Browsing by Author "Sandoval, Cristián"

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    A new method for assessing compatibility of consolodation procedures with conservation principles: Intervention Qualitiy Index
    Llera Martin, Juan Carlos de la; Palazzi, Nuria Chiara; Misseri, Giulia; Sandoval, Cristián; Tonietti, Ugo; Rovero, Luisa
    In current times, built heritage is being lost at an alarming rate due to natural and human hazards. Policies for its protection and rehabilitation involve, among other things, challenges related to the refinement of suitable structural strengthening approaches. The arduous balance between gaining acceptable safety levels for occupants without deploying intrusive devices, inconsistent with conservation principles such as those of the ICOMOS charters, is not a simple task. The interest and efforts of the scientific community in this regard have been increasing for decades, but still, it is the structural professional´s responsibility and experience which must define this arduous balance on a case-to-case basis. This study addresses the question: How can the quality of structural rehabilitation interventions be assessed in light of conservation principles such as those given by ICOMOS? Here, a preliminary method - called “Intervention Quality Index” (IQI) method is proposed. It assesses the restoration intervention quality in relation to: (i) the level of compliance given by the conservation´s principle score (conservation´s factor, CF); and (ii) the current state of conservation of the monument (safety factor of building considering the seismic intensity, Δs). The IQI method considers the compliance level of the designed reinforcement with conservation principle, formalized through the fulfillment of a category, i.e. respected, partially respected, and not respected. Then, these judgments are translated into scores and statistically evaluated. Scores are attributed in relation to the relevance of the fulfillment of a certain conservation principle (authenticity, minimal intervention and intrusiveness, compatibility, recognizability and reversibility) for the seismic structural safety point of view. Preliminary results show that an effective employment of traditional earthquake-resistant practices together with a wise use of modern retrofit strategies allow for the preservation and reinforcement of built heritage without harming its identity
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    Partially grouted masonry walls with different horizontal reinforcement types: North American-compliant experimental performance for low seismic risk areas
    (2023) Rahim, Amr Ba; Pettit, Clayton; Cruz-Noguez, Carlo; Sandoval, Cristián
    The type of horizontal reinforcement can play a major role in the shear response of partially grouted (PG) masonry walls, particularly in the damage pattern and the post-peak behavior. Bond beam reinforcement and bed joint reinforcement are the two reinforcement types most commonly used in practice; however, there is a lack of comparative studies between these two reinforcement strategies. To advance knowledge on this matter, this paper presents the results of an experimental study made up of 4 full-scale walls tested under cyclic lateral loading. Two height-to-length aspect ratios (H/L = 1.0, 1.86) and two reinforcement types per aspect ratio were considered. These walls were designed to reflect practical details and construction practices for PG walls in low seismic hazard areas. Lateral load tests showed that the peak strength of walls with similar aspect ratios had no significant difference regardless of the reinforcement type used. Bed-joint reinforcement proved to be a vital option as a shear reinforcement for controlling the crack width. The preliminary assessment of in-plane strength prediction equations for PG walls revealed that the general flexural analysis method provides a satisfactory estimation of flexural strength. In contrast, code-based equations had a highly conservative prediction of shear strength when imposing the upper limit. In addition, the Canadian Standards Association (CSA) and The Masonry Society (TMS) equations used to predict the in-plane shear strength had a noticeable discrepancy in the contribution of the equation's parameters, particularly in the axial stress, horizontal reinforcement, and the upper limit, which highlighted the need to revise and reconsider the contribution of each design parameter used by these expressions.
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    Seismic Vulnerability Assessment of the Yungay's Historic Urban Center in Santiago, Chile
    (2022) Chiara Palazzia, Nuria; Barrientos, Marco; Sandoval, Cristián; Llera Martín, Juan Carlos de la
    In this paper, a modified empirical large-territorial-scale procedure to assess the seismic vulnerability of aggregate buildings in urban areas located within a highly seismic context is proposed. The methodology is applied to a group of unreinforced masonry (URM) aggregates located in the Yungay's historic center in downtown Santiago, Chile. This assessment was carried out by modifying and integrating a vulnerability-index-based procedure, a specific existing approach called first level macro-seismic method used to predict seismic damage and loss scenarios through fragility curves of structural components. The procedure was calibrated using the observed damage after the 2010 Chile earthquake in 292 URM structural units. The results of this new damage index for URM aggregate buildings are used to derive Probability Mass Functions (PMFs) of the different damage states and preliminary Empirical Fragility Functions (EFFs). To the best of the authors' knowledge, these EFFs are the first publicly available for aggregate Chilean URM buildings. This research and its results are the starting point for a more comprehensive study for assessing damage sce-narios and vulnerabilities of aggregate URM buildings in historic centers of older Chilean cities. These functions may be used in risk assessment, and are useful to prioritize possible future damage mitigation strategies and other processes involving this historical heritage. We foresee that these results could be at least partially applied to other historical urban areas in Chile, and perhaps other old Latin American cities located along the sub-duction convergence region between the Pacific and Continental plates, which were founded similarly.