Theme 1 Projects (2002-2006):
Intelligent Sensing and Structural Health Monitoring
Director: Dr. J.J. Roger Cheng, University of Alberta
Focus Area 1.1: Fibre Optic Sensing
Bragg Grating Sensing and Demodulation (1.1.1)
Project Leader: Dr. Roderick Tennyson, University of Toronto
This research was based on previous work undertaken at the University of Toronto Institute for Aerospace Studies on a long-gauge Bragg grating demodulation system developed in Phase 1 of ISIS Canada’s research program. Conventional Bragg grating sensors, which have been installed by ISIS on several bridges, provide a measure of the local average strains and temperatures. However, to measure actual strain/temperature distributions over a small region rather than a local average value, a longer gauge sensor is required. This long Bragg sensor provides information based on the measurement of wavelength and phase shift of the reflected Bragg signal over the length of the Bragg sensor. The prototype system available today requires major new research efforts to integrate it into the multi-channel Bragg grating instrument developed in Phase 1. The intent is to develop a multi-purpose instrument that can measure both average and distributed strains using Bragg gratings. Field demonstration projects are scheduled for the newly developed Bragg grating systems and will be jointly undertaken with other ISIS members.
 Key Accomplishments
 Back
Brillouin Sensing and Demodulation (1.1.2)
Project Leader: Dr. Xiaoyi Bao, University of Ottawa
The objective of this research is to develop a portable and economical distributed FOS system based on Brillouin scattering for remote monitoring of temperature and strain. It has been demonstrated that the Brillouin frequency that is actually measured by Brillouin scattering is proportional to temperature and strain. Hence, it is essential to separate them for purposes of determining the structural response. During the last several years, ISIS Canada has characterized the Brillouin gain spectrum and discovered that it is linearly proportional to both temperature and strain. Hence, by monitoring both Brillouin frequency shift and Brillouin gain coefficients, simultaneous temperature and strain measurements can be achieved. However, due to the polarization dependence of the Brillouin gain coefficient and laser power/frequency drifts, the measurement accuracy for both temperature and strain is low. This is unacceptable for field monitoring of civil engineering structures. In addition, the size, complexity and cost of the current systems render them unsuitable for field use. This project addresses these issues and efforts are being directed toward reducing the size and complexity of the unit by enhanced use of software, lower cost lasers, and reduced resolution without compromising the system requirements for actual civil structures. New sensing mechanisms to achieve simultaneous temperature and strain sensing at high measurement accuracy and short spatial resolution are being explored. Through the first phase of the research, simultaneous temperature and strain sensing using photonic crystal fibres have been realized using multiple Brillouin peaks and using polarization maintained fibres using Brillouin bandwidth, intensity of Brillouin frequency at cm spatial resolution. The next phase of the research will be: 1) to develop new mechanisms to realize distributed temperature and strain sensors at high spatial resolutions; 2) to find new specialty fibres to realize simultaneous temperature and strain sensing; 3) to develop the offset locking technique to realize distributed fibre senor system; 4) to develop signal processing schemes to enhance signal to noise ratio of the distributed sensor system and; 5) to increase the sensing length while maintaining good spatial resolution.
Key Accomplishments
Back
Laser Light Sources for Fibre Optic Sensing Technology (1.1.3)
Project Leaders: Dr. David Thompson/Dr. John Simmons, McMaster University
The purpose of this project was to produce and characterize a laser light source operating at wavelength near 1550 nm and delivering > l mW output power in order to drive a new, general purpose, multi-channel fibre Bragg grating (FBG) strain measurement system developed in Project 1.1.1. This new generic system incorporates both long and short FBG. The laser is tunable over a 10 nm wavelength range. Additional criteria include that the fabrication process produce a low-cost device and not be complex.
The ISIS team at McMaster University has demonstrated expertise in the fabrication of semiconductor diode lasers in the wavelength region of interest. Experiments were carried out to investigate possible methods by which these lasers can be re-designed to allow for the wavelength to be tunable over the required range.
Key Accomplishments
Back
Advancement of Bragg and Long Gauge Fibre Optic Measurement Equipment for SHM (1.1.4)
Project Leader: Dr. Douglas Thomson University of Manitoba
Fibre optic sensors have demonstrated the ability to measure strain in civil structures with a resolution of 1 micro-strain or better. This capability has been recognized as a valuable new approach to civil infrastructure monitoring, and a number of vendors have developed Bragg grating-based and, more recently, long gauge sensors to measure strain in civil structures.Bragg sensors offer tremendous potential, particularly when used with the new generation of swept wavelength readout units. This project will advance the capabilities of the Bragg readout units by integrating a wavelength standard. This advance will give Bragg readout units a level of stability and accuracy that has not been possible with past technologies. The expectation is to be able to achieve absolute long term accuracy of better than 5 micro-strain. In addition, this project will evaluate new techniques for wavelength multiplexing of sensors and new swept wavelength sources for use in the interrogation of FBG sensors.These advances provide ISIS Canada with reliable, leading-edge fibre optic strain sensing instrumentation.
