Annual Report 1999/2000

Demonstration Projects For infrastructure owners, one of the greatest values of ISIS Canada's research lies in its practical application. Over the past year there have been many new opportunities for applying ISIS Canada's technology as evidenced in the growing number of field demonstration projects underway. There are currently seven projects on stream which brings the total to 36. The projects range from a new concrete bridge deck for Calgary's Centre Street Bridge, to the strengthening of a nuclear containment structure in Quebec, to the testing of timber piles for use in an Inuvik housing project. Maryland Street Bridge, MB The City of Winnipeg has implemented a trial application of carbon FRP sheets as a first step in upgrading the shear capacity of the Maryland Street Bridge in Winnipeg. The twin five-span continuous precast prestressed concrete structures were designed and constructed in 1969. However, analysis using current codes indicates that the shear strength of the I-shaped girders is not sufficient to withstand today's increased truck loads. ISIS Canada conducted an experimental study at the University of Manitoba to examine the use of carbon FRP sheets on this particular girder shape. Laboratory tests began in 1996 with seven, ten-metre long beams which were strengthened using various types of carbon FRP sheets in ten different configurations. The beams were then tested to shear failure at each end to determine the most efficient shear strengthening scheme for the Maryland Bridge's I-shaped girders. During the field testing phase, local contractors participated in the process of wrapping (strengthening) the beams. Work crews from Concrete Restoration Services Ltd. and Vector Construction Group took part in applying the composite material and its epoxy-resin base in preparation for the field application. Phase Two has been completed with four of the Maryland Street Bridge girders having been strengthened with vertical FRP sheets and a horizontal layer placed across the top and bottom of the web. Horizontal and vertical strain gauges were applied so that the structure can be monitored over a two-year period. ISIS Canada researchers will determine how the technique stands up to Winnipeg's extreme weather conditions. There are numerous concrete structures throughout Winnipeg which are currently restricted to carrying weights well below the legal limits. Preliminary research conducted for the Maryland Street Bridge will result in the saving of millions of dollars because it can be applied extensively. Centre Street Bridge, Calgary, AB Rehabilitation of Calgary's Centre Street Bridge began in August 1999. The structure was built in 1916 and underwent extensive repairs in 1974, including a new precast concrete bridge deck placed above the original deck. However, harsh environmental conditions, including salt-laden moisture, have caused progressive deterioration of the bridge deck and other structural elements which required immediate attention to ensure the bridge remained serviceable. The lower bridge deck has been replaced and a portion of the deck slab reinforced with FRPs. Hall's Harbour Wharf, Hall's Harbour, NS The 96-year-old combination wharf/breakwater is the world's first marine structure with fibre optic sensors embedded in a steel-free concrete deck for remote monitoring. It is designed to last 80 years - three times longer than traditional construction methods. The new structure consists of pile support concrete beam and deck elements above an armour stone and timber crib breakwater. The concrete beams are designed with a hybrid reinforcement scheme of steel and glass FRP rods. The outer durable layer of FRP protects the inner core of steel reinforcement which was included for code considerations. The deck consists of precast steel-free concrete bridge deck panels modified to meet the durability needs of this structure. The design is based on draft versions of both the Canadian Highway Bridge Design Code and the American Concrete Institute Code. It is anticipated that rehabilitation of marine structures using FRPs will become standard practice through time, with the inner core of steel reinforcement considered unnecessary. Inuvik Housing Project, NWT Arctic buildings are typically supported using untreated timber piles - a large percentage of which are in a serious state of decay causing structural instability. In response to this problem, ISIS is developing a method for repairing the heavily decayed timber piles using glass FRP sheets. Typically, the use of FRP sheets provides an advantage over other conventional materials due to their high strength, light weight and easy installation. In this application, the added advantage is that the light-weight material will significantly reduce the high cost of transporting construction materials to remote regions of the Arctic. The project has begun with a feasibility study to determine the cost and structural reliability of using FRPs. This will be followed by a freeze-thaw durability study, culminating in the repair and monitoring of the severely decayed piles. Fibre optic sensors will be used to monitor the success of this technique. John Hart Bridge, Prince George, BC Carbon FRP sheets were used to upgrade the shear capacity of the John Hart Bridge by 15 to 20 percent in order to support ever increasing loads. The next phase of this project involves a monitoring program to collect data on the long-term performance of carbon FRP sheets for shear strengthening in this particular type of cross-section. The bridge has been