Instruction and Assessment of Mohr's Circle Concepts in Undergraduate Geotechnical Engineering Courses
Document Type
Article
Publication Date
8-23-2022
Meeting Name
2022 ASEE Annual Conference & Exposition
Meeting Date
June 26-29, 2022
Meeting Location
Minneapolis, MN
Abstract/ Summary
Mohr’s circle, the graphical representation of the plane-stress transformation equations, is a critical engineering concept for quantifying normal and shear stresses on various planes and for determining the strength of materials. Within undergraduate civil engineering curricula at most institutions, Mohr’s circle is introduced in the sophomore-level Mechanics of Materials (or Strength of Materials) course. In the subsequent junior- and senior-level civil engineering curriculum, Mohr’s circle arguably receives the greatest emphasis in geotechnical engineering courses. Recent studies have shown that students struggle to retain fundamental Mohr’s circle concepts between the Mechanics of Materials course and upper-level geotechnical engineering courses. Due to the importance of Mohr’s circle in quantifying subsurface stresses and soil shear strength, an analysis of the effectiveness of various instructional styles on this topic could prove beneficial for increasing student learning. Nonetheless, the current pedagogical literature on Mohr’s circle instruction tends to be focused on mechanics courses rather than upper-level civil engineering courses. With this literature gap in mind, the purpose of this paper is to describe best practices for teaching and evaluating Mohr’s circle concepts in undergraduate geotechnical engineering courses.
Instructional strategies for Mohr’s circle as implemented by geotechnical engineering instructors from ten different U.S. institutions are described in this paper, along with methods of evaluating student knowledge in each instructor’s course. This paper delineates ready-to-implement techniques that may be useful in geotechnical engineering courses, as well as in Mechanics of Materials and other engineering courses. Student learning of Mohr’s circle concepts is assessed at different institutions, highlighting techniques that may lead to retention of concepts.
In this study, students’ understanding of Mohr’s circle was assessed via a three-question concept inventory at a subset of five of these institutions. This concept inventory, administered on or about the first day and last day of the semester in the introductory geotechnical engineering course, allows for the quantification of students’ knowledge gained in Mohr’s circle throughout the semester, and an evaluation of the pedagogical techniques employed. The same concept inventory was also employed at two institutions in a subsequent geotechnical engineering course (Foundation Engineering), allowing for an analysis of the retention of Mohr’s circle concepts after completion of the introductory geotechnical engineering course. The instruction and assessment strategies in this paper will contribute to a better understanding of the effectiveness of instructional methods on students’ understanding and retention of Mohr’s circle in geotechnical engineering courses.