Browsing by Author "Vargas Carvajal, Laura Andrea"

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    Seismic behavior of partially grouted masonry shear walls containing openings: Experimental testing
    (2023) Vargas Carvajal, Laura Andrea; Sandoval Mandujano, Cristián; Bertolesi, Elisa; Calderón Díaz, Sebastián Andrés
    This article presents an experimental study aimed at understanding the effect of openings on the seismic response of partially grouted reinforced masonry (PG-RM) walls. For this purpose, four full-scale PG-RM walls with different opening sizes were built and tested under the combined action of constant axial compression and cyclic lateral loading. All the specimens had the same external dimensions. The effect of openings was assessed in terms of wall hysteresis and force–displacement curves and the quantification of different seismic parameters such as shear capacity, degradation of lateral stiffness, energy dissipated, equivalent viscous damping ratio, and displacement ductility. A 2D Digital Image Correlation (DIC) system was implemented to monitor principal strain fields and cracking patterns during the tests. The paper also includes the assessment of the shear capacity of the tested walls according to three existent approaches developed for in-plane shear panels, which rely on the definition of an effective height of piers. The results indicate that the shear capacity of the walls decreased when the aspect ratio of the piers increased. From DIC analysis results, it was observed that damage extended beyond piers also covering spandrels and that directionality of shear loads played a fundamental role in the damage development. Therefore, the identification of the pier’s effective height and direction of seismic loads should be incorporated into the estimation of the shear capacity. Finally, the performance of the selected shear expressions and different approaches to estimate the effective height of the piers was evaluated. It was concluded that the most accurate approach was to define an effective piers height according to Augenti (2006)’s proposal using the Calderón et al. (2022) shear expression to assess piers’ lateral resistance.
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    Seismic strengthening of partially grouted masonry walls with openings: Evaluation of ferrocement and BTRM solutions
    (2024) Pérez Pinedo, Luis Elías; Sandoval Mandujano, Cristián; Alvarado Funes, Rolando José; Vargas Carvajal, Laura Andrea; Calderón Díaz, Sebastián Andrés; Bernat, Ernest
    This paper presents an experimental study on the seismic performance of partially grouted reinforced masonry (PG-RM) walls strengthened with two solutions: Ferrocement coating (welded wire steel mesh embedded in cementitious mortar, WWM) and Basalt Textile Reinforced Mortar (BTRM) layer. For this purpose, two full-scale walls were built with hollow concrete units, with identical geometry and construction details of a previously reported tested wall, which acts as the control specimen (unstrengthened case) in this study. The walls, with a window-type opening and another door-type opening, were strengthened on one of their sides and tested under the combined action of constant axial compression and cyclic lateral loading up to failure. The experimental results show that both strengthening solutions increased the investigated walls' initial stiffness and lateral capacity. The increase in lateral capacity of both solutions was similar, about 37%. The 2D-DIC analysis implemented during the tests was instrumental in highlighting the areas on the strengthened walls where high strains were developed. The damage registered on the BTRM layer was more consistent with what was observed on the surface of the unstrengthened wall. Meanwhile, the damage reported on the wall strengthened with WWM did not exhibit apparent damage at higher drift levels due to the detachment between the ferrocement coating and the masonry substrate. Finally, the performance of some procedures to compute the contribution of the studied strengthening solutions was also assessed.
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    Shear design equation and updated fragility functions for partially grouted reinforced masonry shear walls
    (2022) Calderón Díaz, Sebastián Andrés; Vargas Carvajal, Laura Andrea; Sandoval Mandujano, Cristián; Araya Letelier, Gerardo Andrés; Milani, Gabriele
    This paper proposes specific ultimate shear strength expressions for partially-grouted reinforced masonry (PG-RM) shear walls that are bed-joint reinforced (BJR) and made with either multi-perforated clay bricks (MPCLBs) or hollow concrete blocks (HCBs). For each unit type, a set of constant coefficients of an arbitrary mathematical expression is optimized to minimize the error against experimental databases of walls made with the same unit types. Additionally, the assembled databases are employed to calculate lognormal empirical fragility functions, following performance-based earthquake engineering (PBEE) methodologies. For this, two different engineering demand parameters (EDPs) (story drift ratio, SDR, and normalized diagonal shear demand, NDSD) are proposed, and two damage states (DS) (named DS4 for moderate damage and DS5 for severe damage) are investigated. The proposed shear formulae are used in the normalization of calculated NDSD values. Moreover, databases are sorted by a selected design parameter (aspect ratio) to calculate design parameter-sensitive fragility functions. Overall, the results indicate that the proposed expressions are more accurate than the corresponding expressions proposed by the American and Canadian codes when assessing BJR-PG-RM shear walls in terms of the average error and dispersion of relative prediction error. All the fragility curves adjusted to the whole database pass the Lilliefors goodness of fit test (). Comparing SDR-based curves of walls of a different unit type, DS4 curves present a smaller difference in the median value () than DS5 curves. Additionally, the variations in the of NDSD-based curves of walls of different units are smaller than those observed in SDR-based fragility functions, indicating that NDSD represents a less variant EDP to describe the probability of shear damage at DS5 when a proper expression is employed for the normalization. Regarding design parameter-sensitive fragility functions, sorting databases reduces the number of data points used to calculate the functions, which produced two SDR-based and one NDSD-based function to fail the Lilliefors test (). In general, the value of SDR-based curves increases in proportion to the aspect ratio. Additionally, classifying the databases by a design parameter (aspect ratio) corroborated that the proposed expression has acceptable accuracy based on the adjusted NDSD-based DS5 fragility functions. It is highlighted that calculating design parameter-sensitive functions might increase the accuracy of PBEE assessments (e.g., loss estimations) when an EDP insensitive to design parameters normalization (e.g., SDR) is employed.