Browsing by Author "Ramos, Luis F."
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- Monitoring historical masonry structures with operational modal analysis: two case studiesPublication . Ramos, Luis F.; Marques, Leandro; Lourenço, Paulo B.; Roeck, G.; Costa, Alfredo Campos; Roque, JoãoThe paper addresses two complex case studies of modal and structural identification of monuments in Portugal: the ClockTower of Mogadouro and the Church of Jerónimos Monastery, in Lisbon. These are being monitored by University of Minho with vibration, temperature and relative air humidity sensors. Operational modal analysis is being used to estimate the modal parameters, followed by statistical analysis to evaluate the environmental effects on the dynamic response .The aim is to explore damage assessment in masonry structures at a nearly stage by vibration signatures, as a part of a health monitoring process that helps in the preservation of historical constructions. The paper presents the necessary preliminary dynamic analysis steps before the monitoring task, which includes installation of the monitoring system, system identification and subsequent FE model updating analysis, automatic modal identification and investigation of the Influence of the environment on the identified modal parameters.
- Monitoring historical masonry structures with operational modal analysis: two case studiesPublication . Ramos, Luis F.; Marques, Leandro; Lourenço, Paulo B.; Roeck, G.; Costa, Alfredo Campos; Roque, JoãoTwo monuments in Portugal are being monitoring by the University of Minho: the Clock Tower of Mogadouro and the Church of Jerónimos Monastery, in Lisbon. Vibration sensors and temperature and relative air humidity sensors are installed in the two monuments. Operational modal analysis is being used to estimate the modal parameters, followed by statistical analysis to evaluate the environmental effects on the dynamic response. The aim is to explore damage assessment in masonry structures at an early stage by vibration signatures as a part of a heath monitoring process to preserve the historical constructions. The paper presents all the preceding dynamic analysis steps before the monitoring task, which includes the installation of the monitoring system, the system identification and subsequent FE model updating analysis, the automatic modal identification and the investigation of the influence of the environment on the identified modal parameters.
- A multidisciplinary approach to assess the health state of heritage structures: the case study of the Church of Monastery of Jerónimos in LisbonPublication . Masciotta, Maria Giovanna; Roque, João; Ramos, Luis F.; Lourenço, Paulo B.The preservation and risk mitigation of built cultural heritage require the use of reliable tools which enable to give a better insight into the complex behaviour of these structures, by providing a correct diagnosis of their health conditions, and to identify potential vulnerabilities in order to prevent the risk of damage and to design in advance adequate retrofit solutions. The present paper describes an extensive experimental/numerical investigation campaign carried out on the Church of Monastery of Jerónimos in Lisbon in accordance with an iterative multidisciplinary approach and with the purpose of assessing the health state of one of the most prominent Portuguese monument, in light of future prevention actions. Special stress is given to the diagnostic procedure which includes and details in situ and laboratory testing, dynamic identification, continuous structural health monitoring and analysis of environmental effects on the static and dynamic behaviour of the church. The structural performance of the temple under conditions of gravity loading is analysed as well and potential collapse mechanisms are identified. The results are compared with the actual response of the temple allowing to evaluate its safety level.
- Structural monitoring of the Monastery of JerónimosPublication . Oliveira, Daniel V.; Ramos, Luis F.; Lourenço, Paulo B.; Roque, JoãoThe paper details two monitoring systems implemented in the main nave of Santa Maria of Belém Church of the Monastery of Jerónimos, in Lisbon. The monitoring systems were installed to better understand the static and dynamic behavior of the structure, aiming at the damage detection and the improvement of seismic resistance of the monument. Preliminary investigations, numerical non-linear analyses and the first dynamic modal identification analyses are described in the paper. Also the preliminary works for the monitoring systems are presented, including the points selected for observation, discussion of the sensors technical characteristics, as well as preliminary inspection and diagnosis. The first results of the dynamic monitoring system are shown and the future developments on the systems are presented, aiming at a full integration of all the adopted techniques. INTRODUCTION Architectural heritage is a key issue to modern societies due to both cultural and economical aspects. Besides the historical aspect, tourism and leisure will be a major industry in the 3rd millennium and the existence of a monument or a monumental compound is often a key attraction of cities and countries. In the process of preservation of ancient masonry structures, damage evaluation and monitoring procedures are particularly attractive, due to the modern context of minimum repair and observational methods, with iterative and step-by-step approaches. High-priority issues related to damage assessment and monitoring are global non-contact inspection techniques, improved sensor technology, data management, diagnostics (decision making and simulation), improved global dynamic (modal) analysis, self-diagnosing / self-healing materials and improved prediction of early degradation. The present paper aims at several of the referred issues and is focused in the structural observation of a Portuguese monument: the Santa Maria of Belém Church of the Monastery of Jerónimos, in Lisbon. In the main nave of the church two monitoring structural systems were recently installed in order to understand the static and dynamic structural behaviour with the purpose of damage detection and the improvement of seismic resistance of the monument. Preliminary investigations, numerical non-linear analysis and the first dynamic modal identification analysis are described. Also the preliminary works for the monitoring systems are presented, including the selected points for observation, the discussion of the technical characteristics of the sensors, as well as preliminary inspection and diagnosis. The first results of the dynamic monitoring system are shown and the future developments on the two systems are presented. GENERAL DESCRIPTION OF THE MONUMENT The Monastery of Jerónimos is, probably, the crown asset of Portuguese architectural heritage dating from the 16th century. The monumental compound has considerable dimensions in plan, more than 300×50 m2, and an average height of 20 m (50 m in the towers). The monastery evolves around two courts. The construction resisted well to the earthquake of November 1, 1755. Later, in December 1756, a new earthquake caused the collapse of one column of the church that supported the vaults of the nave, which resulted in the partial ruin of the nave. In this occasion also the vault of the high choir