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9998197
Influence of Deficient Materials on the Reliability of Reinforced Concrete Members
Authors:
Abstract:
The strength of reinforced concrete depends on the member dimensions and material properties. The properties of concrete and steel materials are not constant but random variables. The variability of concrete strength is due to batching errors, variations in mixing, cement quality uncertainties, differences in the degree of compaction and disparity in curing. Similarly, the variability of steel strength is attributed to the manufacturing process, rolling conditions, characteristics of base material, uncertainties in chemical composition, and the microstructure-property relationships. To account for such uncertainties, codes of practice for reinforced concrete design impose resistance factors to ensure structural reliability over the useful life of the structure. In this investigation, the effects of reductions in concrete and reinforcing steel strengths from the nominal values, beyond those accounted for in the structural design codes, on the structural reliability are assessed. The considered limit states are flexure, shear and axial compression based on the ACI 318-11 structural concrete building code. Structural safety is measured in terms of a reliability index. Probabilistic resistance and load models are compiled from the available literature. The study showed that there is a wide variation in the reliability index for reinforced concrete members designed for flexure, shear or axial compression, especially when the live-to-dead load ratio is low. Furthermore, variations in concrete strength have minor effect on the reliability of beams in flexure, moderate effect on the reliability of beams in shear, and sever effect on the reliability of columns in axial compression. On the other hand, changes in steel yield strength have great effect on the reliability of beams in flexure, moderate effect on the reliability of beams in shear, and mild effect on the reliability of columns in axial compression. Based on the outcome, it can be concluded that the reliability of beams is sensitive to changes in the yield strength of the steel reinforcement, whereas the reliability of columns is sensitive to variations in the concrete strength. Since the embedded target reliability in structural design codes results in lower structural safety in beams than in columns, large reductions in material strengths compromise the structural safety of beams much more than they affect columns.
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References:

[1] S.A. Mirza, M.Hatzinikolas, and J.G. MacGregor, "Statistical descriptions of strength of concrete,” Journal of Structural Division, ASCE, Vol. 105, No. 6, 1979, pp. 1021-1037.
[2] F.D. Anderson, "Statistical controls for high-strength concrete,” Texas Civil Engineer, Vol. 58, No. 1, 1988, pp. 16-20.
[3] S.W. Tabsh, and A. Aswad, "Statistics of High Strength Concrete Cylinders," ACI Materials Journal, American Concrete Institute, Vol. 94, No. 5, 1997, pp. 361-364.
[4] T. Chmielewski, T., and E. Konopka, "Statistical evaluations of field concrete strength,” Magazine of Concrete Research, Vol. 51, No. 1, 1999, pp. 45-52.
[5] S.A. El-Desoky, and N.M. Nofal, "Variability of the 28-day to 7-day strength ratio of concrete compressive strength,” Journal of Engineering and Applied Science, Vol. 48, No. 5, 2001, pp. 865-882.
[6] R.M. Diwan, S. Shah, and J. Eggers, "Statistical Quality Control and Quality Assurance Evaluation of Structural and Paving Concrete,” Transportation Research Record, No. 1861, 2003, pp. 71-85.
[7] K. Obla, "Sources of Concrete Strength Variations – Part II of Concrete Quality Series,” Concrete Infocus, NRMCA, July/August, 2010, pp. 21-23.
[8] S.A. Mirza, and J.G. MacGregor, "Variability of mechanical properties of reinforcing bars,” ASCE J StructDiv, Vol. 105, No. 5, 1979, pp. 921-937.
[9] C.P. Joshi, and R. Ranganathan, "Variations in strength of reinforcing steel bars,” Journal of the Institution of Engineers (India): Civil Engineering Division, Vol. 68, No. 6, 1988,pp. 309-312.
[10] S. Akyz, and M.Uyan, "Study on the reinforcing steel bars used in Turkey,” TeknikDergi/Technical Journal of Turkish Chamber of Civil Engineers, Vol. 3, No. 1, 1992, pp. 136-138.
[11] A.M. Arafah, "Statistics for concrete and steel quality in Saudi Arabia,” Magazine of Concrete Research, Vol. 49, No. 180, 1997, pp. 185-193.
[12] C. Galasso, E. Cosenza, and G. Maddaloni, "Statistical analysis of reinforcing steel properties for seismic design of RC structures,” Proceedings of the 14th European Conference on Earthquake Engineering (14 ECEE 2010), Ohrid, Macedonia, 30 Aug – 03 Sept, 2010, pp. 3715-3722.
[13] ASTM C39/C39M-09a, 2009, "Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens,” Annual Book of ASTM Standards, Volume 04.02, American Society for Testing and Materials, Conshohocken, PA.
[14] ASTM A370 - 09ae1, "Standard Test Methods and Definitions for Mechanical Testing of Steel Products,” Annual Book of ASTM Standards, Volume 04.02, American Society for Testing and Materials, Conshohocken, PA, 2009.
[15] ASTM A615/A615M-09b, "Standard Specification for Deformed and Plain Billet-Steel Bars for Concrete Reinforcement,” Annual Book of ASTM Standards, Volume 01.04, American Society for Testing and Materials, Conshohocken, PA, 2009.
[16] ASTM A996/A996M-09b, "Standard Specification for Rail-Steel and Axle-Steel Deformed Bars for Concrete Reinforcement,” Annual Book of ASTM Standards, Volume 01.04, American Society for Testing and Materials, Conshohocken, PA, 2009.
[17] ASTM A706/A706M-09b, "Standard Specification for Low-Alloy Steel Deformed and Plain Bars for Concrete Reinforcement,” Annual Book of ASTM Standards, Volume 01.04, American Society for Testing and Materials, Conshohocken, PA, 2009.
[18] ACI318, "Building Code Requirement for Structural Concrete and Commentary,” ACI318-11, American Concrete Institute, Detroit, 2011, 503 p.
[19] R. Rackwitz, and B. Fiessler, "Structural reliability under combined random load sequences,” Computers & Structures, Vol. 9, Issue 5, 1978, pp. 484–494.
[20] M.M. Szerszen, and A.S. Nowak, "Calibration of Design Code for Buildings (ACI 318): Part 2 - Reliability Analysis and Resistance Factors,” ACI Structural Journal, American Concrete Institute, Vol. 100, No. 3, 2003, pp. 383-391.
[21] B. Ellingwood, T.V. Galambos, J.G. MacGregor, and C.A. Cornell C.A., "Development of a Probability Based Load Criterion for American National Standard A58,” Publication 577, National Bureau of Standards, Dept. of Commerce, Washington, D.C., 1980, 228 pp.
[22] A.S. Nowak, and K.R. Collins, "Reliability of Structures,” McGraw-Hill, New York, 2000, 338 p.
[23] C.J. Turkstra, "Theory of Structural Design Decisions,” Study No. 2, Solid Mechanics Division, University of Waterloo, Ontario, 1970.
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