Rodrigo Astroza

University of the Andes (Chile) | UANDES · Faculty of Engineering and Applied Sciences

This study assesses the feasibility of the incorporation of fibrillated polypropylene fibers (FPFs), an engineered multidimensional and multifilament fiber mostly used to reinforce concrete mixtures, into adobe mixtures (AMs), a traditional and manually-made material used to produce adobe blocks. The incorporation of FPFs was assessed using increas...

Nonlinear finite-element model updating (FEMU) is a promising approach for post-event damage assessment of civil structures. This paper conducted FEMU for a full-scale reinforced concrete bridge column tested under a sequence of earthquakes and examined the evolution of seismic damage across different earthquake ground motions. It was found that us...

This paper proposes a Bayesian framework based on particle filters for online fatigue damage diagnosis and prognosis for wind turbine blades (WTBs). The framework integrates theoretical and practical aspects with the purpose of developing a robust monitoring tool. Besides, a damage indicator based on identified modal frequencies of the WTB is defin...

In this paper, we employ a Bayesian approach to estimate the parameters of a high cycle accumulation model for sands using experimental data. Global sensitivity analysis and Markov-Chain Monte Carlo simulation are conducted for each of the twenty-four available experimental drained triaxial test results, considering the effect of estimating soil pa...

The need to build tall buildings has been increasing worldwide, creating new challenges in earthquake engineering and design. Many of the current analysis methods cannot be extrapolated beyond the definition under which they were established. Prior studies and existing seismic design guidelines have indicated that the current fixed-base hypothesis...

Stochastic filtering strategies, such as the unscented Kalman filter (UKF), are widely used for system or damage identification problems in various fields. However, in civil engineering, it is rarely used to learn about unknown modeling aspects using experimental data, despite of many studies using simulated data. This paper uses the UKF to estimat...

A promising and attractive way of performing structural health monitoring (SHM) and damage prognosis (DP) of engineering systems is through utilizing a nonlinear finite element (FE) model. Often, FE models contain parameters that are unknown or known with significant level of uncertainty. Such parameters need to be estimated/updated/calibrated usin...

Damage detection (DD) is one of the primary goals of health monitoring of civil structures. Vibration-based techniques aim to identify the modal properties (or vibration characteristics) of structures and are one of the most popular approaches for structural damage detection. The use of vibration characteristics (natural frequencies, damping ratios...

An energy dissipation mechanism form of a cable-pulleys system placed in series with a spring-damper device (fluid viscous) is experimentally studied. The system aims to provide high damping ratios for all the structural modes by using a unique spring-damper device to dissipate the seismic energy of the entire structure (and all its structural mode...

While high-rise mass-timber construction is booming worldwide as a more sustainable alternative to mainstream cement and steel, in South America, there are still many gaps to overcome regarding sourcing, design, and environmental performance. The aim of this study was to assess the carbon emission footprint of using mass-timber products to build a...

Abstract: This study presents the seismic performance assessment of the Aguila Norte Bridge, which is a five span simple supported prestressed concrete girder bridge-considered a typical Chilean bridge. The bridge was modeled with OpenSees, in which all the primary elements of the bridge were modeled, such as bridge deck, columns, piles, elastomeri...

The 2010 Maule, Chile earthquake demonstrated that many bridges were highly vulnerable to seismic demands. Among these bridges, skewed multi-span prestressed concrete girder bridges supported on non-anchored elastomeric bearings were the most vulnerable ones. After the 2010 Maule earthquake, several damaged skewed bridges were repaired and retrofit...

The time-variant dynamic properties related to the superstructure of base-isolated (BI) buildings are identified using a simple substructure approach. Based on the acceleration data recorded in BI buildings during earthquake events, the short-time deterministic-stochastic subspace identification (STDSI) method and a novel short-time transfer functi...

Las barras sísmicas son elementos de acero que se utilizan en Chile para evitar desplazamientos relativos verticales entre la superestructura y la infraestructura de puentes tradicionales. Por otra parte, Martínez (2015) observó, en campañas experimentales de probetas a escala con y sin diafragma, que estos elementos pueden jugar un rol relevante e...

Santiago, Chile Resumen Se estiman las propiedades dinámicas (frecuencias naturales y formas modales) de tres puentes con aislación sísmica a partir de mediciones de microvibraciones ambientales realizadas con arreglos de acelerómetros que se disponen en forma transitoria sobre las estructuras. Todos los puentes estudiados tienen un sistema de aisl...

Santiago, Chile Resumen Este estudio trata sobre la evaluación de amenaza sísmica, aplicada al caso de estudio del puente Águila Norte, mediante las metodologías determinística y probabilística. Para la metodología determinística, se emplearon técnicas de ajuste espectral ("spectral matching"). Esta necesita de un espectro objetivo y un registro se...

