Completed Research 1995 to 2006

Theme 3 Projects (2001-2002):
Remote Monitoring and Field Assessments

Director: Dr. J.J. Roger Cheng, University of Alberta

Remote Monitoring (T3.1.1)
Project Leader: Dr. J.J. Roger Cheng, University of Alberta

The work is directed toward achieving remote monitoring capability that will allow a sensor system to detect significant events at a bridge, initiate communication via a telemetry link and deposit measured data associated with the event at some central and generally accessible site. Some initial success has been achieved with a dial in system as utilized on the Salmon River Field Demonstration Project [Mufti, A.A., et al., 1997]. The primary objective of this research is to continue to investigate methods of achieving effective remote monitoring of innovative structures through the following five tasks: wireless transmission; various sensor interfaces and data compression; dial out remote monitoring; remote connection to Internet and satellite; and microchip data acquisition system [Mufti, A.A., et al., 1997].

The remote monitoring system developed in this project will be able to communicate with various types of sensor, such as transducers, strain gauges, thermisters, corrosion sensors, vibration sensors, and fibre optic sensors. The project will investigate the various interfaces of these sensors with different types of data acquisition systems. Various types of digital filters will be developed to efficiently collect, filter and sample from different types of sensors and to transmit data with minimum loss in data quality. The devices developed will provide wireless transmission between sensor to data logger or data logger to remote monitoring site. Dynamic dial out capability, triggered by a special event, will be developed. The design of appropriate PC software structures will facilitate the connection of a sensor system via Internet and CDPD modem. The feasibility of transmitting data via satellite will also be studied. Finally, the project will integrate the technology into a complete, cost effective and portable integrated remote data acquisition system which will be tested in a number of field monitoring projects across Canada.

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Expert System for Intelligent Interpretation of Sensor Data (T3.2)
Project Leader: Dr. S. Pantazopoulou, University of Toronto

In the first phase of this project an intelligent processing framework was developed for analysis of signals obtained from permanently installed sensors in monitored structures (mainly bridges) [Karasaridis, A., et al., 1997]. The software developed is used to identify the prominent properties that characterize the condition of the structure and changes thereof that might signify the occurrence of damage. However, field application of the proposed methodology in bridge case studies has revealed that interpretation of the significance of the several recorded events requires a considerable amount of familiarity and expertise with the specific structure that is being monitored.

A knowledge based system is therefore required to establish, from the history of the structure, not just the important indices of state for the structure, but also other relevant variables such as the expected range of these indices for structures of the type under consideration, previous values of these indices over the service life of the structure, changes in the reference values observed in the past, and the relative significance of these on the condition of the structure.

During the first phase of Project T3.2 a powerful software package was developed to process collectively groups of signals obtained from each monitoring procedure conducted on a specific structure. To facilitate the development of a knowledge based system, the next phase of project T3.2 includes the task of assembling into a single database, processed information and interpretation results from several bridges of different type, size and location in Canada. The database will be continuously updated and expanded as the ISIS monitoring technologies are applied to additional case studies and as more data becomes available. The software package ESPAN along with the database will be integrated into a knowledge based intelligent expert system which will be designed to perform short term and long term evaluation of the available records of the structure analyzed.

The program will assist not only in quantifying and localizing changes of important structural parameters but will also supplement the user with information about the possible interpretation of the records from accumulated knowledge and expertise that the program will extract from its database for the same structure, as well as from structures of the same type. Because of storage considerations, particularly as the history of the structure increases, the compression of the signals becomes a key design consideration for the development of the database. Algorithms developed in the first phase of Project T3.2 will be refined to address the special needs of the database, particularly with regard to storage of additional information, such as heuristic data, threshold values, previous significant events, and experience from other structures of similar or related type and history. The new algorithms will be developed in close collaboration with all other ISIS teams that are directly or indirectly involved in field assessments across Canada.

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Intelligent Processing of Data Obtained from Instrumented Bridges (T3.2.1)
Project Leader: Dr. Jag Humar, Carleton University

This feasibility study will identify the steps necessary to finalize a software program being developed for storing and archiving data collected from structures via remote monitoring systems.

Several bridge structures in Canada have been instrumented and are now being monitored with data collected at varying frequencies. Archival management is a vital component of structural monitoring. Soon, ISIS will have an online archiving system whereby authorized researchers submit raw data that will be accessible to users. In a user-friendly, worldwide web interface, the site will offer access to sensor characteristics and locations, and response measurements from static and dynamic load tests. The archive will enable interested parties to browse the content, view the relevant documentation and download data for their own analysis.

