Refined-compression field theory for thin low-reinforced sandwich panels subjected to reversed cyclic horizontal loads

Refinements to modified compression-field theory has been recently proposed in order to better predict the behaviour of reinforced concrete members subjected to in-plane shear and axial stresses, leading to the so-called refined-compression field theory, RCFT. This theory is based on the continuum mechanic approach, i.e. satisfy compatibility, equilibrium and constitutive equations in terms of average (i.e. “smeared”) stresses and strains. The original refinement proposed by RCFT, with respect to the two fundamental theories for reinforced concrete member subjected to shear, i.e. the Modified Compression-Field Theory, MCFT, and the Rotating-Angle Softened Truss Model, RA-STM, deals with the introduction of an embedded bar model based on the tension stiffening in concrete. In this paper further refinements are proposed with reference to two different typologies of thin low-reinforced sandwich panels subjected to reversed cyclic lateral loads: (a) reinforced concrete sandwich panels produced by “Nydion Costruzioni s.p.a.”; (b) cement-stucco plastered straw bale walls; a total of 4 full-scale “Nydion panels” and 3 full-scale straw-bale walls were tested. The predictions of the RCFT are compared with the experimental data as well as with the predictions given by the MCFT and RA-STM.