Preliminary Results on the Monitoring of an In-Service Bridge Using a 32-Channel Fiber Bragg Grating Sensor System

Preliminary Results on the Monitoring of an In-Service Bridge Using a 32-Channel Fiber Bragg Grating Sensor System
Author: S. Vohra
Publisher:
Total Pages: 24
Release: 1998
Genre:
ISBN:

This report describes the preliminary results of the performance of a 32-channel fiber Bragg grating (FBG) system used to monitor the dynamic response of an in-service interstate bridge (North-bound span, 1-10 at University Blvd., Las Cruces, New Mexico). Fiber Bragg grating sensors were attached on four different support girders in groups of three at various locations along the span of the bridge. Using an interrogation approach based on the scanning Fabry-Perot system, the sensors were monitored for various vehicle loading conditions. They dynamic response of the bridge to a typical traffic load event as detected by a group of three sensors on a particular girder is illustrated in some detail by describing the data both in time and frequency domains. This is followed by a description of the response of all 32 sensors on the bridge to two traffic loading events. The field test results indicate that the natural resonant frequencies of the first two longitudinal modes of the bridge are 2.5 Hz and 3.8 Hz, respectively. The preliminary results reported here clearly demonstrate that an optical FBG sensor system is ideally suited for monitoring weigh-in-motion traffic events as well as for providing the dynamic properties of bridge structures.

Structural Monitoring with Fiber Optic Technology

Structural Monitoring with Fiber Optic Technology
Author: Raymond M. Measures
Publisher: Elsevier
Total Pages: 736
Release: 2001-04-10
Genre: Science
ISBN: 0080518044

This book is the first to address the field of structurally integrated fiber optic sensors. Fiber optic sensors embedded within materials and systems are able to measure a variety of parameters (i.e. temperature, vibration, deformation, strain, etc.) that allows for real time non-destructive evaluation. Examples include the following: monitoring structural fatigue in aging aircraft or loads in bridge structures. In more advanced applications, fiber optic sensors control actuators that allow materials to adapt to their environment. This gives rise to the names, "smart," "intelligent," and/or "adaptive" materials or structures.Structural Monitoring with Fiber Optic Technology is the firs single author book on the new field of fiber optic structural sensing. As such it provides: coverage of the fundamentals of the technology, a coherent and systematic discussion on the most important aspects of the subject, a broad view of the subject, while retaining a degree of focus on those advances most significant in terms of their future potential, particularly in regard to broad implementation of the technology. The book provides an introduction to the relevant value to structural monitoring. It also highlights the advantages of fiber optic based sensors over conventional electrical measurement technology.The book richly illustrates the subject matter with 615 figures and provides many examples of fiber optic structural sensing, including a detailed overview of a number of major field site applications. Most of these large scale applications are drawn from the civil engineering community as they have been the first to strongly embrace fiber optic structural monitoring. This is especially true for bridges, where innovative new designs and the use of fiber reinforced polymer composite materials to replace steel represents a major advance that is expected to revolutionize the construction industry. Examples include new bridges, which are serving as testbeds for these new materials and are instrumented with arrays of fiber optic structural sensors. In one case, this state-of-the-art monitoring system permits engineers at a distant site to track the response of the bridge to traffic loads and keep an eye on the long term performance of the new materials. Fiber optic structural sensing technology is equally applicable to other industrial sectors, such as the aerospace and marine industries. Indeed, several examples of ships being instrumented with arrays of fiber optic sensors are also included. * The author directed one of the leading laboratories in the development of this technology and its application to civil engineering* Provides a strong, concise foundation in the basics of the technology* Includes many examples of the application of the technology, including many major field site case studies* Richly illustrated with 615 figures, many redrawn to make them easier to understand; also includes over 600 references* Written in a style designed to help the reader unfamiliar with fiber optic technology appreciate what can be accomplished with this new form of structural monitoring

Structural Health Monitoring of Civil Infrastructure Systems

Structural Health Monitoring of Civil Infrastructure Systems
Author: Vistasp M. Karbhari
Publisher: Elsevier
Total Pages: 553
Release: 2009-08-25
Genre: Technology & Engineering
ISBN: 1845696824

Structural health monitoring is an extremely important methodology in evaluating the ‘health’ of a structure by assessing the level of deterioration and remaining service life of civil infrastructure systems. This book reviews key developments in research, technologies and applications in this area of civil engineering. It discusses ways of obtaining and analysing data, sensor technologies and methods of sensing changes in structural performance characteristics. It also discusses data transmission and the application of both individual technologies and entire systems to bridges and buildings. With its distinguished editors and international team of contributors, Structural health monitoring of civil infrastructure systems is a valuable reference for students in civil and structural engineering programs as well as those studying sensors, data analysis and transmission at universities. It will also be an important source for practicing civil engineers and designers, engineers and researchers developing sensors, network systems and methods of data transmission and analysis, policy makers, inspectors and those responsible for the safety and service life of civil infrastructure. Reviews key developments in research, technologies and applications Discusses systems used to obtain and analyse data and sensor technologies Assesses methods of sensing changes in structural performance

Monitoring and Safety Evaluation of Existing Concrete Structures

Monitoring and Safety Evaluation of Existing Concrete Structures
Author: fib Fédération internationale du béton
Publisher: fib Fédération internationale du béton
Total Pages: 316
Release: 2003
Genre: Technology & Engineering
ISBN: 9782883940628

