Ahsanullah University Of Science and Technology

Department Of Civil Engineering

CE-418 Prestressed Concrete and Design Sessional

Presented By

Name : Md. Kamrul islam Roll : 10.01.03.056Section : A

Topic

Bearing&Punching Shear

What is Punching Shear?

Punching Shear Punching shear is a type of failure of reinforced

concrete slabs subjected to high localized forces. In flat slab structures this occurs at column support points. The failure is due to shear

The shear stress calculated by dividing the load on a column by the product of its perimeter and the thickness of the base or cap, or by the product of the perimeter taken at one-half the slab thickness away from the column and the thickness of the base or cap.

Punching shear in concrete slabs is a problem

Punching shear in concrete slabs is a serious problem in certain structural systems, such as flat slabs

Punching Shear

Punching Shear

Punching Shear

Bearing stress

• Bearing stress is a compressive stress applied to the contact surface between two connecting members. This stress can commonly be found on a pin & hole connection.

• Like general stress, bearing stress is not evenly uniform over the cross-sectional area but is generally assumed for simplicity.

• The average bearing stress is the force pushing against a structure divided by the area. Exact bearing stress is more complicated. Experiments have shown that the bearing stress distribution is more elliptical shaped and not uniform.

Bearing Stress Equation

σavg=P/Aσ avg – Stress (Average)P – Applied LoadA – Cross-Sectional Area (Preload) Bearing Stress

Bearing stress is a normal stress, not a shearing stress.

Bearing Stress

THANK YOU