Dynamic analysis of a masonry wall with reinforced concrete lintels or tie-beams

In order to study the unilateral contact effects (i.e. separation, sliding) between the lintels of reinforced concrete over the openings or the reinforced concrete tie beams at floor levels and the masonry wall, a parametric non-linear dynamic analysis was performed. The nonlinear behavior of the masonry is modeled by means of appropriately modified elastoplastic laws. Different values of the friction coefficient and various dynamics loadings and earthquakes are considered. From the analysis it is shown that the influence of these reinforcements on the dynamic response of masonry structures depends on many parameters like the magnitude of the ground motion and the friction coefficient of the interface between the lintels or tie beams and the masonry. The positive effects of contact mechanisms can be reduced in case of a strong base excitation motion where spatially restricted relaxation in accompanied with stress concentration to other places appears. The energy dissipation mechanism which work in the case of small displacements would leads to negative results when the sliding movements between the lintels and the masonry goes beyond some limits.