"Innovator" Newsletter
February 1999

CONTENTS

Feature Stories
FRPs Restore Water Chamber, Sherbrooke Québec
New Partnership Delivers Sensors, Toronto, Ontario

Focus On Research
Corrosion Research for Smart Patch Repairs
ISIS Researcher Recipient of Matching Awards

Demonstration Projects and Innovative Products
Hall's Harbour Wharf, Nova Scotia
Country Hills Boulevard Bridge, Alberta
Bishop Grandin Boulevard Extension

Awards
Field Application Wins International Industry Advancement Award
Engineering Research Scholarships

FRPs Restore 1910 Water Chamber to Original Capacity

Fibre reinforced polymers (FRPs) for repair applications are gaining acceptance for a wide variety of civil engineering structures such as bridges, buildings, multi-storied parking garages and highway overpasses. When it comes to the rehabilitation of waterworks however, very few projects involving FRPs have been tackled. This is due only to a lack of hands-on experience installing the materials under challenging conditions, as well as a lack of data on how the FRPs perform. With the recent rehabilitation of Québec's Hydro-Sherbrooke Frontenac Power Plant, the knowledge base of FRP applications in high-humidity environments has opened up new opportunities. The Frontenac Power Plant was built in 1910 and includes a water chamber that is part riveted steel and part concrete with a diameter of 3.66 metres. In 1917 the water chamber underwent major repairs and in 1987 light sandblasting was applied to remove rust from the walls. The steel inner wall was reduced from 9.52 mm to a residual thickness of 6.35 mm. Moreover, the concrete section of the chamber was in an advanced state of erosion.

At this point, the Hydro-Sherbrooke authorities decided to rehabilitate the chamber using a process that would not only protect what remained of the walls, but also restore the chamber to its original capacity. Applying FRPs to both the steel and concrete sections was the best solution. In addition to reinforcing the water chamber, the repair would also contribute to a burgeoning knowledge base of FRP applications in high-humidity environments. A total of 275 square metres of FRP material was installed. For the steel section, two layers of FRP were applied to the surface - one each to the exterior and interior. This structure was built using riveted plates, the rivet heads of which were in various states of decay. Special precautions were necessary to ensure continuity in the long term behaviour of the FRP.

Two layers of FRP were applied to the interior of the concrete section where incessant water leakage presented a real challenge to completing the rehabilitation. Water was seeping through the door during the installation and so to prevent the resin from eroding, the water was canalized. In addition, it appeared water was seeping through the highly porous concrete. By doubling the amount of resin applied, the porous concrete surface was saturated (having accounted for absorption) and an impenetrable bond was achieved.

Laboratory Testing
Tests were carried out in the University of Sherbrooke laboratories at the outset of this project in order to verify the bond of the composite to a steel surface. For this purpose, eight 12.7 -mm-thick by 100-mm-dia. plates were manufactured and a 25.4-mm nut was welded to one side of each plate, while sandblasting was applied to the other side. Four specimens were manufactured: two with clear resin, and two using a denser resin.

Repair Work
The repairs began on August 25, 1998 and were completed less than one month later on September 23rd. Sandblasting was initially used to eliminate all rust deposits on the steel surface and all other particles on either the steel or concrete. Different resin mixes were used to accommodate the repair site conditions.

Owner: Hydro-Sherbrooke
General Contractor: Les coffrages mauriciens inc.
Supplier: CM Tech, Service technique inc.
Consultant: Gestion conseil SCP inc.
Supervisor: ISIS Sherbrooke

 

New Partnership Delivers Experimental Sensors in Large Quantities

A new partnership between isis canada and electrophotonics corporation will provide university researchers in civil engineering and construction access to large quantities of low cost fibre optic sensors in an effort to promote their use in civil engineering structures. ElectroPhotonics Corporation will manufacture the fibre Bragg grating (FBG) sensors which will be distributed by the University of Toronto Institute of Aerospace Studies (UTIAS) - one of ISIS Canada's 11 networked universities. The wavelength and reflectivity of each FBG will be defined by researchers at UTIAS's Fibre Optic Sensing (FOS) Laboratory.

