Title:
Computing Deflections Using ACI CODE-318-19 and Beyond, Part 5
Author(s):
Peter H. Bischoff, Wassim Nasreddine, and Hani Nassif
Publication:
Concrete International
Volume:
47
Issue:
12
Appears on pages(s):
35-41
Keywords:
load, deflection, member, force
DOI:
10.14359/51749338
Date:
12/1/2025
Abstract:
This is the last article in a five-part series on calculating deflections for members not meeting minimum thickness requirements in accordance with ACI CODE-318-19. The Code’s approach for calculating immediate deflection of reinforced (nonprestressed) concrete is broadened to include prestressed concrete loaded above the cracking moment (Class T and Class C prestressed members).
Related References:
1. Bischoff, P.H., “Computing Deflections Using ACI CODE-318-19 and Beyond, Part 1,” Concrete International, V. 47, No. 2, Feb. 2025, pp. 47-50.
2. Bischoff, P.H., “Computing Deflections Using ACI CODE-318-19 and Beyond, Part 2,” Concrete International, V. 47, No. 3, Mar. 2025, pp. 51-54.
3. Bischoff, P.H., “Computing Deflections Using ACI CODE-318-19 and Beyond, Part 3,” Concrete International, V. 47, No. 4, Apr. 2025, pp. 47-50.
4. Bischoff, P.H., “Computing Deflections Using ACI CODE-318-19 and Beyond, Part 4,” Concrete International, V. 47, No. 5, May 2025, pp. 62-65.
5. ACI Committee 318, “Building Code Requirements for Structural Concrete (ACI 318-19) and Commentary (ACI 318R-19),” American Concrete Institute, Farmington Hills, MI, 2019, 624 pp.
6. Branson, D.E., Deformation of Concrete Structures, McGraw-Hill, New York, NY, 1977, 546 pp.
7. Bischoff, P.H.; Nasreddine, W.; and Nassif, H., “Proposed ACI 318 Equations for Immediate Deflection of Prestressed Concrete Members,” ACI Structural Journal, V. 122, No. 6, Nov. 2025, pp. 127-139.
8. Bischoff, P.H.; Naito, C.J.; and Ingaglio, J.P., “Immediate Deflection of Partially Prestressed Concrete Flexural Members,” ACI Structural Journal, V. 115, No. 6, Nov. 2018, pp. 1683-1693.
9. Bischoff, P.H., “Deformation Model for Reinforced and Cracked Prestressed Concrete,” ACI Structural Journal, V. 119, No. 1, Jan. 2022, pp. 243-254.
10. Nilson, A.H., “Flexural Stresses After Cracking in Partially Prestressed Beams,” PCI Journal, V. 21, No. 4, July-Aug. 1976, pp. 72-81.
11. Nasreddine, W.; Obeidah, A.; Bischoff, P.H.; and Nassif, H., “Assessment of Deflection Prediction Models for Cracked Prestressed Concrete Beams,” ACI Structural Journal, V. 120, No. 6, Nov. 2023, pp. 167-179.
12. PCI, PCI Design Handbook: Precast and Prestressed Concrete, seventh edition, Precast/Prestressed Concrete Institute, Chicago, IL, 2010, 804 pp.
13. Mast, R.F., “Analysis of Cracked Prestressed Concrete Sections: A Practical Approach,” PCI Journal, V. 43, No. 4, July-Aug. 1998, pp. 80-91.