Title:
Does the Size Effect Exist in Reinforced Masonry?
Author(s):
Salah R. Sarhat and Edward G. Sherwood
Publication:
Symposium Paper
Volume:
328
Issue:
Appears on pages(s):
5.1-5.18
Keywords:
Beams, Masonry; Shear Strength, Size Effect
DOI:
10.14359/51711149
Date:
9/12/2018
Abstract:
The research described in this paper studies the effect of the effective depth, d, on the shear behavior of large reinforced masonry beams. Five fully grouted shear critical reinforced masonry beams ranging in effective depth from 300 mm to 1400 mm were tested to failure under three point loading to investigate their cracking behavior and ultimate shear strengths. The experimental shear strengths were compared with the failure shear stresses predicted using three different design codes: the TMS 402 code, the CSA S304.1-2004 code and the CSA A23.3-14 code for reinforced concrete. The test results show that the size effect in reinforced masonry is real and very significant, in that failure shear stresses decreased as the effective depth increased. It is shown that as the effective depth increases, the longitudinal crack width and spacing at mid-depth increase as well. These wider cracks initiate shear failure at a lower shear stress due to reduced aggregate interlock capacity. It is shown that the TMS masonry design code gives non-conservative predictions of the shear strength of large masonry beams. The most accurate prediction of the size effect in masonry is given by the CSA A23.3 -2014 code which is based on the General Method of shear design used extensively to design reinforced concrete. The paper highlights the necessity to revise masonry design codes to address the size effect.
Related References:
ACI Committee 318 (2014) Building Code Requirements for Structural Concrete and Commentary, ACI-318, American Concrete Institute, Farmington Hills, Michigan 520pp.
Alfy Samy, B., Sarhat, S. and Sherwood, E.G. (2015) “Comparing Flexural Capacity of Reinforced Masonry Members in Different Codes,” 12th North American Masonry Conference, Proceedings, Denver, Colorado, May 17-20
Bazant, Z.P., Kazemi, M.T. (1991) "Size Effect on Diagonal Shear Failure of Beams without Stirrups." ACI Structural Journal, Vol. 88, No. 3, pp. 268-276.
Bentz, E.C., Vecchio, F.J. and Collins, M.P., “Simplified Modified Compression Field Theory for Calculating Shear Strength of Reinforced Concrete Elements,” ACI Structural Journal, Vol. 103, No.4, 2006, pp. 614-624
Brick Institute of America, BIA (1999), BIA Technical Note No.17B: Reinforced Brick Masonry. Brick Industry Association, Reston, VA, 1999.
Collins, M.P. and Kuchma, D. (1999) “How Safe Are Our Large, Lightly Reinforced Concrete Beams, Slabs, and Footings?,” ACI Structural Journal, Vol. 96, No. 4, pp. 482-490
CSA Committee A23.3 (2014), Design of Concrete Structures, Canadian Standards Association, Toronto, Ontario, 214 pp.
CSA Committee S304.1 (2004), Design of Masonry Structures, Canadian Standards Association, Toronto, Ontario, 126 pp.
Dhanasekar, M, and Wong, K. (2001) “Evaluation of Shear Capacity Equation for Masonry Beams Without Web Reinforcement” Proceeding of the 6th Australasian Masonry Conference, Adelaide University, 2001, pp 115-124.
Drysdale, R. G., Hamid, A. A., & Baker, L. R. (1994). Masonry Structures: Behavior and Design. Prentice Hall, 767pp.
Ghannoum W. M. (1998) Size Effect on Shear Strength of Reinforced Concrete Beams, MASc. Thesis, Department of Civil Engineering and Applied Mechanics, McGill University, Montréal.
Jourawski, D. J. (1856) “Sur le Résistance d’un Corps Prismatique et d’une Pièce Composée en Bois ou on Tôle de Fer à une Force Perpendiculaire à leur Longeur,” Annales des Ponts et Chauseés, Mémoires et Documents, 3rd Series, V. 12, Part 2, pp. 328-351.
Kani, G.N.J. (1967) “How Safe are Our Large Reinforced Concrete Beams?” ACI Structural Journal, Vol. 64, No. 3, pp. 128-141.
Mörsch, E. (1909) Concrete-Steel Construction (Der Eisenbetonbau), English translation of 3rd German Edition, McGraw-Hill Book Co., New York, 368 pp.
Sarhat, S. and Sherwood, E.G. (2010) “Effective Shear Design of Reinforced Masonry Beams” The Masonry Society Journal, Vol. 28, No. 2, pp. 27-39
Sarhat, S. (2016) The Size Effect and Strain Effect in Reinforced Masonry, Ph.D. Thesis, Department of Civil and Environmental Engineering, Carleton University, Ottawa, Canada, 520pp.
Sherwood, E. G., Bentz, E. C., and Collins, M. P. (2007) “Effect of Aggregate Size on Beam-Shear Strength of Thick Slabs” ACI Structural Journal, Vol. 104, No. 2, pp. 180-190
Sherwood E.G. (2008) One-Way Shear Behavior of Large, Lightly-Reinforced Concrete Beams and Slabs, Ph.D. Thesis, Department of Civil Engineering, University of Toronto, Toronto, Ontario.
Shioya, T., Iguro, M., Nojiri, Y., Akiyama, H., and Okada, T. (1990) “Shear Strength of Large Reinforced Concrete Beams” Fracture Mechanics: Application to Concrete, SP 118, American Concrete Institute, Detroit, pp. 259-280.
Suter, G. T., Keller, H. (1980) Carleton University Concrete Masonry Beam Tests: Shear, Carleton University Research Report, Department of Civil and Environmental Engineering, Carleton University, Ottawa, Ontario 62 pp.
TMS Committee 402 (2013) Building Code Requirements and Specification for Masonry Structures and Related Commentaries, The Masonry Society, Boulder, Colorado, 236pp.
Walraven, J.C. (1981) “Fundamental Analysis of Aggregate Interlock,” Journal of the Structural Division, ASCE, Vol. 107, No. 11, 1981, pp. 2245-2270.