As a result of the collaborative agreement with UTIAS, ElectroPhotonics Corporation will manufacture experimental new sensors developed by UTIAS including a long gauge sensor (two FBGs on a single fibre) and a serial multiplexing sensor (multiple FBGs on a single fibre), as well as a conventional single FBG, single fibre sensor. As a member of the ISIS Canada research program, the UTIAS FOS Laboratory will provide ISIS partners and researchers with on-site assistance in the installation and measurement of FBGs.

The UTIAS FOS Laboratory is one of the founding members of ISIS Canada and is headed by aerospace scientist Dr. Rod Tennyson who specializes in composite materials for space structures and micrometeoroid impact damage in space. Fibre optic sensing is a natural outgrowth of aerospace research because of its use in monitoring aeronautical and space structures composed of composite materials. Applications of fibre optic sensors results from their light weight and immunity to electromagnetic interference, together with evidence of long-term stability in composite materials. The UTIAS FOS Laboratory has been involved in a number of high -profile installations including the Confederation Bridge linking Prince Edward Island to the mainland; the award winning Taylor Bridge in Manitoba; and the Beddington Bridge in Calgary.

ElectroPhotonics Corporation, founded in 1993, manufactures and markets a line of fibre optic test equipment and fibre optic sensing systems for high-precision strain or high-temperature measurements using fibre grating sensors. ElectroPhotonics Corporation provides hardware and software products for civil engineering applications, as well as the heavy industry, power and fibre optic telecommunications sectors. The Company is licenced by the federal Communications Research Centre to manufacture and distribute fibre Bragg gratings worldwide.

 

Focus On Research

Corrosion Research for Smart Patch Repairs

Over the next few decades, important decisions will be made on how to respond to deteriorating structures built in the 1950s. Extending the service life of these structures, as opposed to rebuilding, is naturally the favoured response if associated costs can be kept relatively low. Current research shows that externally-bonded fibre reinforced polymers (FRPs) are attractive alternatives to new construction or short-lived conventional patching approaches. This is especially well documented in scenarios where reinforced concrete requires strengthening in order to resist increasing load demands. Much less, however, is known about methods and the effectiveness of using FRP wraps to repair and extend the service life of structural elements already in an advanced state of corrosion. Thus, ISIS Canada's team at the University of Toronto is researching the effects of reinforcement corrosion on concrete columns and beams, as well as developing a safe, convenient and predictable system for economically extending the service life of concrete structures with corroding reinforcements.

In addition to experimental studies which have helped to refine the applications and prove their efficacy, repair designs are being developed using FRP wraps on corrosion-damaged concrete columns and flexural members. Structural tests on repaired specimens show that proper application of externally-bonded composites will restore columns and beams to their original strength and deformation capacities, or better. FRP wraps confine the damaged area and compensate for the loss of reinforcement and damage to the concrete. ISIS Canada's research builds on this basic knowledge by integrating monitoring systems with the FRP wrap and using the transmitted data to evaluate the repair's effectiveness.

To determine the effect of the FRP wrap on post-repair corrosion, the rate of corrosion in the repaired element is monitored in collaboration with Corrosion Services Co., Ltd. of Toronto using a Multi-Element Probe. External monitoring of post-repair corrosion is done using long-gauge fibre optic sensors integrated with the externally-bonded composite fibres. So-called "smart" repairs made in this manner not only restore structural function, but also give continuous information about any corrosion that might occur after repair.