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Confederation Bridge and Salmon River Bridge Field Assessments (T3.3)
Project Leader: Dr. Aftab Mufti, University of Manitoba

The purpose of this project is to provide to the members of the ISIS Network a means of assessing the field performance of their innovative intelligent structures. A core group of investigators responsible for coordinating the field assessment projects and ensuring that consistent and effective evaluation is provided. Along with the general goal of field assessment, a specific objective will be to involve as many as possible of the Network participants, technicians and students in the field assessment projects, so as to maximize the benefits of the Network as a whole. Participants will be involved mainly in projects utilizing their own technologies.

The first phase of this project focused on two elements: the evaluation of the steel free bridge deck technology and the evaluation of fibre optic sensors in a bridge structure. The former used the Salmon River Bridge project as its field environment while the later used the Confederation Bridge [Doncaster et al., 1996].

The monitoring of the Confederation Bridge by fibre optic sensor will continue. The setback in collecting data was due to delay in obtaining the fibre optic data acquisition system, communication line from the bridge and easy access to the bridge. However, these problems are being addressed. The data from fibre optic sensors will be collected and compared to the conventional monitoring that is in progress.

The Salmon River bridge, the first bridge in the world that has no reinforcement in the concrete deck has been performing well. The data collected from fibre optic gauges and conventional gauges indicated that deck is participating in sharing of the live loads in the girders as per design assumptions. The fibre optic gauges have proven to be durable and resilient. The monitoring of the fibre reinforced concrete deck and fibre optic sensor will be continued to assess their durability.

See Salmon River Bridge Field Demo
See Confederation Bridge Field Demo

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Headingley Bridge Field Assessment (T3.3.1)
Project Leader: Dr. Aftab Mufti, University of Manitoba

Construction of the world's largest span bridge using CFRP as prestressing and shear reinforcement for four girders has been completed in Headingley, Manitoba, Canada. CFRP was also used to reinforce a part of the deck slab, while GFRP reinforcements were used in a part of the barrier wall. The bridge is instrumented with 63 fibre optic sensors coupled with 21 conventional electric strain gauges embedded in the bridge girders, deck slab, and barrier wall. Data is transmitted through two telephone lines for continuous monitoring of the performance of the bridge under traffic loads and extreme environmental conditions. The bridge, formally named the Taylor Bridge, was opened for traffic in October 1997 [Rizkalla et al., 1997].
The funds for the following years will be used to install a camera to provide video information synchronized with the optic sensor readings. The work on intelligent processing of the collected data will be in close collaboration with Project T3.2 to monitor the performance of the bridge. The monitor will be focused on evaluation of the behaviour of the carbon and glass fibre reinforced polymer reinforcements used in prestressing the main girder, the deck slab and the glass FRP for the barrier wall. The levels of prestress losses, possible initiation of crack, crack propagation and deflection will be used to evaluate the health of the bridge as a function of time.

See Field Demo

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Chatham Bridge Field Assessment (T3.3.2)
Project Leader: Dr. Natalya Hearn, University of Toronto

The goal of the project is to remotely monitor the performance of the Chatham Bridge using a new sensing technology [Mufti et al., 1997]. The bridge performance would be evaluated based on static and dynamic response from the conventional and fibre optic gauges attached to the key structural elements, natural frequency readings from the accelerometers, stability of cracks under static and dynamic conditions, and monitoring of the changes in the concrete slab performance using piezoelectric/fibre optic transducers for acoustic and sonic measurements.

The existing instrumentation consists of resistive strain gauges attached to the steel flanges and webs of the steel girders, the steel straps, NEFMAC reinforcement embedded in concrete, and two fibre optic gauges embedded into the concrete slab.

This initial instrumentation was installed by the Ministry of Transportation, Ontario (MTO). The main shortcoming of the present system is that many of the monitoring instruments are located where deformations are minimal. Many of the gauges have failed, indicating the main problem of using such gauges in the field.

An instrumentation system complementary to that of the MTO is proposed for the Chatham Bridge for remote and non destructive testing of its performance. The key elements, which provide guidelines of structural and material integrity of a structure are strains, changes in the natural frequencies, stability of existing cracks and degradation of the slab due to the exposure to the aggressive environment.

See Field Demo

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Crowchild Bridge Field Assessment (T3.3.3)
Project Leader: Dr. J.J. Roger Cheng, University of Alberta

The Crowchild Trail Bridge in Calgary, Alberta was rehabilitated by replacement of the existing superstructure made of concrete with a new superstructure consisting of steel girders and a fibre reinforced concrete bridge deck devoid of steel reinforcement. The bridge consists of three continuous spans and is the first continuous span bridge to utilize the fibre reinforced steel free deck system. External steel straps between girders and internal fibre reinforced plastic (FRP) bars in the cantilever portions were used to reinforce the deck. The bridge was instrumented using fibre optic sensors and conventional sensors. The performance of the steel free deck and fibre optic sensors has been very encouraging. This field assessment will continue to prove the durability and robustness of ISIS Canada technologies [Tadros et al., 1998].

