Key Research Accomplishments

Theme 3 (2002-2005):
Structural Strengthening and Rehabilitation with FRPs

Focus Area 3.1: Assessment of FRP Repairs in Canadian Environments

FRP Repair Systems for Cold Weather Conditions (3.1.1)
Project Leader: Dr. Mark Green, Queen's University

2002-03

The main objectives for this year were to start investigations of the combined effects of freeze-thaw and fatigue on concrete beams rehabilitated with FRP sheets or plates. Two test programs have started: one on small-scale specimens to test the bond of FRP to concrete, and the other on larger-scale prestressed concrete beams post-tensioned with FRP sheets. The testing of 45 small-scale specimens (1.2 m long beams) under combined freeze-thaw and fatigue loading is progressing well. All the specimens have been constructed and freeze-thaw tests started in January 2003. Fatigue testing will start in summer 2003. For the larger scale beams (3.0 m span), six (6) prestressed beams have been constructed and strengthened with prestressed carbon FRP sheets. Some of these specimens are currently undergoing freeze-thaw exposure while others are being tested in fatigue. The specimens subjected to freeze-thaw will also subsequently be tested in fatigue. The numerical modelling and design guideline work has also started. An initial numerical model has been developed to predict the flexural behaviour of FRP strengthened beams, and this model will be modified to take into account deterioration due to exposure to cold regions. For design guidelines, flexural data from freeze-thaw studies in the first phase of ISIS have been compared against predictions from the ISIS design manual approach to determine if modifications to the design approach are required to account for possible freeze-thaw damage. A paper summarizing this work has recently been accepted for publication in the Canadian Journal of Civil Engineering.

2003-04

Small scale tests – complete fatigue and freeze-thaw testing of 45 specimens: Forty-five small scale beam specimens (1.0 m span) were exposed to 200 freeze-thaw cycles followed by 2 million fatigue cycles. The specimens were strengthened with 3 different types of FRP sheets or plates. The sheets or plates were bonded at the ends of the beams and left unbonded at the middle to study the bond between the FRP and the concrete. After the freeze-thaw and fatigue exposure, the specimens were tested to failure in flexure. The results of these tests are currently being analyzed.

Large scale tests – complete fatigue and low temperature testing of 6 specimens: Six large scale beams prestressed concrete beams (3.0 m span) were strengthened with prestressed CFRP sheets and then exposed to approximately 100 freeze-thaw cycles followed by up to 2 million fatigue cycles. These tests indicated that freeze-thaw exposure reduces the fatigue resistance of these beams.

Field applications: In collaboration with Vector Construction and the Manitoba Department of Highways, a bridge near Winnipeg was strengthened in October 2003 with prestressed CFRP sheets. This was the first application of its kind in North America.

2004-05

Numerical modelling – Preliminary work has been conducted to implement freeze-thaw and fatigue damage will into existing models for flexural strength. More work is needed in this area to better understand the damage mechanics.

Design guidelines – The most recent experimental results have been compared against predictions of current or proposed design approaches. Appropriate design recommendations have been developed. At this point, the damage due to freeze-thaw appears to be within the variability accounted for in current design practices, and no further reduction factors to account for freeze-thaw damage appear necessary.

Freeze-thaw tests under sustained load – Cylinders were wrapped with GFRP or CFRP sheets and subjected to sustained loads (comparable to service levels) while being exposed to 300 cycles of freeze-thaw. The cylinders were then tested in axial compression to failure. The results have shown that the wrapped cylinders are resistant to freeze-thaw degradation even when under significant load.

Work on beam tests where small-scale beams (1.0 m span) were exposed to freeze-thaw (up to 200 cycles) and then to fatigue (up to 2 million cycles) was completed. The combined effect of fatigue cycling and freeze/thaw cycling appears to slightly degrade FRP plated reinforced concrete beams in terms of ultimate load and ultimate stress in the FRP, but the failure mode, failure surface, crack distribution and pattern do not appear to be affected by fatigue and/or freeze/thaw cycling.

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FRP Repair Systems for Corrosion Damaged Flexural Members (3.1.2)
Project Leader: Dr. Khaled Soudki, University of Waterloo

