Ultimate behavior of heavy steel section welded splices and design implications

Full- and partial-penetration butt-welded splices of American Institute of Steel Construction (AISC) group four and five rolled steel sections are tested. Test specimens are devised so splices are located in regions of pure bending. The partial-penetration splice is able to develop and exceed its nominal capacity. However, it fails in a brittle manner with no apparent ductility. Qualitative explanations are given as to the cause of the observed failure. The adequacy of simple strength-design methods to predict that behavior is assessed. Also, an example is presented for braced frames designed according to the Uniform Building Code (UBC). The acceptability of partial-penetration welds in that design is reviewed by comparing the member forces obtained from the static analysis with those resulting from an inelastic step-by-step dynamic analysis. The specimen with a full-penetration welded splice exhibits satisfactory strength and ductility. It is believed, however, that a great amount of care must be taken in the execution of this type of weld. Design implications of those results for seismic resistant structures are examined.