See Field Demo

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Waterloo Bridge Field Assessment (T3.3.4)
Project Leader: Dr. Carlos Ventura, University of British Columbia

The Waterloo Creek Bridge is part of the new Vancouver Island Highway. The bridge consists of two separate single span decks with integral abutments. The north bound structure was constructed using the innovative steel free bridge deck technology of Project T4.1 and is the main study of this field assessment project. The bridge has been instrumented with conventional and fibre optic sensors. As well, several smart reinforcement bars developed in Project T3.4 have been embedded in the concrete deck.

The instrumentation will be used to monitor the strains and cracks at various locations in both the steel free deck and the conventional concrete deck. This will permit a direct comparison of the performance of both structural systems under serviceability conditions. The strains in the girders will be monitored to assess the load sharing characteristics of the steel free bridge deck system. The south abutment wall will also be monitored to determine load transmitted to the substructure from both the girders and the backfill pressure. The project will allow for an assessment of the effectiveness of the steel free bridge deck in the an integral deck girder abutment system. The monitoring database will also be used to perform reliability analysis of the steel free bridge deck system.

See Field Demo

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Joffre Bridge Field Assessment (T3.3.5)
Project Leader: Dr. Brahim Benmokrane, Université de Sherbrooke

The proposed field assessment project will demonstrate the usefulness of smart and noncorrosive reinforcements [Benmokrane et al., 1997]. Over 180 permanent monitoring instruments have been installed at critical locations and will be connected to a telephone line for remote monitoring of the structure's behaviour. The purpose of the research program is to determine the static and key dynamic characteristics of the bridge. The dynamic response of the bridge will be evaluated under normal traffic and with a calibrated highway truck. The findings will be used to calibrate a finite element program.

The most important aspect of the concrete deck slab reinforced with CFRP is the durability of the concrete deck. A special instrumentation strategy has been implemented with special attention being given to possible material degradation. In order to evaluate the material degradation, several locations of the concrete deck slab have been reinforced with FRPs. Long term assessment of the FRP reinforcement durability will be conducted using coring directly in the concrete deck slab.

See Field Demo

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Hall's Harbour Field Assessment (T3.3.6)
Project Leaders: Dr. Aftab Mufti, University of Manitoba, and Dr. John Newhook, Dalhousie University

Hall's Harbour is located on the Bay of Fundy in Nova Scotia and as such is subjected to the extreme tides and severe marine storms of the area. The community currently relies on an existing timber wharf breakwater for protection from these conditions. This existing wharf is a typical timber wharf constructed with a concrete deck slab and a large armour stone embankment on the exposed face. A large section of this wharf has failed due to the severe pounding from storms and the remainder of the wharf is expected to deteriorate with time. A repair scheme has been designed which consists of steel piles, spaced approximately 2.0 m apart, anchored back through the existing wharf. Between the piles are reinforced concrete panels which both retain the fill in the wharf and protect the existing structure from wave action. A design is being developed to utilize glass FRP reinforcement instead of steel reinforcement in these panels to substantially increase the life span of this structure. Other innovative technologies are being investigated such as the use of CFRP tie rods as anchors for the piles and the use of GFRP reinforced concrete piles in place of the steel piles.

The purpose of this project, is to provide a field assessment of the durability and structural performance of the glass FRP reinforced concrete panels in a marine application. The site will be monitored through physical assessment and instrumentation. A unique feature of this wharf is its entire height is within the tidal zone of the Bay of Fundy. Visual inspection of the entire face of the wharf is thereby possible on a daily basis. As major storm events are the critical load parameter for the panels, monitoring will coincide with the occurrence of major storm events. The visual inspection will focus on the general condition of the panels and the extent of cracking which occurs. Cores will be taken at predetermined locations on a periodic basis to determine if any strength or physical deterioration of the FRP occurs. If required, specific laboratory simulations will be developed to assist in the assessment of the actual field performance of the panels. A series of beams will be designed and positioned at the site which will be exposed to the same environmental loads as the panels. At periodic intervals these beams will be taken to the lab for testing.

In addition to the physical testing the panels will utilize a number of FRP bars instrumented with embedded fibre optic sensors from the research conducted by Project T3.4. These instrumenting bars will serve a two fold purpose. Firstly, they will be a field assessment of the performance of the instrumented bars in a marine environment. Secondly, they will provide field data on the stress levels in the bars, particularly during major storm events.

See Field Demo

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Sainte Émélie-de-l'Énergie Bridge Field Assessment (T3.3.7)
Project Leader: Dr. Pierre Labossière, Université de Sherbrooke

In 1997, ISIS-Sherbrooke obtained a research contract with the Ministry of Transportation of Québec to identify a potential bridge-strengthening scheme with composite materials, and to conduct an analytical study of such a repair. The selected structure was a single-span, simply supported bridge with T-section, which is characteristic of many bridges currently in use in Québec.

