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Strength of footing with punching shear preventers.

Lee SS, Moon J, Park KS, Bae KW - ScientificWorldJournal (2014)

Bottom Line: The punching shear failure is an undesirable failure mode, since it results in a brittle failure of the footing.The validation and effectiveness of PSP were verified through a series of experimental studies.Finally, the design recommendations for the footing with PSPs were suggested.

View Article: PubMed Central - PubMed

Affiliation: Advanced Building Research Division, Korea Institute of Civil Engineering and Building Technology (KICT), Goyang-si, Gyeonggi-do 411-712, Republic of Korea.

ABSTRACT
The punching shear failure often governs the strength of the footing-to-column connection. The punching shear failure is an undesirable failure mode, since it results in a brittle failure of the footing. In this study, a new method to increase the strength and ductility of the footing was proposed by inserting the punching shear preventers (PSPs) into the footing. The validation and effectiveness of PSP were verified through a series of experimental studies. The nonlinear finite element analysis was then performed to demonstrate the failure mechanism of the footing with PSPs in depth and to investigate the key parameters that affect the behavior of the footing with PSPs. Finally, the design recommendations for the footing with PSPs were suggested.

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Related in: MedlinePlus

Crack pattern in the middle plane of the test specimen: (a) P5_6 and (b) P5H_3.2.
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fig8: Crack pattern in the middle plane of the test specimen: (a) P5_6 and (b) P5H_3.2.

Mentions: After the test, the specimens were cut to document the crack patterns. Figures 7–9 show the crack patterns of each test specimen. For P0_RC specimen, the cracks were developed in diagonal direction from the top to the bottom of the footing, as shown in Figure 7(a). This is a typical shear crack developed by punching shear. On the other hand, for P5_3.2, P5_6, and P5H_3.2 specimens, major cracks initiated at the interface between the column and the top surface of the footing were stopped approximately at the center of the exterior part of PSP, as shown in Figures 7(b), 8(a), and 8(b). As a result, shear cracks were isolated by PSP and the resistance was not significantly reduced. In the case of P7_3.2 specimen, it can be seen that the distance from the interface between the column and the top surface of the footing, where the shear crack initiated, to the exterior part of PSP is relatively far away compared to P5_3.2, P5_6, and P5H_3.2 specimens. Thus, the shear cracks were not effectively isolated. Taken as a whole, the following observations and conclusions were made from the experimental study.


Strength of footing with punching shear preventers.

Lee SS, Moon J, Park KS, Bae KW - ScientificWorldJournal (2014)

Crack pattern in the middle plane of the test specimen: (a) P5_6 and (b) P5H_3.2.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4221878&req=5

fig8: Crack pattern in the middle plane of the test specimen: (a) P5_6 and (b) P5H_3.2.
Mentions: After the test, the specimens were cut to document the crack patterns. Figures 7–9 show the crack patterns of each test specimen. For P0_RC specimen, the cracks were developed in diagonal direction from the top to the bottom of the footing, as shown in Figure 7(a). This is a typical shear crack developed by punching shear. On the other hand, for P5_3.2, P5_6, and P5H_3.2 specimens, major cracks initiated at the interface between the column and the top surface of the footing were stopped approximately at the center of the exterior part of PSP, as shown in Figures 7(b), 8(a), and 8(b). As a result, shear cracks were isolated by PSP and the resistance was not significantly reduced. In the case of P7_3.2 specimen, it can be seen that the distance from the interface between the column and the top surface of the footing, where the shear crack initiated, to the exterior part of PSP is relatively far away compared to P5_3.2, P5_6, and P5H_3.2 specimens. Thus, the shear cracks were not effectively isolated. Taken as a whole, the following observations and conclusions were made from the experimental study.

Bottom Line: The punching shear failure is an undesirable failure mode, since it results in a brittle failure of the footing.The validation and effectiveness of PSP were verified through a series of experimental studies.Finally, the design recommendations for the footing with PSPs were suggested.

View Article: PubMed Central - PubMed

Affiliation: Advanced Building Research Division, Korea Institute of Civil Engineering and Building Technology (KICT), Goyang-si, Gyeonggi-do 411-712, Republic of Korea.

ABSTRACT
The punching shear failure often governs the strength of the footing-to-column connection. The punching shear failure is an undesirable failure mode, since it results in a brittle failure of the footing. In this study, a new method to increase the strength and ductility of the footing was proposed by inserting the punching shear preventers (PSPs) into the footing. The validation and effectiveness of PSP were verified through a series of experimental studies. The nonlinear finite element analysis was then performed to demonstrate the failure mechanism of the footing with PSPs in depth and to investigate the key parameters that affect the behavior of the footing with PSPs. Finally, the design recommendations for the footing with PSPs were suggested.

Show MeSH
Related in: MedlinePlus