composite applications in concrete structures professor john l clarke the concrete society
TRANSCRIPT
Composite applications in concrete structures
Professor John L Clarke
The Concrete Society
Why use FRP reinforcement?
• Corrosion of steel reinforcement in concrete structures in aggressive environments is a major problem
• Current concrete approaches are often inadequate
• Stainless steel reinforcement is expensive
• FRP should offer a viable alternative
Japanese road bridge
Bridge with FRP prestressing
Japanese foot and cycle bridge
Berlin Footbridge
Oslo Footbridge
Herning Bridge,Denmark
Casting ‘steel-free’ deck
Fender support beam, Qatar
Non-magnetic fencing
Summary - FRP reinforcement
• Correctly specified FRP materials are suitable for use in concrete
• Initial design guidance is now available
• Initial conservative safety factors will be modified as experience grows
• Demonstration structures world-wide show that the material is viable
Reasons for strengthening
• Requirement for increased load capacity (e.g. change of use or regulations)
• Insufficient/incorrectly located reinforcement
• Change of structural form (e.g. cutting holes through slabs or removal of supports)
• Damage (e.g. corrosion or impact)
Types of strengthening
• Beams and slabs– Bending– Shear
• Columns– Axial load– Bending– Shear (impact)– Seismic loading
Types of materials
• Pultruded composite plates
• Fabrics– Sheet materials – Tapes
• Pre-formed shells
• Pre-formed shear straps
Coil of carbon plate
Strengthening concrete with FRP
• Advantages– Cost effective solution - rapid installation and
hence limited possession time– Limited preparation - no bolts required
• Disadvantages– Lack of agreed design approaches– Lack of long term experience– Approach appears to be too easy (!!)
Strengthening canal bridge
Installing FRP strips on bridge deck
Bridge strengthened with FRP
Strengthening Glade Bridge
Applying adhesive to fabric
Fabric impregnation machine
Wrapping column
Wrapping column
Column wrapping machine
Bridge over Bodmin Bypass
Contents of Concrete Society Technical Report 55
• Introduction • Background
• Material types and properties
• Review of applications
• Structural design - flexure, shear, columns
• Detailing
• Workmanship
• Available materials • Quality control