 

ISIS Researcher Recipient of Matching Awards

Dr. Khaled Soudki, an ISIS Canada project leader at the University of Waterloo, has secured substantial financial support for his research on repairing corroded structures with fibre reinforced polymers. Dr. Soudki was awarded funds by the Canada Foundation for Innovation (CFI) under its New Opportunities Program. Eight new faculty members at the University of Waterloo will benefit from the $192,533 award which was matched by the newly established Ontario Research & Development Challenge Fund (ORDCF), a $14.5 million program established to provide infrastructure support, including labs and equipment, to researchers recently appointed to the faculty of provincial research institutions. The announcement was made December 10, 1998 by the Energy, Science and Technology Minister, Jim Wilson. "This new investment from the Ontario Research and Development Challenge Fund provides additional support for young researchers, a group we have targeted with our Premier's Research Excellence Awards," Minister Wilson said. "Working together, these two new programs move us closer to our goal of attracting and retaining the best young researchers."

 

Demonstration Projects and Innovative Projects

Hall's Harbour Wharf, Nova Scotia
The use of advanced technologies and composite materials in the Hall's Harbour Wharf reconstruction is attracting interest from Harbour Authorities around the world. There are hundreds of wharfs in Nova Scotia alone that will benefit from this development. on february 21, 1998, the people of hall's harbour in Nova Scotia awoke to find the mid-section of the west breakwater of their wharf had collapsed during the night. This small community supports an active fishing fleet, a major export-oriented Lobster-Pound, and is a working fishing village with a thriving tourism industry. It also has the only safe harbour on the Fundy Shore north of Digby which is open throughout the winter months. With the collapse of a 50-metre section of the wharf, the need to rehabilitate the 1904 structure took on the highest level of urgency.

Vaughan Engineering Associates Limited was retained to perform an engineering assessment of the Harbour and conventional reconstruction solutions were investigated. They included the traditional designs of timber, concrete caissons, steel sheet pile walls and a concrete deck on piles option, . The concrete deck with piles was by far the most cost effective. As cost and longevity were the major factors in the assessment, it was decided to pursue solutions involving advanced technologies, materials and methods. To this end, Vaughan Engineering is working with ISIS Canada at Dalhousie University.

In their preliminary design work, Vaughan and ISIS Canada's Dalhousie team have shown that the cost of the innovative materials and technologies is no more than that associated with conventional methods. The long-term benefits however, are substantially more attractive because the absence of steel reinforcements extends the life of the wharf from approximately 30 years to between 60 to 80 years with minimal maintenance - critical factors given that communities are solely responsible for maintaining their wharfs. The inclusion of fibre optic monitoring technology embedded in glass rods, will add solid data to support the application of the fibre reinforced polymers in other marine environment structures.

Early in 1998 a team of ISIS researchers including representatives from the Nova Scotia CAD/CAM Centre at Dalhousie University, the Universities of Sherbrooke and British Columbia, and the ISIS Canada Technical Applications Consultant, and CAN/ACM Consultants Ltd., began preliminary design work. Using their extensive pool of contacts, they assembled a consortium of interested companies including material suppliers, designers, a construction company and a pre-cast company, that have all committed to working and providing materials and products either at cost, or at a substantial reduction. Their commercial interest in the project stems from the possibility of creating a modular wharf system whereby the piles, the deck beams, and the panels incorporate fibre reinforced polymers and fibre optic optic sensors, and can be marketed throughout Canada and around the world.

 

Country Hills Boulevard Bridge, Alberta
In 1996, CH2M Gore & Storrie Limited, with the assistance of Dr. Gamil Tadros of ISIS Canada, began a material testing program at the University of Calgary to review the strengthening effects of carbon fibre reinforced polymer (CFRP) strips on existing bridge beams. In 1997, CH2M Gore & Storrie Limited was appointed by the City of Calgary to strengthen the bridge carrying Country Hills Boulevard over the Deerfoot Trail in north-east Calgary.

One of the main problems with the bridge was that its thin deck would be over-stressed in lateral bending under full CS-600 loading due to the skew angles at abutments and piers. Conventional strengthening with the addition of reinforcement would have required breaking the deck into strips, adding reinforcement, and re-concreting each strip. Hit and miss strip construction would have been required since the bridge had to have one lane open at all times and it was feared that to do otherwise would weaken the deck such that failure could occur. To avoid this problem and to strengthen the deck in a non-destructive way, the contract alternative of applying CFRP strips was chosen.

