee Beams, Masters Thesis, Department of Civil Engineering, University of Glasgow.

Darwish

M. N.

Gesund

and Lee

D. D.

(2000). “A discussion of “recent approaches to shear Design of Structural Concrete””, Journal of Structural Engineering, ASCE, Vol. 126, No.7, pp. 853–854.

Fok

W. K.

(1972). The Shear Strength of Reinforced Concrete T Beams with Unreinforced and Shear-reinforced Webs, PhD Thesis, Department of Civil Engineering, University of Glasgow.

Ferguson

P. M.

and Thomson

J. N.

(1953). “Diagonal Tension in T-Beams without Stirrups”, ACI Journal, Vol. 50, pp. 665–675.

10.

Giaccio

Al-Mahaidi

R. S.

and Taplin

(2004). “Flange contribution of the flange to the resistance of shear of an RC T-beam. Part II: Flange contribution”, Submitted to ACI Structural Journal for possible publication.

11.

Giaccio

Al-Mahaidi

R. S.

and Taplin

(2004). “Flange effectiveness in the shear strength of RC T-beams”, Accepted for publication in the Proceedings of the 18^th ACMSM Conference, Perth, Australia.

12.

Giaccio

(2003). Flange Effectiveness in the Resistance of Sectional Shearing Forces in Web Reinforced RC T-Beams Subjected to a Concentrated Point Load, PhD Thesis, Department of Civil Engineering, Monash University, Victoria, Australia.

13.

Giaccio

Al-Mahaidi

R. S.

and Taplin

(2002). “Experimental study on the effect of flange geometry on the shear strength of point loaded RC T-beams”, Canadian Journal of Civil Engineering, Vol. 29, No. 6, pp. 911–918.

14.

Giaccio

Al-Mahaidi

R. S.

and Taplin

(2000). “Flange effectiveness in the shear strength of RC T-beams”, APSEC 2000, K.L., pp. 462–472.

15.

Hoang

L. C.

(1997). Shear Strength of Non-Shear Reinforced Concrete Elements Part 2. T-Beams, Technical University of Denmark, pp. 32.

16.

Hsu

T. T. C.

(1988). “Softened truss model theory for shear and torsion”, ACI Structural Journal, Vol. 85, No. 6, pp. 624–635.

17.

Klein

G. J.

and Popovic

P. L.

(1985). Strength Evaluation of Existing Bridges, Publication SP ACI 88, pp. 199–224.

18.

Levi

(1961). “Work of the European concrete committee”, Journal of the American Concrete Institute, Vol. 32, No. 9, pp. 1041–1069.

19.

Pang

X. B.

and Hsu

T. T. O.

(1996). “Fixed angle softened truss model for reinforced concrete”, ACI Structural Journal, Vol. 93, No. 2, pp. 197–207.

20.

Placas

and Regan

P. E.

(1971). “Shear failure of reinforced concrete beams”, ACI Journal, Vol. 68, pp. 763–773.

21.

Swamy

and Qureshi

S. A.

(1971). “Strength, cracking and deformation similitude of reinforced T-beams under bending and shear”, ACI Journal, Vol. 68, No. 187–195.

22.

Swamy

R. N.

(1969). “Shear failure in reinforced concrete beams without web reinforcement”, Civil Engineering and Public Works Review, pp. 237–243.

23.

Taplin

and Al-Mahaidi

(2000). “Experimental investigation of shear critical T-beams”, 3rd Structural Specialty Conference, Canada, pp. 486–492.

24.

Vecchio

F. J.

(2001). “Disturbed stress field model for reinforced concrete: Implementation”, Journal of Structural Engineering, ASCE, Vol. 127, No. 1, pp. 12–20.

25.

Vecchio

F. J.

(2000). “Disturbed stress field model for reinforced concrete: Formulation”, Journal of Structural Engineering, ASCE, Vol. 126, No. 9, pp. 1070–1077.

26.

Vecchio

F. J.

(1990). “Reinforced concrete membrane element formulations”, Journal of Structural Engineering, ASCE, Vol. 116, No. 3, pp. 730–751.

27.

Vecchio

F. J.

(1999). “Predicting the response of concrete beams subjected to shear using modified compression theory”, ACI Journal, Vol. 85, No. 3, pp. 258–268.

28.

Vecchio

F. J.

and Collins

(1986). “The modified compression-field theory for reinforced concrete elements subjected to shear”, ACI Journal, Vol. 83, No. 2, pp. 219–231.