Influence of Uplift Load on Torsional Restraint Provided to Steel Thin-Walled Purlins by Sandwich Panels

Abstract

The sandwich panels have been widely used as members of roof and wall cladding. In addition to their primary function, they can provide lateral and torsional restraints to the supporting members and therefore contribute to their buckling resistance. The availability of the provided restraints is influenced by the direction of the load applied to the surfaces of the panels. For the uplift load, no torsional restraint is conservatively considered due to reduction of the contact area between the panels and the supporting metal members. Possible small rate of the torsional restraint should be verified by experimental investigation. The paper focuses on the experimental verification of the torsional restraint provided to steel purlins of thin-walled cold-formed cross-sections by adjacent sandwich panels. For the first series of tests a simple test set-up with no external load applied to the surface of the panel was utilized. The second series comprises tests of the torsional restraint provided to steel purlins by sandwich panels under uplift load. A complex test set-up taking into account the external load applied to the surfaces of the panels was used. The results of both test approaches are compared and the influence of the uplift load on the torsional restraint for the tested specimens is evaluated.The sandwich panels have been widely used as members of roof and wall cladding. In addition to their primary function, they can provide lateral and torsional restraints to the supporting members and therefore contribute to their buckling resistance. The availability of the provided restraints is influenced by the direction of the load applied to the surfaces of the panels. For the uplift load, no torsional restraint is conservatively considered due to reduction of the contact area between the panels and the supporting metal members. Possible small rate of the torsional restraint should be verified by experimental investigation. The paper focuses on the experimental verification of the torsional restraint provided to steel purlins of thin-walled cold-formed cross-sections by adjacent sandwich panels. For the first series of tests a simple test set-up with no external load applied to the surface of the panel was utilized. The second series comprises tests of the torsional restraint provided to steel purlins by sandwich panels under uplift load. A complex test set-up taking into account the external load applied to the surfaces of the panels was used. The results of both test approaches are compared and the influence of the uplift load on the torsional restraint for the tested specimens is evaluated.