Kern Points and Pressure Line: Understanding Flexure A kern point is a region within a concrete member that resists crushing and deforms in the direction...
A kern point is a region within a concrete member that resists crushing and deforms in the direction of bending. This region is typically located near the edges of the member and may be identified by the presence of sharp corners or protrusions.
A pressure line is a line that runs through the center of the kern point and experiences the maximum compressive stress during bending. This means that the material is most concentrated at the center, with less stress at the edges.
Understanding the interplay between Kern points and pressure lines is crucial for designing flexure-resistant concrete structures. This interplay leads to the development of optimum shapes for the member that provide both high strength and ductility.
Examples:
Thin rectangular beams: The kern point is located near the edges, and the pressure line runs along the center line.
Round columns: The kern point is located at the top and bottom, and the pressure line follows a spiral path around the circumference.
Channels: The pressure line may be located inside or outside the channel, depending on the desired flexural behavior.
By understanding the relationship between kern points and pressure lines, engineers can select shapes and sizes for concrete members that can withstand bending while maintaining their integrity