Cost Effective
- System provides for faster, safer construction with a smaller crew
- High strength-to-weight; translates into lower equipment and transportation costs compared to precast
- Eliminate time and cost of rebar and form-work
Sustainable
- Highly resistant to corrosion
- Performs up to 2x the lifespan of conventional bridge design
- Generates a smaller carbon footprint than comparative concrete/steel bridge construction
Performance Tested
- Arch elements maintain load carry capacity past initial failure
- Tested to 50+ years of truck traffic, UV durability, fire, freeze-thaw and abrasion resistance
- Instrumentation, field load testing
Expansive
- System is applicable to a wide range of geometries
- Single span bridges from 25 ft. to 70 ft. and multi-span designs exceeding 800 ft.
CONCRETE-FILLED CARBON FIBER (FRP) TUBES FOR BRIDGE DESIGN AND CONSTRUCTION
Low Cost, Easy to Deploy Bridges
According to FHWA, as of December 2010 there are over 45,000 structurally deficient or functionally obsolete bridges in the National Highway System (NHS) and an additional 248,000 deficient bridges outside of the NHS. The majority of deficient bridges are primarily due to corrosion of steel and steel reinforcement. If 20% of the deficient bridges under 100 ft in span size were replaced with hybrid composite-concrete bridges like the Bridge-in-a-Backpack (FRP composite tubes), $4 to $6 billion could be saved up front with additional billions of dollars saved in lifecycle costs due to low maintenance and increased service life.
This hybrid composite-concrete bridge technology can save money through reduced up front costs including materials, fabrication time, transportation, accelerated bridge construction time, and lifetime maintenance.
The product application is being widely accepted within the engineering community as evidenced by a rising number of installations and by the recent announcement of ASCE's 2011 Charles J. Pankow Award for Innovation.
Carbon Fiber and Concrete
FRP composite tubes are a lightweight, corrosion resistant bridge construction technology. The system performs as hybrid composite product marrying the powerful strength characteristics of carbon fiber composites with the durability and availability of concrete.
1. The FRP tubes provide external reinforcement and permanent formwork for cast-in-place concrete structures. As sole reinforcement for concrete, the FRP exoskeleton eliminates the need for steel rebar within the structure.
2. This external composite shell protects concrete from corrosive environmental impacts, eliminating the maintenance requirements related to rusting metal or cracking concrete, and reducing the costly rehabilitation activities related to painting or concrete spalling.
Together these factors lead to reduced maintenance costs and increased structural lifespan. With further R&D more money could be saved by broadening the applicability of this technology to more bridges and a broader array of applications.
Costs of Corrosion
In 2001, the Federal Highway Administration (FHWA) initiated a systematic study to estimate the total metallic corrosion cost on the U.S economy and to provide preventive strategies to minimize the impact of corrosion. The majority of deficient bridges are primarily due to corrosion of steel and steel reinforcement. The study found that the Annual Direct Cost Of Corrosion for highway bridges is estimated at $8.3 billion, consisting of $2.0 billion for annual maintenance and cost of capital for concrete substructures (minus bridge decks), and $0.5 billion for annual maintenance painting of steel bridges. Life-cycle analysis estimates indirect costs to the user due to traffic delays and lost productivity at more than 10 times the direct cost of corrosion maintenance, repair, and rehabilitation. This study ranked Highway Bridges as the 4th most costly sector of the 26 sectors analyzed in the report. (Source: Publication No. FHWA-RD-01-156)
Advancements in research and recent field installations continue to improve composite applications competitiveness. FRP hybrid composite-concrete applications are highly competitive on a First-cost basis (installed) reducing bid project pricing by as much as 20% in certain cases, in addition to a quantifiable maintenance savings benefit due to lack of corrosion.
Built in Corrosion Protection
FRP composites provide for enhanced durability and fatigue characteristics, as proven in related applications from other industries. Extensive laboratory testing indicates the technology exceeds the accepted industry code requirements while demonstrating increased service life of the structures with ability to resist cracking, oxidation, corrosion, wear, fatigue, and other general effects of weathering over time.
Target Market for Bridge Improvements
According to FHWA, as of December 2010 there are over 45,000 structurally deficient or functionally obsolete bridges in the National Highway System (NHS) and an additional 248,000 deficient bridges outside of the NHS. In total, this represents almost 49% of the total number of bridges in the National Bridge Inventory (NBI) that are considered deficient or worse.
Currently, FRP composite tubes can be fabricated/designed for single-span and multi-span bridge projects of up to 75 feet in length. Further analysis of the FHWA NBI data shows that there are over 345,000 bridges under 75 feet in length, representing nearly 57% of the national inventory.
FRP composite tubes can be considered for installation in any bridge replacement or new construction project that meets these criteria. With further R&D more money could be saved by broadening the applicability of this technology to more bridges and a broader array of applications.
Cost Effective - Savings Now & Long Term Benefits
Using FRP composite tubes allows for accelerated bridge construction reducing traffic congestion and lengthy construction schedules. In fact, one of the under-appreciated advantages of a composite-hybrid product is its reduced weight.
This means lower erection costs in addition to time savings, since the bridge pieces can be handled with lighter equipment and smaller crews. The contractor can also use smaller cranes and other equipment for site preparation and installation. Construction impact on an environment is lessened, which also adds to environmental benefits making this technology a greener solution.
FRP hybrid composite and concrete products and engineered systems generally offers the civil engineer an improved design performance, strength/safety characteristics that exceed industry standards, reduced construction time, reduced ongoing maintenance requirements, and an extended service life of the structure compared to conventional construction materials.
Composite systems can produce an immediate quantifiable economic impact of $4 to $6 billion in annual savings on maintenance, repair, rehabilitation, and replacement costs due to lack of corrosion, while reducing initial bid project pricing by as much as 20%.
