Assessment of partial joint penetration welds on bolted end-plate connections

Abstract

End-plate moment connections are a very common connection type used in today’s metal building industry. Bolted end-plate connections are especially popular because they can be engineered to meet design requirements for moment resisting connections used in seismically active areas. The current industry standard for end-plate moment connections is to use complete joint penetration (CJP) welds when making end-plate to flange welds. An alternative to CJP welds is partial joint penetration (PJP) welds, which leaves some portion of the base metals’ thickness unfused. PJP welds may save time and money in the fabrication of the end-plate connections but the use of PJP welds in this application is currently not considered in the Seismic Provisions for Structural Steel Buildings AISC/ANSI 341-10[1]. The objective of this research was to evaluate the effectiveness of properly detailed PJP flange welds on end-plate connections when subjected to seismic loading by using a pseudo-static loading protocol. Two of the same multiple row extended end-plate moment connection tests were conducted at the University of Oklahoma’s Donald G. Fears Structural Engineering Laboratory. The tested specimens were 44 in. (111.76 cm) deep, cantilevered beams connected to a column via a bolted end-plate. A concentrated load was applied on the beam’s tip creating a moment at the beam to column connection. This created forces acting on the flange to end-plate welds. The specimens were tested in accordance to AISC 341-10’s[1] criteria on cyclic tests for qualification of beam to column connections. Both six-bolt multiple row extended end-plate connections made with PJP welds met AISC 341-10’s[1] requirements for beam to column connection in Intermediate Moment Frames. The specimens’ flanges and webs deformed plastically, while no weld failures were observed during testing. The PJP welds used on the tested beams’ flange to end-plate connections performed favorably. It is the authors’ beliefs that these results may serve as a good starting point for further examination of PJP weld capabilities when subject to seismic loading. Further testing of PJP welds would help to understand their ultimate capabilities. To date the 44 in. (111.76 cm) deep test sections are to our knowledge, the deepest sections that examined PJP flange to end-plate connections subject to seismic loading successfully achieving a 0.02 rad story drift angle.