My Personal Page, for Academic Use
Papers and Reports in Progress
This section presents a curated list of research papers, including both proposals planned for development over the next five to seven years and works that have already been accepted for publication. Please note that the titles and scopes of the proposed papers are provisional and may undergo partial or complete revision
Papers
TREQ Project - Report D261: Seismic Risk Assessment for the Metropolitan District of Quito.
Authors: Calderón A. , Yepes C. , Celi C.
This document is the result of collaborative efforts between the GEM Foundation, the United States Geological Survey, the Metropolitan Risk Management Directorate, the Quito Mayor's Office, the Pontifical Catholic University of Ecuador, and the Metropolitan Public Water and Sanitation Company of Quito. The aim of this report is to present the results of the urban risk assessment for the Metropolitan District of Quito (DMQ), obtained within the context of the TREQ Project. All the information generated for Quito can be found in this repository: https://github.com/gem/treq-riesgo-urbano/tree/main/Quito.
Fragility Analysis of One of the Most Relevant Structural Typologies in Quito. TREQ-GEM Project.
Authors: Palacios P. , Celi C.
This study showcases the results from nonlinear static analyses of various potential combinations, focusing on the vulnerability assessment of four to six-story structures with irregular plan shapes, comprised of cast-in-place concrete slabs supported by masonry-filled frames. We derived theoretical capacity curves and evaluated them against multiple seismic scenarios as outlined in the Ecuadorian Construction Code. These scenarios span return periods from 25 to 475 years, assessed at 10-year intervals, and incorporate variations for soil types C and D. This study showcases the results from nonlinear static analyses of various potential combinations, focusing on the vulnerability assessment of four to six-story structures with irregular plan shapes, comprised of cast-in-place concrete slabs supported by masonry-filled frames. We derived theoretical capacity curves and evaluated them against multiple seismic scenarios as outlined in the Ecuadorian Construction Code. These scenarios span return periods from 25 to 475 years, assessed at 10-year intervals, and incorporate variations for soil types C and D.
Reliability of Seismic Modeling in the Non-Linear Range, Based on the Length of Assumed Plastic Zones for Beams.
Authors: Celi C. , Arellano R.
ISSN: 1390-0129 / eISSN: 2477-8990
This article showcases the findings from a mathematical analysis of a frame spanning four bays and five stories. This frame is subjected to monotonic loading with the distribution of lateral forces derived from a combination of the structure's first and second vibration modes. The forces are incrementally applied in cycles until a predetermined control displacement is achieved, indicating the implementation of a Nonlinear Static Analysis (NSP). The study introduces energy dissipation mechanisms based on three distinct lengths for the frame beams' plastic zones, with a consistent plastic zone length designated for all columns. Through the use of software tools like Python and Matlab, 200 combinations of these potential mechanisms were tested and compared. This publication constitutes the initial phase of a research project titled "Parametric Reliability Analysis of Seismic Modeling in the Nonlinear Range Based on Chosen Modeling Type". The overarching goal is to delineate the efficiency of two disparate mathematical simulation processes for energy dissipation: the Fibers Method and the Assumed Plastic Zone Method.
Seismic Vulnerability of Quito Ecuador, Phase 1: Capacity Curves of Structural Typologies, Project Gem - Sara.
Authors: Celi C. , Pantoja J. , Sosa D. , Ayala. C.
ISSN: 2528-8156
This research showcases the results of the nonlinear static analysis of the different probable combinations for multi-family buildings in the Metropolitan District of Quito (DMQ). For this study, the four most recurring typologies within a sample of 11,556 structural units were identified. Special emphasis is placed on modeling the nonlinear-fragile behavior of masonry elements, both framed and unframed. From the analysis, a global nonlinear behavior of the structure is derived, approximating the real behavior represented by capacity curves. The various capacity curves of each theoretical model are subjected to two seismic scenarios (with return periods of 100 and 475 years), considering the seismic amplification due to soil types B-C as outlined in the NEC15. This analysis provides an initial glimpse into the replacement cost in the event of a collapse of the structures examined under the proposed seismic scenarios. These findings will be validated in the subsequent study titled "Fragility Curves, based on Spectral Scenarios applied to Structural Typologies of Quito-Ecuador, Project GEM-SARA.
Evaluation and Reinforcement of a Heritage Adobe Structure with Plan Irregularity.
Authors: Chacon J. , Suquillo B., Sosa D. , Celi C.
Ecuador is home to numerous heritage structures constructed from fragile, earth-based materials, notably adobe. Recent seismic activities have exposed the inadequate performance of these buildings, attributed to their significant mass and limited seismic resistance. This article delves into the assessment of the old building of Simon Bolívar high school, highlighting various reinforcement methodologies for this adobe wall system featuring plan irregularities, situated in downtown Quito. The study posits that external forces apply in the direction of the wall's most robust plane, and such adobe walls exhibit limited resilience to in-plane lateral loads. A sensitivity analysis of the finite element discretization is showcased, leveraging a commercial software. This analysis determines empirical values connecting the proportion of the finite element to the wall's primary length. Consequently, this finite element meshing proposal aims to discern initial ratios for element size, facilitating an introductory calibration analysis centered on stress and displacement regulation. The paper scrutinizes the finite element meshing typically employed in two-dimensional structures, underscoring the critical nature of the meshing's initial calibration to yield dependable outcom.
