TimeDependent Analysis of ShearLag Effect in Composite Beams
by Luigino Dezi, (Prof. of Struct. Engrg., Inst. of Struct. Engrg., Univ. of Ancona, via Brecce Bianche, Monte D’Ago, 60131, Ancona, Italy. Email: dezi@popcsi.unian.it), Fabrizio Gara, (Grad. Engr., Inst. of Struct. Engrg., Univ. of Ancona, via Brecce Bianche, Monte D’Ago, 60131, Ancona, Italy), Graziano Leoni, (Postdoct. Res., Inst. of Struct. Engrg., Univ. of Ancona, via Brecce Bianche, Monte D’Ago, 60131, Ancona, Italy), and Angelo Marcello Tarantino, (Assoc. Prof., Dept. of Engrg. Sci., Univ. of Modena, via Campi 213/B, 41100, Modena, Italy. Email: tarantino@unimo.it)
Journal of Engineering Mechanics, Vol. 127, No. 1, January 2001, pp. 7179, (doi: http://dx.doi.org/10.1061/(ASCE)07339399(2001)127:1(71))
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Document type: 
Journal Paper 
Abstract: 
Taking into account the longterm behavior of the concrete, a model for analyzing the shearlag effect in composite beams with flexible shear connection is proposed. By assuming the slab loss of planarity described by a fixed warping function, the linear kinematics of the composite beam is expressed by means of four unknown functions: the vertical displacement of the whole cross section; the axial displacements of the concrete slab and of the steel beam, and the intensity of the warping (shearlag function). A variational balance condition is imposed by the virtual work theorem for threedimensional bodies, from which the local formulation of the problem, which involves four equilibrium equations with the relevant boundary conditions, is achieved. The assumptions of linear elastic behavior for the steel beam and the shear connection and of linear viscoelastic behavior for the concrete slab lead to an integraldifferential type system, which is numerically integrated. The numerical procedure, based on the stepbystep general method and the finitedifference method, is illustrated and applied to an example of practical interest. 
