Further developments of a simplified modelling of infilled frames for reinforced concrete buildings

The main proposals for the modelling of the infilled frames are calibrated on the results deriving from experimental testing data. In many cases, the experimental laws acquired that concern samples packaged with materials and executive methods (for frame-panel interface conditions, for mechanical properties⋯) are extended to different with several uncertainties. Several researchers suggest approaches that ranging from the macro-scale to micro-scale analysis. The different proposals confirm the complexity to simulate the kinematic mechanism between constitutive elements (mortar and bricks) and between masonry panel and surrounding frame. Therefore, the great variability of models and available studies do not allow to apply a univocal model adaptable in all cases, (Except by adopting, micro-modelling approaches, increasing the computational effort). This raises the need to define simplified models that take into account the geometry, mechanical properties of the masonry walls and elements of the surrounding frame. For these purposes, the present study proposes a Rigid Blocks Method in a simplified format for simulating of the infilled frames in order to define the main parameters that characterize the simplified "Equivalent Strut model" (i.e. the macro-modelling of the infill walls). The method falls in the meso-scale approaches commonly used for analysis of masonry structures. The use of an equivalent rod for modelling the infill panels is simple and reduces the computational costs when it is need to evaluate the global behavior on building scale. In order to demonstrate its multiple advantages, the method is presented. The opportunity to simulate the behavior of the infilled frame varying the mechanical properties and modality to derive ad hoc constitutive laws in presence of openings are just some the potential of the method. With the help of numerical benchmarks having similar characteristics to those widespread into building heritage these results are widely discussed.