Abstract
The effect of continuous or discrete lateral and torsional restraints of metal thinwalled members along their spans can positively influence their buckling resistance and thus contribute to more economical structural design. The prevention of displacement and rotation of the cross-section results in stabilization of the member. The restraints can practically be provided e.g. by planar members of cladding supported by metal members (purlins, girts). The rate of stabilization of a member can be quantified using values of shear and rotational stiffness provided by the adjacent planar members. While the lateral restraint effected by certain shear stiffness can be often considered as sufficient, the complete torsional restraint can be safely considered in some practical cases only. Otherwise the values of the appropriate rotational stiffness provided by adjacent planar members may not be satisfactory to ensure full torsional restraint and only incomplete restraint is available. Its verification should be performed using theoretical and experimental analyses. The paper focuses on problem of steel thin-walled coldformed beams stabilized by planar members and investigates the effect of the magnitude of the rotational stiffness provided by the planar members on the resistance of the steel members. Cold-formed steel beams supporting planar members of cladding are considered. Full lateral restraint and incomplete torsional restraint are assumed. Numerical analyses performed using a finite element method software indicate considerable influence of the torsional restraint on the buckling resistance of a steel thin-walled member. Utilization of the torsional restraint in the frame of sizing of a stabilized beam can result in more efficient structural design. The paper quantifies this effect for some selected cases and summarizes results of numerical analysis.
Highlights
Utilization of thin-walled metal members in civil engineering can result in light and effective structures, on the other hand these members are prone to stability problems reducing their resistance
While the lateral restraint effected by certain shear stiffness can be often considered as sufficient, the complete torsional restraint can be safely considered in some practical cases only
The paper focuses on problem of steel thin-walled coldformed beams stabilized by planar members and investigates the effect of the magnitude of the rotational stiffness provided by the planar members on the resistance of the steel members
Summary
Utilization of thin-walled metal members in civil engineering can result in light and effective structures, on the other hand these members are prone to stability problems (global and local buckling) reducing their resistance. The adjacent planar members (e.g. sandwich panels, trapezoidal sheeting) can provide lateral and torsional restraint for the member along its span which prevents the displacement and rotation of the cross-section and might positively influence its buckling resistance. In [1] provisions for minimum required shear and rotational stiffness for full stabilization are provided including formula for elastic critical moment of a continuously laterally and torsionally restrained thin-walled beam. The availability of the restraint can be dependent on direction of the external load This problem was studied for sandwich panels supported by metal members (purlins, girts). The attention will be paid specially to steel thin-walled beams stabilized by planar members providing full lateral and incomplete torsional restraint under uplift load which results in compressed free flange of the beam (prone to buckling). The buckling resistance of the free flange in compression will be investigated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
