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The Analysis of Open Web Steel Joists in Existing Buildings

Matthew Stuart, P.E., S.E., F.ASCE

Course Outline

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.

Learning Objective

At the conclusion of this course, the student will:

Course Introduction

In 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.

Course Content

The course content is contained in the following PDF file:

The Analysis of Open Web Steel Joists in Existing Buildings

Please click on the above underlined hypertext to view, download or print the document for your study. Because of the large file size, we recommend that you first save the file to your computer by right clicking the mouse and choosing "Save Target As ...", and then open the file in Adobe Acrobat Reader. If you still experience any difficulty in downloading or opening this file, you may need to close some applications or reboot your computer to free up some memory.

If you have trouble reading any of the material on line, it is recommended that the course material be printed out for better resolution.

Course Summary

The 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.

Additional Resource

You can download a program from Vulcraft's website called Vulcraft Assistant that helps you design joists with concentrated loads ( The program does not do any deflection calculations.

Related Links

For additional technical informaion related to this subject, please visit the following websites or web pages:

Steel Joist Institute


Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

Take a Quiz

DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered professional engineer. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.