Beam example (6:38)
The first step when deciding what shape, size and strength of beam to use is to perform a structural analysis of the beam’s position in the structure. As demonstrated in the accompanying video, after the analysis one then develops shear and moment diagrams from the beam’s length, supports, and the load(s) applied to it. Based on the bar joist framing above, one can determine that an unbraced length of 5 feet is needed and can then locate a member in the AISC Steel Construction Manual 14th Edition that will satisfy these given constraints. Recall Rules of Thumb, found in Unit 1. A starting point for sizing a steel beam would be to take the length of the beam, in feet, and divide it by two. This answer will provide a launching point for the beam depth in inches. For the example in the videos a 30’-0” span is used. This would result in a 15” deep beam as a starting point. Referencing wide flange sections in the AISC manual (2:19), it is noted that wide flange members do not come in at 15” deep, so we round up to 16”. As you follow along in the video the capacity of the beam can then be checked using the AISC steel manual.
Base Plate example (12:55)
This video, through an example of a scaled drawing of a column and base plate, shows many of the standards for hand sketching, such as symbols and abbreviations. Additionally, it gives practical structural engineering advice for clear communication and problem solving. Through the example, viewers will see how a simple sketch can sometimes save much trouble and time by discovering issues before they become a problem in the field.