Structural Engineering and Mechanics

Techno-Press (테크노프레스)
권호 표지
DOI QR코드

DOI QR Code

Splitting of reinforced concrete panels under concentrated loads

  • Foster, Stephen J. (School of Civil and Environmental Engineering, The University of New South Wales) ;
  • Rogowsky, David M. (Department of Civil and Environmental Engineering, University of Alberta)
  • Published : 1997.11.25
⟨ Previous Next ⟩

Abstract

It is well understood that concentrated forces applied in the plane of a beam or panel (such as a wall or slab) lead to splitting forces developing within a disturbed region forming beyond the bearing zone. In a linearly elastic material the length of the disturbed region is approximately equal to the depth of the member. In concrete structures, however, the length of the disturbed region is a function of the orthotropic properties of the concrete-steel composite. In the detailing of steel reinforcement within the disturbed regions two limit states must be satisfied; strength and serviceability (in this case the serviceability requirement being acceptable crack widths). If the design requires large redistribution of stresses, the member may perform poorly at service and/or overload. In this paper the results of a plane stress finite element investigation of concentrated loads on reinforced concrete panels are presented. Two cases are examined (i) panels loaded concentrically, and (ii) panels loaded eccentrically. The numerical investigation suggests that the bursting force distribution is substantially different from that calculated using elastic design methods currently used in some codes of practice. The optimum solution for a uniformly reinforced bursting region was found to be with the reinforcement distributed from approximately 0.2 times the effective depth of the member ($0.2D_e$) to between $1.2D_e$ and $1.6D_e$. Strut and tie models based on the finite element analyses are proposed herein.

Keywords

References

  1. Darwin, D. (1977), and Pecknold D.A. "Nonlinear biaxial stress-strain law for concrete", Journal of the Engineering Mechanics Division, ASCE, 103(EM2), Apr., 229-241.
  2. Foster, S.J. (1992a), "The structural behviour of reinforced concrete deep beams", School of Civil Engineering, University of New South Wales, Sydney, Australia, August.
  3. Foster, S.J. (1992b), "An application of the arc length method involving concrete cracking", Int. J. Num. Meth. Eng., 33(2), 269-285. https://doi.org/10.1002/nme.1620330204
  4. Foster, S.J., Budiono, B. and Gilbert, R.I. (1996), "Rotating crack finite element model for reinforced concrete structures", Computers & Structures, 58(1), 43-50. https://doi.org/10.1016/0045-7949(95)00109-T
  5. Foster, S.J., and Rogowsky, D.M. (1996), "Design of concrete panels subject to bursting tension forces resulting from in-plane concentrated loads", UNICIV Report, R-347, School of Civil Engineering, University of New South Wales, Kensington, 47pp.
  6. Foster, S.J. and Rogowsky, D.M. (1997), "Bursting forces in concrete panels resulting from in-plane concentrated loads", Magazine for Concrete Research (in press).
  7. Guyon, Y. (1953), Prestressed Concrete, FJ. Parsons, London.
  8. Morsch, E. (1924), "Uber die berechnung der gelenkquader", Beton und Eisen, 23(12), 156-161.
  9. Rogowsky, D.M. and MacGregor, J.G. (1983), "Shear strength of deep reinforced concrete continuous beams", Structural Eng. Report, 110, Dept. of Civil Engineering, University of Alberta, Edmonton, Alberta, Canada, Nov., 178pp.
  10. Saenz, L.P. (1964), "Discussion of equation for the stress-strain curve for concrete", by Desayi and Krishnan. ACI Journal, Proceedings, 61(9), 1229-1235.
  11. Vecchio, F.J. and Collins, M.P. (1986), "The modified compression field theory for reinforced concrete elements subjected to shear", ACI Journal Proceedings, 83(22), 219-231.