Sectional response of non-rectangular concrete walls with minimum vertical reinforcement

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DOI:

https://doi.org/10.5459/bnzsee.1619

Abstract

Past research that investigated the behaviour of rectangular lightly reinforced concrete walls resulted in revisions to minimum vertical reinforcement provisions in concrete design standards in both New Zealand (NZS 3101:2006) and the United States (ACI 318-19). However, the minimum vertical reinforcement provisions developed for rectangular wall sections may not be suitable for non-rectangular walls due to the influence of flanges on the nominal flexural and cracking section capacities. A parametric study confirmed that non-rectangular wall sections with minimum vertical reinforcement in accordance with current NZS 3101 design provisions exhibit a lower margin between cracking and nominal flexural strength than comparable rectangular wall sections. The ratio of the sectional nominal flexural strength to cracking strength (Mn/Mcr ) was less than 1.0 for non-rectangular sections with long flange lengths and low axial loads. The model results indicated that current vertical reinforcement requirements are insufficient to prevent a sudden and potentially unstable strength drop when cracking occurs in non-rectangular walls. A theoretical equation to calculate the required minimum vertical reinforcement was proposed for the typical I-shaped wall sections, including the impact of concrete strength and flange to web ratio. The proposed equation highlighted the need for an increase in the minimum vertical reinforcement limits for non-rectangular wall sections compared to the existing minimum vertical reinforcement requirement applicable to rectangular wall sections.

References

Bruneau M and MacRae GA (2017). “Reconstructing Christchurch: A Seismic Shift in Building Structural Systems”. Technical Report, The Quake Centre, University of Canterbury. DOI: https://doi.org/10.4028/www.scientific.net/KEM.763.11

Pascua MCL, Henry RS and Toma C (2020). “Review of recently constructed buildings that combine steel frames and concrete walls”. Proceedings of the 2020 New Zealand Society for Earthquake Engineering Annual Technical Conference, Wellington.

Henry RS (2013). “Assessment of minimum vertical reinforcement limits for RC walls”. Bulletin of the New Zealand Society for Earthquake Engineering, 46(2): 88–96. https://doi.org/10.5459/bnzsee.46.2.88-96 DOI: https://doi.org/10.5459/bnzsee.46.2.88-96

Puranam AY and Pujol S (2019) “Reinforcement limits for reinforced concrete elements with high-strength steel”. ACI Structural Journal, 116(5), 201–212. https://doi.org/10.14359/51716762 DOI: https://doi.org/10.14359/51716762

Lu Y, Henry RS, Gultom R and Ma Q (2017). “Cyclic testing of reinforced concrete walls with distributed minimum vertical reinforcement”. Journal of Structural Engineering, 143(5). https://doi.org/10.1061/(ASCE)ST.1943-541X.0001723 DOI: https://doi.org/10.1061/(ASCE)ST.1943-541X.0001723

SNZ (2017). “NZS 3101:2006-A3: Concrete Structures Standard”. Standards New Zealand, Wellington, New Zealand.

ACI Committee 318 (2019). “Building Code Requirements for Structural Concrete (ACI 318-19)”. American Concrete Institue, Farmington Hills, MI

Lu Y and Henry RS (2017). “Minimum vertical reinforcement in RC walls: Theoretical requirements for low and high ductility demands”. Bulletin of the New Zealand Society for Earthquake Engineering, 50(4): 471–481. https://doi.org/10.5459/bnzsee.50.4.471-481 DOI: https://doi.org/10.5459/bnzsee.50.4.471-481

O’Hagan J and Stuart T (2021). “The effects of the extent of cracking on the design of reinforced concrete wall structures”. SESOC Conference, Hamilton, New Zealand.

Canterbury Earthquake Royal Commission (2012). “Final Report Volume 2: The Performance of Christchurch CBD Buildings”. Wellington, New Zealand.

Paulay T and Priestley MJN (1992). Seismic Design of Reinforced Concrete and Masonry Buildings. John Wiley & Sons, Inc., New York.

SNZ (2006). “NZS 3101:2006-A2. Concrete Structures Standard”. Standards New Zealand, Wellington, New Zealand.

Menegotto M and Pinto PE (1973). “Method of analysis for cyclically loaded RC plane frames including changes in geometry and non-elastic behavior of elements under combined normal force and bending”. In IABSE Reports of the Working Commissions.

Filippu FC, Popov EP and Beryero VV (1983). “Effects of Bond Deterioration on Hysteretic Behavior of Reinforced Concrete Joints”. Earthquake Engineering Research Center, University of California.

FIB (2010). “FIB Model Code 2010 Volume 1”. FIB Bulletin 65, The International Federation for Structural Concrete (fib), Lausanne, Switzerland.

Lu Y and Henry RS (2018). “Comparison of minimum vertical reinforcement requirements for reinforced concrete walls.” ACI Structural Journal., 115 (3): 673–687. https://doi.org/10.14359/51701146 DOI: https://doi.org/10.14359/51701146

SNZ (2019). “AS/NZS 4671:2019: Steel for the Reinforcement of Concrete”. Australia/New Zealand Standards, Sydney/Wellington.

Paulay T and Priestley MJN (1992). Seismic Design of Reinforced Concrete and Masonry Buildings. John Wiley and Sons Inc., New York. DOI: https://doi.org/10.1002/9780470172841

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Published

29-02-2024

How to Cite

Deng, T., & Henry, R. S. (2024). Sectional response of non-rectangular concrete walls with minimum vertical reinforcement. Bulletin of the New Zealand Society for Earthquake Engineering, 57(1), 58–68. https://doi.org/10.5459/bnzsee.1619

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