Effect of Shape, Number, and Location of Openings on Punching Shear Capacity of Flat Slabs

Ekkachai Yooprasertchai,Theerawee Wittayawanitchai,Jiranuwat Angsumalee,Yonlada Tiawilai,Panuwat Joyklad,Qudeer Hussain

doi:10.3390/buildings11100484

Ekkachai Yooprasertchai, Theerawee Wittayawanitchai + Show 4 more

Open Access

https://doi.org/10.3390/buildings11100484

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Abstract

Experimental evidence have proved that punching shear capacity of flat slabs deteriorate with the presence of openings located within the critical perimeter around columns. It is understood that this deterioration varies inversely with the distance of openings from column’s face. However, effect of the shape of openings on punching shear capacity is not well known. This study presents experimental results of 14 flat specimens to investigate the effects of the number (2 and 4), shape (circular, square, and rectangular), and location (1 and 4 times of slab’s thickness from column’s face) of openings on punching shear strength. It was found that circular openings had least influence on punching capacity followed by square and rectangular openings, respectively. Further, placing openings at a distance of four times the slab’s thickness from column’s face had minimal impact on punching capacity. Further, increasing the number of openings from 2 to 4 substantially reduced the punching capacity. An effort was made to predict the punching capacities of all specimens using the descriptive equations of ACI 318-19 and Eurocode 2. Mean of the ratio of experimental to analytical results and standard deviation of ACI equations were found to be more accurate than those of Eurocode 2 predictions.

Highlights

Nowadays, flat slabs are widely used because of their simple reinforcement details, reduced building heights, rapid construction etc
ACI 318-19 and Eurocode 2 consider the maximum location at which an opening can still affect the punching shear capacity of flat slabs to be 4H and 6d from column’s face, respectively
The objectives of this study are to investigate the effect of the shape on the punching shear capacity of flat slab, to study the effects of the distance of an opening from the column’s face, and to assess the applicability of existing punching shear capacity analytical formulations of ACI 318-19 [18] and Eurocode 2 [19] on the results of this study

Summary

Introduction

Flat slabs are widely used because of their simple reinforcement details, reduced building heights, rapid construction etc. ACI 318-19 and Eurocode 2 consider the maximum location at which an opening can still affect the punching shear capacity of flat slabs to be 4H and 6d from column’s face, respectively (where “H” and “d” are slab thickness and effective depth, respectively). The objectives of this study are to investigate the effect of the shape (circular and square) on the punching shear capacity of flat slab, to study the effects of the distance of an opening from the column’s face, and to assess the applicability of existing punching shear capacity analytical formulations of ACI 318-19 [18] and Eurocode 2 [19] on the results of this study.

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