Browsing by Author "Carrillo, Julian"

Now showing 1 - 7 of 7
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    Compression behavior of square and circular SFRC columns confined with external steel straps
    (2024) Carrillo, Julian; Hube, Matias; Blandon, Carlos; Mata, Ramon; Abellan-Garcia, Joaquin
    Steel-Strapping Tensioning-Techniques (SSTT) have been proposed recently as a confinement strategy to enhance the strength and deformation capacity of new and existing Reinforced Concrete (RC) columns. Main advantages of SSTT are the low cost, simple installation and modest installation time. Existing methods to quantify the increase of the compressive strength and deformation capacity of actively confined concrete have been obtained considering conventional deformed steel. Additionally, previous studies have observed that toughness and deformation capacity of concrete increase when adding steel fibers to the concrete matrix. However, the combined effect of SSTT applied to Steel Fiber Reinforced Concrete (SFRC) columns has not been assessed. Hence, the objective of this study is to evaluate the compressive behavior of SFRC columns confined with SSTT. A total of 34 short columns with SFRC and plain concrete were subjected to monotonic compression tests. The studied variables consider the cross-section of the columns (square and circular), the steel fibers dosage (15, 30 and 60 kg/m3), 3 ), and the spacing of the steel straps (37.5, 50 and 75 mm). The obtained results demonstrate that the SSTT increased the compressive strength between 4 % and 18 %, and the deformation capacity up to 800 %. Additionally, the use of steel fibers was effective in further increasing the deformation capacity of columns confined with SSTT. A numerical model based on a database of 150 tests, where 34 are from this study, is also proposed to predict the compressive behavior of SFRC columns confined with SSTT.
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    Effect of Material Epistemic Uncertainty on the Seismic Response of RC Moment-Resisting Frame Buildings and Their Nonstructural Components
    (2025) Novoa, Daniela; Arroyo, Orlando; Obando, Juan C.; López-García González, Diego; Carrillo, Julian
    Reinforced Concrete Moment Resisting Frames (RCMRFs) are widely used in seismic hazard regions, but recent events have highlighted the significant impact of Nonstructural Components (NSCs) on repair costs. NSC behavior has become an active area of research, yet epistemic uncertainty stemming from material variability is often overlooked. This study explores the effects of epistemic uncertainty on RCMRFs and NSCs using Monte Carlo simulations in OpenSeesPy. Results show that concrete strength affects slight-moderate damage probabilities, while steel yielding stress impacts severe-collapse probabilities. Epistemic uncertainty introduces multi-modal behavior in the distribution of maximum acceleration of NSC, highlighting its relevance for performance assessment.
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    Effect of Material Epistemic Uncertainty on the Seismic Response of RC Moment-Resisting Frame Buildings and Their Nonstructural Components
    (2025) Novoa, Daniela; Arroyo, Orlando; Obando, Juan C.; López-García González, Diego; Carrillo, Julian
    Reinforced Concrete Moment Resisting Frames (RCMRFs) are widely used in seismic hazard regions, but recent events have highlighted the significant impact of Nonstructural Components (NSCs) on repair costs. NSC behavior has become an active area of research, yet epistemic uncertainty stemming from material variability is often overlooked. This study explores the effects of epistemic uncertainty on RCMRFs and NSCs using Monte Carlo simulations in OpenSeesPy. Results show that concrete strength affects slight-moderate damage probabilities, while steel yielding stress impacts severe-collapse probabilities. Epistemic uncertainty introduces multi-modal behavior in the distribution of maximum acceleration of NSC, highlighting its relevance for performance assessment.
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    Influence of the Inelastic Response of Reinforced Concrete Frame Buildings on the Inelastic Displacement and Acceleration Ratios of Nonstructural Elements
    (2025) Obando, Juan C.; Novoa, Daniela; Arroyo, Orlando; López-García González, Diego; Carrillo, Julian
    Damage to Nonstructural Elements (NEs) observed during recent major earthquakes indicates that the seismic design of NEs can significantly affect the overall seismic performance of buildings. NEs are subjected to floor accelerations that are usually higher than ground accelerations, resulting in an increased likelihood of inelastic deformations at their anchorages or support elements. However, the inelastic response of NEs has not been comprehensively analyzed. This research evaluates the influence of the inelastic behavior of Reinforced Concrete Frame Buildings (RCFBs) on the Inelastic Displacement Ratios (IDRs) and Inelastic Acceleration Ratios (IARs) of acceleration sensitive NEs, IDRs and IARs being important parameters to characterize the inelastic response of NEs. For this purpose, three RCFBs located in Colombia were subjected to scaled ground motions representing different levels of seismic intensity. The findings of this research are: a) as buildings enter the inelastic range, the IDRs show a reduced oscillation amplitude, and the local minima of the IDRs occur at the effective modal periods of the building rather than at the modal periods; b) existing prediction equations for IDRs provide good estimates for low seismic intensities (i.e. essentially elastic building response) and reasonable estimates for higher seismic intensities; c) the characteristic period of the IARs remains relatively insensitive to seismic intensity levels; and d) prediction equations for IARs provide accurate results regardless of seismic intensity levels, especially when the NE damping ratio is relatively low.
