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Project data
Project Adhesive bonding of reinforcing steel plates to steel bridge decks
Site Noordelijke Scharsterrijnbrug (direction Lemmer-Joure, Netherlands)
Principal Ministry of Transport, Public Works and Water Management (Rijkswaterstaat)
Execution Takke LSBV Brugdekken VOF
Data start 13 March 2009, end 21 March 2009
Takke LSBV Brugdekken VOF
The combination Takke LSBV Brugdekken VOF consists of the companies Takke Breukelen B.V. and Lightweight Structures B.V.
Takke Breukelen B.V is a well experienced company in the area of repair of steel bridges. It is one of the few companies qualified by Rijkswaterstaat to weld steel patches in bridge decks and thus involved in almost all big steel bridge and bridge deck rehabilitation projects (the Hagesteinsebrug, the Moerdijkbrug, the Galecopperbrug and the Van Brienenoordbrug). Lightweight Structures B.V. develops and manufactures lightweight composite structures, mostly applying its vacuum infusion expertise. With this background expertise the adhesive bonding process was developed.
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if you need a steel bridge repaired!
Holland is a water-rich country. The numerous bridges are therefore an important factor in the infrastructure. These bridges however do not have an indefinite service life. Apart from environmental attack by moisture and temperature variations, the traffic loads slowly degrade the bridge structural integrity. Many Dutch bridges were rebuilt just after World War II.
These bridges are now over 50 years old and have reached their original design life. But also due to an enormous increase in traffic loads by more and heavier traffic, many bridges suffer from fatigue damage and cracks have appeared in several bridge decks. Especially recent changes in the transport sector like the shift to different axle and tire configurations of trucks have taken their toll. Until the last decennium of the 20th century, the design of bridge decks was performed using requirements based on static loads as laid down in VOSB63 design rules from 1963.
The Civil Engineering Division of the Ministry of Transport, Public Works and Water Management is looking for ways to enhance the life of bridge decks with fatigue damage or to prevent fatigue damage all together. One option is to apply steel reinforcing plates on top of the bridge to reduce the stresses. Until now, bonding of these large plates proved to be an unreliable and cumbersome process step. We developed and applied a vacuum infusion process where an epoxy resin is infused between the steel bridge deck and the reinforcing steel plate. March 2009 vacuum infusion was applied for the first time for the repair of the Scharsterrijnbrug in the A6 motorway between Lemmer and Joure, the Netherlands.
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| Conventional application of adhesives..... |
.... results in air pockets according to C-scan |
Adhesive bonding of steel plates to steel bridge decks was already investigated on laboratory scale over 10 years ago by the Adhesion Institute of Delft University of Technology. Application of adhesives on big surface areas however was cumbersome. The biggest challenge was to prevent the air pockets between the steel plates which is necessary to reach suffcient fatigue properties.
In the composites industry vacuum infusion has been used since many decades to impregnate glass and carbon fibre materials with liquid epoxy or polyester resins. Lightweight Structures B.V., being experst in this area, executed in 2002 the first infusion trials to investigate the adhesive bonding of steel plates.
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Bonding test with a piece of a bridge deck
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| Fatigue testing of the bridge sample |
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After the first these first successful experiments a full scale test was performed on an old piece of the bridge deck of the Van Brienenoordbrug. In co-operation with steel company Takke Breukelen B.V. Lightweight Structures B.V. all the necessary actions for the adhesive bonding were carried out. The bridge section was 10 by 3.5 meters. The reinforcing steel plate was bonded in a one stage process without any problems. A test article was cut from this section for successful mechanical testing.
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| The Scharsterrijn bridge |
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The Ministry of Transport, Public Works and Water Management (Rijkswaterstaat) then decided to have this bonding technique used to repair the heavily loaded right laneof the Scharsterrijnbrug in the A6 motorway close to the city of Joure. Rijkswaterstaat commissioned the execution of the repair to the combination Takke LSBV Brugdekken VOF.
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Load measuring with the test-truck
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Expert of Delft University measuring |
Prior to the reapir a load measurement was carried out by Delft University; strain gauges on the back side of the bridge deck measured the loads on critical areas when the calibrated test-truck was positioned. This type of measurements will be repeated after the repair to establish the effect of the bonded reinforcing steel plate.
The wear layer was removed from the deck. The steel deck was inspected for cracks. These cracks were cut out and repaired by welding new steel plates. In total 3 small plates (typically 0.5 by 1.5 meters) were added. To reduce internal stresses the weld lines were treated with ultrasonics.
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| Preparatoy local steel repair |
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After a tent was placed over the bridge the deck was degreased and coated with a primer. The cure of the primer (and the adhesive) needed a raise of temperature in the tent. In a specificly designed pattern small spacers were positoned on the deck to guarantee a correct thickness of the adhesive layer. Then the reinforcing steel plate of 8.2 by 4.2 meters was palced on top of these spacers.
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| Positioning of the reinforcing steel plate |
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The reinforcing plate was sealed airtight to the bridge deck. At one end of the plate the liquid epoxy resin will be introduced; at the other end a vacuum pump is connected.
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| Vacuum infusion of the liquid epoxy resin between the plates |
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After the cure of the epoxy adhesive the bond is checked for air pockets by ultrasonic testing. It was concluded that the space between the plate and deck was completely filled with adhesive and that there were no indications of air pockets. A new wear layer was put in the deck. With this wear layer also differences in height between the left and right lane were leveled. Naturally a second measurement using the strain gauges and the test-truck was executed: a load reduction of 60% was measured in the highliest loaded areas of the bridge (ref. publication).
This load reduction guarantees an extended life of this bridge: approximately 25 years!
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| Repaired Scharsterrijn bridge! |
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During one year similar measurements will be carried out on a monthly basis to check the performance of the adhesive bonding. If the deck performs according to the expectations the other lane of the Scharsterrijnbrug will be reinforced in a similar way. Rijkswaterstaat controls 6 other movable bridges that need to be repaired (or replaced) within 5 years. If the Scharsterrijn bridge is successful the other bridges may be repaired too using the vacuum infusion process.
Publication
S. Teixeira de Freitas, M. H. Kolstein, F. S. K. Bijlaard, W. S. Souren (senior engineer of Lightweight Structures B.V.). Orthotropic Deck Renovation of the Movable Bridge Scharsterrijn. Nordic Steel Construction Conference September 2-4 2009, Malmö, Sweden
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