Key Accomplishments
Back
Wireless Sensing for SHM (1.1.5)
Project Leader: Dr. Douglas Thomson University of Manitoba
The objective of this project is threefold: to build on the completed ISIS research of a strain sensor and complete the development of a wireless sensor by creating an antenna that can be embedded into concrete through which the sensor can be interrogated; to conduct a field demonstration project; and thirdly, followed by the development of a field useable interrogation system.
Key Accomplishments
Back
Focus Area 1.2: Structural Health Monitoring
Intelligent Wireless Remote Monitoring (1.2.1)
Project Leader: Dr. J.J. Roger Cheng, University of Alberta
This research is based on previous ISIS work at the University of Alberta on an intelligent wireless monitoring system. The system includes a low-cost plug-and-play battery-operated data acquisition unit and state-of-the-art wireless data transmission and communication technologies. Currently, the system can handle up to four strain gauges and four temperature sensors with a scan rate of 30 Hz.
The objective of this project is to continue improving and optimizing the current wireless remote monitoring system. The project is divided into three parts: first, enhance the capability of the existing data acquisition unit; second, improve the wireless communication technology; and third, demonstrate the system’s usefulness in field applications. This project is also intended to provide the essential technology for Project 1.2.2. Finally, the project will integrate the fibre optic sensing technology developed in Focus Area 1.1 into the intelligent wireless monitoring system.
Key Accomplishments
Back
Central Monitoring and Management for ISIS Field Applications (1.2.2)
Project Leader: Dr. John Newhook, Dalhousie University
The main objective of this project is to accelerate the acceptance and utilization of ISIS technologies by assembling and centralizing data from the numerous demonstration projects across Canada. This project focuses on the broader issue of assessing the feasibility and reliability of a specific technology rather than specific structures. In addition, the team collects a vital database of performance history and of field monitoring experience, identifies on-going research needs and assists in developing a cohesive strategy for monitoring of field projects. Through close collaboration with the ISIS SHM Support Center at the University of Manitoba, recent progress includes the development of the architecture for a centralized web-based monitoring system for several ISIS projects and participation in the development of Civionics specifications. Having the broader perspective of all field monitoring applications, the project continues to provide support to the development and testing of a new Bragg grating instrument and as well as data management and interpretation techniques. Concurrently, the project has a fundamental laboratory research component which is focusing on the development SHM techniques for monitoring internal FRP reinforcement, FRP external laminates and steel-free bridge deck systems.
Key Accomplishments
Back
Numerical Modelling for Damage Detection of ISIS Innovative Bridge Decks (1.2.3)
Project Leader: Dr. Leon Wegner, University of Saskatchewan
The focus of this project is on the development of vibration-based damage detection (VBDD) techniques for monitoring the structural health of innovative and conventional bridge superstructures. The fundamental premise is that changes to dynamic characteristics (notably natural frequencies and mode shapes) are indicators of the presence and location of damage. The dynamic characteristics of structural components and systems in both the laboratory and the field are being measured as damage is incrementally induced. Measured changes are being used to evaluate and improve the reliability of techniques to detect and locate damage. Numerical models are being calibrated to measured responses and used to simulate additional damage scenarios and investigate the limitations of the VBDD methods.
Results have shown that small scale damage on a bridge deck or other superstructure components may be detected and located using VBDD techniques in well-controlled laboratory conditions using a relatively small number of measurement points and measured changes to only the fundamental mode shape. The current focus of this research is on whether the necessary levels of measurement repeatability are possible under field conditions.
Key Accomplishments
Back
Intelligent Processing and Decision Making Using Data from ISIS Field Applications (1.2.4)
Project Leader: Dr. Jag Humar, Carleton University
Vibration-based damage detection and health monitoring techniques are being developed for application in ISIS field projects. This involves the development of damage detection algorithms and their validation through computer simulation and testing on laboratory specimens. Laboratory tests have been carried out on a scaled three-dimensional frame to assist in the validation. The analytical and experimental studies show that a combination of modal energy based methods and neural network techniques has the potential for application in the vibration based health monitoring of slab-on-girder bridges, including those with a steel-free concrete deck. Finite element models of selected ISIS structures have been built. In cases where data on measured values of dynamic characteristics exist, the models have been refined so that they correlate to the measured vibration properties. These refined models have been used in the assessment of simulated damage of predetermined location and specific severity to validate the damage detection techniques. It is intended that these baseline models be used for existing and future structural health monitoring projects.