2002-03

Post-repair performance of CFRP repaired beams with shear-zone and uniform corrosion is complete. A total of 15 reinforced concrete (RC) specimens (150x254x3200 mm) were constructed. The specimens were exposed to accelerated corrosion by means of a constant impressed current. Half of the specimens were chloride contaminated within the shear zone only and the other half were chloride contaminated over the entire length at the bottom third of the cross-section. Three different levels of corrosion were considered (minor, moderate, severe) and the specimens were repaired following each corrosion phase. The rehabilitation scheme consisted of externally bonded flexural Carbon FRP sheets with fibres transversely oriented around the cross-section of the beam. Two specimens were repaired at a minor degree of corrosion and further corroded to a severe level to monitor the expansive stresses in the U-shaped FRP sheets due to corrosion. After the completion of the corrosion phase, all specimens were tested under monotonic loads were characterized in this phase of the project. Analytical modelling of time to corrosion cracking under load is complete. A new model that predicts the time from corrosion initiation to corrosion cracking of beams with corroding reinforcement under sustained loads was developed. The ability of the proposed model was confirmed by experimental data to give reasonable lower and upper bounds for the time to corrosion cracking for loaded and unloaded beams exposed to corrosion. Behaviour of CFRP repaired corrosion damaged beams under sustained load is on-going. The activities include: Fabrication of thirty beams that are under going corrosion activity. Fabrication of the corrosion exposure chamber with the sustained loading set-up to study the combined effects of corrosion under service load. Initiation of corrosion damage, FRP repairing and instrumentation of the specimens to examine the post-repair performance under combined effects of corrosion and load. After combined corrosion and sustained load, the specimens were tested under monotonic loading. Confining effects of CFRP repair on bond of corroded beams under fatigue loads is on-going. Phase one included fabrication of 20 bond specimens for the characterization of the bond mechanism of corroded reinforcement to FRP repaired concrete under cyclic loads – necessary data for field conditions. This phase of the experiment will investigate the confining effects of CFRP wrap under load without corrosion. Analytical modeling for flexural response of corroded and FRP repaired beams is underway to predict the response of corroded strengthened or repaired concrete beams using strain compatibility approach and accounting for bond degradation due to steel reinforcement corrosion. Strong links are established with several industrial and government partners including SIKA Canada, Canadian Construction Control, Regional Municipality of Waterloo and the Toronto District School Board. Dr. Soudki has acted as consultant on a few projects involving the use of FRPs in rehabilitation of bridges and structures.

2003-04

• Behaviour of CFRP repaired corrosion damaged beams under sustained load is complete. The activities include: Testing 30 beams that under went corrosion activity. Fabrication of the corrosion exposure chamber with the sustained loading set-up to study the combined effects of corrosion under service load. Corrosion damage, FRP repairing and instrumentation of the specimens to examine the post-repair performance under combined effects of corrosion and load. After combined corrosion and sustained load, the specimens were tested under monotonic loading. Effectiveness of FRP to repair corroded beams under load was established.
• Analytical modeling for flexural response of corroded and FRP repaired beams is complete. The model predicts the response of corroded strengthened or repaired concrete beams using strain compatibility approach and accounting for bond degradation due to steel reinforcement corrosion and sustained load.
• Confining effects of CFRP repair on bond of corroded beams under fatigue loads is on-going. Phase one will investigate the confining effects of CFRP wrap under load without corrosion. 20 bond specimens were tested for the characterization of the bond mechanism of uncorroded reinforcement to FRP strengthened concrete under cyclic loads Analysis of test results is underway. Fabrication of bond specimens for the characterization of bond mechanism of corroded reinforcement in FRP repaired concrete under cyclic loads. Initiation of corrosion damage (minor corrosion) in the bond-fatigue specimens (20 large-scale beams) will be in Spring 2004.
• CFRP repair of corroded beams under fatigue loads is on-going. A total of 20 flexure specimens for the characterization of the fatigue life of corroded reinforcement to FRP repaired concrete under cyclic loads. These tests will be undertaken in 2004/2005 to investigate the effects of CFRP to increase the fatigue life of corroded flexural members.

2004-05

• Confining effects of CFRP repair on bond of corroded beams under fatigue loads is ongoing. A total of 40 specimens are considered. Phase one will investigate the confining effects of CFRP wrap under load without corrosion. 20 bond specimens were tested for the characterization of the bond mechanism of uncorroded reinforcement to FRP strengthened concrete under cyclic loads. Analysis of test results is underway. Fabrication of bond specimens for the characterization of bond mechanism of corroded reinforcement in FRP repaired concrete under cyclic loads. Initiation of corrosion damage (minor corrosion) in the bond-fatigue specimens (20 large-scale beams) is done and specimens are being tested under cyclic loads.
• CFRP repair of corroded beams under fatigue loads is ongoing. A total of 20 flexure specimens for the characterization of the fatigue life of corroded reinforcement to FRP repaired concrete under cyclic loads. These tests are undertaken to investigate the effects of CFRP to increase the fatigue life of corroded flexural members. The specimens are subjected to 3 corrosion levels: minor (completed), moderate (in progress), severe (in progress). Following corrosion exposure, the specimens will be tested under 4 different ranges of cyclic loads. The first corrosion level (minor) under fatigue load is complete.
• Analytical models for FRP repair of corroded beams under fatigue loads. Ongoing development of models for the flexural strengthening of beams with FRP under fatigue loads utilizing the effect of bond degradation due to corrosion and the confinement by FRP wraps.

