Moment frame including lateral bracing system and coped beam
A construction formed of column and a beam, where the beam has top and bottom flanges coupled to the column by a lateral bracing system, and a web between the top and bottom flanges. The lateral bracing system may include a column-mounted plate including a horizontal portion and a vertical portion, the vertical portion affixed to the column. The beam may be coped at top and bottom edges of the web to prevent binding of the beam flange with the column-mounted plate upon rotation of the beam relative to the column.
1. A construction, comprising:
a vertical column;
a horizontal beam including a top flange and a bottom flange, and a web between the top and bottom flange;
a shear tab having a length oriented vertically and affixed between the column and beam, between the top and bottom flange of the beam, the shear tab comprising a bolt hole;
a lateral bracing system affixed between the column and beam, including:
first and second buckling restraint assemblies, one each on the top and bottom flange of the beam, each buckling restraint assembly including:
a column mounted plate including a horizontal portion and a vertical portion, the vertical portion affixed to the column,
a beam mounted plate including a horizontal portion mounted to the beam, and
a yield plate connected between the column mounted plate and the beam mounted plate, the yield plate having a smaller width than the column mounted plate and the beam mounted plate, the smaller width of the yield plate defining first and second notches on opposite sides of the yield plate, between the column mounted plate and beam mounted plate, the yield plate yielding in tension and compression to dissipate stress within the construction upon a lateral load applied to the beam and/or column;
first and second coped sections in the web configured to prevent binding of the top and bottom flanges with the column-mounted plate upon rotation of the beam relative to the column, the top flange terminating at a first end of the first coped section, the first coped section including a second end terminating at the shear tab, the top flange terminating along a vertical axis that passes through a center of the shear tab bolt hole.
2. The construction of claim 1 , wherein the bottom flange terminates at a first end of the second coped section, where the second coped section meets the bottom beam flange.
3. The construction of claim 2 , wherein the second coped section has a second end terminating at the shear tab.
4. The construction of claim 1 , wherein one or more coped sections form an angle of between 80° and 40° with the top and/or bottom flange.
5. The construction of claim 1 , wherein one or more coped sections form an angle of 60° with the top and/or bottom flange.