Title:
Historical Development of the Simplified Modified Compression Field Theory
Author(s):
Evan C. Bentz and Michael P. Collins
Publication:
Symposium Paper
Volume:
365
Issue:
Appears on pages(s):
35-49
Keywords:
Code equations, shear behavior, shear design, stirrups, variable angle truss, modified compression field theory.
DOI:
10.14359/51746683
Date:
3/1/2025
Abstract:
The modified compression field theory (MCFT) is a general model for the behavior of diagonally cracked reinforced concrete. When applied to beams and columns, a number of very significant simplifications can be made to make it easier to apply in practice for day-to-day design and strength assessment. While the methods used to generate the simplified MCFT have been explained in previous papers, the actual historical and technical process that led to the work was somewhat different than the technical arguments made in the previous publications. This paper explains the procedures that actually occurred in 1999 to 2002 to generate the equations of the simplified MCFT for members with stirrups. The process shows the importance of working backwards from solutions and engineering intuition in the generation of technical theories. While the analysis method ended up being practical and technically sound, its creation was a people-based process and learning about it can hopefully be helpful to future researchers who want to know how “it really happened”.
Related References:
1. Vecchio, F. J. and Collins, M. P., “The Modified Compression-Field Theory for Reinforced Concrete Elements Subjected to Shear”, ACI Structural Journal, Vol. 83, No. 2, Mar.-Apr., 1986, pp. 219-231.
2. Bentz, E.C., Vecchio, F.J., and Collins, M.P., “The Simplified MCFT for Calculating the Shear Strength of Reinforced Concrete Elements”, ACI Structural Journal, V.103, No. 4, July-Aug. 2006, pp.614-624.
3. Bentz, E.C., and Collins, M.P., “Development of the 2004 CSA A23.3 Shear Provisions for Reinforced Concrete,” Canadian Journal of Civil Engineering, V.33, No.5, May 2006, pp.521-534.
4. CSA Technical Committee on Reinforced Concrete Design, “CSA A23.3-04 Design of Concrete Structures”, Canadian Standards Association, Mississauga, Ontario, Canada, 2004, 214 pp.
5. Canadian Standards Association “S6: Canadian Highway Bridge Design Code”, CSA Rexdale Ontario, 2019.
6. Standards Australia, “AS5100: Bridge Design”, 2017
7. Standards Australia, “AS3600: Concrete Structures”, 2018
8. Fédération Internationale du Béton (fib), ModelCode 2010 - final draft, Vol. 1, Bulletin 65, and Vol. 2, Bulletin 66, Lausanne, Switzerland, 2012, 318 pp and 312 pp.
9. fib 2020 Model Code (2023). “fib Model Code for Concrete Structures 2020”, International Federation for Structural Concrete [in-press].
10. AASHTO LRFD (2020). “Bridge Design Specifications”, 9th Edition, 1912 pp.
11. ACI Committee 318, “Building Code Requirements for Structural Building (ACI 318-22) and Commentary,” American Concrete Institute, Farmington Hills, MI, 2022, 624 pp.
12. Sherwood, E.G., Bentz, E.C., and Collins, M.P., “Effect of Aggregate Size on Beam-Shear Strength of Thick Slabs,” ACI Structural Journal, V. 104, No. 2, Mar.-Apr. 2007, pp. 180-190.
13. Bentz, E.C., Collins, M.P., “The Toronto Size Effect Series,” ACI Special Publication Number 328, pp. 2.1-2.12, September 12th 2018.
14. MacGregor, J.G., “Design of Beams, Deep Beams, and Corbels for Shear-ACI 318-71 and Revisions Proposed by ACI Committee 426”, ACI Structural Journal Vol. 59, pp 71-91, 1979.
15. Collins, M.P. and Mitchell, D. 1991. Prestressed concrete structures. Prentice Hall, Englewood Cliffs, 1991
16. Mitchell, D., and Collins, M.P., “Rational Approach to Shear Design-The 1984 Canadian Code Provisions”, ACI Journal, Proceedings, V. 83, No. 6, Nov.-Dec. 1986, pp. 925-933.
17. Canadian Standards Association 1984. CAN CSA A23.3-M84 Design of concrete structures for buildings. CSA, Rexdale, Ontario
18. Canadian Standards Association 1994. CAN CSA A23.3-94 design of concrete structures, CSA, Rexdale, Ontario
19. Rahal, K.N. and Collins, M.P. “Background to the general method of shear design in the 1994 CSA-A23.3 standard”. Canadian Journal of Civil Engineering, 26:827-839., 1999
20. Cavagnis, F., Fernández Ruiz, M., and Muttoni, A. (2018). “An analysis of the shear-transfer actions in reinforced concrete members without transverse reinforcement based on refined experimental measurements.” Structural Concrete, 19(1), 49–64.
21. Poldon, J.J., Hoult, N.A., Bentz, E.C., “Understanding Shear Resistance Mechanisms in Concrete Beams Monitored with Distributed Sensors”, ACI Structural Journal, Vol. 119, No. 6, Nov 2022, pp. 329-340.
22. Gupta, P.R., “Shear design of reinforced concrete members under axial compression”, PhD thesis, University of Toronto, Department of Civil Engineering, 1998
23. Helmy, A.I.I, “1 Behaviour of Offshore Reinforced Concrete Structures under Hydrostatic Pressure”, PhD thesis, University of Toronto, Department of Civil Engineering, 1998
24. Bentz, E.C., “Sectional Analysis of Reinforced Concrete Members”, PhD Thesis, University of Toronto, Department of Civil Engineering, 200 pp., 2000
25. Collins, M.P., Xie, L. Mihaylov, B., and Bentz, E.C., “Shear Response of thin walled continuous girders” ACI Structural Journal, Vol. 113, No. 3, pp. 447-457