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Structures Design / Design Innovation
Fiber Reinforced Polymer (FRP)
Reinforcing Bars and Strands
The deterioration of reinforcing and prestressing steel within concrete is one of the prime causes of
failure of concrete structures. In addition to being exposed to weather, concrete transportation structures
in Florida are also commonly located in aggressive environments such as marine locations and inland water
crossings where the water is acidic. Cracks in concrete create paths for the agents of the aggressive
environments to reach the reinforcing and/or prestressing steel and begin the corrosive oxidation process.
An innovative approach to combat this major issue is to replace traditional steel bar and strand reinforcement
with Fiber Reinforced Polymer (FRP) reinforcing bars and strands. FRP reinforcing bars and strands are made
from filaments or fibers held in a polymeric resin matrix binder. FRP reinforcing can be made from various
types of fibers such as glass (GFRP), basalt (BFRP) or carbon (CFRP). A surface treatment is typically provided that
facilitates a bond between the reinforcing and the concrete.
Beneficial characteristics of FRP reinforcing include:
Like any construction material, there are pros and cons to the use of FRP reinforcing:
Due diligence must be done to ensure FRP benefits outweigh the costs of implementation for each concrete component.
Traditionally, composite materials like FRP have been used extensively in aerospace and consumer sporting goods applications where the material's
high strength to weight ratios were first exploited. In the 1960s US Government agencies recognized the potential benefits that composites can provide
to society's infrastructure and thus begin funding significant amounts of research in the field of FRPs. Since then advances in the field of polymers,
advancements in production techniques and implementation of authoritative design guidelines have resulted in a rapid increase in usage of FRP bars and
strands, especially in the last 5 years. Because of these advances, the FDOT Structures Design Office
has implemented its first specifications
and design criteria to support the use of FRP bars and strands in major bridge components.
BFRP is an emerging technology in the US, and as such still in a
development phase by the Department for Specation and Standards. The
use of these innovative material in certain Florida
bridge components will keep Florida on the leading edge in the design of state-of-the-art transportation facilities.
GFRP, BFRP and/or CFRP reinforcing bars may be used in the following concrete components when approved by the SSDE:
The use of GFRP, BFRP and/or CFRP reinforcing bars in other locations will be considered on a case-by-case basis.
Standard Plans for 12, 14, 18, 24
and 30 inch square piles as well as 54 and 60 inch cylinder piles with CFRP strands are available and can be used following the
FDOT Structures Manual, Volume 1 Structures Design Guidelines (SDG)
Table 3.5.1-1 requirements. Design Standards for precast
concrete CFRP/GFRP and HSSS/GFRP sheet pile wall are also available
for use following SDG 3.12 requirements. CFRP strands may be used in other prestressed concrete piles when approved by the SSDE.
These usage restrictions take into consideration the following items:
See the following references for the application of FRP bars and strands for concrete reinforcement:
Additional design and detailing criteria are available in the
Structures Manual, Volume 4 Fiber Reinforced Polymer Guidelines.
The potential use of FRP reinforcing bars or strands for a given application will be evaluated on a project by project basis.
Extensive coordination with the Structures
Design Office will be required in order to develop acceptable final designs.
Structures Manual, Volume 4, Fiber Reinforced Polymer Guidelines
for more information.
Specifications 400, 410, 415, 450, 932 and 933 are available on the
Specifications webpage for the use of FRP reinforcing bars and strands. Additional Developmental
Specifications for other concrete structural components will be written and made available on an as-needed basis.
The following Standard Plans and associated Instructions are available on the
Standards webpage for the following applications:
The following Developmental Design Standards and associated
Instructions are available on the
Developmental Design Standards webpage:
Development of additional Developmental Design Standards for Concrete Box Culverts is planned for the future.
FRP producers seeking to be included on the FRP Production Facility Listing may find guidance for material acceptance on the State Materials Office
Fiber Reinforced Polymer Composites webpage.
FDOT and affiliated projects in Florida (completed and under construction) can be explored using the FRP-Projects GIS-Mapping Tool (pending).
Please contact the coordinators at the bottom of the page to have your project included in the Map.
Fast-Facts sheets for selected projects are listed below:
The following links to FDOT meetings, seminars and workshops are provide as background information for potential users and industry partners:
AASHTO Innovation Initiative (A.I.I.)
Active or recently completed FDOT sponsored research projects:
- BE694, Improving “Testing Protocol and Material Specifications for Basalt Fiber Reinforced Polymer Bars” (2019-2021):
Deliverable 1 “Background and Existing Standards”
Deliverable 2 “Research Plan and Characterization Tasks”
- STIC-0004-00A Incentive Project - BFRP Reinforcing Standardization (2018-2020):
i. 12-Month FDOT Progress Report
ii. Phase 1: BVD30 986-01 “Performance Evaluation of Basalt Fiber Reinforced Polymer (BFRP) Reinforcing Bars Embedded in Concrete” (2018-2019):
iii. Phase 2: BVD34 986-02 “BFRP Reinforced Bridge-Link Slab Instrumentation and Monitoring” (2019-2020):
Deliverable 1 “Literature Review”
Deliverable 2 “Instrumentation Plan”
iv. Phase 3: Technology Transfer:
2019 FDOT Transportation Symposium - FRP-RC Design Training.
2019 HDOT Peer Exchange Seminar – BFRP-RC Standardization of Design & Materials:
- BDK82 977-05: Chapter 5 - CHARACTERIZATION AND DURABILITY OF BASALT FIBER-REINFORCED POLYMER BARS, “Degradation Assessment of Internal Continuous Fiber Reinforcement in Concrete Environment” (2014)
- BDV29 977-52 “Epoxy Dowel Pile Splice Evaluation” (2019-2021) Deliverable 1 “Literature Review”
- BDV30 977-27 “Evaluation of Glass Fiber Reinforced Polymers (GFRP) Spirals in Corrosion Resistant Concrete Piles” (2018-2021)
- BDV30 977-18 “Performance Evaluation of Glass Fiber Reinforced Polymer (GFRP) Reinforcing Bars Embedded in Concrete Under Aggressive Environments” (2018)
- BDK82 977-05: Chapter 3 - CHARACTERIZATION AND DURABILITY OF GFRP, “Degradation Assessment of Internal Continuous Fiber Reinforcement in Concrete Environment” (2014)
- BDV29 977-10 “Use of Fiber Reinforced Polymer Composite Cable for Post-Tensioning Application” (2015)
- BDK83 977-17 Investigation of Carbon Fiber Composite Cable in Prestressed Concrete Piles (2014)
- BDK82 977-05: Chapter 4 - CHARACTERIZATION AND DURABILITY OF TOKYO ROPE CFCC, “Degradation Assessment of Internal Continuous Fiber Reinforcement in Concrete Environment” (2014)
Florida Department of Transportation
Safety, Mobility, Reliability