Behavior of R.C Slab-Column Connections with Square and Circular Columns under Gravity and Lateral Cyclic Loading Conditions

Abathar M. Al- Yaseri; Laith  Al-Hadithy

doi:10.29194/NJES.29020198

Authors

Abathar M. Al- Yaseri Civil Engineering Department, Kerbala University, Karbala, Iraq
Dr. Laith Kh. Al-Hadithy Department of Civil Engineering, College of Engineering, Al -Nahrain University, Baghdad, Iraq

DOI:

https://doi.org/10.29194/NJES.29020198

Keywords:

Slab-Column Connections, Gravity load, Lateral Cyclic Loading, Circular Columns

Abstract

This experimental investigation evaluates the structural behavior of reinforced concrete slab-column connections incorporating columns with square and circular cross-sectional geometries under gravity and lateral cyclic loading. Four interior slab-column specimens were designed, fabricated, and tested, with identical slab dimensions of 1050×1050×80 mm and a column height of 500 mm. The circular columns were intended to have an equivalent second moment of inertia to the square column, ensuring a fair comparison of geometric effects. One specimen identified as SC-G, incorporating a square column, was tested under a progressively increasing vertical load to determine its maximum gravity load-bearing capacity. The remaining three specimens SC-2 with a square tied column, SC-9 with a circular spirally-reinforced column, and SC-10 with a circular column incorporating a column capital were tested under a constant gravity load equivalent to 60% of SC-G’s ultimate capacity (75 kN), combined with a lateral displacement protocol conforming to ACI 374 guidelines. Results indicated that the shape of the column (circular) and reinforcement (spiral) in SC-9 produces a comparatively higher ultimate load, stiffness, and ductility than SC-2 of the square column and tied reinforcement. The ultimate lateral load increase was +13.3%, -26.1%. Circular spiral columns with column capital in slab-column connections led to a noticeable rise in ultimate lateral load by about +62%, -80%. It was also shown that incorporating a column capital in SC-10 significantly enhanced the punching shear resistance and energy dissipation capacity. Circular columns demonstrated more stable hysteretic behavior and improved ductility compared to the square column specimen.

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References

H. N. G. Al‑Maliki, A. Al‑Balhawi, and A. M. Ali, "Punching shear resistance of reinforced concrete flat slabs strengthened by CFRP and GFRP: A review of literature," Eng. Technol. J., vol. 39, no. 8, pp. 1281-1290, 2021.

https://doi.org/10.30684/etj.v39i8.2011 DOI: https://doi.org/10.30684/etj.v39i8.2011

A. S. Genikomsou, "Seismic damage assessment of reinforced concrete slab‑column connections: Review of test data, code provisions and analytical models," Buildings, vol. 14, no. 2, p. 465, Feb. 2024.

https://doi.org/10.3390/buildings14020465 DOI: https://doi.org/10.3390/buildings14020465

S. Agudze, D. K. Amoah, and B. K. Sasraku‑Neequaye, "Comparative study of RCC flat slab and RCC beam‑and‑slab floor systems," Civil Environ. Res., vol. 10, no. 8, pp. 17-26, 2018.

R. Z. Alrousan and B. R. Alnemrawi, "Punching shear behavior of FRP reinforced concrete slabs under different opening configurations and loading conditions," Case Stud. Constr. Mater., vol. 17, e01508, Dec. 2022.

https://doi.org/10.1016/j.cscm.2022.e01508 DOI: https://doi.org/10.1016/j.cscm.2022.e01508

ACI Committee 318, Building Code Requirements for Structural Concrete (ACI 318‑19) and Commentary. Farmington Hills, MI, USA: ACI, 2019.

European Committee for Standardization, Eurocode 2: Design of Concrete Structures - Part 1‑1: General Rules and Rules for Buildings (EN 1992‑1‑1). Brussels, Belgium: CEN, 2004.

Canadian Standards Association, Design of Concrete Structures (CSA A23.3‑19). Toronto, ON, Canada: CSA Group, 2019.

JSCE, Standard Specifications for Concrete Structures - 2007: Design. Tokyo, Japan: Japan Soc. Civil Eng., 2007.

E. Yehia, A. H. Khalil, E.‑E. Mostafa, and M. A. El‑Nazzer, "Experimental and numerical investigation on punching behavior of ultra‑high performance concrete flat slabs," Ain Shams Eng. J., vol. 14, no. 10, 102208, Oct. 2023.

https://doi.org/10.1016/j.asej.2023.102208 DOI: https://doi.org/10.1016/j.asej.2023.102208

Applied Technology Council, Effects of Strength and Stiffness Degradation on Seismic Response, FEMA P440A. Washington, D.C., USA: FEMA, Jun. 2009.

