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<p>Punching shear behavior usually governs the design of flooring of heavy storage facilities due to the stress concentration below the steel supports of the storage shelves. This paper presents a comprehensive experimental study to investigate the effect of various parameters on the punching shear behavior of the reinforced concrete footings supported on sand soil. Nine square footings were designed, fabricated, and loaded to investigate the influence of the footing concrete compressive strength (34.50&#xa0;MPa, 42.50&#xa0;MPa and 61&#xa0;MPa), column aspect ratio (1:1, 1:2 and 1:3), additional vertical reinforcement (8Ø6 and 8Ø8) and the relative eccentricity to the footing dimension (1:0.08 and 1:0.16). All footings were rested on the same type of soil of dense sand soil. During loading, both load and settlement were recorded at various positions, and load pressure were measured at the same LVDT locations. Strains in the footing’s main reinforcement, as well as in any additional reinforcement, were also monitored. All footing specimens failed due to punching. Footings punching shear strength is enhanced by 12% and 34% with the increase of concrete compressive strength to 42.5&#xa0;MPa and 61&#xa0;MPa, respectively. The bigger column aspect ratio enhanced the punching ultimate strength by 33% and 74% in case of 1:2 and 1:3, respectively. Also, addition of vertical reinforcement enhanced the ultimate punching capacity by 12% and 24% in case of using eight rebars with 6&#xa0;mm and 8&#xa0;mm in diameter. Increase of load eccentricity increased the ultimate load till the failure cone area extends reached the edges of the footing/soil interface. Modulus of subgrade reaction increased with the increase of all parameters under the center of each footing. Footing with big eccentricity achieved zero subgrade reaction at low-loaded side with increased values at high loaded side by 31%, 46% and 180%, 103% at edges and corners for footings with small and big eccentricity, respectively. The results demonstrate that current code provisions are conservative in predicting punching shear capacity, particularly for footings with large column aspect ratios more than 1:2. These findings provide useful insights for improving foundation design approaches, supporting safer and more economical design of reinforced concrete footings.</p>

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Experimental Investigation on Punching Shear Behavior of Isolated Footings Resting on Sand

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年5月8日

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  • Dina M. Ors,
  • Nada M. Abdelhamid,
  • Amr H. Zaher,
  • Ahmed M. Ebid

摘要

Punching shear behavior usually governs the design of flooring of heavy storage facilities due to the stress concentration below the steel supports of the storage shelves. This paper presents a comprehensive experimental study to investigate the effect of various parameters on the punching shear behavior of the reinforced concrete footings supported on sand soil. Nine square footings were designed, fabricated, and loaded to investigate the influence of the footing concrete compressive strength (34.50 MPa, 42.50 MPa and 61 MPa), column aspect ratio (1:1, 1:2 and 1:3), additional vertical reinforcement (8Ø6 and 8Ø8) and the relative eccentricity to the footing dimension (1:0.08 and 1:0.16). All footings were rested on the same type of soil of dense sand soil. During loading, both load and settlement were recorded at various positions, and load pressure were measured at the same LVDT locations. Strains in the footing’s main reinforcement, as well as in any additional reinforcement, were also monitored. All footing specimens failed due to punching. Footings punching shear strength is enhanced by 12% and 34% with the increase of concrete compressive strength to 42.5 MPa and 61 MPa, respectively. The bigger column aspect ratio enhanced the punching ultimate strength by 33% and 74% in case of 1:2 and 1:3, respectively. Also, addition of vertical reinforcement enhanced the ultimate punching capacity by 12% and 24% in case of using eight rebars with 6 mm and 8 mm in diameter. Increase of load eccentricity increased the ultimate load till the failure cone area extends reached the edges of the footing/soil interface. Modulus of subgrade reaction increased with the increase of all parameters under the center of each footing. Footing with big eccentricity achieved zero subgrade reaction at low-loaded side with increased values at high loaded side by 31%, 46% and 180%, 103% at edges and corners for footings with small and big eccentricity, respectively. The results demonstrate that current code provisions are conservative in predicting punching shear capacity, particularly for footings with large column aspect ratios more than 1:2. These findings provide useful insights for improving foundation design approaches, supporting safer and more economical design of reinforced concrete footings.