It would thus be eventually possible to apply the same strengthening method to other bridges presenting similar structural deficiencies. Test beams were fabricated to evaluate various reinforcing schemes in bending and in shear, and were used to check the validity of the analytical procedures developed for this project. The four T-beams were reinforced in order to demonstrate the potential increase in strength as was requested for the reference bridge proposed by the MTQ. Special attention was paid to the scale effect in order to demonstrate acceptable correlation between the laboratory results and the actual structure being considered.

Durability of the composite material reinforcement was also included in the study. Specimens were tested to evaluate the influence of freeze-thaw or wet-dry cycles on both the composite materials and the concrete-composite interface. Preliminary results obtained in this project confirm that the two kinds of cycles have a negligible effect on the composites themselves and on their bond to the support surface. Long-term durability tests continue.

The experimental study was followed, in the fall of 1998, by the strengthening of the actual reference bridge. Preparation of the site, including curing of some concrete used in the repair, took three weeks. Installation of the composites took five days over a two-week period.

Sensing devices were installed on the bridge in order to monitor its behaviour. The 66 instruments on the bridge include 28 strain gauges, 10 thermocouples, 20 optic fibres with Bragg sensors and 8 with Fabry-Perot sensors. Positions of the sensors were selected in such a way that complementary readings can be obtained from the various types of instruments, and to validate the data obtained from the experimental optic fibre sensors. The repair work was done under close supervision of the Ministry of Transportation, which conducted the loading tests before and after the repair work. Additional loading tests will be conducted in the future in order to evaluate the behaviour of the repaired structure, and to validate the optic fibre technology for this type of application.

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FRP for Underground Concrete Chambers (T3.3.8)
Project Leader: Dr. Brahim Benmokrane, Université de Sherbrooke

The objective of this project is to investigate the feasibility of using FRP rods as reinforcement for underground concrete chambers, to develop design procedures, to study the durability, and to predict the service life of such FRP reinforced concrete structures.

A consortium has been created for this research program which includes Hydro-Quebec, Lecuyer et Fils Ltée, Pultrall Inc., Speco Engineering Ltd., and ISIS Canada. In all, 10 experimental FRP reinforced underground chambers are proposed to be undertaken. Two of them will be tested at the Unviersité de Sherbrooke under static and cyclic loadings. The remaining eight chambers will be installed at different locations in Quebec to simulate different terrain environmental characteristics.

All experimental chambers will be instrumented with gauges and fibre optic sensors to monitor structural performance and long term behaviour.

Taking into account the work involved both in the laboratory and field, the program is planned to last two years. Monitoring will continue for a longer period to collect data. The research program will produce a working manual including design procedures and construction methods for the use of FRP reinforcement.

All the chambers under investigation will be reinforced by new FRP ISOROD rebars produced by Pultrall Inc.

Underground concrete chambers reinforced with steel bars are used frequently in construction and civil engineering. In Quebec, more than 50,000 of these structures measuring 2,000 x 3,500 x 3,000 mm have been installed by Hydro-Quebec during the last 30 years to house special devices used for electric transmission lines. However, like other conventionally reinforced concrete structures, corrosion of the steel reinforcement is a major problem. Each year, two percent (approximately 1,000) of Hydro-Quebec's steel-reinforced underground concrete chambers become corroded and must be replaced with new ones.

The use of FRP reinforcement for such underground chambers has advantages such as non-corrosiveness, electrical non-conductivity and overall light weight. Research performed by ISIS Sherbrooke on FRP reinforcements for concrete structures demonstrates that there are numerous benefits to using FRP in underground chambers. At the Université de Sherbrooke, studies have been conducted with respect to physical and mechanical properties of FRP rods, bond properties of FRP to concrete, flexural behaviour of FRP-reinforced concrete elements and durability of FRP reinforcements.

The objectives of the research program are:

• To investigate the feasibility of using FRP reinforcements in underground concrete chambers
• To develop design procedures suitable for FRP-reinforced underground concrete chambers (straight and bent FRP rebars)
• To examine and monitor the structural performance and long term behaviour
• To prepare a working manual from the results of the research and to predict the service life of FRP-reinforced underground concrete chambers.

During the summer of 1998, two chambers were constructed with FRP reinforcement as part of a preliminary feasibility study and were installed at Longueuil and Valleyfield, Quebec. From this study, information was gained regarding fabrication of FRP reinforcement cages, installation of the cages into formwork and casting of the concrete.

In this research program, 10 underground chambers are to be evaluated. Two of the 10 chambers, measuring 2,000 x 3,500 x 3,000 mm, will be tested by using a newly-built reaction wall at the Université de Sherbrooke. Static and cyclic loadings will be used (static loading for one chamber and cyclic loading for the second chamber) to simulate field conditions such as weight of tracks and soil and water pressure.