Sika Carbodur strips were installed in eight areas of the slab found to be in need of strengthening. Strips were installed at 500 mm centres. The hydromilled deck surface was rough and an initial levelling course of Sikadur 30 epoxy was applied to the levelling course as well as a 2 mm layer to each strip. A convex application tool was used so that initially, more epoxy was applied to the middle. The strip was then rolled to remove the excess epoxy. One day later, the strip's back, which would be in contact with the new deck overlay, was cleaned, sanded and given an application of Sika Armatec 110 binding agent approximately four hours prior to installing the overlay.

The encouragement and the dynamic approach by the City of Calgary under the direction of Ms. Jadwiga Kroman and Mr. Peter Wilson made it possible to strengthen this bridge using fibre reinforced polymers.

 

Bishop Grandin Boulevard Extension, Manitoba
Approximately 26,000 vehicles a day travel along Bishop Grandin Boulevard in Winnipeg and over the test site for 780 glass FRP dowels used in concrete joints instead of conventional epoxy-covered steel dowels. This is the first Canadian field application of FRP dowels in concrete pavement - a joint achievement of the City of Winnipeg, UMA Engineering and ISIS Canada.

Generally, concrete pavement failures are due to the expansive forces experienced during the oxidation of conventional steel dowels. Tests conducted in the laboratory at the University of Manitoba prior to the field installation indicated that the glass FRP dowel joints would, in fact, be more effective than the steel dowel joints.

Three manufacturers of corrosion free FRP participated in this field application: RJD Industries, Laguna Hill, California; Glasforms Inc., San Jose, California; and Creative Pultrusions, Alum Bank, Pennsylvania.

 

Awards

ISIS Canada Field Application Wins International Industry Advancement Award
The Precast/Prestressed Concrete Institute gives an annual award for projects demonstrating superior creativity and innovation, thereby advancing technological expertise in the industry. The 1998 Harry H. Edwards Award for Industry Advancement was bestowed on Manitoba's Taylor Bridge. With its state-of-the-art fibre optic sensing technology and fibre reinforced polymer (FRP) reinforcements, there was no question about its innovative design concept.The awards jury commented, "This project features an unusual design that takes advantage of CFRP in both the pre-stressing tendons and reinforcement. This technique offers great potential for the future. This approach should create an excellent ability to resist corrosion and should be able to increase the load carrying capacity as well. That latter element provides a very attractive feature."

Doug Stewart of Wardrop Engineering, the Engineer of Record for the Taylor Bridge and the PCI award recipient noted that the award gives broad recognition to important research that is quickly making its way from university and private research facilities to the marketplace through partnerships with companies like Wardrop Engineering. It draws attention to one of Manitoba's leading edge projects and promotes Canadian innovation.

At an awards ceremony held October 8, 1998 at the University of Manitoba, with Premier Gary Filmon as the guest speaker, Mr. John Fowler, President of the Canadian Precast/Prestressed Concrete Institute, presented the award to Wardrop Engineering. Participatory awards were also presented to the bridge owner, Province of Manitoba; the innovator of the new technology, ISIS Canada; and the pre-caster, Con-Force Structures Limited. Funding for the design and implementation of the new technology came from the Province of Manitoba, from Industry, Science and Technology through the Japanese Science and Technology Fund, and from the Industrial Research Assistance Program.

 

Engineering Research Scholarships

Two $5,000 research scholarships acknowledging Women and/or Aboriginals in Engineering Excellence are awarded by ISIS Canada annually to women or to people of Aboriginal descent who are graduates of a Canadian Engineering or Applied Sciences degree program. Applicant must either be currently enrolled in a degree program, registered, or intending to pursue graduate studies in Engineering or Applied Sciences. For more details contact the ISIS office.

Deadline for applications is March 31, 1999.