Design of extended & coped beam shear plate connections and welding of heavy plates and shapes

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The proposed research directed towards improving the state of knowledge, design and detailing provisions in Canada of structural steel shear tab connections and of welded assemblies that utilize thick plates and heavy rolled sections. ADF Group Inc. and their engineers at DPHV have experienced difficulties in applying existing design procedures and have found potential performance issues with these connections and welded assemblies. Heavy rolled shapes, typically called "jumbo sections", with flange thicknesses exceeding 50 mm and built-up heavy shapes will be the subject of the first component of this research project. The recent fabrication by ADF Group Inc. of heavy steel plate built-up box columns that utilized 75mm thick steel plates and heavy rolled sections with doubler plates resulted in a significant number of cracked members that had to be scrapped and refabricated. The fractures occurred in the complete absence of service load, and were instead caused by either shrinkage stresses or by residual stresses on the thermally cut surface. The total industry loss was reported to approach $2M. Research to develop detailed recommendations on how to weld these heavy shapes is needed for different steel grades since their use is on the rise due to seismic and blast-resistant design in Canada. The second component of the proposed research addresses the behaviour and design of shear tab connections. The current design procedure recommended by the Canadian Institute of Steel Construction is limited to relatively small configurations with a single column of bolts. A lack of design guidance exists for beam-to-girder connections where either an extended shear tab or a coped beam-to-shear tab connection is used. The influence of axial load in the connection combined with shear is of particular interest. Testing of representative shear tab connections as well as material tests of the heavy plates and shapes will be carried out. This will be supplemented with finite element modeling of the shear tab connections to evaluate a wider range of loading scenarios and of welding procedures for the heavy sections. The general objective is to recommend design and welding procedures.