The remaining eight chambers will be located in different parts of Quebec taking into account terrain and environmental conditions. Hydro-Quebec will advise the exact locations and they will extend all cooperation regarding installation.

All chambers under investigation will be instrumented with gauges and fibre optic sensors for monitoring. The research program will be executed with collaboration from the consortium. Fabrication of the FRP reinforced underground concrete chambers will take place at the Lecuyer et Fils plant, FRP reinforcement will be provided by Pultrall, and Speco Engineering will assist in the design of the underground concrete chambers. The research team at the Université de Sherbrooke will lead this research endeavour.

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John Hart Bridge Field Assessment (T3.3.9)
Project Leader: Dr. Robin Hutchinson, University of Manitoba

It is one of the largest strengthening projects of its kind. Carbon fibre reinforced polymer (CFRP) sheets have been used to upgrade the shear capacity of the John Hart Bridge in Prince George, British Columbia. The bridge, owned by B.C.'s Ministry of Transportation Central Northeast Region, required shear strengthening in order to support heavier truck loads.

It consists of seven simply supported spans with six prestressed concrete girders per span. The 42girders are 1500 mm deep with a typical I-shaped AASHTO cross-section. They were strengthened with FRP sheets covering a four-m length at each end of the girder. By strengthening 64 girder ends, shear capacity was increased by 15 to 20 percent.

Similar to the Maryland Street Bridge in Winnipeg, Manitoba, the John Hart bridge was strengthened by applying diagonal CFRP sheets. Dave Scouten, a principal of Scouten and Associates Ltd., located in Prince George, British Columbia, consulted with ISIS Canada on the design. Replark sheets manufactured by Mitsubishi Chemical Corporation were chosen and then installed by specialty contractor Retro, of Vancouver. The project was completed in six weeks with the assistance of the general contractor, SureSpan, also of Vancouver. During this time the bridge remained completely accessible to traffic.

Phase II of the project involves a monitoring program to collect data on the long-term performance of CFRP sheets for shear strengthening this particular type of cross-section. The bridge was instrumented to monitor its behaviour under dynamic vertical and service load conditions. Periodic site visits and visual inspections are conducted to assess the bridge's long term performance. In the future, a twin bridge will be constructed and, upon opening of the new lanes, the existing bridge will undergo further rehabilitation. The existing high density overlay will be replaced with a reinforced concrete deck topping, and the use of CFRP reinforcing bars has been proposed.

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Portage Creek Bridge Field Assessment (T3.3.10)
Project Leader: Dr. Aftab Mufti, University of Manitoba

This project calls 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 bridge is described as follows:

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.

The bridge was designed in-house in 1982 by the Department of Highways Bridge Engineering Branch and crosses Interurban Road and Colquitz River at McKenzie Avenue.

The bridge was designed prior to the introduction of current bridge seismic design codes and construction practices. Therefore, it was not designed to resist the earthquake forces as required by today’s standards, although consideration appears to have been given to some seismic aspects as evidenced by reviewing the drawing details. The bridge is classified as a Disaster-Route Bridge and is to be retrofitted to prevent collapse during a design seismic event, with a return period of 475 years.

Most of the bridge is being retrofitted by conventional materials and methods. The dynamic analysis of the bridge predicts the two tall columns of Pier No. 1 will form plastic hinges under an earthquake. Once these hinges form, additional shear will be attracted by the short columns of Pier No. 2. A nonlinear static pushover analysis indicates that the short columns will not be able to form plastic hinges prior to failure in shear. Therefore, it is decided that FRP wraps should be used to strengthen the short columns for shear without increasing the moment capacity.

This is a relatively high profile bridge in Victoria, B.C. The involvement of ISIS Canada will be very important to assist in the retrofit involving the FRP wraps to strengthen the short columns, as well as to provide monitoring of the structure.

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Inuvik Timber Piles Field Assessment (T3.3.11)
Project Leader: Dr. Robin Hutchinson, 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 is being 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 four-phased program for development of the repair technique is currently underway, beginning with an initial feasibility study to determine the cost and structural reliability of the technique. The first phase involves experimental testing of repaired pile specimens and is now nearing completion. The first phase will be followed by a freeze-thaw durability study in the laboratory, and the research program will culminate with the repair and monitoring of severely decayed piles in the field.

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Centre Street Bridge Field Assessment (T3.3.12)
Project Leader: Dr. Nigel Shrive, University of Calgary

The upper layer of reinforcement of the north span of the lower deck of the Centre Street Bridge in Calgary is NEFMAC. The deck is supported by crossbeams between hangars from the main deck above. One section of the NEFMAC (between hangars) and the underlying steel bottom reinforcement has been instrumented with electrical and optical strain gauges together with thermistors. An equivalent section of the steel/steel reinforcement in the centre span has been similarly instrumented. As there is a load limit of 25 kN on the lower deck, it is thought that the main effects will be thermal. The bridge lies on a north/south axis and the lower deck is shaded by the main upper roadway. The east side of the lower deck therefore receives direct sunlight only in the early morning and the west side in the afternoon.
The deck slabs have been cast and the check on gauge viability and the first control test are scheduled for the second half of September, 2000.