2005-06

• Confining effects of CFRP repair on bond of corroded beams under fatigue loads is on-going. A total of 40 specimens are considered and will be tested under fatigue testing.  Testing of specimens repaired after minor & moderate corrosion level is complete.  Testing of specimens repaired after severe corrosion level is in progress.  Analysis of test results is underway.  Modeling the bond behaviour of repaired and corroded beams is in progress.
• CFRP repair of corroded beams under fatigue loads is complete. A total of 20 flexure specimens for the characterization of the fatigue life of corroded reinforcement to FRP repaired concrete under cyclic loads.  These tests are undertaken to investigate the effects of CFRP to increase the fatigue life of corroded flexural members. The specimens were subjected to 3 corrosion levels: minor, moderate, severe. Following corrosion exposure, the specimens were tested under 4 different ranges of cyclic loads.
• Analytical models for FRP repair of corroded beams under fatigue loads. A model using strain life approach was developed to predict the fatigue life of strengthened corroded beams with FRP.

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FRP Repair Systems for Corrosion Damaged Columns (3.1.3)
Project Leader: Dr. John Bonacci, University of Toronto

2002-03

• Developed “MORE FRP” (Management of Repair with Fibre-Reinforced Polymers), a Windows-based software package. MORE FRP is a decision support tool using life-cycle cost analysis and performance prediction for the rehabilitation of corrosion damaged reinforced concrete members.
• Conducted structural tests of CFRP wrap-repaired corrosion-damaged concrete columns under varied amounts of eccentric compression. These are the first tests to evaluate the effectiveness of FRP wraps for repaired columns under combined loading.
• Initiated test series to evaluate the relationships between FRP wrap design, service life and repaired structural performance.
• Initiated test series to compare conventional column patching techniques with FRP wraps from the viewpoints of post-repair corrosion and structural performance.

2003-04

• Completed tests showing long-term performance of wrap repaired columns as a function of post-repair corrosion and wrap design
• Completed tests showing effect of pre-wrap repair treatments on post-repair corrosion rate and long-term structural performance
• Developed design equations for repair of corrosion damaged columns with FRP wrap
• Assembled review of literature on service life models for various concrete repair types to enable development of performance-based life cycle evaluation of FRP repairs

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Repair and Strengthening of Specialized Concrete Structures (3.1.4)
Project Leader: Dr. Shamim Sheikh, University of Toronto

2002-03

• Ontario Power Generation (OPG) and Kinectrics, Inc. are funding research to investigate application of FRP in nuclear structures. They have made extensive laboratory facilities available to our research team.
• Four research reports were completed with present results from 30 full-scale columns and specimens and finite element modeling of confinement of concrete with FRP.
• Based on the research carried out at the University of Toronto as part of ISIS work, retrofitting of a high-rise apartment building in Toronto with CFRP was completed this year. Total FRP retrofitting work was valued at approximately $600, 000.

2003-04

• Based on the research carried out at the University of Toronto as part of ISIS work, extensive retrofitting of a tower in a cement manufacturing plant in Guatemala has recently been carried out with carbon FRP.
• Four research reports based on one Ph.D. and three M.A.Sc. thesis were completed.
• Procedure for the design of FRP retrofitting of columns was developed and design guidelines for ISIS Manual based on this procedure are being developed.
• Finite element models and mechanical models were developed to simulate the response of concrete structural components retrofitted with FRP.
• Durability and structural tests on several hundred specimens were completed.

2004-05

• Based on the research carried out at the University of Toronto as part of the ISIS Network, extensive retrofitting of a tower in a cement manufacturing plant in Guatemala was carried out with carbon FRP in early 2004. Another cement plant in El Salvador has been found to be deficient and its owners have approached our research group to develop a retrofitting scheme for seismic upgrade of this structure. These are high profile direct field applications of ISIS technologies.
• A rational procedure for the design of FRP retrofitting of square columns was developed based on which modifications of design guidelines for ISIS Manual have been developed.
• Durability and structural tests on several hundred specimens were completed. Of particular mention are the tests on concrete in which the existing damage before retrofitting was investigated.
• Analytical models were developed to simulate the response of concrete structural components retrofitted with FRP that also takes into account the existing structural damage.
• Dissemination of ISIS funded work was carried out by delivering lectures to designers, engineering students and researchers at conferences and universities in various parts of the world including China, South Africa, South Korea, Pakistan and the United States.