Santiago, Chile Resumen Los topes sísmicos empleados en puentes generalmente corresponden a elementos de hormigón armado que tienen como función limitar los desplazamientos transversales excesivos del tablero sobre cepas y estribos, de manera que no se genere colapso por falta de soporte de la superestructura. De acuerdo con el Manual de Carreteras...

Santiago, Chile Resumen Desde 1998, RENADIC instrumenta el puente el Salto Largo (ex Marga-Marga) lo cual ha permitido estudiar la respuesta sísmica del primer puente con aislación sísmica en Chile. Desde esa fecha se han registrado múltiples eventos sísmicos de la estructura, incluyendo el terremoto del Maule de 2010, lo que ha permitido generar i...

Santiago, Chile Resumen En el marco del proyecto FONDEF ID18I-10103, es empleado como caso de estudio, aplicación y ejemplo, a un puente tradicional chileno, el puente Águila Norte (AN) ubicado en Paine (Región Metropolitana). Este puente corresponde a un puente recto de 5 vanos y de 146 m de longitud y comparte varias de las características sugeri...

En la práctica ingenieril, es común el uso del software SAP2000 para realizar modelos y diseños de puentes chilenos conforme a las directrices dispuestas en el Manual de Carreteras (MdC), que se focalizan en análisis estáticos o análisis modales espectrales. Actualmente, existe la tendencia internacional a llevar a cabo evaluaciones del desempeño d...

En países forestales en vías de desarrollo como Chile la construcción de viviendas en al-tura con tecnología de madera masiva (predominantemente madera laminada y contrala-minada), ofrece una oportunidad única para contribuir a su desarrollo económico, bienes-tar social y cuidado ambiental. En Chile, el sector de la edificación es responsable de un...

En países forestales en vías de desarrollo como Chile la construcción de viviendas en al-tura con tecnología de madera masiva (predominantemente madera laminada y contrala-minada), ofrece una oportunidad única para contribuir a su desarrollo económico, bienestar social y cuidado ambiental. En Chile, el sector de la edificación es responsable de un...

En el presente trabajo se combinan avances recientes en modelación de geometrías 3D complejas mediante el método del Análisis Isogeométrico (IGA) con el fin de simular el comportamiento en fatiga de materiales compuestos. Para el análisis estructural, se implementa la modelación IGA mediante geometría NURBS en el software de código libre OpenSees,...

This paper presents a method to update linear time-variant finite element (FE) models of civil structures experiencing nonlinear behavior due to earthquake excitation. First, the time-varying modal parameters of the structure are identified using the input-output dynamic data recorded during a damaging seismic event by employing a short-time window...

With ever-advancing structural design and evaluation techniques becoming available for structural engineers, the required level of knowledge about nonlinear material behavior in civil structures has increased accordingly over recent years. In the context of finite element (FE) modeling, constitutive material models play a crucial role in the comput...

Los puentes viales son elementos críticos y esenciales en la conectividad de las redes de transporte, por lo cual deben ser cuidadosamente diseñados para asegurar una resiliencia adecuada cuando se emplazan en zonas de alta sismicidad. Durante el terremoto del Maule de 2010 (Mw=8.8), 292 puentes viales resultaron dañados dentro de un grupo aproxima...

This paper presents the analysis of the seismic response and the identification of the dynamic properties of an equivalent linear time-invariant model of a full-scale five-story base-isolated reinforced concrete building tested on the unidirectional NEES@UCSD shake table. A sequence of seven scaled historic earthquake records was applied by the sha...

The modeling of structural damping due to the excitation of elastic-waves into the surrounding soil domain, and its effect on structural response as apparent modal damping is explored herein. Four high-fidelity, linear finite-element models of building-site systems, with 20–50 storeys and 2–7 basement levels, are simulated in OpenSees to evaluate t...

With the structural design paradigm shift since the early 2000′s from the traditional approach to performance-based design (PBD), there has been a growing need for reliable nonlinear finite element (FE) models that can accurately predict the response of structures when subjected to extreme loads, such as earthquakes. In the case of reinforced conc...

Accurate and computationally efficient building energy models are critical to the development of online or pseudo-online control strategies and other building management activities. However, such models need to overcome the large uncertainty involved with continuously changing occupant activities and building status. The present study uses unscente...

To enable optimal building energy management in response to the ever-changing building and boundary conditions, it is critical to have numerical models that can provide accurate online prediction based on economically measurable inputs and feedback. The present study explores the capabilities of using the unscented Kalman filtering (UKF) in combina...

