Browsing by Author "Sumner, Emmett A."

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    Experimental and analytical investigation of the LRFD strength of tapered members
    Sumner, Emmett A. (Virginia Tech, 1995)
    Single story, rigid gable frames are commonly used by the metal building industry for light, industrial buildings. These rigid gable frames are usually constructed of built-up, web tapered, columns and rafters for reasons of economy. The tapering of the webs optimizes the members to develop a fully-stressed design. The purpose of this study was to investigate the AISC LRFD strength of the rigid knee portion of gable frames. The experimental portion of this study was sponsored by Kawada Industries, Inc., Costa Mesa, California. Eight specimens consisting of a tapered column and a portion of the tapered rafter were tested to failure under three types of loading that approximated the gravity, lateral, and cyclic load cases. The analytical portion of this study investigated the LRFD strength of the eight tapered knee specimens. The calculated LRFD strengths were compared to the experimentally obtained capacities. It was concluded that the LRFD shear strength provisions were overly conservative. The LRFD shear strength for tapered members was limited to the elastic or inelastic buckling strength of the web plate. Procedures for the application of the LRFD tension field action model to account for the post-buckling strength of tapered webs were presented. The application of tension field action to end panels, panels with large aspect ratios, and hybrid girders was also addressed. It was shown that the application of the LRFD tension field model to tapered members produced less conservative results.
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    Experimental Investigation of the Multiple Row Extended 1/2 End-Plate Moment Connection
    Sumner, Emmett A.; Murray, Thomas M. (2001-12-01)
    End-plate moment connections are widely used by the low-rise metal building industry to provide the rigid connections necessary in gable frames. There are numerous end-plate moment connection configurations. The multiple row extended 1/2 (MRE 112) end-plate moment connection configuration is the focus of this investigation. The MRE 1/2 end-plate moment connection has three rows of bolts at the tension flange, one row located outside the beam flange and two rows located inside the beam flange. Six MRE 1/2 end-plate moment connection tests were conducted at the Virginia Tech Structures and Materials Laboratory. The purpose of the tests was to investigate the moment strength of the connections and to validate the current design procedures. Details of the connection design, test set-up, testing procedure, and test results are presented within this report. It is concluded that the current design procedures, presented in the forthcoming AISC Steel Design Guide 16, Flush and Extended Multiple Row Moment End-Plate Connections (Murray and Shoemaker, 2002), conservatively predict the strength of MRE 112 end-plate moment connections. The strength predictions are adequate for MRE 1/2 end-plate connections utilizing A325 or A490 bolts with a standard or a large inner pitch distance.
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    Unified Design of Extended End-Plate Moment Connections Subject to Cyclic Loading
    Sumner, Emmett A. (Virginia Tech, 2003-06-17)
    Experimental and analytical research has been conducted to develop unified design procedures for eight extended end-plate moment connection configurations subject to cyclic/seismic loading. In addition, the suitability of extended end-plate moment connections for use in seismic force resisting moment frames was investigated. Eleven full-scale cyclic and nine monotonic extended end-plate moment connection tests were conducted. Design procedures for determining the required bolt diameter and grade, end-plate thickness, and column flange thickness were developed. The proposed design procedure utilizes a strong column, strong connection, and weak beam design philosophy. This forces the connecting beam to provide the required inelastic deformations through formation of a plastic hinge adjacent to the connection region. The proposed design procedure was used to make comparisons with ninety experimental tests conducted over the past twenty-six years. A limited finite element study was conducted to investigate the behavior of the column flange. The experimental results demonstrate that extended end-plate moment connections can be detailed and designed to be suitable for use in seismic force resisting moment frames. The proposed design procedure strength predictions correlated well with the results from ninety experimental tests. The limited finite element modeling conducted as a part of this study, correlated well with the strength predictions produced by the proposed design procedure.