HERA Report R8-43: Full penetration of T-butt welds in welded moment connections

This report introduces a new type of partial penetration butt weld, the “effective full penetration butt weld” (EFPBW) that can be used in lieu of complete penetration/strength butt welds (CPBWs) in moment-resisting frames (MRFs) and other connections with a similar load path in the welds. The EFPBW has performance equivalent to that of the CPBW, while being significantly lower cost to fabricate. It allows for the welds specified as the CPBW to be replaced by EFPBW following the procedure outlined in this report.

Welded moment-resisting connections are used in the rigid frames of high-rise buildings designed to NZS 3404.1 and detailed to HERA Reports R8-15 and R8-28 and SCNZ Connection Guides (SCNZ 14.1&2: 2007). The Connection Guides and NZS 3404.1 allow using fillet welds for MRCs, however, most of the design specifications call for CPBWs – which while easier to design (as they do not require additional calculations), are more expensive to fabricate than fillet welds and partial penetration welds.