Nonrectangular cross sections are a common occurrence in reinforced concrete design typically taking the form of flanged beam sections, circular columns, and square or rectangular columns subject to biaxial bending. Instructors typically introduce the theory behind nonrectangular beams using two-dimensional sketches of flanged sections. Students can struggle to visualize the examples when presented in two dimensions; deciphering the multiple resultant compressive forces and their corresponding moment arms are particularly difficult. This paper presents an overview of nonrectangular beam theory and select active learning methods along with three specific examples used by the authors to teach nonrectangular beams in an undergraduate reinforced concrete design course. The first method is a simple problem-based learning example to dissuade students from “plug and chug” calculations using improper equations; the second method illustrates three cases for a traditional flanged T-beam section using physical three-dimensional models; and the third method uses virtual three-dimensional models to derive the depth of the equivalent stress block and corresponding nominal flexural strength for various cross sections. Each description provides the reader with the best practices to implement the respective technique. Lastly, the authors provide some lessons learned from their past implementations. The overall goal is to provide educators with examples to simplify the presentation of nonrectangular beams theory.


Architectural Engineering



URL: https://digitalcommons.calpoly.edu/aen_fac/153