On projects with steel braced frames, do you typically show transfer forces on your drawings (for delegated connection designs)? Would a refresher on how to calculate these forces be helpful for you or your staff?
During our October 2015 session, Understanding Load Paths, Carol Drucker, SE, PE, P.Eng, from Drucker Zajdel Structural Engineers, described transfer forces as the axial load in the beams on either side of a column that are transferred to the vertical lateral resisting system. Transfer forces can be found, for example, in drag struts leading to a vertical frame.
Carol offered a clear and concise 2-step process to determining transfer forces, using an illustrative example as a basis. Below are the two steps delineated during the session:
- Identify the transfer planes in the braced frame on each level
- Sum forces on either side of each plane
Further discussion can be found in this video clip below. The suggested 2-step process starts on Slide 39 (timestamp 2:19).
Following the video clip, Carol further explained that transfer forces are dependent on the load path of the frame, diaphragm strength, the actual load combinations, and any special project requirements. We hope you find this information helpful in your vertical braced frame design and detailing.