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Pro118-2

Longitudinal Reinforcement Limits in RC Vertical Elemets Based on Creep and Shrinkage Prediction Models



Author(s): Najeeb Shariff and Devdas Menon
Paper category: Proceedings
Book title: Proceedings of International Conferences (ICACMS) Advances in Construction Materials and systems Vol 2
Editor(s): Manu Santhanam, Ravindra Gettu, Radhakrishna G. Pillai, Sunitha K. Nayar
ISBN: 978-2-35158-194-0
e-ISBN: 978-2-35158-191-9
Publisher: RILEM Publications SARL
Publication year: 2017
Pages: 374-381
Total Pages: 8
Language : English


Abstract: International codes of practice specify limits on reinforcement percentage in Reinforced Concrete (RC) columns and walls. The upper limit to reinforcement is usually attributed to congestion of rebars. However, an additional check on tensile stress in concrete, as a consequence of restrained shrinkage due to high steel ratio, is necessary. Similarly, the lower limit to reinforcement is generally attributed to accidental loading and crack control. However, passive yielding of steel on account of excessive compressive stress due to creep and shrinkage in concrete must also be checked. This paper compares the creep and shrinkage strains predicted using four models, viz. ACI 209, EC2, CEB-FIP MC10 and GL2000, for different cross-sections, grades of concrete and humidity ranges, in addition to different ages of concrete. These strains are used in computing the reinforcement limits for RC columns and walls based on analytical method suggested by Lin and Furlong, 1995. Based on the design life of the structure, geometry, material properties and environmental conditions, reinforcement limits are proposed. Finally, the reinforcement ratios are checked against codal provisions, and it is established that the additional checks proposed are required in some cases for maximum steel ratio. However, the minimum steel ratio in columns can be lower than the values specified in codes, provided accidental loads and crack-widths are taken care
of.


Online publication : 2017
Publication type : full_text
Public price (Euros) : 0.00


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