Non-linear finite element analysis of shear critical high strength concrete beams

• Autorzy: Sagaseta, J. , Vollum, R.
• Języki publikacji: EN

Abstrakty

EN

Experimental evidence shows that the bond between the aggregate and cement paste can be sufficiently strong in highstrength concretes for cracks to pass through the aggregate. Cracks that pass through coarse aggregate are smooth and significantly reduce the potential for shear transfer through aggregate interlock action. Current design methods for shear do not take the aggregate type into consideration. This paper describes a series of non-linear finite element analyses the authors carried out to assess the influence of crack roughness on the shear strength of beams. The models incorporated both smeared and discrete cracking elements. The numerical models were validated with data from 22 beams tested at Imperial College London. In general, the ultimate load, crack patterns and relative crack displacements were satisfactorily reproduced. The reduction in strength due to aggregate fracture was found to be greatest in slender beams without stirrups and insignificant in short span beams where the cracks tended to open rather than slide.

PL

Badania doświadczalne wskazują, że w betonie wysokiej wytrzymałości siły przyczepności pomiędzy kruszywem i zaczynem cementowym mogą być na tyle duże aby zarysowanie powstawało w kruszywie. Rysy przechodzące przez kruszywo są gładkie i znacząco redukują zdolność do przenoszenia sił tnących poprzez zazębianie się kruszywa. W artykule przedstawiono nieliniowe analizy numeryczne, przeprowadzone przez autorów w celu oceny wpływu charakteru zarysowania na nośność na ścinanie belek. Analizy wykonano zarówno dla modelu z rozmytym jak i dyskretnym obrazem zarysowania. Modele numeryczne zostały porównane z wynikami badań 22 belek. Największe obniżenie nośności na ścinanie spowodowane zniszczeniem kruszywa obserwowano w belkach smukłych, nie zbrojonych strzemionami.

Słowa kluczowe

PL

zazębianie kruszywa; beton o dużej wytrzymałości; analiza nieliniowa metodą elementów skończonych; projektowanie nośności na ścinanie

EN

aggregate interlock; high-strength concrete; non-linear finite element analysis; shear design

• Czasopismo: Architecture Civil Engineering Environment
• Rocznik: 2009
• Tom: Vol. 2, no. 4
• Strony: 95-105
• Opis fizyczny: Bibliogr. 17 poz.

Twórcy

autor

Sagaseta, J.

autor

Vollum, R.

• Ecole Polytechnique Federale de Lausanne (EPFL),

Bibliografia

• [1] CEB; High performance concrete, recommended extensions to the Model Code 90, research needs. CEB Bulletin d'Information, Report 228, July 1995
• [2] Sherwood E. G., Bentz E. C, Collins M. P.; Effect of aggregate size on beam-shear strength of thick slabs. ACI Structural, Vol.104, No.2, March-April 2007, p.180-190
• [3] Vecchio F. J., Collins M. P.; The modified compression-field theory for reinforced concrete elements subjected to shear. ACI Structural, No.83-22, October 1986, p.219-231
• [4] British Standards Institution; European Standard EN-1992-1-1:2004, Eurocode 2: Design of Concrete Structures. Part 1, General Rules and Rules for Buildings. BSI, 2004, London
• [5] Regan P. E., Kennedy-Reid I. L., Pullen A. D, Smith D. A.; The influence of aggregate type on the shear resistance of reinforced concrete. The Structural Engineer, December 2005, p.27-32
• [6] Taylor H. P. J.; Investigation of the forces carried across cracks in reinforced concrete beams in shear by interlock of aggregate. CCA, London, November 1970
• [7] Sagaseta J.; The influence of aggregate fracture on the shear strength of reinforced concrete beams. PhD Thesis, Department of Civil & Environmental Engineering, Imperial College London, 2008
• [8] TNO DIANA BV; User's Manual Release Notes. Frits C. de Witte and Gerd-Jan Schreppers (Eds.), Delft 2005
• [9] Cornelissen H. A. W., Hordijk D. A., Reinhardt H. W; Experimental determination of crack softening characteristics of normalweight and lightweight concrete. Heron, Vol.31,1986
• [10] Feenstra P. H.; Computational aspects of biaxial stress in plain and reinforced concrete. PhD Thesis, Delft University of Technology, 1993
• [11] Vecchio F. J., Shim W; Experimental and analytical reexamination of classic concrete beam tests. Journal of Structural Engineering, Vol.130, No.3, March 2004, p.460-469
• [12] Bresler B,, Scordelis A. C; Shear strength of reinforced concrete beams. Journal of American Concrete Institute, Vol.60, No.l, 1963, p.51-72
• [13] Sagaseta J., Vollum R.; Shear design of short span beams. Magazine of Concrete Research (paper accepted for publication in June 2009)
• [14] Feenstra P. H., De Borst R., Rots J. G.; Numerical study on crack dilatancy I: Models and stability analysis. Journal of Engineering Mechanics, Vol.117, No.4, April 1991, p.733-753
• [15] Hamadi Y. D, Regan P. E.; Behaviour of normal and lightweight aggregate beams with shear cracks. The Structural Engineer, 58B(4), 1980, p.71-79
• [16] Sagaseta J., Vollum R,; Relative crack displacements in high strength concrete beams failing in shear. Proceeding of the 11th International fib Symposium, London, 2009
• [17] Walraven J. C, Reinhardt H. W.; Theory and experiments on the mechanical behaviour of cracks in plain and reinforced concrete subjected to shear loading. Heron, Vol.26, No.l(a), 1981, p.5-68