Free Vibrations of Steel–Concrete Composite Beams by the Dynamic Direct Stiffness Method

Abstract

A new dynamic direct stiffness method for analyzing the natural vibration characteristics of steel–concrete composite beams (SCCBs) is proposed, which considers the effect of partial interaction between the interface of the concrete slab and steel beam. The advantage of the method is that exact solutions can be obtained due to no introduction of approximated displacement and/or force fields in the derivation. Besides, the method is especially useful for the dynamic analysis of SCCBs with axial variable stiffness under four common boundary conditions. The proposed method is validated by comparing with the theoretical and experimental results available in the literature. Finally, the effects of different boundary conditions, shear connection, cross-sectional stiffness ratio, and other parameters upon the frequencies of the beam are discussed in detail.