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TRANSCRIPT
Replacement Pedestrian Bridge Design using Pultruded Fiber Reinforced Polymer (FRP)
Dr. Amit Sagar, Bridge Engineer
pitt&sherry
Presentation Pathway
Page 2
• Background
• Client Requirements
• New Bridge Design
• Construction Photos
• Conclusion
• Questions
Background: Original Bridge
Page 3
Bridge Type Simply Supported
Usage Pedestrian and Cyclists
Material Superstructure Timber
Footing Concrete Strip Footing
Construction Date 1988
Total Length of Bridge 30.36 m
Width of Bridge 2.4 m
No of Spans 12
Crossing Blind Creek
Owner City of Knox
Location of Bridge
Page 4
Bridge Location
Fire Damage
Page 5
Client Requirements
New Construction Material: FRP
Use Existing Concrete Strip Footing
New Bridge Configuration to Match Old Bridge
Page 6
FRP Bridge Design
Why FRP Bridge ?
Extended Service Life
More Durable
Less Maintenance Cost than Timber
Fire Resistant
Page 7
FRP Bridge Design
Design Load = 5 Kpa (AS5100.2-2017)
Codes – Australian Standards : AS5100-2017– Pre-Standard for Load & Resistance Factor Design (LRFD) of Pultruded Fiber Reinforced Polymer
(FRP) Structures developed by American Society of Civil Engineers
FRP Material Properties– FRP Composites are Anisotropic – Properties are established by Direction of Fibres
• Characteristic longitudinal modulus of flange is different to the web • Characteristic transverse modulus of the web is different to the flange
Challenge– Current gap in knowledge of Material Behaviour and Design Guidelines
Page 8
New Bridge Configuration
Page 9
Total Length of Bridge 30.36 m
Width of Bridge 2.40 m
No of Spans 12
Span Length 2.53 m
New bridge design has approximately same lengthand width as original bridge.
Number of spans are same, i.e. 12.
Construction
Page 10
• Project Awarded in Late 2018
• Construction Commenced Jan 2019
• Bridge Completed Feb 2019
• Two Weeks Prior to Scheduled Opening Date
CONCLUSION
Page 11
• Existing timber bridges are decaying and in need of replacement, anopportunity to use FRP as primary design material
• Durable and Less Maintenance Costs for Asset Owners
• Common place for asset owners to use FRP for re-decking existing timberstructures
• Australian Standards provide Limited Guidance
Acknowledgements
City of Knox
David Chow
Mr Nathan Hadfield
Pitt&Sherry
Mr Chris Morton
Dr Andrew Sonnenberg
Page 12
QUESTIONS
Page 13
Natural Bridge, Queensland
Its name is taken from a rock arch in Springbrook National
Park. A waterfall along Cave Creek, a tributary of the Nerang
River flows through the arch
Picture Taken By: Amit Sagar
Fire Resistant Supporting Information
C1.10 refers to Clause A2.4 Fire Hazard Properties which requires the material to be tested to AS/NZS 1530.3 for flame spread index and smoke developed index
The mean critical radiant flux rating for our material as tested in the attached certification has a result of 10.9kW/m2 and 0 smoke developed index. This is well above the highest rating for a Fire-isolated exit and fire control rooms requirement of minimum 4.5kW/m2 according to Table 2 of C1.10
Page 14