2005-06

• A two-storey large reinforced concrete frame was tested in which the shear-deficient beams were repaired with CFRP after damage. The retrofit scheme strengthened the frame in the most economical manner for severe earthquakes. In addition, structural tests on small scale FRP-retrofitted specimens have been completed with special emphasis on pre-existing damage.
• Based on the research carried out as part of ISIS Network (see # 1 above), retrofit of a pre-heater tower in a cement plant in El Salvador was designed to upgrade the structure to meet the design codes and resist severe earthquakes safely. A similar retrofit using ISIS technologies was completed in Guatemala in 2004.These are high profile direct field applications of ISIS technologies.
• A rational procedure for the design of FRP retrofitting of square columns was developed in 2004-2005. The procedure is now being extended to circular columns.
• A large research program on FRP durability was completed in which over three thousand specimens were tested under a variety of environmental exposures including nuclear radiation. 
• Dissemination of ISIS funded work was carried out by delivering lectures to designers, engineering students and researchers at conferences and at universities around the world.

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Focus Area 3.2: Concrete Structures

Strengthening of Existing Structures (3.2.1)
Project Leader: Dr. Pierre Labossière, Université de Sherbrooke

2002-03

Confinement of Reinforced Concrete Columns with FRPs: Extensive statistical analysis of all previous tests on RC-columns confined with FRPs, submitted either to an axial load or to a combination of axial and lateral loads; over 300 specimens are included in the data, either from a literature survey or from previous ISIS projects completed in Sherbrooke (follow-up to M.Sc.A. theses of Demers 1994, Picher 1995, Rochette 1996, Parent 1997 and Lavergne 1998; current work of B.Ing. co-op student E. St.-Georges, entering masters program in Jan. 2004). Definition of specifications for RC-columns to be tested under combined axial and lateral loads in the structural laboratory from September 2003 to August 2004; it is anticipated that some of the columns will be damaged by cyclic loads before installation of the FRP repair.

Strengthening of Reinforced Concrete Beams with FRPs: Final testing of 24 RC-beams externally strengthened for bending with FRPs. All strengthened beams were damaged by submitting them to a combination of environmental ageing and cyclic loading. The cyclic loads applied to the beams range from 50 000 to 2 000 000 cycles, and are followed by quasi-static loading up to failure (completion of PhD thesis of C. Gheorghiu expected no later than April 1st, 2004). In addition to the structural data, all beams were instrumented with FOSs, and will provide useful comparative data on the behaviour of the monitoring devices under the harsh loading conditions described above.

Development of Smart Patch Technology: Final analysis of data and modelling of behaviour of FRP cruciform specimens integrating FOSs, under biaxial in-plane loads (follow-up to PhD thesis of P. Rochette, Nov. 2001; in collaboration with Prof. D. Bigaud, Université Claude-Bernard Lyon, France).

FRP Repairs of Prestressed Concrete Beams: A set of PC-beams externally reinforced with FRPs has been fabricated but only one specimen was tested so far (work of PhD student A. Harraq, under joint direction of K.W. Neale and P. Paultre). Changes in the test program must be defined due to unexpected results in the control specimen.

Field Applications of FRPs and FOSs to Reinforced Concrete Structures: The current applications of interests include the Sainte-Emélie de l’Energie bridge, the Gentilly Nuclear Power Plant, and the Décarie expressway bridges in Montréal. Follow-up to the Sainte-Emélie de l’Energie Bridge project (that no longer receives any direct funding for monitoring for ISIS) involves on-site measurements of strains every two months, and six sets of data have been acquired accordingly in 2002/03. Data analysis and modelling of the bridge are continuing. The Décarie project, undertaken at the request of the Ministère des Transports du Québec, involves the design of a wrap-up method for the Prestressed concrete beams, and a series of pull-out tests of the FRP wraps. This project is slightly behind schedule, and will be completed in 2003.

2003-04

Confinement of Reinforced Concrete Columns with FRPs: Extensive analysis of all previous tests on RC-columns confined with FRPs, submitted either to an axial load or to a combination of axial and lateral loads; over 300 specimens are included in the data, either from a literature survey or from previous ISIS projects completed in Sherbrooke (follow-up to M.Sc.A. thesis of Demers 1994, Picher 1995, Rochette 1996, Parent 1997 and Lavergne 1998). This Work was completed by then-undergraduate co-op student É. St-Georges, who has entered Masters program in Jan. 2004. Specifications for 2.5-meter-height RC-columns to be tested under combined axial and lateral loads in the structural laboratory from January 2004 to December 2004 were completed, and construction of the first columns is currently underway; some of the columns will be damaged by cyclic loads before installation of the FRP repair. One column fabricated.

