Aspect Ratio Consideration in Flat Plate Concrete Slab Deflection

  • sarkawt asad hasan Department of Civil Engineering, Erbil Engineering Technical College, Erbil Polytechnic University
  • Bahman Omar Taha Department of Civil Engineering, Erbil Engineering Technical College, Erbil Polytechnic University
Keywords: Flat Plate Floor, Aspect Ratio, Long Term Deflection, Permissible Deflection, ACI318-14

Abstract

This paper addresses the effect of the aspect ratio (long span/short span), concrete strength grade and live load on the long-term deflection of uniformly loaded corner flat plate floor panels without edge beams.  It outlines in particular the effects of not considering the aspect ratio parameter in five national codes of practice provisions for the minimum slab thickness and tries to search for the “slab reference span” along which the calculated actual relative deflection and the maximum permissible deflection are determined. The calculations of deflections have been done by the finite element SAFE software through a parametric study with variable long span length, aspect ratio, thickness as recommended by ACI 318-14, concrete grade and live load.

The results showed that, for the range of concrete grade and live load studied, the slab panel aspect ratio parameter has the largest effect on the long-term deflection; the parameter which is overlooked by all the five codes of practice. In spite of this effect, the applicability of the ACI 318-14 provisions for thickness of flat plat floors without beams seemed to be adequate for the L/360 limit, L/240 limit for typical spans and concrete strength grade but showed to be inadequate in many cases to satisfy the L/480 limit. Further, the results showed that the relative deflection along the long span could be recommended for deflection control in flat plate floors without edge beams.

References

ACI 318-14. (2014). Building Code Requirments for Reinforced Concrete (ACI 318-14) and Comentray . Detroit: American Concrete Institute, Farmington Hills.
ACI 435R-95. (2003). Control of Deflection in Concrete Structures (ACI435R-95). Detroit: American Concrete Institute.
ACI SP-17(14): Volume 2. (2015). "The Reinforced Concrete Design Handbook" An ACI Handbook; A Companion to ACI 318-14. Detroit: American Concrete Institute, Farmington Hills.
AS 3600-18. (2018). Australian Standard for Concrete Structures. Sydney: Standards Australia.
ASCE/SEI 7-10. (2010). Minimum Design Loads for Buildings and Other Structures. Virginia: American Society of Civil Engineers.
Bondy, K. B. (2005). ACI Code Deflection Requirements - Time for a Change ? Serviceability of Concrete: A Symposium Honoring Dr. Edward G. Nawy,. ACI Special Publications. SP-225-06, 133-145 pp.
BS EN 8110-1-97. (1997). British Standard Code: Design of Concrete Structures. London,: British Standards Institution.
CSA A23.3-14. (2014). Design of Concrete Structures. Ontario, Canada: Canadian Standards Association.
EN 1992-1-1-04. (2004). Eurocode 2: Design of Concrete Structures. General Rules and Rules for Buildings - Part 1-1 : General rules and rules for buildings. London: British Standards Institution.
Gilbert, R. I. (1985). "Deflection Control of Slabs using Allowable Span to Depth Ratios". ACI Journal, 82(01), 67-72 pp.
Hwang, Sh. J. and Chang, K. Y. (1996). Deflection Control of Two-way Reinforced Concrete Slab. ASCE, Journal of Structural Engineering, pp 160-169.
MacGregor, J G. and Wight, J K. (2012). Reinforced Concrete: Mechanics & Design (6th ed.). New Jersey, USA: Pearson Education, Inc.
Nawy, E. G. (2009). Reinforced Concrete: A Fundemental Approach (6th Edition. ed.). New Jersey: Pearson International Edition.
Nilson, A., Darwin, D., Dolan, C. (2016). Design of Concrete Structures (15th Edition ed.). New York: McGraw-Hill Company.
Regan, P. I. (1981). "Behaviour of Reinforced Concrete Flat Slabs". The Construction Industry Research and Information Association (CIRIA). London: CIRIA Report 89.
Scanlon, A. and Lee, Y. H. (2010). Comparison of One- and Two-Way Slab Minimum Thickness Provisions in Building Codes and Standards. ACI Structural Journal, 107(2), pp 157-163.
Published
2020-10-13
How to Cite
hasan, sarkawt and Taha, B. (2020) “Aspect Ratio Consideration in Flat Plate Concrete Slab Deflection”, Zanco Journal of Pure and Applied Sciences, 32(5), pp. 62-77. doi: 10.21271/ZJPAS.32.5.6.
Section
Mathematics ,Physics and Engineering Researches