Concrete
3.8 Chapter Review
This chapter reviewed the composition and structure of concrete as an aid to understanding its mechanical properties. For seismic design purposes, the most important mechanical properties are stiffness, strength, and deformation capacity. Although highly variable, the modulus of elasticity of concrete can be related to the compressive strength as measured in a standard cylinder test. That compressive strength is an index for the strength potential of concrete in an actual structure, where strength varies as a function of curing conditions, time, and stress state. We should anticipate
that actual concrete strength in a structure will usually exceed the specified compressive strength because of some of these effects and because concrete suppliers usually target a strength that is higher than the specified value.
Under some loading conditions, however, such as under biaxial tension–
compression loading, the effective compressive strength will be less than the uniaxial compressive strength. Strain capacity of concrete at the compressive strength is limited to approximately 0.002 to 0.003. That strain capacity, as well as the compressive strength, can be increased by confining the concrete along the three principal directions.
Chapter 4 will further explore the behavior of confined concrete, and later chapters will use information from Chapters 2 to 4 to derive models for behavior of structural concrete members under typical loadings.
References
ACI 214R-11 (2011). “Guide to Evaluation of Strength Test Results of Concrete,” ACI Manual of Concrete Practice, American Concrete Institute, Farmington Hills, MI, 16 pp.
ACI 214.4R-10 (2010). “Guide for Obtaining Cores and Interpreting Compressive Strength Results,” ACI Manual of Concrete Practice, American Concrete Institute, Farmington Hills, MI, 17 pp.
ACI 215R-92 (1992). “Considerations for Design of Concrete Structures Subjected to Fatigue Loading” (reapproved 1997), ACI Manual of Concrete Practice, American Concrete Institute, Farmington Hills, MI, 24 pp.
ACI 228.1R-03 (2003). “In-Place Methods to Estimate Concrete Strength,”
ACI Manual of Concrete Practice, American Concrete Institute, Farmington Hills, MI, 44 pp.
ACI 228.2R-98 (1998). “Nondestructive Test Methods for Evaluation of Concrete in Structures” (reapproved 2004), ACI Manual of Concrete Practice, American Concrete Institute, Farmington Hills, MI, 62 pp.
ACI 308R-01 (2001). “Guide to Curing Concrete” (reapproved 2008), ACI Manual of Concrete Practice, American Concrete Institute, Farmington Hills, MI, 31 pp.
ACI 318 (2014). Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary, American Concrete Institute, Farmington Hills, MI.
ACI 363R-92 (1992). “Report on High-Strength Concrete,” ACI Manual of Concrete Practice (reapproved 1997), American Concrete Institute,
Farmington Hills, MI, 55 pp.
ACI 544.1R-96 (1996). “Report on Fiber Reinforced Concrete” reapproved 2009, ACI Manual of Concrete Practice, American Concrete Institute, Farmington Hills, MI, 66 pp.
Ahmad, S., and S.P. Shah (1982). “Complete Triaxial Stress-Strain Curves for Concrete,” Journal of the Structural Division, ASCE, Vol. 108, No.
ST4, pp. 728–742.
Ahmad, S., and S.P. Shah (1985). “Behavior of Hoop Confined Concrete under High Strain Rates,” ACI Journal, Vol. 82, No. 5, pp. 634–647.
ASCE 41 (2013). Seismic Evaluation and Retrofit of Existing Buildings, American Society of Civil Engineers, Reston, VA.
ASTM C469 (2010). Standard Test Method for Static Modulus of
Elasticity and Poisson’s Ratio of Concrete in Compression, ASTM International, 5 pp.
Atchley, B.L., and H.L. Furr (1967). “Strength and Energy Absorption Capabilities of Plain Concrete under Dynamic and Static Loadings,”
ACI Journal, Vol. 64, No. 11, pp. 745–756.
Bing, L., R. Park, and H. Tanaka (2000). “Constitutive Behavior of High- Strength Concrete under Dynamic Loads,” ACI Structural Journal, Vol.
97, No. 4, pp. 619–629.
Blunt, J. and C. Ostertag (2009). “Deflection Hardening and Workability of Hybrid Fiber Composites,” ACI Materials Journal, Vol. 106, No. 3, pp. 265–272.
Bresler, B (1971). “Lightweight Aggregate Reinforced Concrete Columns,”
Lightweight Concrete, ACI Publication SP-29, American Concrete Institute, Farmington Hills, MI, pp. 81–130.
Bresler, B., and V.V. Bertero (1975). “Influence of Strain Rate and Cyclic Loading on Behavior of Unconfined and Confined Concrete in
Compression,” XVII Jornadas Sudamericanas de Ingenieria
Estructural, V Simposio Panamericana de Estructuras, Caracas, 8 al 12 de Diciembre de 1975.
Carrasquillo, R.L., A.H. Nilson, and F.O. Slate (1981). “Properties of High Strength Concrete Subjected to Short-Term Loads,” ACI Journal, Vol.
78, No. 3, pp. 171–178.
CSA (2004). Design of Concrete Structures, CSA A23.3-04, Canadian Standards Association, Mississauga, Canada.
