Comparison of Experimental and Numerical Results for Flexural Capacity of Light-Gage Steel Roof Deck

The objective of this paper is to present a comparison between experimental results to each of two numerical analyses of cold formed steel roof deck in flexure. Prior numerical studies using the Direct Strength Method (DSM) and the Equivalent Width Method (EWM) have shown discrepancies between results obtained by the two methods. The goal of this research initiative was to compare results from each of the two numerical analysis methods to experimental results in an effort to determine which numerical method is most appropriate for analyzing steel deck in flexure. Twenty-four physical tests were conducted using four different deck gages (22, 20, 18 and 16 gage) in both the deck’s positive and negative positions. Detailed measurements of the physical geometry and the material properties of the deck samples were taken. Load was applied in a four-point bending scenario using a loading frame that engaged all flutes across the width of the deck sample. Deck was loaded to failure. Applied load and several displacement measurements were recorded. Maximum load measurements and load-displacement plots were used to determine the maximum moment capacity in the deck. Finite strip modeling using CUFSM v4.03 was conducted and analyses using the DSM and EWM are compared to experimental results. It was found that the DSM and EWM vary in their prediction of the nominal moment capacity across material grades and deck thicknesses, but tend to converge to a constant ratio at higher deck gages. The EWM was found to be more accurate for thinner gages and the DSM was found to be more accurate for thicker gages, but both methods provide reasonable results when determining steel roof deck capacities

STR-806: EXPERIMENTAL EVALUATION OF THE ROBUSTNESS OF SINGLE PLATE SHEAR CONNECTIONS UNDER QUASI-DYNAMIC LOAD

Flexible (simple) shear connections commonly used in steel-framed buildings are very economical and are relatively easy to fabricate. These connections are used for shear resistance, but recent studies have shown that they are capable of sustaining an interaction of rotational and axial load demand necessary for steel-framed building structures to help resist collapse in the event of unanticipated damage scenarios. The objective of this paper is to outline and discuss an experimental effort designed to evaluate the robustness of single plate shear connections under a quasi-dynamic loading scenario simulating the loss of a central column. The experimental program included eleven full-scale tests of a system consisting of two wide flange beams connected to a central wide flange column stub by means of the shear plate connections. Three, four, and five bolt configurations were tested, and two of the tests utilized galvanized bolts. The experimental testing provides important information regarding the ability of these connections to sustain large rotational demands in conjunction with axial tension forces generated through geometric stiffness (catenary) effects when subjected to rapidly applied vertical loads

STR-805: EXPERIMENTAL EVALUATION OF THE ROBUSTNESS OF WT CONNECTIONS UNDER QUASI-DYNAMIC LOAD

Flexible (simple) shear connections commonly used in steel-framed buildings are very economical and are relatively easy to fabricate. These connections are used for shear resistance, but recent studies have shown that they are capable of sustaining an interaction of rotational and axial load demand necessary for steel-framed building structures to help resist collapse in the event of unanticipated damage scenarios. The objective of this paper is to outline and discuss an experimental effort designed to evaluate the robustness of flexible WT connections. The experimental program included twelve full-scale tests of a system consisting of two wide flange beams connected to a central wide flange column stub by means of the WT connections. Three, four, and five bolt configurations were tested. The system was subjected to a quasi-dynamic loading scenario simulating the loss of a central support column. The experimental testing provides important information regarding the ability of these connections to sustain large rotational demands in conjunction with axial tension forces generated through geometric stiffness (catenary) effects when subjected to rapidly applied vertical loads

Experimental Performance of Cold Form Flexural Members Under Distortional Buckling

Recent developments for applications of cold formed steel elements that are increasingly slender have precipitated this investigation. The research focuses on the distortional buckling of C-shaped members in flexure, where the flange stiffeners are in compression and the web in tension. Previous research has been documented for this loading scenario for select shapes. However, there remains a lack of definitive experimental data into the behavior of these elements, particularly typical C-shape cross-sections. The initial results of this research suggest that the current distortional buckling strength curve found in the AISI code may not adequately address these cases. This research seeks to work in concert with these efforts to provide theoretical and experimental results that can be used by the task group to develop recommendations for designers. Three cross-sections at a 14, 16,18, 20 gauge for nominal spans of 3.05 m (10 ft) were tested, resulting in an experimental regime of 51 specimens. Experimental results are presented in terms of ultimate loads, Pts, as well as elastic critical distortional buckling moment, Mcrd, and yield moment, My.This research initiative was supported by the Small Project Fellowship Program through the American Iron and Steel Institute. SCAFCO also provided material support by donating the specimens used for experimental testing. The authors thank these organizations for their support. The authors would also like to thank Mr. Bob Glauz for fruitful discussions and valuable input throughout the project

Experimental Performance of Cold Form Flexural Members Under Distortional Buckling

Recent developments for applications of cold formed steel elements that are increasingly slender have precipitated this investigation. The research focuses on the distortional buckling of C-shaped members in flexure, where the flange stiffeners are in compression and the web in tension. Previous research has been documented for this loading scenario for select shapes. However, there remains a lack of definitive experimental data into the behavior of these elements, particularly typical C-shape cross-sections. The initial results of this research suggest that the current distortional buckling strength curve found in the AISI code may not adequately address these cases. This research seeks to work in concert with these efforts to provide theoretical and experimental results that can be used by the task group to develop recommendations for designers. Three cross-sections at a 14, 16,18, 20 gauge for nominal spans of 3.05 m (10 ft) were tested, resulting in an experimental regime of 51 specimens. Experimental results are presented in terms of ultimate loads, Pts, as well as elastic critical distortional buckling moment, Mcrd, and yield moment, My.This research initiative was supported by the Small Project Fellowship Program through the American Iron and Steel Institute. SCAFCO also provided material support by donating the specimens used for experimental testing. The authors thank these organizations for their support. The authors would also like to thank Mr. Bob Glauz for fruitful discussions and valuable input throughout the project

Life-Cycle Assessment Comparison for Long-Span Cable and Truss Structural Systems: Case Study

AbstractThe architectural engineer has a considerable influence on the sustainability of buildings. The reduction in environmental impacts of building materials, as measured by life-cycle assessment (LCA), has recently become a focus in construction sustainability initiatives. The LCA comparisons of material alternatives in building structures, like concrete and steel, have not captured the material efficiency that the comparisons of structural system alternatives can provide. This paper compares the LCAs of two long-span structural systems, a truss system and a cable system, for the same application. Lower environmental outcomes are shown for the cable system when comparing the two systems’ LCAs. Results showed a 29% reduction in structural system mass, a 65.1% reduction in embodied energy, and a 67.2% reduction in carbon dioxide (CO2) emissions when comparing the cable to the truss system

Diabetes and Drug-Associated Hyperkalemia: Effect of Potassium Monitoring

Renin-angiotensin-aldosterone system (RAAS) inhibitors are associated with hyperkalemia, but there is little evidence demonstrating patients who receive potassium monitoring have a lower rate of hyperkalemia