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Field Assessment of Gentilly I (T3.3.13)
Project Leader: Dr. Kenneth Neale, Université de Sherbrooke

In 1999-2000, ISIS Canada funded two research projects in Theme 5 (T5.11 – K.W. Neale and T5.11.1 – S.H. Rizkalla) related to the use of FRPs for the repair of the ring beam of the Gentilly 1 nuclear reactor containment structure in Gentilly, Québec. As a result of this work, a Technical Report entitled “Repair of the Ring Beam of the Containment Structure at the Gentilly-1 Reactor Unit” was submitted to Atomic Energy of Canada Ltd. (AECL) in June 1999. In this report, an FRP repair scheme using a glass fibre fabric was proposed to secure the concrete repair of the ring beam. The report also included specifications for the surface preparation, the installation of the FRPs and the quality control of the repair work.

A contract for the repair of the ring beam was subsequently awarded by AECL to Soesca Inc. of Bromptonville, Québec, and field work is scheduled to commence in late April 2000. The FRP repair scheme proposed by ISIS will be implemented in the structural repair of the ring beam, involving over 700 square meters of GFRP fabric.

Field Assessment and Monitoring:

The Gentilly 1 containment structure has been monitored in the past by AECL, and the intention is to monitor various aspects related to the repair of the ring beam. In the above-mentioned ISIS report to AECL, provisions were made for the monitoring of temperature gradients in the ring beam, as well as for the monitoring of the performance of the FRP repair. AECL will assume the costs of monitoring temperature and strains in the concrete and FRP wrap using conventional technologies such as thermistors and vibrating wires. They will also instrument the repair with the low-coherence interferometry fibre optic sensors of Smartec Inc.

This project provides a unique opportunity to implement and evaluate the fibre optic sensing (FOS) technologies currently under development with ISIS. The objective of this project, therefore, is to use and evaluate FOS devices such as short-gauge Bragg sensors, Fabry-Perot sensors and, in particular, the new long-gauge sensors being developed at the University of Toronto by Dr. R. Tennyson. The Brillouin scattering sensor being developed at the University of New Brunswick by Dr. X. Bao may possibly be included in this project.

A Bragg sensor demodulation system will be made available by AECL and this will allow remote monitoring on a continuous basis. The site lends itself extremely well to remote monitoring, as the various instruments can be housed in a special area inside the containment structure near the dome. Other readings (e.g. Fabry-Perot sensors, long-gauge sensors) will be taken at regular intervals. The locations of the sensors will be determined in order to verify the performance of the various sensors and to assess the information obtained from short-gauge sensors in comparison to the newer long-gauge sensors. Temperatures and strain gradients will be monitored by AECL on a continuous basis, and its influence on the strain measurements will be analyzed.

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Over the last five years, an extensive research program on the use of GFRP for the development of transmission and distribution poles has been carried out at the University of Manitoba. This research program, which has been sponsored by ISIS Canada, the Province of Manitoba, Faroex Ltd. and currently by Canzeal Enterprises, has produced a substantial amount of experimental and theoretical data. All the work to date, however, has been limited to laboratory verification of theoretical models. Last year, the University of Manitoba began construction of the SMART (Strong Manitoba Applied Research and Technology) Park. During the development of the site plans, the university asked the architects to incorporate in their plans the use of technologies developed at the University of Manitoba as a demonstration of its excellence in research and development. One such request was the use of filament wound poles as light standards, and the general contractor awarded the contract to Faroex Ltd. This is the first time Faroex Ltd. has undertaken a commercial venture to utilize the technology. As a result, this is a unique opportunity for a demonstration project that will not only incorporate the filament winding technology, but will include remote sensing using ISIS-developed fibre optic sensors wound directly into the poles during fabrication.

The first phase of the Smartpark lighting system will consist of 25, 27-foot poles and 4, 15-foot poles. Another 50, 15-foot poles will be added during the second phase. ISIS fibre optic sensor technology will be integrated directly into the filament wound composite. Because of the winder limitations, 27-foot poles cannot be fabricated as single pieces. The solution is to produce jointed poles that will be surface mounted using a composite flange system that will not require the use of breakaway systems currently used with metal light standards.

The demonstration project will be carried out in close cooperation with the University of Manitoba Physical Plant, Faroex Ltd., the general contractor, and the management of Smartpark.

The project will provide valuable information about the performance of materials and pole components under service conditions, will assist the researchers in their evaluation of various types of foundations, handling and erecting of GFRP poles, and remote monitoring of their performance using wound fibre optic sensors. However, one of the most important benefits of this project will be public awareness of the potential that GFRP holds for the construction of utility poles.

