Xbracing

X-bracing, or cross-bracing, is a structural arrangement in which two diagonal members form an X within a frame plane to resist lateral loads such as wind and earthquakes. The braces carry axial forces, increasing stiffness and ductility without a large increase in weight, and they help limit sway under lateral demands.

In steel-framed buildings, X-bracing is typically installed in the bays between columns and beams. Braces are commonly made from hollow structural sections or steel bars and are connected by bolted or welded joints. The configuration can be through-bracing, where members pass through columns, or brace-to-frame connections that terminate at beams and columns. X-bracing is widely used in industrial facilities, warehouses, and high-rise frames where rapid installation and high strength are advantageous.

Performance and advantages: Under lateral loads, the braces take axial forces, dissipating energy through controlled deformation and improving redundancy. X-bracing offers a favorable strength-to-weight ratio and relatively straightforward fabrication. Limitations include potential obstruction of interior clearances, sightlines, and partitions, as well as more complex detailing for connections and fireproofing. The system can also introduce stiffness irregularities if not carefully designed with the overall frame in mind.

Variants and related systems: Alternatives such as K-bracing and V-bracing avoid crossing members and can preserve interior space differently. Modern developments include buckling-restrained braces (BRBs), which improve energy dissipation and ductility. Design and detailing follow structural codes that govern member sizes, connections, and inspection.