Reports in Progress
Urban Scale Earthquake Loss Assessment:
A Collaborative Model for Quito's Metropolitan District
Authors: Celi C. , Calderón A. , Yepes C.
Note: Upcoming in the subsequent years.
In this study we present the collaborative effort between seven institutions to establish an earthquake loss assessment model at an urban scale for the Metropolitan District of Quito. Our goal is to provide decision makers with tools that can help identify the drivers of risk at a local level and support the municipal risk management office in efforts of mitigation, planning and emergency response. To achieve this, we have developed a new and open building-by-building inventory for the city that leverages on castrate, treasury, and housing and census databases. This model has been complemented with a fragility and vulnerability catalogue for the building classes identified in the exposure, 13 local amplification functions to account for site-specific soil response in each seismic micro zone, the most recent PSHA model for Ecuador, and 7 earthquake scenarios. In the results we have produced a wide range of deterministic and probabilistic risk metrics for the city, which are presented in the form of mitigation and emergency response profiles
Comparative Analysis of Nonlinear Performance in Buildings with Fixed Base and Base Isolation: A Multi-Parametric Variation Approach.
Authors: Celi C. , Palacios P.
Note: Upcoming in the subsequent years.
The study delves into estimating damage in specially-used structures, providing a succinct overview of methods for seismic evaluation in both fixed base and base-isolated buildings. We employ nonlinear analysis tools, adopting a probabilistic approach that utilizes parametric analysis fine-tuned to a lognormal distribution. The capacity spectrum methodology (CSM) is integral in deriving capacity curves. In advocating for the broader adoption of isolation systems in Ecuador—where, notably, they aren't mandated by construction codes—we model a representative 6-story structure. This structure is designed both with a fixed base and diverse base isolation configurations, incorporating LRB along with a range of geometric and mechanical property variations. We subsequently assess how these variations in mathematical models influence the building's superstructure performance.
The structure's nonlinear behavior is illustrated using capacity curves. These curves are then converted to fragility curves via direct static methods (MED). When determining the bounds of these capacity curves, we account for the inherent fragility of the lateral load-resisting system, acknowledging that numerical stability analyses might yield more conservative global ductility estimates. The analytical procedures and result compilations utilize Matlab and OpenSees software tools. Our findings are showcased in damage probability matrices, corresponding to seismic scenarios characterized by specific target displacements. In essence, this research seeks to bolster the comprehension and assessment of specially-used structures' performance, urging the broader integration of isolation systems within Ecuador.
Proposal for Seismic Hazard Model for Ecuador
Authors: Palacios P. , Celi C. , Poveda J.
Note: Upcoming in the subsequent years.
This paper introduces a newly proposed Seismic Hazard Model for Ecuador. By seamlessly integrating comprehensive geological and engineering data with the latest advancements in discrete mathematics, our model delivers a refined understanding of Ecuador's seismic threats. We utilize up-to-date attenuation equations, harmonized with the available dataset, and supplement our analysis with probabilistic methods rooted in seed conditions and logical trees. A standout feature of our research is the development of interactive tools for seismic disaggregation calculations, designed for applicability across any location within continental Ecuador. Crafted using Python, these tools are made freely available to researchers, policymakers, and the general public. In essence, our model and its accompanying tools aspire to bolster seismic preparedness and understanding in Ecuador, not by sidelining prior endeavors, but by building upon them to achieve a comprehensive grasp of the region's seismic landscape.
Bridging Mathematical Tools:
Utilizing Chaos Theory and Wavelets in the Creation of Synthetic Accelerograms for Civil Engineering Students.
Authors: Celi C.
Note: Upcoming in the subsequent years.
The dynamic field of civil engineering consistently seeks innovative methodologies to enhance student understanding of intricate seismic phenomena. This study investigates the confluence of two robust mathematical tools: Chaos Theory and Wavelets, and their combined efficacy in crafting synthetic accelerograms. By deeply exploring the foundational principles of both methodologies, we illuminate their synergistic potential in producing accurate and ducationally beneficial seismic models. Central to our approach is the strategic utilization of these mathematical paradigms to generate synthetic accelerograms, aiming to enrich the scope and depth of seismic catalogs for educational purposes. Through this endeavor, students gain exposure to a more diverse range of seismic data, underscoring the profound capabilities of these mathematical tools in confronting and navigating real-world challenges in civil engineering. It is our aspiration that this research not only addresses existing gaps in seismic catalogs but also galvanizes upcoming civil engineers to harness advanced mathematical tools in their future professional pursuits.
Urban Scale Earthquake Loss Assessment:
A Collaborative Model for Quito's Metropolitan District
Authors: Celi C. , Calderón A. , Yepes C.
Note: Upcoming in the subsequent years.
In this study we present the collaborative effort between seven institutions to establish an earthquake loss assessment model at an urban scale for the Metropolitan District of Quito. Our goal is to provide decision makers with tools that can help identify the drivers of risk at a local level and support the municipal risk management office in efforts of mitigation, planning and emergency response. To achieve this, we have developed a new and open building-by-building inventory for the city that leverages on castrate, treasury, and housing and census databases. This model has been complemented with a fragility and vulnerability catalogue for the building classes identified in the exposure, 13 local amplification functions to account for site-specific soil response in each seismic micro zone, the most recent PSHA model for Ecuador, and 7 earthquake scenarios. In the results we have produced a wide range of deterministic and probabilistic risk metrics for the city, which are presented in the form of mitigation and emergency response profiles