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    Influence of the Inelastic Response of Reinforced Concrete Frame Buildings on the Inelastic Displacement and Acceleration Ratios of Nonstructural Elements
    (Elsevier, 2025) Obando, Juan C.; Novoa, Daniela; Arroyo, Orlando; López-García González, Diego; Carrillo, Julian
    Damage to Nonstructural Elements (NEs) observed during recent major earthquakes indicates that the seismic design of NEs can significantly affect the overall seismic performance of buildings. NEs are subjected to floor accelerations that are usually higher than ground accelerations, resulting in an increased likelihood of inelastic deformations at their anchorages or support elements. However, the inelastic response of NEs has not been comprehensively analyzed. This research evaluates the influence of the inelastic behavior of Reinforced Concrete Frame Buildings (RCFBs) on the Inelastic Displacement Ratios (IDRs) and Inelastic Acceleration Ratios (IARs) of acceleration sensitive NEs, IDRs and IARs being important parameters to characterize the inelastic response of NEs. For this purpose, three RCFBs located in Colombia were subjected to scaled ground motions representing different levels of seismic intensity. The findings of this research are: a) as buildings enter the inelastic range, the IDRs show a reduced oscillation amplitude, and the local minima of the IDRs occur at the effective modal periods of the building rather than at the modal periods; b) existing prediction equations for IDRs provide good estimates for low seismic intensities (i.e. essentially elastic building response) and reasonable estimates for higher seismic intensities; c) the characteristic period of the IARs remains relatively insensitive to seismic intensity levels; and d) prediction equations for IARs provide accurate results regardless of seismic intensity levels, especially when the NE damping ratio is relatively low.
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    Seismic performance of mid-rise thin concrete wall buildings lightly reinforced with deformed bars or welded wire mesh
    (2021) Arroyo, Orlando; Feliciano, Dirsa; Carrillo, Julian; Hube, Matias A.
    The increasing demand of housing in urban areas in Latin America has driven the construction of a significant number of buildings using reinforced concrete (RC) walls with thickness equal or lower than 100 mm, with a single layer of reinforcement provided by a welded-wire mesh (WWM) or by deformed bars (DB). Several concerns related to the lack of ductility, scarce evidence on its behavior during earthquakes, and the lack of clarity of design guidelines in earthquake-resistant codes for this structural system have risen in recent years. This research aims at providing evidence on the seismic risk of thin concrete wall buildings reinforced with two types of reinforcement. A six-story building, constructed in Bogot ' a, Colombia with walls having 100 mm thickness and detailed with WWM is used as case study. After gathering relevant information from the building structural drawings, a nonlinear model was created in OpenSees using the shear-flexure interaction multiple vertical line element (SFI-MVLEM). To evaluate the effect of steel ductility, a second benchmark model of the studied building was created using deformed bars (DB) as reinforcement. Incremental dynamic analyses were conducted on the models using the far field ground motion suite provided by the FEMA P-695 and a set ground motions for subduction zones, which served as input for the development of fragility functions for the building. The results show that the fracture of reinforcing steel is a frequent failure mode of the building reinforced with WWM, whereas the failure of the building reinforced with DB was controlled by the drift limit of the walls. The findings also show that probabilities of failure for the ground motions scaled to the maximum credible earthquake are 41% and 25% for the building reinforced with WWM and DB, respectively. These large probabilities suggest that the use of thin RC walls for mid-rise buildings should be limited in seismic prone areas, especially those detailed with WWM.
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    Seismic response of acceleration-sensitive nonstructural components in a Thin Lightly-Reinforced Concrete Wall (TLRCW) mid-rise building
    (2022) Obando, Juan Carlos; Arroyo, Orlando; Lopez-Garcia, Diego; Carrillo, Julian
    Experience in recent earthquakes has shown that Non-Structural Components (NSCs) in multi-story buildings exert a significant influence on economic losses. Different topics about the seismic behavior of NSCs have been investigated; however more research is needed in several areas such as the type of building structural system and the type of seismic hazard. Motivated by this observation, floor accelerations in a novel structural system, namely the Thin and Lightly-Reinforced Concrete Wall (TLRCW) building, are examined in this paper. The TLRCW system comprises thin and slender walls with deficient or nonexistent confinement at the wall edges, and web reinforcements made of welded-wire mesh with limited ductility. In this study, seismic demands on NSCs in a TLRCW building are analytically calculated and compared with current characterizations included in earthquake-resistant building codes and presented in the literature. Comparisons are performed in terms of peak floor accelerations, floor spectra, inelastic displacement ratios, and the still not completely characterized in-elastic absolute acceleration ratios. Influence of elastic and inelastic behavior of NSCs as well as of the structure is also evaluated. Since the TLRCW system is becoming common in some South American countries prone (in part or wholly) to subduction earthquakes, possible influence of the type of seismic hazard (i.e., crustal earthquakes or subduction earthquakes) is accounted for. It was found that, under design-level seismic demands, floor ac-celerations can be very large even though the structure undergoes a significant level of inelastic excursion. It was also found that floor accelerations are, for the most part, reasonably approximated by current characterizations. Finally, the type of seismic hazard has a negligible qualitative influence on floor accelerations (only minor quantitative differences were found).