Digital twin-based approaches for structural health monitoring (SHM) and damage prognosis (DP) are emerging as a powerful framework for intelligent maintenance of civil structures and infrastructure systems. Model updating of nonlinear mechanics-based Finite Element (FE) models using input and output measurement data with advanced Bayesian inferenc...

A novel approach to deal with nonlinear system identification of civil structures subjected to unmeasured excitations is presented. Using only sparse global dynamic structural response, mechanics-based nonlinear finite element (FE) model parameters and unmeasured inputs are estimated. Unmeasured inputs are represented by a time-varying autoregressi...

This paper studies the performance of recursive and batch Bayesian methods for nonlinear model updating. Unscented Kalman filter (UKF) is selected to represent the recursive Bayesian method, and two UKF approaches are investigated and compared, i.e., non-adaptive UKF and adaptive UKF. The proposed new adaptive filter, forgetting factor adaptive UKF...

Digital twin-based approaches for structural health monitoring (SHM) and damage prognosis (DP) are emerging as a powerful framework for intelligent maintenance of civil structures and infrastructure systems. Model updating of nonlinear mechanics-based Finite Element (FE) models using input and output measurement data with advanced Bayesian inferenc...

A novel approach to deal with nonlinear system identification of civil structures subjected to unmeasured excitations is presented. Using only sparse global dynamic structural response, mechanics-based nonlinear finite element (FE) model parameters and unmeasured inputs are estimated. Unmeasured inputs are represented by a time-varying autoregressi...

A damper-spring energy dissipation device connected in series with a cable that is extended throughout the entire structure by an array of pulleys is proposed, which is experimentally tested and validated on a reduced-scale five-story shear building. A series of seismic tests conducted on a shake table show that the proposed system concentrates the...

The Santiago City is located in Central Chile on a sedimentary basin, whose seismic response is controlled by the properties and geomorphology of the shallower quaternary deposits, as well as the impedance contrast with the underlying geological formations, among other factors. In this study, we built three representative two-dimensional (2D) cross...

This paper discusses the system identification of a full-scale 5-story reinforced concrete building tested on the unidirectional NHERI-UCSD shake table. The purpose of the test program, carried out in 2012, was to study the seismic response of the structure and nonstructural components and systems (NCSs) and their dynamic interaction at different l...

An actual traditional Chilean highway bridge is analyzed in order to carry out a detailed nonlinear analysis of the structure subjected to strong ground motions. The selected non-skewed bridge was built in 2008; it has five spans of 30 m long and is supported by four multi-column bents and two seat-type abutments. The superstructure is supported ov...

This paper presents two adaptive Kalman filters (KFs) for nonlinear model updating where, in addition to nonlinear model parameters, the covariance matrix of measurement noise is estimated recursively in a near online manner. Two adaptive KF approaches are formulated based on the forgetting factor and the moving window covariance-matching technique...

The poultry industry, highly prevalent worldwide, generates approximately 7.7 × 10 6 metric tons of chicken feathers (CFs), which become a major environmental challenge due to their disposal when considered waste or due to their energy transformation consumption when considered by-products. CFs are mainly composed of keratin (approximately 90%), wh...

A novel framework to accurately estimate nonlinear structural model parameters and unknown external inputs (i.e., loads) using sparse sensor networks is proposed and validated. The framework assumes a time-varying auto-regressive (TAR) model for unknown loads and develops a strategy to simultaneously estimate those loads and parameters of the nonli...

Finite element (FE) model updating aims to minimize the discrepancy between measured and FE-predicted responses of instrumented structural systems. In the last decades, significant efforts have focused on linear FE models, including recent studies investigating applications with large models (i.e., models with many degrees-of-freedom) and/or models...

In this study, an experimental program for testing steel concrete composite slabs subjected to symmetrical double line loads has been carried out to investigate the longitudinal shear bond behaviour. Different configurations of steel concrete composite slabs with and without embossments were studied. The flexural characteristics, ultimate strength...

This paper describes a framework to update nonlinear finite element (FE) models. The method combines advanced mechanics-based nonlinear FE models and the Unscented Kalman filter (UKF) to estimate unknown time-invariant model parameters of FE models of civil structures subjected to earthquake excitation. The performance and computational cost of dif...

Blades are one of the main and more costly components of wind turbines and, besides, are difficult to inspect and maintain. Due to operational conditions, wind turbine blades (WTBs) are prone to suffer structural damage, chiefly because of fatigue or extreme loading. Therefore, it is crucial to monitor the state of health (SoH) of these components...

This paper presents an information-theoretic approach for identifiability assessment of model parameters in nonlinear finite-element (FE) model updating problems. Rooted in the Bayesian inference method, the proposed approach uses the Shannon information entropy as a measure of uncertainty in the model parameters. The difference in the entropy of a...