The torsional restraint of sandwich panels to resist the lateral torsional buckling of beams

Experimental investigations and parametric finite element analyses show that the moment-rotation characteristic of sandwich panels providing support against the lateral torsional buckling of beams subjected to gravity loading can be represented as tri-linear. Formulae for calculating the parameters of this characteristic are given for different types of beam combined with sandwich panels for roofs and walls. According to available design codes, the torsional restraint coefficient for rotational stiffness cϑ required for design against lateral torsional buckling of beams is governed by the rotational stiffness cϑA of the connection, which can be obtained from the characteristic mentioned as the secant stiffness for all common types of sandwich panel and different types of structural arrangement. These values allow the maximum spans of beams to be increased and help to improve the economy of lightweight structures.