M. Tonidis, A. Sharma, and V. Birtel, "Experimental and numerical investigations on the influence of transverse beams and slab on the seismic behavior of non‑seismically designed exterior beam‑column joints," Earthq. Eng. Struct. Dyn., vol. 53, no. 14, pp. 4451-4476, Sep. 2024. https://doi.org/10.1002/eqe.4228 DOI: https://doi.org/10.1002/eqe.4228

T.‑K. Lee and C.‑C. Chen, "Seismic investigation of reinforced concrete columns with different transverse reinforcements," Adv. Struct. Eng., vol. 25, no. 4, Jul. 2022. https://doi.org/10.1177/13694332221114071 DOI: https://doi.org/10.1177/13694332221114071

B. Isufi, M. Rossi, and A. P. Ramos, "Influence of flexural reinforcement on the seismic performance of flat slab-column connections," Eng. Struct., vol. 242, 112583, Sep. 2021. https://doi.org/10.1016/j.engstruct.2021.112583 DOI: https://doi.org/10.1016/j.engstruct.2021.112583

G. T. Truong, K. K. Choi, and C. S. Kim, "Punching shear strength of interior concrete slab‑column connections reinforced with FRP flexural and shear reinforcement," J. Build. Eng., vol. 46, 103692, 2022. https://doi.org/10.1016/j.jobe.2021.103692 DOI: https://doi.org/10.1016/j.jobe.2021.103692

I. A. Sarhan, A. S. Mahmoud, and M. A. Hussian, "Punching shear resistance of high‑strength GFRP reinforced concrete flat slabs," Iraqi J. Civil Eng., vol. 11, no. 1, pp. 72-93, 2017. https://doi.org/10.37650/ijce.2017.134052 DOI: https://doi.org/10.37650/ijce.2017.134052

A. R. Yousif, A. S. Mahmoud, and M. T. Abduljaleel, "Punching strength of GFRP reinforced concrete slab‑column connections with openings by the finite element method," ZANCO J. Pure Appl. Sci., vol. 28, no. 6, pp. 56-67, 2017. https://doi.org/10.21271/ZJPAS.28.6.8 DOI: https://doi.org/10.21271/ZJPAS.28.6.8

M. Zhou and T. D. Hrynyk, "Numerical investigation on the structural performance of post‑tensioned precast concrete two‑way slab‑column connections," Structures, vol. 69, 107520, Nov. 2024. https://doi.org/10.1016/j.istruc.2024.107520 DOI: https://doi.org/10.1016/j.istruc.2024.107520

Y. Jia and J. C. L. Chiang, "Finite element analysis of punching shear of reinforced concrete mushroom slab‑column connections using ABAQUS," in Advances in Frontier Research on Engineering Structures, Y. Yang, Ed. Lecture Notes in Civil Engineering, vol. 286. Springer, 2023. https://doi.org/10.1007/978-981-19-8657-4_8 DOI: https://doi.org/10.1007/978-981-19-8657-4_8

R. B. Babu and R. Thenmozhi, "Experimental and numerical studies on punching shear strength of concrete slabs containing sintered fly ash aggregates," Rev. Constr., vol. 20, no. 1, pp. 15-24, 2021. https://doi.org/10.7764/RDLC.20.1.15 DOI: https://doi.org/10.7764/RDLC.20.1.15

S. Rafiee, A. Hosseini, and M. S. Marefat, "Seismic details for exterior connections of post‑tensioned flat slabs to steel columns using steel plates, vertical stiffeners and bolts," J. Build. Eng., vol. 36, 102140, Apr. 2021. https://doi.org/10.1016/j.jobe.2020.102140 DOI: https://doi.org/10.1016/j.jobe.2020.102140

S. Rafiee and M. S. Marefat, "Experimental and numerical evaluation of new seismic details for connection of post‑tensioned flat slabs to edge steel columns," Curr. Trends Civil Struct. Eng., vol. 6, no. 4, pp. 1-11, Nov.

ACI Committee 374, Acceptance Criteria for Moment Frames Based on Structural Testing and Commentary (ACI 374.1‑05). Farmington Hills, MI, USA: ACI, 2005.

Sika Group, Technical Data Sheet: Sika® ViscoCrete®‑180 GS - High‑Performance Superplasticizer. Baar, Switzerland: Sika Services AG.

ASTM International, ASTM A615/A615M‑20: Standard Specification for Deformed and Plain Carbon‑Steel Bars for Concrete Reinforcement. West Conshohocken, PA, USA: ASTM Int., 2020.

I.Q.S, Aggregate from Natural Sources for Concrete and Construction, Iraqi Specification No. 45. Baghdad, Iraq: COSQC, 2019.

ACI Committee 308, Guide to External Curing of Concrete, ACI 308R‑16. Farmington Hills, MI, USA: ACI, 2016.

ASTM International, ASTM C496/C496M‑17: Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens. West Conshohocken, PA, USA: ASTM Int., 2017.

ASTM International, ASTM C78/C78M‑18: Standard Test Method for Flexural Strength of Concrete (Using Simple Beam with Third‑Point Loading). West Conshohocken, PA, USA: ASTM Int., 2018.

ASTM International, ASTM C469/C469M‑14: Standard Test Method for Static Modulus of Elasticity and Poisson's Ratio of Concrete in Compression. West Conshohocken, PA, USA: ASTM Int., 2014.

C. S. Lee and S. W. Han, "An accurate numerical model simulating hysteretic behavior of reinforced concrete columns irrespective of types of loading protocols," Int. J. Concr. Struct. Mater., vol. 15, no. 1, Dec. 2021. https://doi.org/10.1186/s40069-020-00446-5 DOI: https://doi.org/10.1186/s40069-020-00446-5

I. N. Robertson and G. P. Johnson, "Cyclic lateral loading of non‑ductile slab‑column connections," ACI Struct. J., vol. 103, no. 3, pp. 356-364, Jun. 2006. https://doi.org/10.14359/15313 DOI: https://doi.org/10.14359/15313

M. Ahmed, "Strengthening of reinforced concrete slab‑column connections using CFRP," presented at the 2nd Conf. Civil Eng., Khartoum, Sudan, Dec. 2018.