Upper Bound limit analysis model for FRP-reinforced masonry curved structures. Part I: Unreinforced masonry failure surfaces

摘要

A two-steps approach for the FE limit analysis of FRP reinforced curved masonry structures is presented in this paper. In step I, discussed extensively in the present Part I, a simplified kinematic procedure is proposed at a cell level to obtain macroscopic masonry behavior in the case of unreinforced masonry curved structures. In step II, discussed in the companying paper (Part II) strips are applied at a structural level on the already homogeneous material.rnUnreinforced masonry strength domain is obtained by means of a compatible approach in which each brick is supposed to interact with its six neighbors by means of rigid-plastic interfaces with frictional behavior representing mortar joints. A sub-class of possible elementary deformations is a-priori chosen to describe joints cracking under in- and out-of-plane loads. Suitable internal macroscopic actions are applied on the boundary of the representative element of volume, in analogy to the flat case. The limit analysis problem at a cell level is finally solved adopting an upper bound approach and discretizing the seven bricks by means of six-noded rigid infinitely resistant wedge elements. In this way, internal power dissipation is possible only at the interfaces between wedge adjoining elements (brick-brick interfaces and mortar joints with zero thickness).rnSeveral examples consisting of single and double curvature elementary cells are analyzed. For each representative element of volume, in- and out-of-plane failure surfaces are provided. Macroscopic strength domains so recovered will be utilized in Part II for the limit analysis of entire vaults FRP reinforced.