Quality Light Steel Framing Connections and Members
Your Link to the Steel Industry®

CALL US TODAY 1-888-474-4876

Home > Wall Bridging Background

Wall Bridging Background

Bridging for load bearing studs is needed to resist the following forces:

  1. Weak axis buckling induced by axial compression load.
  2. Torsion induced by wind load.

AISI Wall Stud Design Standard (2004), referenced by 2006 IBC; or AISI-NAS Specification (2007) provides the load and stiffness requirements for bracing members due to the effects of axial compression load and wind load as given in the table below. Contact TSN Technical Support (888) 474-4876 if further information is needed regarding wall bridging design.

Fig1

As axial compression and lateral wind loads are applied, wall studs react with weak axis buckling and torsional rotation. To offset these forces, a form of bridging is incorporated into the wall system. Bridging loads accumulate over the run of the wall, requiring transfer of lateral forces in bridging at columns or to the floor slab into the structural load path to the foundation.
Bridging Requirements
AISI Wall Stud Design Standard 2004 AISI-NAS Specification 2007
Stud Axial Compression Load Capacity:
Bracing Load PBrace* = 0.02 x Stud Axial
Strength (PStud) x # of studs braced.
Load Capacity:
Bracing Load PBrace* = 0.01 x Stud Axial Strength
(PStud) x # of studs braced.

Stiffness Capacity:
Lateral Stiffness βBrace = 4 x Stud Nominal Axial
Strength / Unbraced Length (for one row of bridging).

Lateral Stiffness βBrace = 6 x Stud Nominal Axial
Strength / Unbraced Length (for two rows of bridging).

Wind Load Capacity:
Twist Load PL = 1.5 x Wind Load x Bridging Spacing x Stud Spacing x m(Shear Center Distance) / Stud Depth.
Twist Moment M1 = PL x Stud Depth.

* Bracing forces accumulate over the run of the wall until anchored.

Bridging load bearing studs against torsion by wind.
Ref1
Ref3
Bridging load bearing studs against weak axis buckling. 
Ref2
Ref4