Key Accomplishments
Back
Active Control Systems for Extreme Dynamic Loading (1.2.5)
Project Leader: Dr. Jean Proulx, Université de Sherbrooke
The research focuses on the development of vibration-based damage detection techniques, including model-based damage detection. The objective of the experimental and analytical work is to develop reliable methods for the assessment of damages (probability, quantity, location) that occur in structures subjected to dynamic loading (earthquake, wind, traffic, etc.). Applications will be developed for buildings, and applied on a full scale two-story building in the Sherbrooke laboratory. The damage identification techniques will also be applied to a scaled model of a 3D spatial truss, as well as a small hydro-electrical pylon. Finally, it is planed to develop vibration control techniques, using a 3 x 3 m shake table to be constructed in late 2004 at Sherbrooke.
Key Accomplishments
Back
Field Monitoring of Pipelines (1.2.6)
Project Leader: Dr. J.J. Roger Cheng, University of Alberta
Depletion of traditional oil and gas resources in Alberta has led to increased activity in remote regions, specifically the Arctic and sub-Arctic regions of the Canadian North. Large-size buried pipelines have proven to be an effective method of transporting these resources to urban regions. However, increased exploration of these resources has exposed the buried pipelines to extreme harsh environments, such as discontinuous permafrost in the Canadian North. There is a need to better understand the behaviour of buried pipelines subjected to these complex and severe load conditions. The structural behaviour of steel pipes under combined loading conditions has been studied extensively by laboratory investigation. However, there is very little information available for the actual behaviour of buried pipelines in operation. Structural Health Monitoring (SHM) has become a promising and effective technology for design, operation, and maintenance of these infrastructures. Two pilot projects, laboratory buckling test and field excavation test, were designed to investigate the feasibility of using SHM technology to study the field behaviour of buried pipes under various operational and loading conditions. Both distributed Brillouin scattering Fibre Optic Sensors (FOSs) and foil strain gauges were employed in these tests.
The objectives of this research project are to develop reliable and economical technologies for monitoring the behaviour of buried pipelines in operation and assessing the risk of pipeline failure. The laboratory buckling test is designed to obtain the characteristics and signatures of pipes under various loading conditions leading to failure. The field excavation test is used to study the interaction between buried pipes, surrounding soil, and excavation load. The distributed Brillouin Scattering FOSs are used to identify, locate, and quantify the structural damage along the pipelines. Meanwhile, the potential of using the FOS system in buried pipelines can be also examined.
Back
Data Interpretation of Monitoring Hall's Harbour and Salmon River Bridge (1.2.7)
Project Leader: Dr. John Newhook, Dalhousie University
The Hall’s Harbour Wharf represents the first application of GFRP reinforcement in a marine structure. It was monitored using Fabry-Perot type fibre optic sensors from 1999 through 2003. The data will be examined and correlated against similar data from land-based structures to determine what can be interpreted regarding the durability of GFRP reinforcement. This will be supported by examination of physical specimens. The project also provides an opportunity to examine methods for thermal correction of field strain readings and visualization of continuous strain readings.
Salmon River Bridge is the oldest field demonstration project in the ISIS program and the first application of the steel-free bridge deck technology. In the past, data from the Salmon River Bridge has proved vital in understanding the field behaviour of this system versus behaviour observed in laboratory testing. A significant characteristic of these systems is the development of longitudinal cracks in the concrete deck between adjacent girders due to fatigue loading. The bridge continues to be visually monitored to provide a record of crack development and behaviour with time. As well, the strain response of girders and straps are periodically monitored under vehicle loads to provide a long-term performance history for this technology.
Key Accomplishments
Back
Focus Area 1.3: Demonstration Field Assessments
Portage Creek Bridge Field Assessment (1.3.1)
Project Leader: Dr. Aftab Mufti, University of Manitoba
This disaster-route bridge in Victoria, British Columbia was built prior to current seismic design codes and construction practices and would not resist potential earthquake forces as required by today’s standards. ISIS Canada assisted with a retrofit involving FRP wraps to strengthen the short columns and a system for structural health monitoring. The project called for a retrofit to strengthen the Pier No. 2 columns of the Portage Creek Bridge, which could potentially fail in catastrophic shear during a large earthquake.
The Portage Creek Bridge was designed in 1982 by the Department of Highways Bridge Engineering Branch and crosses Interurban Road and Colquitz River at McKenzie Avenue. It is a 125-m (410-ft) long three-span steel structure with a reinforced concrete deck supported on two reinforced concrete piers and abutments on steel H piles. The deck has a roadway width of 16 m (52 ft) with 2-1.5 m (5-ft) sidewalks and aluminum railings. Most of the bridge was retrofitted by conventional materials and methods. The dynamic analysis of the bridge predicted the two tall columns of Pier No. 1 would form plastic hinges under an earthquake. Once these hinges form, additional shear would be attracted by the short columns of Pier No. 2. A nonlinear static pushover analysis indicated that the short columns would not be able to form plastic hinges prior to failure in shear. Therefore, it was decided that FRP wraps should be used to strengthen the short columns for shear without increasing the moment capacity.
