BRBF
Encyclopedia
Buckling Restrained Braced Frame (BRBF) is a structural steel frame
that provides lateral resistance to buckling
, particularly during seismic activity.
The BRBF is typically a special case of a concentrically braced frame. Tests have demonstrated BRBF systems are highly effective for energy dissipation, while being vulnerable to large deformations and story drift.
A Buckling Restrained Brace
(BRB) consists of a steel core surrounded by a hollow steel section, coated with a low-friction material, and then grouted with a specialized mortar
. The encasing and mortar prohibit the brace from buckling when in compression, while the coating prevents axial load from being transferred to the encasement, thus preventing strength loss and allowing for better and more symmetric cyclic performance. These elements most commonly brace a bay diagonally or in a chevron pattern. Because maximum tension and compression forces in a BRB are much closer than in a standard brace, there is much less imbalance of force in the chevron configuration.
Steel frame
Steel frame usually refers to a building technique with a "skeleton frame" of vertical steel columns and horizontal -beams, constructed in a rectangular grid to support the floors, roof and walls of a building which are all attached to the frame...
that provides lateral resistance to buckling
Buckling
In science, buckling is a mathematical instability, leading to a failure mode.Theoretically, buckling is caused by a bifurcation in the solution to the equations of static equilibrium...
, particularly during seismic activity.
The BRBF is typically a special case of a concentrically braced frame. Tests have demonstrated BRBF systems are highly effective for energy dissipation, while being vulnerable to large deformations and story drift.
A Buckling Restrained Brace
Buckling restrained brace
Buckling Restrained Braces are composed of a slender steel core continuously supported by a concrete casing in order to prevent buckling under axial compression. The core and the casing are decoupled to prevent interaction between them....
(BRB) consists of a steel core surrounded by a hollow steel section, coated with a low-friction material, and then grouted with a specialized mortar
Mortar (weapon)
A mortar is an indirect fire weapon that fires explosive projectiles known as bombs at low velocities, short ranges, and high-arcing ballistic trajectories. It is typically muzzle-loading and has a barrel length less than 15 times its caliber....
. The encasing and mortar prohibit the brace from buckling when in compression, while the coating prevents axial load from being transferred to the encasement, thus preventing strength loss and allowing for better and more symmetric cyclic performance. These elements most commonly brace a bay diagonally or in a chevron pattern. Because maximum tension and compression forces in a BRB are much closer than in a standard brace, there is much less imbalance of force in the chevron configuration.