Applying Statics to Community Examples

Most statics courses begin with a considerable amount of abstract discussion of forces and vectors. Since the mechanical engineering technology department's goal is to focus on practical, concrete instruction methods, the faculty has been working to expose students to more exercises that involve the practical application of statics to daily life. For the statics curriculum, a laboratory was developed that investigates the use of trusses in the surrounding community. Each truss is examined to determine its primary purpose, its type and any unique design features. Small groups discuss each example qualitatively (quantitative analysis of the forces in the truss is not performed) and then the whole class meets to compare the results. The trusses include the following: • Sherman Minton Bridge - Double arch truss. • K&I Railroad Bridge - Parker and Warren through trusses with a swing section and a cantilevered road deck parallel with the tracks. • Pedestrian Bridge - Pratt truss. • Pennsylvania Railroad Bridge - Combination of Parker through trusses over shipping lanes with Warren deck trusses. • Clark Memorial Bridge - Cantilever truss. Since each truss serves a similar transportation purpose, each truss is compared to the others to determine why its particular design was chosen. This paper describes each example and the effects the exercise had on student learning. This includes discussion of: increased interest by relating statics to daily experiences, experience with reverse engineering, practice identifying members in tension and compression, comparison of a standard truss with a cantilever truss bridge and recognition of changing design practices as technology changes over the years. Lastly is a description of the assessment, evaluation and planned improvements to the truss laboratory.