Key Accomplishments
Field Demo
Back
Inuvik Timber Piles Field Assessment (1.3.2)
Project Leader: Dr. Aftab Mufti, University of Manitoba
Buildings in the Arctic are typically supported using untreated timber piles. A recent study has revealed that decay is present in a large percentage of existing piles, potentially causing buildings to become unstable. In response to this problem, a method for the repair of existing heavily decayed timber piles using glass fibre reinforced polymer (GFRP) sheets and grout injection was examined.
Typically, the use of GFRP sheets provides an advantage over other conventional materials due to their high strength, light weight and ease of installation. In this application, the use of a lightweight material such as GFRP may also reduce the significant cost of transporting materials to remote regions in the Arctic. The use of fibre optic sensing technology will also be implemented to monitor the success of this repair technique in service.
A program for development of the repair technique was recommended, beginning with an initial feasibility study to determine the cost and structural reliability of the technique. The first phase would involve experimental testing of repaired pile specimens, followed by a freeze-thaw durability study in the laboratory. The research program would culminate with the repair and monitoring of severely decayed piles in the field.
Field Demo
Back
Centre Street Bridge Field Assessment (1.3.3)
Project Leader: Dr. Nigel Shrive, University of Calgary
Centre Street Bridge in Calgary has undergone an extensive rehabilitation. Deterioration has been repaired and structural strength has been raised to current load standards. The City of Calgary utilized GFRP grid as top reinforcement instead of conventional steel rebar in approximately two-thirds of one span of the lower deck. The aim of this project is to complement this effort by providing an intelligent sensing system to monitor the performance of this innovative repair.
In cooperation with the City of Calgary and the FRP supplier, strain gauges were glued in key locations of the FRP reinforcement. In addition, conventional steel reinforcement in similar parts of the bridge deck was instrumented as a control and to provide additional information on structural behaviour. The instrumentation was installed during construction and the leads run to a central monitoring cabinet at the structure. The data acquisition, processing and communications equipment is installed such that the bridge can be monitored from the University of Calgary, the University of Alberta, the City engineer's office and from any other appropriate location. The project utilizes remote monitoring technology developed by ISIS.
Key Accomplishments
Field Demo
Back
Field Assessment of Gentilly I (1.3.4)
Project Leader: Dr. Kenneth Neale, Université de Sherbrooke
Gentilly-1, the first nuclear plant at Gentilly, Quebec, became operational in May 1972 and was operated intermittently until 1978, after which it was partially decommissioned. International (IAEA) and Canadian (AECB) guidelines are being followed to provide monitoring and surveillance programs which ensure conditions at the site continue to meet safety requirements. While it was originally to be maintained for 40 years after decommissioning, plans now are to extend this maintenance period to 100 years.
AECL and ISIS carried out a testing program to determine the strength and durability characteristics of the concrete containment structure. Innovative FRP technology has been used to enhance the strength of the structure and to improve the durability and appearance of the building.
Field Demo
Back
Monitoring GFRP Poles for Light Standards at the University of University of Manitoba Smartpark (1.3.5)
Project Leader: Dr. Dimos Polyzois, University of Manitoba
The increasing demand for pole-type transmission structures, coupled with a shortage of wooden poles and the ever-increasing cost of steel poles, has prompted hydroelectric utility companies to search for cost-effective alternative materials, such as GFRP, for poles. The research at the University of Manitoba in the development of GFRP poles is the most comprehensive in the world. However, without evidence of satisfactory field performance, utilities will continue to be apprehensive about accepting GFRP as a material of choice for poles.
In cooperation with Manitoba Hydro, a Pole Park was established to evaluate the field performance of various types of full scale poles, including GFRP, hybrid (wood-GFRP) and wood. Some wooden poles were intentionally damaged and repaired on site using the robotic system under development at the University of Manitoba. All poles were instrumented using ISIS-developed fibre optic technology for remote monitoring of their performance. This project provided valuable information about the performance of materials and pole components under service conditions. Researchers were able to evaluate various types of foundations, and hydro utility crews learn how to handle, erect and climb GFRP poles. It also provided a unique setting for the actual repair of poles using new techniques and innovative robotic systems.
Key Accomplishments
Field Demo
Back
Field Monitoring of the New Hampshire Bridge with Distributed Sensor System (1.3.6)
Project Leader: Dr. Xiaoyi Bao, University of Ottawa
The distributed sensor has shown great potential over conventional sensors in the lab. However, it needs field testing to prove its advantages. Strain monitoring within the New Hampshire Bridge is an excellent application for this type of sensor. With continuous monitoring of strain and temperature, it will provide bridge engineers with an indication of the performance of this state-of-the-art material and provide data on the long term performance of the structure.
