Sergi Villalba

Universitat Politècnica de Catalunya | UPC · Department of Project and Construction Engineering

This paper addresses the implementation of a Distributed Optical Fiber Sensor system (DOFS) to the TMB L-9 metro tunnel in Barcelona for Structural Health Monitoring (SHM) purposes as the former could potentially be affected by the construction of a nearby residential building. With the aim of assessing the performance of this newly developed monit...

In this paper, the authors present the results of a laboratory test where two reinforced concrete beams were instrumented with Distributed Optical Fiber Sensors (DOFS)to allow the monitoring g of strain in four different longitudinal segments bonded to their bottom surface. The test objective was to confirm the ability and good performance of the D...

This paper outlines the second part of an experimental study to show the capabilities of distributed optical fiber sensors (DOFS) in their application to the structural health monitoring (SHM) of the shear performance of concrete structures. SHM seeks to obtain the shear crack characteristics of concrete elements: detection, localization and quanti...

An experimental methodology to obtain the shear cracking pattern in concrete elements is presented. The method is based on the use of Distributed Optical Fibre Sensors (DOFS) connected to an Optical Backscattered Reflectometer (OBR). Using this OBR system and a 2D grid conformed by one or two DOFS, the crack patterns of three partially pre-stressed...

This document showcases the latest research conducted within UPC–BarcelonaTech on the performance of distributed optical fiber sensors (DOFS), more specifically the case of the optical backscattered reflectometry (OBR) system, in the structural health monitoring (SHM) of bridges, and large scale structures. This technology has demonstrated promisin...

In this paper, the authors conducted an experiment where a reinforced concrete beam was instrumented with a 5‐m long polyimide single distributed optical fibre sensors (DOFS) performing four equal segments externally bonded to the bottom surface of the element, using for each segment a different type of adhesive. Three strain gauges were also used...

Optical fiber sensors (OFS) have become increasingly popular on civil engineering structural health monitoring (SHM) applications in the last two decades. This is due to several advantages when compared to the more conventionally used electrical sensors. Nevertheless, while this technology has been largely studied and applied in its discrete form,...

The use of fiber optic sensors on civil engineering structural health monitoring (SHM) applications have become quite popular for the past two decades. Within this type of sensors however, the study and use of Optical Backscatter Reflectometry (OBR) based Distributed Optical Fiber Sensors (DOFS) is relatively new. In this way, there is still some u...

The authors conducted a laboratory experiment where two reinforced concrete beams were instrumented with a Distributed Optical Fiber Sensors that were adhered to allow the measuring of strain on four different longitudinal segments on their bottom surface. A fatigue test was then conducted on these elements where the load range was the one expected...

In this paper, the authors conducted an experiment where a reinforced concrete beam was instrumented with a single DOFS performing four equal segments externally bonded to the bottom surface of the element. Each segment was adhered to the concrete using a different adhesive. This beam was then loaded, producing expected equal levels of tension in e...

When using distributed optical fiber sensors (DOFS) on reinforced concrete structures, a compromise must be achieved between the protection requirements and robustness of the sensor deployment and the accuracy of the measurements both in the uncracked and cracked stages and under loading, unloading and reloading processes. With this in mind the aut...

The versatility and ease of installation of Distributed Optical Fibre Sensors (DOFS) compared with traditional monitoring systems are important characteristics to consider when facing the Structural Health Monitoring (SHM) of real world structures. The DOFS used in this study provide continuous (in space) strain data along the optical fibre with hi...

p>In this paper, an experiment where distributed optical fiber sensors (DOFS) were implemented in two small concrete beams subjected to a three-point load test is outlined. Here, an optical backscatter reflectometry based DOFS is implemented simultaneously embedded in the concrete (glued to the steel rebar) and attached to the outer surface of the...

In this work, an experiment on two small concrete beams is described where Rayleigh based distributed optical fiber sensors (DOFS) are implemented together with traditional electrical strain gauges for the monitoring of these elements during a three-point load test. Part of the DOF sensor is embedded without protective coating directly in the rebar...

The application of structural health monitoring (SHM) systems to civil engineering structures has been a developing studied and practiced topic, that has allowed for a better understanding of structures' conditions and increasingly lead to a more cost-effective management of those infrastructures. In this field, the use of fiber optic sensors has b...

The paper describes the design, development and experimental checking of a modified type of structural joint with limited length between concrete segments cast in‐situ. The design concept is based on the developed length of an anchorage hook stiffened by transverse reinforcement bars and is particularly suited for the case of in‐situ construction o...

This paper provides an overview of the use of different Distributed Optical Fiber Sensor systems (DOFSs) to perform Structural Health Monitoring (SHM) in the specific case of civil engineering structures. Nowadays, there are several methods available for extracting distributed measurements from optical fiber, and their use have to be according with...

In this paper, a method to obtain crack initiation, location and width in concrete structures subjected to bending and instrumented with an optical backscattered reflectometer (OBR) system is proposed. Continuous strain data with high spatial resolution and accuracy are the main advantages of the OBR system. These characteristics make this structur...

This work shows how the experimental strain data obtained with an OBR (Optical Backscattered Reflectometer) measuring system can be used to locate cracking before being visually observable and also to estimate the crack width for different levels of load. The method is checked in a test up to failure carried out on a reinforced concrete slab, where...

The objective of this research has been to design, develop, and evaluate experimentally a modified type of construction joint of limited length between concrete slab segments. The design concept is based on an anchorage hook of reduced development length stiffened by transverse reinforcement bars. The purpose of this paper is to investigate the mec...

The use of Optical Backscatter Reflectometer (OBR) sensors is a promising measurement technology for Structural Health Monitoring (SHM) as it offers the possibility of continuous monitoring of strain and temperature along the fiber. Several applications to materials used in the aeronautical construction have demonstrated the feasibility of such tec...

RESUMEN En ocasiones se producen patologías que aun siendo singulares como es el caso que se presenta, ya se han producido anteriormente, y pese a ello, no se ha sabido transmitir las enseñanzas de esas tipologías de daños, y vuelven a repetirse. Se quiere hacer resaltar que los estudios de daños han de servir para implementar en la normativa los...

The use of Optical Backscaterr Reflectometer (OBR) sensors is a promising measurement technology for SHM as it offers the possibility of continuous monitoring of strain and temperature along the fibre. Several applications to materials used in the aeronautical construction have demonstrated the feasibility of such technique. These materials (compos...