Comparative Study of Bolted versus Welded SCBF Connections

Many large industrial projects are located in remote areas where the local labor pool does not include a significant number of skilled welders. As a result, field bolted connections are favored over field welded connections. Special Concentrically Braced Frames (SCFB) are a preferred structural system for many industrial structures. However to meet the detailing requirements for a SCBF structure in which member performance dictates the connection design loads, bolting can become complicated. The decision to use bolted versus welded field connections in industrial projects needs to be carefully evaluated before proceeding. A comparison of utilizing field bolted versus field welded connections for vertical braces is explored. A recent fossil power plant project employed a SCBF in a seismic design category D. It became evident in preliminary reviews of this project that the complexity of bolted bracing connections would create a challenge for the erector. The final conclusion for the project was that field bolted connections would be employed. However the actual design of the connections has cause the authors to revisit this decision and to closer evaluate alternatives for the next project that will require SCBF detailing.