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Abstract
There are many challenges involved in the design of hollow structural sections [HSS] steel endplate connections. To solve these challenges, structural designers use design guides which have been developed based on several simplifying assumptions to streamline the design procedure, such as Steel Design Guide 24 [Packer et al., 2010]. The purpose of this research is to investigate if the current design procedures in Steel Design Guide 24 for rectangular HSS steel end-plate connections are comprehensive and accurate. Twelve axial physical HSS end-plate connection specimens using square HSS designed with varying bolt patterns [side and corner] and weld patterns [all-around and workable-flats] were tested under axial tensile loading. Another twelve flexural specimens using rectangular HSS were designed with the varying bending axes [strong and weak] and weld pattern configurations [all-around and workable-flats] were tested under lateral eccentric loading. Linear strain gages, and strain rosettes were used to measure strains in the end-plates and HSS. Linear variable differential transformers [LVDTs] were used to measure end-plate and HSS displacement. The results for the axial specimens indicate that side bolt configurations provide more capacity than corner bolt configurations and the all-around weld provides more capacity than the workable-flats weld. The side bolts connections reached the 100-kip capacity of the test load cell without yielding, so the results were inconclusive. However, because of the stiff behavior of the end-plate, it is reasonable to suggest that the calculated connection capacity using the design procedure in Section 5.6 of AISC Design Guide 24 [2010], governed by bolt strength, would have been reached. The corner bolt specimens underwent significant yielding at loads less than the calculated capacity, suggesting that the design procedures in AISC Design Guide 24 are not applicable to the corner bolt configuration and would require a separate design procedure with adjusted equations. Results from the flexural tests indicate that the strong axis configurations provide more capacity than the weak axis configurations and the all-around weld provides more capacity than the workable-flats weld. Results were compared to calculated capacities using the design procedure from Example 4.1 in AISC Design Guide 24 [2010] and the design procedure developed by Wheeler et al. [1998]. The capacities from weld strength based on the AISC Design Guide 24 [2010] procedure for the allaround weld specimens were conservative and showed good correlation; however, for the workable-flat welds specimens some capacities were unconservative. The calculated strength and serviceability capacities, based on plate and bolt strength from the Wheeler et al. [1998] design procedure, were conservative and showed good correlation with results for the all-around weld specimens. Therefore, it is recommended that the design procedure be considered for implementation into AISC Design Guide 24.