Field Demo
Back
Saskatoon Overpass Field Assessment (1.3.7)
Project Leader: Dr. Leon Wegner, University of Saskatchewan
The Attridge Drive Overpass in the City of Saskatoon is a two-span continuous slab-on-girder structure with integral abutments constructed in 2001. Data from 53 permanently installed strain gauges and six accelerometers, temporarily installed at 21 locations, have been used to measure the dynamic properties of the structure (i.e. its natural frequencies and mode shapes) periodically. Changes to these properties over time are being investigated as possible indicators of progressive damage due to deterioration of structural components. In addition to generating a baseline dynamic signature which can be used for future comparison, this project evaluated the effectiveness of ambient traffic to excite vibrations, studied the effectiveness of strain gauges and accelerometers for dynamic measurements in the field, and helped to identify important issues that must be addressed for the successful implementation of vibration-based damage detection (VBDD) techniques in field applications.
Among the most significant issues identified by this project are the influence of changing ambient temperature on the dynamic properties, and the need to improve the repeatability of mode shape measurements when ambient traffic is used for dynamic excitation. Finite element modelling is being used to simulate the dynamic response at various stages of progressive damage in order to further investigate the performance of VBDD techniques on this structure.
Key Accomplishments
Field Demo
Back
Monitoring Sprayed Bridge in B.C. (1.3.8)
Project Leader: Dr. Nemkumar Banthia, University of British Columbia
In cooperation with the Ministry of Transportation and Highways of British Columbia (MoTH), ISIS researchers repaired the Safe Bridge in the Cowichan Lake area on Vancouver Island using the spray composite technique. The concrete on the girders was severely spalled and the girder sections needed to be reformed before the FRP spray could be applied. Several girders were instrumented before and after placement of the spray. For instrumentation before the spray, traditional sensors were placed on the rebars, and after spraying, fibre optic sensors were installed. Measurements from these sensors are carried out remotely.
Key Accomplishments
Field Demo
Back
Structural Health Monitoring of Golden Boy (1.3.9)
Project Leader: Dr. Aftab Mufti, University of Manitoba
On February 9, 2002, the 1,650-kilogram (3,640-pound) Golden Boy was removed from his perch on top of the Manitoba Legislative Building for the purpose of restoration, which was completed during the summer of 2002. The Golden Boy was reinstalled in September 2002, in time for the visit of Queen Elizabeth II.
ISIS Canada designed and installed a structural health monitoring system for Golden Boy, consisting of three types of gauges: accelerometers, strain gauges, electric resistance and fibre optic, and temperature sensors.
wo accelerometers placed at the top of the column that supports the statue measure beat, or vibration. The top of the support column inside the Golden Boy comes to approximately chest height, close to where the Golden Boy's heart would be if it were human. Just like measuring the human heart rate provides us with valuable health information, measuring the beat rate provides valuable structural health information. If the accelerometers give a reading outside the normal range, further examination into the health of the structure is required. The accelerometers measure movement in three directions. As wind and various weather systems cause the Golden Boy and his support column to move or vibrate, the accelerometers detect these motions.
The second type of gauge measures strain. Strain is caused in the support column by the action of the wind. The strain gauges have been placed in several locations around the support column, near the foot on which the Golden Boy stands.
A combination of strain gauges and Bragg grating fibre optic sensors monitor normal ranges of strain on the column support. If the strain readings fall outside the normal range, an alert is provided to potential structural health issues well before a major problem develops.
Temperature, which has a direct effect on the material properties of the column, is measured by temperature sensors.
With access to these three state-of-the-art diagnostic tools, the Golden Boy's health will be well monitored. This is a very important step for moving the care of the statue away from a high cost, acute care method of maintenance towards a more cost efficient, preventative health care model of maintenance. Much like today's surgery techniques, structural health monitoring of the Golden Boy is non-invasive to the statue itself. The sensors are mounted on the support column only.
Key Accomplishments
Field Demo
Back
Monitoring of FRP-Reinforced Pedestrian Bridge, Université de Université de Sherbrooke (1.3.10)
Project Leader: Dr. Pierre Labossière, Université de Sherbrooke
A student design competition for a pedestrian bridge enabled the use of new-generation structural technologies. Set up by ISIS, the aim of this competition was to design a pedestrian bridge with a six-metre covering with access to a new entrance to the Faculty of Engineering at the Université de Sherbrooke. The objective of this project was to provide the opportunity for ISIS Canada students to participate in the design of a construction project incorporating composite materials with the integration of new fibre optic monitoring technologies. The composite materials for the structures and the monitoring of fibre optics are two main research goals of ISIS Canada. The winning team from Queen’s University was invited to participate in the final design of the project with the engineering firm responsible for the project. The Pedestrian Bridge is continuously monitored and data are made available on a web site.