The condition assessment of aged structures is becoming a more and more important issue for civil infrastructure management systems. The continued use of existing systems is, due to environmental, economical and socio-political assets, of great significance and is growing larger every year. Thus the extent of necessary repair of damaged reinforced concrete structures is of major concern in most countries today. Monitoring techniques may have a decisive input to limit expenditures for maintenance and repair of existing structures. Modern test and measurement methods as well as computational mechanics open the door for a wide variety of monitoring applications. The need for quantitative and qualitative knowledge has led to the development and improvement of surveillance techniques, which have already found successful application in other disciplines such as medicine, physics and chemistry. The design of experimental test and measurement systems is inherently an interdisciplinary activity. The specification of the instrumentation to measure the structural response will involve the skills of civil, electrical and computer engineers. The main aim of fib Commission 5, Structural servicer life aspects, is to provide a rational procedure to obtain an optimal technical-economic performance of concrete structures in service and to ensure a feedback of experience gained to design, execution, maintenance and rehabilitation. Against this background fib Task Group 5.1 Monitoring and Safety Evaluation of Existing Concrete Structures had been established to evaluate the existing practice worldwide. The objective of this state-of-art report is to summarize the most important inspection and measuring methods, to describe the working process and to evaluate the applicability to structural monitoring. Particular emphasis is placed upon non-destructive systems, lifetime monitoring, data evaluation and safety aspects.

Rehabilitating and Repairing the Buildings and Bridges of the Americas

Rehabilitating and Repairing the Buildings and Bridges of the Americas
Author: Daniel A. Wendichansky
Publisher:
Total Pages: 256
Release: 2002
Genre: Political Science
ISBN:

This collection contains 17 papers presented at a workshop, Rehabilitating and Repairing the Buildings and Bridges of the Americas: Hemispheric Workshop on Future Directions, held in Mayaguez, Puerto Rico, April 23-24, 2001.

Monitoring of an Interstate-25 High Performance Concrete Bridge with an Embedded Optical Fiber Sensor System

Monitoring of an Interstate-25 High Performance Concrete Bridge with an Embedded Optical Fiber Sensor System
Author: Rola Labban Idriss
Publisher:
Total Pages: 223
Release: 2009
Genre: Concrete bridges
ISBN:

The I-25/Dona Ana Interchange in Las Cruces NM is a simple span, high performance concrete (HPC)prestressed girder bridge. The girders are six prestressed, BT-63 HPC girders with a span length of 112.5 ft (34.2 m). The bridge was monitored from fabrication through service with an embedded optical fiber sensor system. Thirty two Fiber Bragg Grating (FBG) optical fiber deformation sensors were installed in the beams during fabrication. The strands were 6/10 inch ( 1.5 cm ) low relaxation strands and the concrete had a design compressive strength of 8 ksi (55.2 MPa) at release and 9.5 ksi (66.5 MPa) at 28 days. The bridge was monitored for two years, from transfer of the prestressing force through service. Several topics that are studied in this project: prestress losses, camber, shear and moment girder distribution factors, impact factor, insitu material properties and serviceability under traffic loads. The results from sensor measurements were compared to the values predicted by the AASTHO codes and other design codes or empirical equations, to check the accuracy of these codes when applied to HPC girder bridges.

Strain Monitoring During Construction of a Steel Box-Girder Bridge with Arrays of FIber Bragg Grating Sensors

Strain Monitoring During Construction of a Steel Box-Girder Bridge with Arrays of FIber Bragg Grating Sensors
Author: Sandeep Vohra
Publisher:
Total Pages: 51
Release: 1999
Genre:
ISBN:

Field performance of arrays of wavelength division multiplexed (WDM) fiber Bragg grating strain sensors is presented. Data from two field tests, carried out in February 1998 and October 1998 on an in-construction box-girder bridge, are presented and compared to data obtained from arrays of conventional sensors, where possible. The results in this report represent one of the first extensive tests of WDM Bragg grating sensor arrays on real world infrastructure. The results show that most of the well known advantages of fiber optic sensors, for example smaller array size, electromagnetic immunity, versatile data sets, easy installation, built-in telemetry and high sensitivity can be realized in real world environments.

Strain Transfer Behavior of Notch Embedded Fiber Bragg Gratings

Strain Transfer Behavior of Notch Embedded Fiber Bragg Gratings
Author: Daniel Thomas Maurais
Publisher:
Total Pages: 85
Release: 2012
Genre: Bridges
ISBN: 9781267842299

The vehicle loads seen on Wyoming roadways are continuously increasing due to the demanding transportation needs of Wyoming's expanding energy industry. The resulting overload conditions experienced by Wyoming's aging bridges have called for the implementation of a structural health monitoring (SHM) system. A SHM system utilizing fiber optic strain sensors called Fiber Bragg Gratings (FBGs) have proven in recent years to be an innovative and effective solution for monitoring bridge conditions. Such a system will allow WYDOT engineers to monitor the damages and fatigue effects of overloaded Wyoming bridges over years of service. This research examined a new method of attaching FBG strain sensors to concrete structural members via adhesive embedment in concrete notches. The proposed method is ideal because it provides ample fiber protection from weathering and vandalism. Additionally, the FBG becomes a rooted component of the structure that is unlikely to detach or be scraped off throughout years of service. Both a finite element analysis (FEA) and an experimental investigation were conducted to analyze the effectiveness and feasibility of the proposed concrete strain monitoring method. The strain loss over the adhesive layer between the concrete and the FBG sensor was the primary variable of interest in the study. The strain loss directly affects the accuracy of the sensors in measuring the strain of the concrete. Several attachment configurations with different parameters were tested. The results of this study support the conclusion that there are certain notch embedment configurations that will provide accurate strain measurement of a concrete structural member. It was found that the FEA predicts slightly higher strain transfer than what occurs in real conditions. A feasible procedure for implementing the proposed sensing method in field conditions was developed during the experimental tests.