Strengthening of Reinforced Concrete Beams with FRPs: Final testing of 24 RC-beams externally strengthened for bending with FRPs was completed in the Spring of 2003. All strengthened beams were damaged by submitting them to a combination of environmental ageing and cyclic loading. The cyclic loads applied to the beams range from 50 000 to 2 000 000 cycles, and are followed by quasi-static loading up to failure. Completion of the PhD thesis of C. Gheorghiu occurred in July 2003, much earlier than the anticipated date. In addition to the structural data, all beams were instrumented with FOSs, and will provide useful comparative data on the behaviour of the monitoring devices under the harsh loading conditions described above. Since May 2003, testing of the beams with the impact resonance method was investigated by Dr. Gheorghiu, and an extensive evaluation of the data is being conducted in continuation of his PhD thesis.
Development of Smart Patch Technology: Final analysis of data and modelling of behariour of FRP cruciform specimens integrating FOSs, under biaxial in-plane loads (follow-up to PhD thesis of P. Rochette, Nov. 2001; in collaboration with prof. D. Bigaud, Université Claude-Bernard Lyon, France).
FRP Repairs of Prestressed Concrete Beams: A series of PC-beams externally reinforced with FRPs has been fabricated and tested so far (work of PhD student A. Harraq, under joint direction of K.W. Neale and P. Paultre). Changes in the test program had to be defined due to unexpected results in the control specimen.

Field Applications of FRPs and FOSs to Reinforced Concrete Structures: The current applications of interests include the Sainte-Émélie de l’Énergie Bridge, the Gentilly Nuclear Power Plant, and the Décarie expressway bridges in Montréal. Follow-up to the Sainte-Émélie de l’Énergie Bridge project (that no longer receives any direct funding for monitoring from ISIS) involves on-site measurements of strains every two months, and six sets of data have been acquired accordingly in 2003/04. Data analysis and modelling of the bridge are continuing (January and March 2004). Data acquisition from the Gentilly Nuclear Power Plant can now be managed remotely, the system being operational since August 2003. The Décarie project, undertaken at the request of the Ministère des Transports du Québec, involved the design of a wrap-up method for the prestressed concrete beams, and pull-out tests of the FRP wraps. The Final report was completed in December 2003.

2004-05

Confinement of Reinforced Concrete Columns with FRPs:

• Extensive analysis of all previous tests on RC-columns confined with FRPs, submitted either to an axial load or to a combination of axial and lateral loads: over 300 specimens are included in the data, either from a literature survey or from previous ISIS projects completed in Sherbrooke by Ė. St Georges in 2004.
• Specifications for 2.5-meter height, RC-columns to be tested under combined axial and lateral loads in the structural laboratory completed, construction of columns began in December 2004.
• All columns have been cast, some wrapped with FRPs; one column damaged by cyclic loads up to failure, for calibration of all tests; more columns will be damaged by cyclic loads before installation of the FRP repair.
• January to June 2005 – build and test remaining large-size specimens.
• Spring 2005 to August 2005 – analyze data.
• M.Sc.A. Thesis of Ė. St-Georges to be completed by December 2005.

Strengthening of Reinforced Concrete Beams with FRPs:

• Until July 2004, testing of reinforced-concrete beams externally reinforced with FRPs using the impact resonance method was investigated by Dr. Catalin Gheorghiu and an extensive evaluation of the data was conducted in continuation of his Ph.D. thesis.
• Dr. Gheorghiu was hired as an Assistant Professor at the University of Manitoba (July 2004).
• Collaboration between our two universities has been reinforced and joint papers submitted.

Development of Smart Patch Technology:

• The analysis of data and modelling of behaviour of FRP cruciform specimens integrating FOSs, under biaxial in-plane loads. A paper was submitted in April 2005 (1st author: Dr. Pierre Rochette).

FRP Repairs of Prestressed Concrete Beams:

• PC-beams externally reinforced with FRPs were fabricated and tested (work of Ph.D. student A. Harraq, under joint direction of K.W. Neale and P. Paultre). Thesis work to be completed soon.

Field Applications of FRPs and FOSs to Reinforced Concrete Structures – Current Applications:

• Sainte-Ėmélie de l’Ėnergie bridge (no longer funded by ISIS): on-site strain measurements of strains every two months until June 2004; every 6 months afterwards; full testing of the bridge in June 2004, in collaboration with the MTQ; June 2004 tests recorded by a TV crew of the Z-Tele cable channel; the 15-minute clip was broadcasted eight times in September/October 2004; data analysis and modelling of the bridge are continuing.
• Gentilly Nuclear Power Plant: Data acquisition from the Gentilly Nuclear Power Plant is managed remotely, the system being operational (with ups and downs) since August 2003.
• Autoroute 40 expressway bridges in Montréal: Research contract to design a wrap-up method for the prestressed concrete beams, pull-out tests of the FRP wraps.

