Humberto Varum

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In this study, the implementation of an optical accelerometer unit based on fiber Bragg gratings, suitable to monitor structures with frequencies up to 45 Hz, is reported. The developed optical system was used to estimate the structure eigenfrequencies of a steel footbridge, with a total length of 300 m, over the Sao Pedro Creek, located at University of(More)
In this work we proposed a relative humidity (RH) sensor based on a Bragg grating written in an optical fiber, associated with a coating of organo-silica hybrid material prepared by the sol-gel method. The organo-silica-based coating has a strong adhesion to the optical fiber and its expansion is reversibly affected by the change in the RH values(More)
In this paper we summarize the research activities at the Instituto de Telecomunicações--Pólo de Aveiro and University of Aveiro, in the field of fiber Bragg grating based sensors and their applications in dynamic measurements for Structural Health Monitoring of slender structures such as towers. In this work we describe the implementation of an optical(More)
In this paper, we describe the implementation and test of an optical fiber biaxial accelerometer and inclinometer based on fiber Bragg gratings. The proposed sensor is a low cost and simple solution to measure acceleration and relative rotation in two orthogonal directions, which can be used for structural health monitoring. Sensitivities of 87.848 and(More)
Glass can be considered to be a high-technology engineering material with a multifunctional potential for structural applications. However, the conventional approach to the use of glass is often based only on its properties of transparency and isolation. It is thus highly appropriate and necessary to study the mechanical behaviour of this material and to(More)
This paper presents a structural health monitoring system for monitoring, with reduced visual impact, one historical building structure. The system is based on fiber Bragg gratings and comprises 19 displacement sensors and 5 temperature sensors. All the sensors were custom made according to the monitoring points' characteristics. The results obtained over(More)
Usually, the corn cob is considered an agriculture waste. This natural and organic waste material may be used in the industry, in general, and in the building industry, in particular. The work presented in this paper was developed in order to give a contribution to the knowledge of this material, by attempting to describe and assess its macrostructure and(More)
In this paper, we report the monitoring of an adobe structure with optical fiber sensors. Static and dynamic measurements were made during a destructive test on a full-scale wall, in which an in-plane cyclic force was imposed, by a hydraulic jack, until the wall collapse. An optical fiber accelerometer and a network of thirteen multiplexed displacement(More)
The dynamic monitoring of a tower for mobile communications with 50 meters high using a bi-axial optical accelerometer is reported. The resonant frequencies for the first modes were obtained, being consistent with the expected values.
The influence of the infill masonry walls in the structural response of reinforced concrete (RC) structures when subjected to earthquakes is not considered in Nepal National Building code and Indian Standard code. Field observations carried out after the 25th April Gorkha earthquake in Nepal reinforce the importance of the infill walls, namely, through the(More)