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Finite element models were developed to assess the influence of several parameters on the load capacity, deflection, and initial stiffness of multi-story, partially grouted masonry walls with openings. The base model was validated with experimental data from three walls. The analyses indicated that the load capacity of masonry walls was considerably sensitive to the ungrouted and grouted masonry strengths and mortar shear strength; moderately sensitive to the vertical reinforcement ratio and aspect ratio; slightly sensitive to the axial stress; and almost insensitive to the opening size, reinforcement spacing, and horizontal reinforcement ratio. The deflection of the walls had well-defined correlations with the masonry strength, vertical reinforcement, axial stress and aspect ratio. The initial stiffness was especially sensitive to the axial stress and the aspect ratio, but weakly correlated with the opening size, and the spacing and size of the reinforcement.

Wall-beam interaction (wall-beam system) is a phenomenon that requires further investigation in order to be consistently incorporated into structural building analysis. Researchers such as Wood, Rosenhaupt, Burhouse, Stafford Smith, Navaratnarajah, Davies, Riddington and Armed conducted tests on specimens to develop simplified analysis models, emphasizing the behavior of walls without openings under one span beams. The present study performed computational analysis using an specific equivalent frame model in order to study the behavior of the wall-beam system in more complex wall and beam arrangements. The examples considered the linear elastic behavior of materials and consisted of assessing stress distribution and displacements on support beams, in addition to stresses at the bottom of the walls, for panels in a real structural masonry building. Two- and three-dimensional analyses were used and the results showed the importance of three-dimensional analysis of wall interconnections. The effects of eccentricity between the vertical plane of the wall and horizontal support beam axis were also evaluated, showing the strong influence of twisting moments in support beam design.

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Modal identification is a key step in modal analysis. It enables the researcher to extract modal parameters, such as natural frequency, amplitude, and damping from a given structure. There are a considerable number of techniques in the state of the art aiming to address this problem, where multi-mode approaches arise as an appealing choice due to their ability to deal with mode coupling. This tutorial paper focuses on the complex-curve fitting technique, originally conceived for an application distinct from modal analysis. It aims at guiding other researchers by providing a tutorial-like and in-depth analysis of this important method, associated with a nonlinear weighting procedure for improved precision. Additionally, this paper fills a gap on the original technique, which is limited to the ratio of two polynomials, by proposing an automatic parameter extraction technique. The original and improved methods are applied on both simulated and experimental data, highlighting the effectiveness of the proposed changes. The proposed procedure is also compared with the rational fraction polynomial method.

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