2005-06

Confinement of Reinforced Concrete Columns with FRPs

1. Specifications for 2.5-meter-height RC-columns to be tested under combined axial and lateral loads in the structural laboratory completed, construction of columns began in December 2004.
2. January to August 2005 – last remaining large-size specimens planned in program were built.
3. Summer 2005 to March 31, 2006 – Data analysis.
4. Sub-project to be pursued beyond funding

Strengthening of Reinforced Concrete Beams with FRPs

1. Sub-project previously reposted as completed. Since Dr. Gheorghiu was hired as an Assistant Professor at the University of Manitoba (July 2004), collaboration between our two universities has been reinforced and joint papers submitted.

Development of Smart Patch Technology

1. Sub-project previously reported as completed.

FRP Repairs of Prestressed Concrete Beams

1. PC-beams externally reinforced with FRPs were fabricated, tested and analyzed.
2. Sub-project completed.

Field Applications of FRPs and FOSs to Reinforced Concrete Structures – Current Applications

• Sainte-Emelie de l’Energie bridge (no longer funded by ISIS)

1. On-site strains measurements of strains every 6 months since June 2004
2. Data analysis and modelling of the bridge are continuing

• Gentilly Nuclear Power Plant: data acquisition is managed remotely, the system being operational (with ups and downs) since August 2003.
• Autoroute 40 expressway bridges in Montreal: Research contract to design a wrap-up method for the prestressed concrete beams was followed with on-site application.
• Field application sub-projects to continue indefinitely beyond ISIS funding.

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Sprayed FRPs for Rehabilitation (3.2.2)
Project Leader: Dr. Nemkumar Banthia, University of British Columbia

2002-03

In this project a novel technique of strengthening using sprayed fibre reinforced polymers is being developed. Major accomplishments for this year include:

• Continued optimization of the process of sprayed fibre reinforced polymers and use of fibres other than glass. So far only thermoplastic polymers have been used in the process (polyester and polyurethane hybrids). This year for the first time use of thermosetting polymers (various epoxies) was attempted. This created the problem of increased rebound, which is being investigated at the moment through high speed photography. Also, so far, only glass fibre was used in the process. This year, for the first time, the use of other fibres (carbon, polypropylene and aramid) was attempted.
• Use of sprayed fibre reinforced polymers was investigated for column retrofit. Tests were carried out on typical bridge columns designed as per pre-1971 code provisions. The hinge portion was sprayed and the performance under a horizontal load was compared with another column without the spray.
• Use of sprayed fibre reinforced polymers as protective coatings on structures in aggressive environments was investigated. In particular, spray protective coatings were investigated for offshore structures. Here, fibre volume fraction below 15% (normal strengthening projects use over 40%), were investigated.

2003-04

• Continued optimization of the process of sprayed fiber reinforced polymers including modifications to the spray nozzle
• Use of fibers other than glass
• Modeling of the process of rebound and reduction of rebound
• Use of novel epoxies
• Use of novel bonding agents
• Continued investigation of sprayed fiber reinforced polymers for seismic retrofit of columns
• Continued investigation of sprayed fiber reinforced polymers as protective coatings for structures in aggressive environments. In particular, spray protective coatings were investigated for offshore structures with low fiber volume fraction (<15%).

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Creep and Fatigue of FRP Strengthened Structures (3.2.3)
Project Leader: Dr. Kenneth Neale, Université de Sherbrooke

2002-03

• Bibliographic review of creep of concrete
• Key findings: - FRP-confining scheme can limit crack propagation for several months without showing any signs of upcoming failure at a sustained load level equal to the ultimate strength of unconfined concrete.
• In FRP-confined concrete, creep resistance is inversely proportional to the loading level as a fraction of the confined concrete strength.
• For the same type of concrete and identical loading level as a function of the confined specimen ultimate strength, the system with the highest confinement shows the greatest creep resistance.
• Six different types of defects, related to the lay-up process of FRP sheets, which might influence the response of FRP-confined systems were identified.

2003-04

• FRP-confining scheme can limit crack propagation for several years without showing any signs of upcoming failure at a sustained load level equal or greater to the ultimate strength of unconfined concrete. More then 30 cylinders tested are being tested. Parameters of the study: level of loading, level of confinement and level of damage before confinement.
• Creep of FRP strengthened beams seems to be governed by concrete. Several static and creep tests performed. Parameters of the study: level of steel reinforcement, level of FRP loading and strengthening scheme.
• Surface preparation influences the bonding behaviour of the resin. Several static tests on the shear performance of the concrete-resin-FRP interfaces. Creep shear test on interface is in preparation.

