Three-Dimensional Joist Member Studies using Equivalent Beam Theory

When selecting steel joists for a structure, design engineers have traditionally relied on standard load tables, but this is limiting when commercial software is used. Additionally, because joists and joist girders are proprietary members, design engineers can benefit from an automated approach to obtain accurate estimates of member weights and section properties in the software analysis. Changes during the design process such as variations in loading cases can make the design of joists and joist girders tedious for the joist designers. Current structural design software packages lack the necessary capacities to estimate joist and joist girder weights and section properties accurately; however they do enable the implementation of user-defined cross-sectional property tables. For joist designers, custom tables for joists and joist girders can be used with the application of equivalent beam theory which allows joist and joist girder limit states to be analyzed by strength checks built into the design software. The custom tables for joist and joist girders are developed to represent approximate prismatic members based on the properties of typical chord sizes readily used in industry. This study presents the development and validation of custom tables for joist members.  A case study illustrates the application of joist and joist girder tables in the design of a three-dimensional building with drifted snow loads 

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