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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.

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Saskatoon Overpass Field Assessment (T3.3.16)
Project Leader: Dr. Leon Wegner, University of Saskatchewan

Transportation agencies across Canada manage physical assets with a combined value in the billions of dollars. Many of these agencies, including the Saskatchewan Department of Highways and Transportation and the City of Saskatoon, have implemented probability-based asset management systems to optimize the effectiveness of capital and maintenance expenditures on roadways. While the same techniques can be applied to bridge structures with great potential benefit, the lack of a systematic method for quantifying ongoing deterioration in bridges hinders any such objective assessment.

This project is the initial step in investigating response-based approaches for monitoring the structural health of innovative and conventional bridge structures. Ultimately, results from the monitoring programs will be used to facilitate the strategic allocation of funds for the repair, rehabilitation and maintenance of bridges and other structures. In addition, the monitoring methods will provide a quantitative basis for cost/benefit comparisons between the long-term performance of conventional and innovative (ISIS) bridge technologies. It is anticipated that jurisdictions such as the City of Saskatoon and Saskatchewan Highways and Transportation will begin incorporating structural health monitoring systems into new bridge structures, thereby providing an opportunity for reduced long-term repair and maintenance costs.

This project is one component of a larger program with the ultimate goal of developing a reliable and cost-effective damage detection system capable of evaluating the progressive deterioration in a bridge structure using periodic measurements of specific dynamic properties. The primary objectives of the proposed project are twofold: (1) to assess the suitability of different types of instrumentation, including fibre optic sensors, to measure the dynamic characteristics of bridge structures; and (2) to generate field and laboratory data to be used in the calibration of numerical models and the development of an adaptive algorithm for updating critical parameters in the numerical models to match measured response characteristics. Ultimately, by tracking changes over time and correlating these with physical properties used in the numerical models, the monitoring system should enable bridge managers at a remote location to assess the condition of a bridge structure on a regular basis without the need for detailed on-site inspections. Furthermore, data from the monitoring system will provide an objective basis for implementing state-of-the-art asset management techniques for bridge structures.

The project targets one of the new overpass structures in Saskatoon, which will be instrumented with different types of gauges including conventional electronic strain gauges, accelerometers, and fibre optic sensors, applied to girders and deck slab. The instrumentation will be used to measure natural frequencies, mode shapes, and damping characteristics of the bridge at various stages of construction, providing an indication of how these properties change with level of damage. The suitability and reliability of each type of gauge for measuring the dynamic characteristics will be evaluated.

In addition to the field assessment and data generation, there is also a laboratory component. Saskatchewan Highways and Transportation has donated a number of prestressed concrete bridge girders that were reclaimed form a dismantled bridge. Several of these girders will be instrumented and tested in the Structures Laboratory at the University of Saskatchewan. In addition to electronic strain gauges, accelerometers and fibre optic sensors, linear displacement transducers will be used in the laboratory investigation. The dynamic properties of the girders will be measured as various levels of damage are induced. The laboratory component of the project provides an opportunity to assess different types of instrumentation in a well-controlled environment and to carefully control the amount of damage that is induced. It will also permit an evaluation of the effect of very small amounts of damage on dynamic properties, and assist in the determination of a threshold level of damage below which changes to dynamic properties cannot be measured. In addition, the well-controlled laboratory environment will minimize uncertainty relating to important test parameters. The result will be reliable data for use in calibrating numerical models and developing algorithm for damage detection. Furthermore, the limitations of each type of sensor for dynamic measurements will be determined.

See Field Demo

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Remote Monitoring for Pipelines (T3.3.17)
Project Leader: Dr. Roderick Tennyson, University of Toronto Institute for Aerospace Studies

The development of long gauge fibre optic sensors in ISIS Canada presents a unique opportunity to apply this technology to the structural health monitoring of pipelines. Currently, there are over 350,000 km of energy pipeline in Canada. Alberta is the largest holder of these pipelines, where 55 percent of pipelines are older than 15 years and over 30 percent were built more than 20 years ago. There are about 700 pipeline failures each year in Canada alone, and the downtime associated with repair, replacement and inspection is a huge expense. From 1992 to 1999, $1.5 billion was spent on maintenance and inspection of Canada’s major transmission energy pipelines. In addition, the environmental issues associated with leakage and spills are impediments to the installation of new pipelines, such as the Alaska North Shore proposal to traverse much of Alberta to reach U.S. consumers.

