Finite Element Investigation of Reinforced Concrete Flat Slab-Column Connections under Static and Seismic Loading

International Journal of Civil Engineering

© 2026 by SSRG - IJCE Journal

Volume 13 Issue 1

Year of Publication : 2026

Authors : Vinodkrishna M Savadi, Santosh M Muranal, Sreeshail Heggond

10.14445/23488352/IJCE-V13I1P122

How to Cite?

Vinodkrishna M Savadi, Santosh M Muranal, Sreeshail Heggond, "Finite Element Investigation of Reinforced Concrete Flat Slab-Column Connections under Static and Seismic Loading," SSRG International Journal of Civil Engineering, vol. 13,  no. 1, pp. 255-271, 2026. Crossref, https://doi.org/10.14445/23488352/IJCE-V13I1P122

Abstract:

Punching Shear failure is a severe Limit condition that controls the seismic behavior of Reinforced Concrete (RC) flat slab-column connections. Such critical structural connections are widely used in modern construction due to economic design benefits and aesthetic appearances, which reduce the floor height in the absence of beams. The study identifies the key parameters that influence flat slab column connection failures, including punching shear, inadequate reinforcement, and poor detailing. Previous studies have revealed that the punching shear failure is the primary cause of Flat slab column connection failures, strongly influenced by concrete grade and reinforcement detailing. This work is a Finite Element Analysis (FEA) exploration of twelve flat slab-column connection models in FEA software to assess the effect of concrete grades M25 and M30, utilizing different types of reinforcement, including stirrups and stud rails, and loading for both static and seismic conditions. Concrete Damaged Plasticity (CDP) was used to model the nonlinear material behaviour of concrete, and the seismic shear demand was applied as required by the IS 1893. Unstiffened flat slabs in the shear region were brittle and exhibited rapid post-peak strength that declined, resulting in low residual capacity. Conversely, a stiffened flat slab in the shear region has demonstrated significant improvements in mass-carrying capacity, ductility, and energy-dispersing capabilities. Stirrups increased confinement, and stud rails offered better stability at the post-peak by maintaining residual strength and increasing the time to evolve damage. A higher concrete grade increased stiffness and maximum resistance, whereas the type of reinforcement was a key factor in determining ductility. A relative comparison with IS 456, ACI 318, and Eurocode 2 design provisions revealed that the predictions of punching shear using these codes are always conservative compared to those obtained through numerical methods. In general, the results emphasize the significance of reinforcement detailing in increasing the seismic resilience of flat slab systems, with stud rails proving to be the most promising form of reinforcement.

Keywords:

Reinforced Concrete (RC) slab–column connections, Punching shear, Finite Element Analysis (FEA), Concrete Damaged Plasticity (CDP), Seismic performance, Shear reinforcement, Stirrups, Stud rails, Ductility, Residual strength, Flat slab systems.

References:

[1] D.A. Gasparini, “Contributions of C.A.P. Turner to the Development of Reinforced Concrete Flat Slabs, 1905-1909,” Journal of Structural Engineering (ASCE), vol. 128, no. 10, pp. 1243-1252, 2002.
[CrossRef] [Google Scholar] [Publisher Link]
[2] National Bureau of Standards (NBS), Engineering Aspects of the September 19, 1985 Mexico Earthquake (NBS BSS 165), Building Science Series, National Institute of Standards and Technology, Gaithersburg, 1987.
[CrossRef] [Google Scholar] [Publisher Link]
[3] Utkarsh et al., “A Comprehensive Bibliometric Analysis of Punching Shear Failures in Flat Slabs,” Discover Civil Engineering, vol. 2, no. 1, pp. 1-18, 2025.
[CrossRef] [Google Scholar] [Publisher Link]
[4] Martin Classen, “Punching Shear Response Theory (PSRT) - A Two Degree of Freedom Kinematic Theory for Modeling the Entire Punching Shear vs. Deformation Response of RC Slabs and Footings,” Engineering Structures, vol. 291, 2023.
[CrossRef] [Google Scholar] [Publisher Link]
[5] Junping Liu et al., “Experimental Study on Punching Shear Behaviour of Ultra-High-Performance Concrete (UHPC) Slabs,” Buildings, vol. 15, no. 10, pp. 1-20, 2025.
[CrossRef] [Google Scholar] [Publisher Link]
[6] Assefa Erkocho Onse, and Temesgen Wondimu Aure, “Punching Shear Behaviour of HSC Slab-Column Connection under Cyclic Loading,” Transactions of the Indian National Academy of Engineering, vol. 9, no. 1, pp. 155-173, 2024.
[CrossRef] [Google Scholar] [Publisher Link]
[7] Frederico P. Maués et al., “Numerical Modelling of Flat Slabs with Different Amounts of Double-Headed Studs as Punching Shear Reinforcement,” Buildings, vol. 15, no. 6, pp. 1-25, 2025.
[CrossRef] [Google Scholar] [Publisher Link]
[8] Sua Lim et al., “Punching Shear Strength of RC Flat Plate Slab-Column Connections Strengthened with Column Head Steel Plates,” Journal of Building Engineering, vol. 111, 2025.
[CrossRef] [Google Scholar] [Publisher Link]
[9] Junping Liu et al., “Experimental Study on Punching Shear Behavior of Ultra-High-Performance Concrete (UHPC) Slabs,” Buildings, vol. 15, no. 10, pp. 1-26, 2025.
[CrossRef] [Google Scholar] [Publisher Link]
[10] Ahmed Hamoda et al., “Experimental and Numerical Investigations of Punching Shear Strengthening of Slab-Circular Column Connection Incorporating UHPC and Galvanized Threaded Steel Bolts,” International Journal of Concrete Structures and Materials, vol. 19, no. 1, pp. 1-21, 2025.
[CrossRef] [Google Scholar] [Publisher Link]
[11] Sheng Zheng et al., “Explainable Prediction Model for Punching Shear Strength of FRP-RC Slabs based on Kernel Density Estimation and XGBoost,” Scientific Reports, vol. 14, no. 1, pp. 1-15, 2024.
[CrossRef] [Google Scholar] [Publisher Link]
[12] Dina M. Ors et al., “Machine Learning Base Models to Predict the Punching Shear Capacity of Posttensioned UHPC Flat Slabs,” Scientific Reports, vol. 14, no. 1, pp. 1-20, 2024.
[CrossRef] [Google Scholar] [Publisher Link]
[13] Hua-Jun Yan, and Nan Xie, “Optimized Machine Learning Algorithms for Predicting the Punching Shear Resistance of Flat Slabs with Transverse Reinforcement,” International Journal of Concrete Structures and Materials, vol. 18, no. 1, pp. 1-16, 2024.
[CrossRef] [Google Scholar] [Publisher Link]