Key Accomplishments
Field Demo
Back
Rehabilitation of Corrosion-Damaged Flexural Bridge Girders in the Region of Waterloo (1.3.11)
Project Leader: Dr. Khaled Soudki, University of Waterloo
This project focuses on the serviceability and durability of FRP repair systems for reinforced concrete beams in a bridge in the Region of Waterloo that is subjected to aggressive corrosive environments and service loads. This project is the first large-scale field application for using advanced materials to effectively rehabilitate concrete flexural members with steel reinforcement corrosion in Ontario. FRP repair systems will provide significant benefits including increased service life of the bridge structure and decreased negative environmental impact, since the bridge is over a river. In the bridge, the RC beams show signs of corrosion damage through longitudinal cracking and some delamination. Previous crack repairs proved inefficient and alternative repair schemes are required. The beams will be repaired by externally epoxy-bonding FRP sheets to the concrete surface, and the performance of the FRP repair will be monitored over time. Large-scale beams will be fabricated in the laboratory to simulate corroded beams and FRP repair to correlated field and lab measurements. The data collected will be useful for service life prediction models for FRP repair systems of corrosion damaged reinforced concrete beams.
Key Accomplishments
Field Demo
Back
Structural Health Monitoring of Provencher
Pedestrian Bridge (1.3.12)
Project Leader: Dr. Aftab Mufti, University of Manitoba
The Esplanade Riel Pedestrian Bridge in Winnipeg, Manitoba, is a modern cable-stayed structure, light and elegant, featuring a large plaza for commercial activities - a meeting place that will connect Provencher Boulevard to The Forks physically, economically and culturally. Construction of this structure commenced in September 2002 as the second phase of the Provencher Paired Bridges project that includes a new vehicular bridge. The bridges - opened for traffic in December 2003 - strengthen the connection between The Forks and the St. Boniface French Quarter, becoming a symbolic gateway between two of Winnipeg's most historically significant communities and promoting commerce and tourism.
Owned by the City of Winnipeg and designed by Wardrop Engineering, this 200-m long bridge has a concrete deck, steel stay-cables and a 60-m post-tensioned concrete pylon encased in a steel jacket. The 5-m wide deck is being built using a segmental construction technique with post-tensioned concrete. The City of Winnipeg has committed over $300,000 towards a structural health monitoring (SHM) plan for the purpose of assessing the in-service performance of the innovative bridge design and providing a decision-making program that will optimize long-term maintenance costs. This monitoring program will measure movement, traffic flow, wind speed and direction, stay cable forces and strains, ambient temperature, temperature gradient, and 3-D acceleration of the deck and pylon. ISIS Canada will supplement the City's plan with the installation of 18 fibre optic sensors, lead wires, and a fibre Bragg grating strain indicator, and will play a key role in implementation of the decision-making software.
Key Accomplishments
Field Demo
Back
Structural Health Monitoring of PWGSC Parking Garage, University of Ottawa/Hull (1.3.13)
Project Leader: Dr. Brahim Benmokrane, Université de Sherbrooke
Public Works and Government Services Canada (PWGSC) is currently undertaking the reconstruction of the interior structural slabs of the Laurier-Taché parking garage in Ottawa/Hull. FRP-composite bar technology is incorporated into the project and will be monitored over an extended period of time. This project allows direct field assessment and long-term monitoring of FRP composite bars in a structure subjected to harsh environmental and loading conditions. After finalizing the design for the type and amount of FRP reinforcement, full-scale slab prototypes, with identical reinforcement configuration to that of the final design, were constructed and tested. The structural slabs will be instrumented (January 2004) for internal temperature and strain data collection. Embedded gauges will be used to monitor slab behaviour from the time of initial concrete placement to 2009.
Field Demo
Back
Structural Health Monitoring of Trout River Bridge, Alaska Highway, B.C. (1.3.14)
Project Leader: Dr. Aftab Mufti, University of Manitoba
The Trout River Bridge is located in British Columbia's Muncho Lake Provincial Park. As part of the Alaska Highways Program, Public Works and Government Services Canada (PWGSC) will replace this three span bridge with a new structure that will provide 75 years of service life, meet all code requirements and have the capacity to carry all provincial and territorial regulation loads. PWGSC has allocated over $120,000 for a structural health monitoring (SHM) plan for the bridge to assess the in service performance of the innovative bridge design and provide a decision making program that will optimize long term maintenance costs. Elongation of the box girders due to temperature and forces induced in the integral abutments will be measured, as well as strains in GFRP reinforcement in the deck. A data logger and a resident computer will be installed, as well as a Thermal Energy Generator (TEG) for this remote site. Communication between the bridge and the monitoring engineer will be accomplished via satellite using the Internet. ISIS Canada will assist in the interpretation of the monitoring and confirm the practicality of remote monitoring by FOS sensors in an environment where a power supply is not readily available. The project was delayed by PWGSC due to financial constraints; however, it will be re-activated in the 2004-05 fiscal year.
Field Demo
Back
Structural Health Monitoring of Pipelines with
Brillouin Sensors (1.3.15)
Project Leader: Dr. Xiaoyi Bao, University of Ottawa
Energy is a central pillar of modern society’s comfort and prosperity. Energy supply strongly depends on transport systems such as pipelines. There is a need to monitor aging pipelines to detect defects that could lead to irreversible damage. Continuous monitoring of pipelines has been a desirable but elusive objective for many years due to both technical and economic reasons.
