Description of the Project
Two bridges will be constructed side by side over the Rouge River in the city of Southfield, Michigan. Each bridge will have a 15 degree skew and carry one lane of traffic and a sidewalk. Each bridge will have 3 spans of about 20 m each. Construction will be staged to maintain traffic at all times.
The first 3 span bridge will be constructed using conventional prestressed concrete I-beams. After this new conventionally built bridge is finished next spring, the roadway deck of the existing bridge will be replaced with a new CFRP bridge.
The second parallel 3 span double tee bridge will use 4 double tees per span for a total of 12 beams. The double tees will use Carbon Fibre Reinforced Polymer (CFRP) internal prestressing tendons, external post-tensioning strands and mild CFRP reinforcing tendons.
The CFRP reinforced bridge will be unique in the world due to its exclusive use of advanced composite material technologies.
A precast double tee test girder was manufactured in PSI's Windsor plant and shipped to Illinois. The beam was too heavy to cross the Ambassador Bridge so it was taken over the Detroit River by barge where it was shipped by truck to the Construction Technology Laboratories in Skokie, IL for testing. The girder was tested to failure. The girder was subjected to a series of stress tests with measurements taken from sensors strategically placed along the CFRP pretensioning rods inside the girder.
Facts about the test beam:
•Weight: 58 tonnes, length: 21 meters, width: 2.1 meters, depth: 1.2 meters.
•A stressing bed was specially built just to provide the support and base for the workers constructing the girder.
•Reinforcing rods made from Carbon Fibre Polymer have been pretensioned together with 1,140,000 pounds of force for strength and rigidity. Additionally, CFRP tendons were externally post-tensioned to 400,000 pounds of force.
Special Facts about the Project
•Loris Collavino, Dr. Nabil Grace and Dr. George Abdel Sayed are Canadians involved in this project on the leading edge of CFRP construction technology attracting worldwide interest.
• The project will cost $8.5 million.
•Sensors will be strategically placed along the CFRP rods to reveal data about the project throughout its life span that will be monitored by Lawrence Technological University.
•Stainless steel shear reinforcing and hardware will be used in the second CFRP bridge.
•This is a demonstration project.
Reasons for choosing CFRP reinforcing
•Rebar in structures can corrode and drastically shorten the life span of concrete, causing huge headaches and expensive repairs for everything from municipal buildings to parking decks.
•Rods from carbon fibres, while 10 times more expensive than steel reinforcing, never rust, weigh much less than steel, provide superior strength and show promise to vastly extend the use and application of concrete in ways only beginning to be explored.
•Concrete reinforced with what is essentially high-end plastic has the potential to extend the life span of a bridge from 30 years to possibly 80 years.
•CFRP is the new generation of construction materials.
•CFRP offers strength without the weight, making it an ideal material for a variety of applications: it has been used for helicopter blades and in automotive racing - for the body shell of Formula 1 cars
•CFRP rods are actually millions of thin strands of carbon fibre woven and held together with a strong epoxy resin. The reinforcing rods are designed with a slight indentation to grip the concrete and provide a tight bond.
The girder was transported by barge across the Detroit River, departing from Windsor. Bridge officials felt the Ambassador Bridge would not be able to handle the weight of the beam.
The finished test girder is lifted by the A-frame & transferred to the transport truck for transport to the barge area.
To successfully complete this project with the sensitive materials involved, PSI decided to expand. Land was purchased across the street from their Windsor plant where a shelter was set up and new forms constructed. Here PSI employees are working on the Bridge St. Bridge form.
The girder has successfully arrived at the testing laboratory responsible for the testing and analysis of the first CFRP bridge beam.
Testing Frame For Static & Dynamic Loading- 200,000 Lbs Capacity
Prototype Testing at Lawrence Technological University.