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Performance of Retrofitted Structures Under High Strain-Rate Loading (3.2.4)
Project Leader: Dr. Patrick Paultre, Université de Sherbrooke

2002-03

Ongoing project on seismic rehabilitation of bridge piers:

• A ductility-based vulnerability evaluation method was proposed to identify and prioritize bridges in need of seismic rehabilitation
• Several bridges were identified in collaboration with the Quebec Ministry of Transportation and the city of Quebec
• Ductility investigations (based on sectional and structural ductility ratios) was carried for eight bridges
• Finite element models are currently under development for a selected bridge pier (2 columns) to be tested with the substructure pseudo-dynamic technique at the Sherbrooke reaction wall facility. The specimen should be completed during the fall of 2003.

2003-04

• A ductility-based vulnerability evaluation method was proposed to identify and prioritize bridges in need of seismic rehabilitation;
• Several bridges were identified in collaboration with the Quebec Ministry of Transportation and the city of Quebec;
• Ductility investigations (based on sectional and structural ductility ratios) was carried for eight bridges;
• Finite element models were developed for a selected bridge pier (3 columns) to be tested with the substructure pseudo-dynamic technique at the Sherbrooke reaction wall facility. The specimen is under construction;
• Performance-based method for effective rehabilitation is underway;
• Confinement model for retrofitted bridge piers was developed

2004-05

• A ductility-based vulnerability evaluation method was proposed to identify and prioritize bridges in need of seismic rehabilitation.
• Several bridges were identified in collaboration with the Quebec Ministry of Transportation and the city of Quebec.
• Ductility investigations (based on sectional and structural ductility ratios) were carried out for eight bridges.
• Finite element models were developed for a selected bridge pier (3 columns) to be tested with the substructure pseudo-dynamic technique at the Sherbrooke reaction wall facility. The specimen is under construction.
• Performance-based method for effective rehabilitation is underway.
• Confinement model for retrofitted bridge piers was developed.
• Development of fragility curves.
• Initiation of substructure pseudo-dynamic test program.

2005-06

Ongoing project on seismic rehabilitation of bridge piers:

• Ductility investigations (based on sectional and structural ductility ratios) was carried for eight bridges;
• Finite element models were developed for a selected bridge pier (3 columns) to be tested with the substructure pseudo-dynamic technique at the Sherbrooke reaction wall facility. The specimen is under construction;
• Performance-based method for effective rehabilitation is underway;
• New confinement model for retrofitted bridge piers was developed. The model accounts for steel and FRP confinement;
• Development of fragility curves;
• Development and implementation of sub-structure pseudo-dynamic test program;
• Construction of 1/3 – scale bridge bent specimen in laboratory for pseudo-dynamic testing;
• In situ dynamic tests to characterize properties for sub-structure testing;
• Model updating based on dynamic tests;
• Development of sub-structure model in MATLAB;
• Development of bridge model in RUAUMOKO.

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Effects of Low Temperature and High Strain Rate (3.2.5)
Project Leader: Dr. Robert Tremblay, École Polytechnique de Montréal

2003-04

The project progressed at a slow pace in the last year due to unavailability of the structures laboratory caused by the construction of a new CFI funded laboratory. It is expected that testing activities will progressively resume in the 2004-2005 year. So far the following tasks have been completed:

• Compression tests on concrete cylinders subjected to various strain rates and temperature conditions. Statistical treatment of the test data has been performed to develop typical stress-strain curves for various load conditions. A literature review has been performed to collect data on the influence of strain rate and temperature on the tensile stress-strain characteristics of FRP material.
• A MATLAB computer program has been developed to carry out nonlinear sectional axial-flexural analysis of concrete columns subjected to high strain rates at various temperature conditions. The program also accounts for the concrete confinement effects provided by conventional reinforcing steel and FRP material.

Nonlinear dynamic analysis of a typical bridge structure is currently underway to investigate the demand imposed on bridge columns when subjected to various types of ground motions.

2005-06

Experimental study of the combined effects of earthquake-type strain rate and low temperature on the stress-strain behaviour of FRP and concrete.

• Additional compression tests on concrete cylinders subjected to various strain rates and temperatures have been carried out.
• Tension tests on FRP at low temperature have been carried out.
• Tension tests on FRP on combined low temperature and high strain rate will be completed in June 2006.

Experimental study of the shear capacity of deficient columns retrofitted with FRP and subjected to various temperatures and strain rates.

• 11 large scale specimens were fabricated: with GFRP and CFRP wrapping in 2005/2006.
• Tests at room and low temperature have been completed in 2005/2006.
• Tests on combined low temperature and high strain rate will be completed in May 2006.

Determination of the nonlinear moment-curvature characteristics of planar reinforced concrete sections wrapped with FRP taking into account the combined effects of earthquake-type strain rate and low temperature.