For structural health monitoring, it is important to develop a distributed strain and temperature sensor with long sensing length. With the availability of low-cost optical fibres for communications that can also sense strain, this objective is now technically and economically within reach. A distributed fibre optic sensor based on Stimulated Brillouin Scattering (SBS) effect is an ideal candidate for pipeline supervision. This type of sensor exploits the strain and temperature properties of fibres attached to the pipeline structure. It can detect failures and propagate the information. It plays the double role of sensing and media transmission. Moreover, measurements are taken all along the fibre laid around the pipeline and are not limited to discrete point of measures. Nor is it limited to measuring average strain over long gauge lengths. The strength of Brillouin sensors lies in the distributed nature of the information they can provide.
This project will implement an experimental set-up on pipelines for pipeline corrosion, buckling monitoring with BFOS and strain gauges correlated with the result from strain gauges, and develop a methodology to allow the analysis and correlation of the monitoring data obtained with BFOS and strain gauges. The axial and hoop strains in pipe will be studied to confirm the suitability of the Brillouin sensing on pipes.
The first phase of the project focused on detecting steel pipe wall thinning induced by corrosion under different pressures. Small spots of 1.3cm in the hoop direction and 5cm in axial direction have been successfully identified, and the different strain-pressure slopes for 1.3cm x 5cm for 50 percent of steel wall thickness and 60 percent of wall thickness have been measured. In the second phase of the project, the buckling of the steel pipe and beam in axial direction will be monitored, and the measurement will be compared with the strain gauge measurement to confirm the strain accuracy of the distributed sensor system.
Key Accomplishments
Back
Life Cycle Costing and SHM to Reduce Freight Costs (1.3.16)
Project Leader: Dr. Gordon Sparks, University of Saskatchewan
The Hudson Bay bridge in Saskatchewan supports an important timber haul connecting local mills to forested areas. Currently, however, concerns regarding the strength of the bridge have limited permitted truck loads. Efforts that successfully support higher truck loads will therefore lower the trucking costs incurred by industry - leading to a more cost-competitive forestry sector in the province.
To strengthen the bridge, Saskatchewan Department of Highways and Transportation SDHT) has opted for CFRP wraps installed under centre span beams. To ensure the added strength obtained is sufficient to support higher truck loads and to ameliorate concerns regarding long-term durability, SDHT and Weyerhauser agreed to participate in a structural health monitoring (SHM) research program designed to monitor and analyze the behaviour of the bridge under live load before, during and after the installation of the CFRP wraps. The results of this research will help determine whether or not bridge engineers within SDHT permit higher loads over the bridge.
From the standpoint of life cycle costing (LCC), any haul weight decisions reached should balance the cost-savings enjoyed by industry and the infrastructure-related costs incurred by SDHT. While higher haul weights certainly suit industry, concomitant implications for bridge- and road-related efforts and costs must be taken into account to ensure total life cycle costs are indeed minimized. Broadly speaking, the purpose of project 1.3.16 is to establish a haul weight policy that is likely to minimize the total life cycle costs of infrastructure use and management in this regards.
Employing the life cycle engineering and costing (LCE&C) method developed under project 4.1.1, participants in this research program will iteratively model and analyze the life cycle costs associated with the use and management of Hudson Bay bridge to help determine an optimal haul weight policy. Ultimately, the insights reached through this investigation will be embodied in a computer-based LCE&C model linking condition assessment (supported by SHM) to life cycle performance prediction and, finally, to life cycle costs.
Key Accomplishments
Field Demo
Back
Design Manual Update (1.3.17)
Project Leader: Dr. J.J. Roger Cheng, University of Alberta
One of the major accomplishments and tangible results of Phase I of the ISIS mandate was the publication of four design manuals in 2001. These manuals were developed over a two-year period by Network participants under the leadership of the ISIS Theme Directors. These manuals were prepared for two reasons. The first is to provide practicing engineers with detailed guidelines regarding the use of FRPs and FOSs in the design and construction of civil engineering structures. The second is to provide a credible reference for the Code Committees to facilitate and accelerate changes to existing codes which did not envisage the use of advanced composite materials such as FRPs.
New chapters are being added and the manuals are in the process of being updated with additional case studies.
More information on Design Manuals
Back
Data Management and Signal Processing for SHM (1.3.18)
Project Leader: Dr. Dean McNeill, University of Manitoba
The introduction of continuous monitoring in civil engineering structures necessarily results in the collection of a large quantity of measurements acquired from tens to hundreds of parallel sensor channels. These sensors, placed in and around a structure, provide an ongoing record of the physical and environmental effects to which the structure is subjected. Ensuring reliable collection, storage and archiving of this sensory information is a critically important first step if these measurements are to be relied upon in forming an accurate assessment of a structure's health.
