The Analysis of Open Web Steel Joists in Existing Buildings
Stuart, P.E., S.E., F.ASCE
This one hour online course will provide the user with an understanding of the limitations and precautions necessary when analyzing an existing open web joist member for new or additional loads. This course includes a multiple choice quiz at the end.
At the conclusion of this course, the student will:
Course IntroductionIn the course of the career of most structural engineers, one is asked by a client to evaluate the ability of an older existing open web joist to support revised, new or additional loads. In order for the engineer to be able to safely evaluate such a situation it is necessary to have a clear understanding of the limitations of fabricated open web joists and the hazards posed by strengthening these same types of structural members in the field. This course provides the user with a flowchart of the process required to accomplish this task. In addition, an explanation for the proper and accurate interpretation of older joist allowable load tables is provided.
The course content is contained in the following PDF file:
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Course SummaryThe analysis of an existing open web joist member first involves some detective work as required to either locate drawings (original contract or shop drawings) or determine the specific fabricator of the members. If the member size is known it is possible through the use of the original allowable load tables published for the existing joist to determine the ability of the member to safely support the imposed loads. If the member size is not known, or if it is determined that the existing section cannot support the loads, it is necessary to contact the original manufacturer of the joists to either verify the capacity or develop strengthening details for the member. If neither of these two avenues is possible, the engineer-of-record should never take it upon his or herself to design and implement reinforcing details independently. If strengthening of the affected joist is not possible or practical, it is recommended that the new or heavier loads be supported independently from the joists via either roof or floor top clear span frames above or from columns supported by foundations below.
You can download a program from Vulcraft's website called Vulcraft Assistant that helps you design joists with concentrated loads (http://www.vulcraft-in.com/). The program does not do any deflection calculations.
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.