Analysis has shown that long gauge fibre optic sensors can be used to measure hoop strains due to wall thickness changes from corrosion, pressure loss and cracks, and axial strain associated with local bending and buckling. The availability of pipeline test facilities at the University of Alberta and Dr. R. Cheng’s expertise in measuring pipeline buckling phenomena are essential to demonstrating the feasibility of this sensor system. With the participation of FOX-TEK Inc. in the provision of new FT sensor measuring instrumentation and new long gauge FT sensors, it is now possible to construct a full scale test facility to demonstrate the applications of this technology, not only in the laboratory but in the pipeline test sites located in Alberta. Remote monitoring is also an important element of this system in order to transfer the sensor data back to a central monitoring site. Two options include using a cellular network, where feasible, or satellites such as the Globalstar constellation. Optimum Inc. has the wireless capability for transmitting the fibre optic sensor data using cellular networks, and will also investigate the satellite application.

This proposal describes an ISIS pipeline consortium of five partners who will undertake to implement a full scale demonstration of this remote monitoring sensor system supported by laboratory test data: UTIAS, University of Alberta, FOX-TEK Inc., Optimum Inc., and TransCanada Pipelines Ltd.

Project Objectives

1. Design, fabricate and install FT long gauge sensors for different pipeline geometries and load configurations.
2. Implement FT measuring system and test pipeline segments under pressure and axial loading.
3. Demonstrate sensitivity and reliability of FT sensors to measure hoop and axial strains as a function of pressure and load, and compare data with conventional electrical strain gauges and other types of fibre optic sensors.
4. Design and fabricate wireless remote monitoring system for transmitting sensor data from FT Instrument to remote site using cellular network.
5. Implement total remote wireless fibre optic sensor system in field trials on pipeline segments.
6. Publish ISIS design guide for pipeline applications of fibre optic sensor systems addressing its capabilities for measuring the following parameters:

• Wall thinning due to corrosion
• Pressure loss
• Leakage
• Local cracks, holes
• Bending of pipeline segment due to sag and settling
• Local buckling
• Axial deformation due to pipeline slippage on slopes

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Monitoring Sprayed Bridge in B.C. (T3.3.18)
Project Leader: Dr. Nemkumar Banthia, University of British Columbia

The Ministry of Transportation and Highways of B.C. (MoTH, BC) has recently approved the repair of the Safe Bridge in the Cowichan Lake area on Vancouver Island using the spray composite technique. The ministry would also like to monitor the placement using FOS. The bridge is a one-span, channel beam bridge built in 1955. The span is 24 feet and there are 10 beams, each three feet wide. There is a sidewalk separated from traffic by a concrete curb.

The clearance under the bridge is about four feet at the upstream end and seven feet at the downstream end. There are three channel legs with severe spalling over a length of about one metre in each case. Other areas have very localized spalling where it appears the cover on the stirrup was too tight. Stirrup spacing is quite far apart (about 125 mm at the ends to about 760 mm in the centre). The concrete is normal density. The longitudinal reinforcing is unusual in that it is square instead of round (approximately 1 inch by 1 inch). It has small bumps on the surface at approximately two-inch spacing. The deck has an asphalt overlay and there is some water leaking through to the underside of the beams.

ISIS is involved in the repair and monitoring of this bridge using sprayed fibre reinforced polymers. The project will involve the following three tasks:
1. Repair/patching of girders using fibre reinforced mortar
2. Placement of sprayed fibre reinforced polymer on girders
3. Instrumentation and monitoring: Several girders will be instrumented before and after placement of the spray. For instrumentation before the spray, traditional sensors will be placed on the rebars. After the spray, fibre optic sensors will be placed. It is expected that measurements from these sensors will be carried out remotely.

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Smart Reinforcements and Connectors (T3.4)
Project Leader: Dr. Alex Kalamkarov, Dalhousie University

The project's major objective during the second phase is to refine the current technology and to accomplish a large volume program of laboratory testing and field assessment, as well as to complete the product specification and manufacturing guidelines for the smart FRP reinforcements incorporating the fibre optic sensors. The product under development and assessment is the smart FRP composite reinforcement which incorporates one or a number of fibre optic sensors embedded into the host composite material during the pultrusion process [Kalamkarov et al., 1997]. A new direction in the proposed research program will focus on the design, manufacturing, testing and application of the innovative strain gauges using composite materials to encapsulate optical fibre sensors. Composite materials have the unique ability to be designed and manufactured with a very wide range of mechanical and thermo mechanical properties. Embedment of the fibre optic sensors into the specially tailored composite host material will ensure the sensor protection, thermal compatibility with the host material, and the proper integration into the concrete structures.

The smart FRP reinforcements and innovative strain gauges will be used for the monitoring of concrete bridges. This work will constitute an important part of the future effort of this project. During the first stage of the project, it has been established that it is possible to incorporate fibre optic sensors into the FRP composite reinforcements during the pultrusion process. This work will be continued to refine the technology and the machinery from one side, and to commercialize and transfer the developed technology to the large scale manufacturing for the commercial use.

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Completed Research 1995 to 2006