Once collected, the data must be analyzed in order to extract the details of external stimuli affecting a structure and the subsequent responses exhibited by that structure as a consequence of those external forces. Again, given the shear volume of measurement information, it would not be feasible for an engineer or technician to perform the majority of the data analysis manually. Instead, an automated signal processing approach must be taken to deal with the bulk of the data analysis task.
The aim of this project is to develop effective tools for the automated analysis of SHM data which are capable of sifting through the vast quantities of raw sensor measurements collected from a given structure in order to locate those specific events which require further scrutiny. Automation of the sifting process is non-trivial, however, due to the fact that the "normal" background response of each individual structure is unique. Thus, before novel events can be detected, it is necessary to characterize the unique, normal response of each system. Once identified, noteworthy events may then be further analyzed and, in some cases, passed on to human experts when the situation warrants such specialized attention.
This work is exploring the use of artificial neural computation as one approach for characterizing a structure's nominal response and guiding further data analysis. Artificial neural networks are capable of modelling the regular response of a structure based upon raw strain, acceleration, and temperature measurements. The learned model then provides a mechanism through which to evaluate new measurements, in real-time, in order to identify those considered novel relative to the model. This capability has been demonstrated to a limited extent on existing field assessment projects. The goal of this project is to further develop and refine these techniques so that they may be employed effectively by structure owners with little or no end user customization.
Key Accomplishments
Back
Development of Monitoring Technology for the Confederation Bridge (1.3.19)
Project Leader: Dr. John Newhook, Dalhousie University
Strait Crossing Bridge Limited (SCBL) and its partners have been actively monitoring the Confederation Bridge since its construction through an extensive system of sensors and data collection infrastructure. Concurrently, ISIS Canada has been developing structural health monitoring technology for civil infrastructure. This project represents a synergy between these two groups to combine expertise and resources to advance SHM technology, with a specific focus on the needs of the Confederation Bridge.
This collaborative project has three distinct components: Bragg grating sensor assessment, ice abrasion rate assessment and SHM real time data management and visualization. During construction 22 fibre optic sensors were installed in the bridge at locations coinciding with SCBL’s conventional sensors. The project will investigate the long-term durability of these sensors as well as test new Bragg sensor instrumentation systems. For the second component, researchers at Dalhousie will continue on-going collaborative research with SCBL to develop methods for the assessment of abrasion rates on the ice shields of the bridge. The third component involves the application of the ISIS experience with web-based data management and visualization to assist in the real-time identification of structural behaviour and extraction of significant monitoring events.
Key Accomplishments
Field Demo
Back
Monitoring Concrete Overlay Using Embedded Sensors at UBC Aquatic Center (1.3.20)
Project Leader: Dr. Nemkumar Banthia, University of British Columbia
Part of the outdoor plaza deck at the University of British Columbia’s Aquatic Center was resurfaced using a high performance fibre reinforced concrete (HPFRC) mixture with shrinkage compensating admixtures. Previous resurfacing efforts had produced unsatisfactory results with overlays exhibiting excessive cracking, premature delamination and unwarranted saturation.
Two adjoining overlays were placed, one with plain concrete and the other with HPFRC. The overlays each contain 16 embedded sensors to monitor strains, temperature variations and the chemical environment in the overlay to better understand the reasons for debonding. Two types of embedded sensors were used. One is a newly developed ceramic sensor from Japan, and the other is the ECFRC (electrically conducting fibre reinforced concrete) sensor being developed at UBC under the auspices of ISIS. Data will be collected for a period of three years following placement of the concrete, using the WebDAQ/100 data acquisition system, which is capable of transmitting signals over the Internet.
This project will endeavour to increase understanding of the behaviour of bonded cement-based overlays and explain the mechanisms causing debonding and lack of adequate durability. It will also contribute to the development of embedded sensors and novel sensors based on ECFRC.
Key Accomplishments
Field Demo
Back
Fairview Cove Terminal Underwater FOS Field Project (1.3.21)
Project Leader: Dr. John Newhook, Dalhousie University
The Halifax Port Authority is undertaking upgrades to the Fairview Cove Container terminal in Halifax Harbour. The project involves installation of sheet pile walls in the harbour bottom. Anchor bolts will be used to fasten the walls to existing concrete cribs approximately 14 metres below the mean water level.
Dalhousie University will be installing Fabry-Perot sensors (eight strain and one temperature sensor) on a number of anchor bolts in conjunction with the MacDonnell Group. ISIS will install complementary Bragg Grating type sensors on these same anchor bolts. The readings are most critical during the construction phase and will be taken with less frequency after construction is completed.
Because this is an underwater application with only periodic readings, it is believed that FOS will have a unique advantage over electronic based sensors. In addition, installation of the gauges will be done by machining a very narrow slit in the bolt making subsequent environmental protection very easy. This is the first ISIS application in a sub-marine environment.
Key Accomplishments
Field Demo
Back
Completed Research 1995 to 2006
|