• This part of the project has been completed in previous year.  A powerful and efficient MATLAB program was written for that purposes and extensive parametric studies have been completed to evaluate strain rate and temperature effects on the flexural response of non retrofitted and retrofitted concrete members.
• Additional analyses may need to be carried out when test data becomes available in 2006.

Experimental study of the performance of lap splice regions of circular, square and rectangular columns retrofitted with FRP and subjected to various temperatures and strain rates.

• 15 large scale specimens with CFRP wrapping have been fabricated in 2005/2006.
• Tests at room and low temperature have been completed in 2005/2006.
• Tests on combined low temperature and high strain rate will be completed in May 2006

Nonlinear seismic analyses of complete reinforced concrete bridges located in active seismic cold regions.

• This part of the project has been completed in previous year. Extensive non linear dynamic seismic analyses of bridge structures have been performed using the Ruaumoko computer program.
• Section properties used in these analyses were obtained from the MATLAB sectional analysis program. Additional analyses may need to be carried out when test data becomes available in 2006.

Instrumentation of some test specimens with fibre-optic sensors in order to evaluate their performance at low temperature and under earthquake-type strain rate.

• This activity has not been completed.  Newly acquired equipment will allow completing this activity in 2006/07 in demonstration projects.

Elaboration of a field demonstration project for the seismic health monitoring of a reinforced concrete bridge in Quebec.

• This task has been initiated with the MTQ.

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Focus Area 3.3: Timber, Steel and Masonry Structures

Strengthening of Existing Timber Structures (3.3.1)
Project Leader: Dr. Ken Johns, Université de Sherbrooke

2002-03

Contract with Hydro-Québec signed and started during this period, to investigate possibilities for reinforcement of timber portal frames for energy transmission lines. This work will be reported on during the next NCE year. Participation in a contract between Forintek Canada and the MTQ, beginning in the closing weeks of the NCE 2002-2003 reporting period, to investigate possible uses of FRP to repair, upgrade and reinforce timber covered bridges. This also will be part of the 2003-2004 report.

2003-04

• Completion of contract with Hydro-Québec
• Completion of a preliminary study on Covered bridges for the MTQ
• Beginning of the Andrade Master’s project on the effect of considering plastic deformations in the model for FRP-reinforced bending elements, and the impact of this on the interpretation of earlier experimental results.

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Durability of FRP Strengthened Timber Bridges (3.3.2)
Project Leader: Dr. Dagmar Svecova, University of Manitoba

2003-04

• Determined the short-term durability of various strengthening schemes for timber.
• Developed formula for calculation flexural stress of strengthened timber.
• Established guidelines for placing FRP dowels for shear strengthening of timber.

2004-05

• Results of this research were used in the new upcoming version of Canadian Highway and Bridge Design Code, Section 16.
• Research was expanded to include strengthening using FRP sheets.
• Durability cycles were established for new year’s testing of various types of FRP systems.

2005-06

• Results of this research on strengthening of timber were included in the new CHBDC Section 16
• Developed design charts for strengthening of timber beams using FRP sheets
• Established testing methods for durability of FRP strengthening systems for timber

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FRP Strengthening Systems for Steel Structures (3.3.3)
Project Leader: Dr. J.J. Roger Cheng, University of Alberta

2002-03

Shear Strengthening of Concrete Bridge Girders Using FRP Sheets: A design model based on the failure mechanism is developed. A refereed journal paper has been either accepted or published.

Repair of Fatigue Cracks in Steel Structures with Composite Fibre Patching: This project is to study the feasibility of using composite fibre patching to repair fatigue cracks in steel structures. A guideline was developed for the design of composite fibre patching for fatigue cracks.

Seismic Rehabilitation of Masonry Structures Using FRP Materials: The project has entered the third phase: slender masonry walls strengthened with various types of FRP materials. A Ph.D. thesis is close to completed.

Behaviour of Concrete Slab-Column Connections Reinforced with Glass Fibre Reinforcements and Repaired using Carbon Fibre Sheets: The project is to study the feasibility of using GFRP internal reinforcement as well as external repair for punching shear strength of concrete slab-column connections. A paper has been accepted by ACI Structural Journal.

Repair of Wrinkled Pipes using FRP Sleeves The project is to develop effective repair techniques using FRP sleeves for wrinkled pipes. Both full-scale tests and numerical study are employed in the project. The ultimate goal is to optimize the sleeve design using FRP composites, in order to eliminate or minimize the effects of subsequent wrinkles after repair. A second M.Sc. thesis is close to being completed.

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Rehabilitation of Masonry and Historical Brick Structures (3.3.4)
Project Leader: Dr. Alaa Elwi, University of Alberta

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Fatigue Repair of Steel Bridges Using FRP Patching (3.3.6)
Project Leader: Dr. J.J. Roger Cheng, University of Alberta

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