instrumented to monitor its behaviour under dynamic vertical and service load conditions. Periodic site visits and visual inspections are also being conducted to assess the bridge's long-term performance. Gentilly-I Containment Structure, QC The Gentilly-I decommissioned nuclear powerplant is being upgraded using ISIS technology in order to efficiently extend the structure's maintenance period from 40 to 100 years. Through the Université de Sherbrooke and the University of Manitoba, ISIS Canada initiated the concept for repairing the plant's immense circular beam measuring 129 metres in circumference and located 46 metres above ground. To ensure long-term durability of the repair scheme, the renovation technique includes the use of FRP sheets bonded to the ring beam surface in an innovative configuration designed by ISIS Canada. In addition, for the first time, ten long gauge sensors varying in length from 1 to 27 metres are being used to measure deformations of the beam, the integrity of the FRP application and the long-term response of the ring beam. Fibre Bragg grating sensors will also be installed as part of the monitoring program. Wireless Datalogger/Optimum Instruments, AB Results of an ISIS Canada research project located at the University of Alberta show that wireless technology achieves continuous monitoring of structures while reducing the volume of data collected and power consumed, thus increasing the life span of instruments. ISIS Canada's University of Alberta research node and Optimum Instruments Inc. have introduced a second generation wireless datalogger and radio modem that connects a monitored site to an office. The DRM-1200 Wireless Datalogger eliminates the need for permanent site installations, phone hookups, power, and site heating. When combined with new Internet management technologies, it also facilitates efficient management of monitoring networks, with minimal overhead costs for data collection and scheduled maintenance. The wireless technology is self-monitoring and issues alarm warnings to a central computer. It can also report low battery or loss of solar power. Currently, the technology is being used with conventional strain gauges although a wireless remote monitoring system for fibre optic sensors is being designed and constructed at ISIS Canada's University of Toronto node. Jacques Lodge Bridge, AB Carbon FRP sheets were used to repair the Jacques Lodge pedestrian bridge which had developed shear cracks due to a lack of horizontal reinforcing bars and to high horizontal forces caused by friction. After jacking up the span, the 1961 structure was cleaned and epoxy was injected into the girder cracks, which were then wrapped with carbon FRP sheets. A finishing coat was applied and the overall aesthetic appeal of this bridge, located in a park-like setting, was preserved. Tourond Creek Bridge, MB The Tourond Creek Bridge, south of Winnipeg on Highway 59, was selected as the first of its kind to undergo an innovative strengthening technique developed by ISIS Canada. Since the rehabilitation, this 39-year-old structure is at least 30 percent stronger. Manitoba Highways and Government Services provided $110,000 to implement the new technology and to monitor the behaviour, anticipating it will be suitable for extending the service life of similar bridges. The Province has 575 timber bridges, all of which were built prior to 1980, that require strengthening in order to accommodate the increased traffic loads permitted by the Transportation Association of Canada (TAC Loads). Manitoba Highways and Government Services has estimated that replacing the Province's aging structures would require an investment of approximately $260 million. It will cost an estimated $90 million to replace the 170 treated timber bridges on the Provincial Trunk Highway system and $170 million to replace the remaining 405 treated timber bridges with new bridges. However, by embedding glass FRP bars longitudinally in the wood stringers and adhering them to construction grooves with an epoxy resin, bridges like the Tourond Creek Bridge can achieve the same strength as a new structure for less than 15 percent of the estimated cost of replacement. The additional benefits of using glass FRP bars are that they do not add significant weight to the structure and do not corrode when exposed to road salt. Structural Health Monitoring Data Archived on Web Site Several bridges in Canada have been instrumented for remote monitoring capability. Data is constantly collected from these structures at varying frequencies. As the data grows daily, so does the need for a sophisticated archival management system. It becomes one of the most vital aspects of structural monitoring. For this reason, ISIS is developing an on-line 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. Several different strategies are being used for data collection. In some cases the sensors are triggered manually at selected intervals of time, and the sensor data is stored on computer disks. In others, sensor data is collected continuously at a specified scan rate and automatically transmitted to a remote location, where it is stored on a computer medium. Data is currently being collected from the following structures: John Hart Bridge, BC Waterloo Creek Bridge, BC Crowchild Bridge, AB Beddington Trail Bridge, AB Taylor Bridge, MB Webster Parkade, QC Saint-Étienne-de-Bolton, QC Sainte-Émélie-de-l'Énergie, QC Joffre Bridge, QC Salmon River Hwy Bridge, NS Hall's Harbour Wharf, NS Confederation Bridge, NB

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