Capacity Prediction of Open-Web Steel Joists Partially Braced by a Standing Seam Roof

A new strength prediction approach is presented for open web joists partially braced by a standing seam roof. The approach employs the existing AISC column curve to calculate top chord flexural buckling capacity using the critical elastic buckling load including standing seam roof bracing stiffness. Recently derived buckling load equations are presented that account for lateral stiffness provided by the roof and the parabolically varying axial load from a uniform vertical pressure along the span. A new hybrid experimental-computational protocol is introduced for approximating standing seam roof lateral stiffness for systems without and with intermediate bridging. The strength prediction approach is demonstrated to be accurate for a small set of experiments, however a larger scale validation effort is still needed.

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