Title:
Revisiting the ACI 318 Unified Design Provisions for Flexure and Axial Load
Author(s):
Charles W. Dolan
Publication:
Concrete International
Volume:
37
Issue:
10
Appears on pages(s):
33-39
Keywords:
beam, slab, high strength, tensile strain
DOI:
10.14359/51688218
Date:
10/1/2015
Abstract:
The 2014 ACI 318 Building Code has inconsistencies if a slab or beam design is attempted between net tensile strains of 0.004 and 0.005. These inconsistencies become more pressing as designers increasingly specify higher strength concrete and reinforcement. The article discusses issues related to design with a specified concrete strength in excess of 8000 psi (55 MPa) and reinforcement yield strength in excess of 60 ksi (Grade 60 bars, 420 MPa) and lists items in the Code that are being considered for revision.
Related References:
1. Mast, R.F., “Unified Design Provisions for Reinforced and Prestressed Concrete Flexural members and Compression Members,” ACI Structural Journal, V. 89, No. 2, Mar.-Apr. 1992, pp. 186-199.
2. ACI Committee 318, “Building Code Requirements for Structural Concrete (318-99) and Commentary (318R-99),” American Concrete Institute, Farmington Hills, MI, 391 pp.
3. ACI Committee 318, “Building Code Requirements for Structural Concrete (318-02) and Commentary (318R-02),” American Concrete Institute, Farmington Hills, MI, 443 pp.
4. ACI Committee 318, “Building Code Requirements for Structural Concrete (318-11) and Commentary (318R-11),” American Concrete Institute, Farmington Hills, MI, 503 pp.
5. ACI Committee 318, “Building Code Requirements for Structural Concrete (318-14) and Commentary (318R-14),” American Concrete Institute, Farmington Hills, MI, 519 pp.
6. Mast, R.F.; Dawood, M.; Rizkalla, S.H.; and Zia, P., “Flexural Strength Design of Concrete Beams Reinforced with High-Strength Steel Bars,” ACI Structural Journal, V. 105, No. 5, Sep.-Oct. 2008, pp. 570-577.
7. ACI ITG-6R-10, “Design Guide for the Use of ASTM A1035/1035M Grade 100 (690) Steel Bars for Structural Concrete,” American Concrete Institute, Farmington Hills, MI, 2010, 90 pp.
8. NIST GCR 14-917-30, “Use of High-Strength Reinforcement in Earthquake-Resistant Concrete Structures,” NIST, Gaithersburg, MD, Mar. 2014, 231 pp.
9. Bae, S., and Bayrak, O., “Examination of Stress Block Parameters for High-Strength Concrete in the Context of the ACI 318 Code,” Reinforced Concrete Columns with High Strength Concrete and Steel Reinforcement, SP-293, American Concrete Institute, Farmington Hills, MI, 2013 pp. 59-77.
10. Structural Concrete, Textbook on Behavior, Design, and Performance, Vol. 2: Basis of Design, second edition, fib, Lausanne, Switzerland, 2010, pp. 145-150.