Rotational stiffness of continuous composite beams with sinusoidal-web profiles for lateral-torsional buckling

In the hogging bending moment region, continuous composite beams are subjected to the ultimate limit state of lateral-torsional buckling, which depends on web stiffness as well as concrete slab and shear connection stiffnesses. These three stiffnesses compose the rotational stiffness of composite beams. Eurocode 4 defines this stiffness in composite beams with plane webs, but there are no conclusive studies on the stiffness of composite beams with sinusoidal-web profiles. This paper presents a formulation to evaluate the rotational stiffness of composite beams with sinusoidal-web steel profiles presented based on (a) test results for four representative prototypes of the inverted U-frame model, (b) the development and calibration of a numerical model using the ANSYS commercial finite element software, and (c) the computational processing of sixty-eight numerical models. In these models, the researchers attempted to vary all the parameters that could influence the rotational stiffness, such as web height and thickness, slab size and type (concrete or composite), number of shear connectors in the cross-section and longitudinal spacing of connectors.

► Experimental tests of prototypes of the inverted U-frame model were performed. ► Finite-element model for the inverted U-frame model have been developed. ► Finite element model was validated by the experimental tests. ► A parametric study was done for composite beams with sinusoidal-web profiles. ► A formula to obtain the rotational stiffness of this type of beam was proposed.