This series of videos will walk you through the design of a simple rectangular concrete beam in accordance with ACI 318-08. These videos were created for those about to take the Civil Professional Engineering exam, and for those taking the Structural Engineering exam.
Feel free to download a pdf version of the slide presentation used in the video to follow along.
The first video discusses the assumptions required for the calculation, and walks you through stress and strain diagrams for a given reinforced concrete beam section. By the end of this video, you’ll be able draw the stress and strain diagram, calculate the depth from the extreme compression fiber to the center of the reinforcing steel, and calculate the depth of the compression region, a, using the Whitney stress block approximation.
The second video shows you how to calculate the depth from the extreme compression fiber to the neutral axis, c, in accordance with ACI 318-08. You’ll then determine the strain in the reinforcing steel at failure, and use it to determine if the steel yields, and if the section can be deemed a tension controlled section per ACI. Finally, you’ll calculate the minimum required steel for the given section per ACI.
Finally, you’ll calculate the nominal moment capacity and shear capacity for the given rectangular concrete beam.