AD 509: Non-slip connections in wind bracing
SCI have received reports that frame designers are specifying non-slip connections for wind bracing – typically on the elevations or in the roof – noting that such connections are subject to load reversal.
Clause 220.127.116.11 of BS 5950 identifies that when load reversal is solely due to wind, preloaded assemblies to produce non-slip joints are not necessary. The guidance is equally appropriate to structures designed to the Eurocodes.
Non-slip joints are more expensive to prepare than connections with ordinary bolts, the fasteners themselves are more expensive and the installation will cost more than connections with ordinary bolts.
In some cases, such as site connections of large trusses or moment resisting connections in plate girder splices, non-slip joints are necessary, but as has been demonstrated by decades of successful practice, this is not the case for wind bracing.
Contact: David Brown
Telephone: 01344 636555