Answer to Question #309391 in Civil and Environmental Engineering for Oxian

Question

What are the advantages of using a third-point loading flexure test over a

center-point loading flexure test? Draw a shear force diagram and a bending

moment diagram for each case to support your answer.

Answer 1

Third point loading:

It is one of the flexural tests using in determining the strength of the concrete. Mostly used in the design and concrete pavements and based on the AASTHO method. It is also known as the modulus of rupture test.

Center point loading:

In this center point of loading overall load acts at the center and this method is used for determining the strength of concrete

—> Advantages of third point loading over center point loading

• In third point loading, the loads will act at two points at a distance of L/3 from each support but in the center point loading the load will act as the center of the beam
• As the beam is being supported at two pints the chances of failure are less and being stressed uniformly throughout the spans to fail at the middle third part but in center point loading the load directly fails at the center and the beam fail under the center of loading
• The center point may not be the weakest point of the beam but the result may not be reasonable in determining the concrete strength
• The third point loading is preparation and testing of the specimen will be easy