What is punching shear in footings?
Punching shear is a phenomenon where a concentrated force on a slab causes a shear failure cone that “punches” through. Punching shear calculations require a demand value and a capacity value. Many hand calculations will consider a punching shear force against a punching shear capacity force.
Why do we check for punching shear?
Therefore we often provide drop slab/panels to increase the bearing CS, so that the reaction/shear force is distributed over a bigger area. This stress due to punching should be checked against safety.
What to do if the footing is unsafe for punching shear?
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.
How do you measure a footing shear?
Concept: Two way/punching shear: It shall be checked around the column a perimeter half the effective depth of footing slab away from the face of column or pedestal. The critical section for two-way shear or punching shear is at a distance of d/2 from the face of the column.
What is one way shear and punching shear in footing?
One way shear. When the footing bend in one direction, critical section is located at a distance “d” from the face of column. d= Effective depth of footing. Two way shear (Punching Shear) When the footing bend in two direction, critical section is located at a distance “d/2” from the face of column.
What is the critical section for punching shear?
critical section for the punching shear appears at a distance “d/2” to from the junction of the column with the footing in the two directions occurs in the rectangular section formed by the points 5, 6, 7 and 8, as shown in Fig. …
What is shear failure?
Failure in which movement caused by shearing stresses in a soil mass is of sufficient magnitude to destroy or seriously endanger a structure. Synonym of: failure by rupture.
Which is the critical section for punching shear?
What is strip footing?
A wall footing or strip footing is a continuous strip of concrete that serves to spread the weight of a load-bearing wall across an area of soil. It is the component of a shallow foundation.