Dilger, W.H., R. Koch, and R. Kowalczyk (1984). “Ductility of Plain and Confined Concrete under Different Strain Rates,” ACI Journal, Vol. 81, No. 1, pp. 73–81.
Hobbs, D.W., C.D. Pomeroy, and J.B. Newman (1977). “Design Stresses for Concrete Structures Subject to Multi-axial Stresses,” The
Structural Engineer, The Institution of Structural Engineers, Vol. 55, No. 4, pp. 151–164.
Hsu, T.T.C. (1993). Unified Theory of Reinforced Concrete, CRC Press, Boca Raton, FL, 313 pp.
Karsan, I.D. and J.O. Jirsa (1969). “Behavior of Concrete under
Compressive Loadings,” Journal of the Structural Division, ASCE, Vol. 95, No. ST12, pp. 2543–2564.
Kupfer, H., H.K. Hilsdorf, and H.Rusch (1969). “Behavior of Concrete under Biaxial Stress,” ACI Journal, Vol. 66, No. 8, pp. 656–666.
Mander, J.B., M.J.N. Priestley, and R. Park (1988). “Observed Stress- Strain Behavior of Confined Concrete,” Journal of Structural Engineering, ASCE, Vol. 114, No. 8, pp. 1827–1849.
Martinez, S., A.H. Nilson, and F.O. Slate (1982). Spirally-Reinforced High-Strength Concrete Columns, Research Report No. 82-10, Department of Structural Engineering, Cornell University, Ithaca, NY.
Mehta, P.K., and P.J. Monteiro (2014). Concrete, 4th ed., McGraw-Hill Professional, New York, NY, 675 pp.
Mindess, S., J.F. Young, and D. Darwin (2003). Concrete, 2d ed., Prentice- Hall, Upper Saddle River, NJ, 644 pp.
Monteiro, P.J., and J.P. Moehle (1995). Stiffness of Reinforced Concrete Walls Resisting In-Plane Shear—Tier 2: Aging and Durability of Concrete Used in Nuclear Power Plants, EPRI TR-102731, T2, Electric Power Research Institute, Palo Alto, CA.
PCA (1988). Design and Control of Concrete Mixtures, 13th ed., Portland Cement Association, Skokie, IL.
Richart, F.E., A. Brandtzaeg, and R.L. Brown (1928). A Study of the
Failure of Concrete under Combined Compressive Stresses, Bulletin No. 185, Engineering Experiment Station, University of Illinois,
Urbana, IL, 104 pp.
Ross, C.A., D.M. Jerome, J.W. Tedesco, and M.L. Hughes (1996).
“Moisture and Strain Rate Effects on Concrete Strength,” ACI Materials Journal, Vol. 93, No. 3, pp. 293–300.
Scott, B.D., R. Park, and M.J.N. Priestley (1982). “Stress-Strain Behavior of Concrete Confined by Overlapping Hoops at Low and High Strain Rates,” ACI Journal Proceedings, Vol. 79, No. 1, pp. 13–27.
Soroushian, P., K-B. Choi, and A. Alhamad (1986). “Dynamic Constitutive Behavior of Concrete,” ACI Journal, Vol. 83, No. 2, pp. 251–259.
TBI (2010). Guidelines for Performance-Based Seismic Design of Tall Buildings, Report No. 2010/05, Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, 84 pp.
Vecchio, F.J., and M.P. Collins (1986). “The Modified Compression Field Theory for Reinforced Concrete Elements Subjected to Shear,” Journal of the American Concrete Institute, Vol. 83, No. 2, pp. 219–231.
Watstein, D. (1953). “Effect of Straining Rate on the Compressive Strength and Elastic Properties of Concrete,” Journal of the American Concrete Institute, Vol. 49, No. 8, pp. 729–744.
Wischers, G. (1979). “Applications and Effects of Compressive Loads on Concrete,” Betontechnische Berichte 1978, Betone Verlag GmbH, Dusseldorf, pp. 31–56.
Wood, S.L. (1991). “Evaluation of Long-Term Properties of Concrete,” ACI Materials Journal, Vol. 88, No. 6, pp. 630–643.
____________
1See Mehta and Monteiro (2014) for detailed discussion of concrete structure and properties.
2This book uses both the U.S. customary units and the International System of Units (abbreviated SI). For some equations, expressions, or variables, the units are consistent, such that the same equation, expression, or variable applies to both unit systems. In others, different equations, expressions, or variables are required for the two unit systems. Where this occurs, the equation, expression, or variable is shown first in the U.S. customary units followed by the abbreviation psi (representing pounds per square inch) and second in the SI units followed by the abbreviation MPa (representing megapascal). The result of the equation, expression, or variable, however, is not necessarily in units of psi or MPa. For example, the result of Eq. (3.2) is in either psi or MPa, but the result of Eq. (6.28) is in2 or mm2 rather than psi or MPa.
3The values reported apply to moderate-strength concretes. For higher-strength concretes,
improved quality control may result in lower coefficients of variation. This can be demonstrated on a project-by-project basis.