Composite Arch “Bridge-in-a-Backpack” System
Outline
1. What & How?
2. Design options
3. Overview of recent projects
4. Specific project details
5. Performance tested in Lab
6. AIT’s services “ How can we work
with you? ”
What is the “ Bridge-in-a-Backpack ” System
Carbon Fiber Composite + Concrete Arch Superstructure
“ A Hybrid bridge system combining benefits of
high-performance composites with durability
and cost savings of cast-in-place concrete”
Image Credit – NY Times/University of Maine
Projects Completed & Underway
Complete
(7)
Fitchburg
Belfast
Bradley
Status
Caribou
Under
Construction
(2)
Design &
Proposal
Bridge Location/Name
Description
Const.
Year
Pittsfield, ME – Neal Bridge
Pilot Project with University of Maine
2008
29.0’ Span
23 Arches
Anson, ME – McGee Bridge
Municipal Design/Build Project
2009
28.0’ Span
9 Arches
Bradley, ME – Jenkins Bridge
Maine Composite Bridge Initiative
2010
28.5’ Span
14 Arches
Auburn, ME – Jenkins Bridge
Maine Composite Bridge Initiative
2010
38.0’ Span
13 Arches
Belfast, ME – Perkins Bridge
Maine Composite Bridge Initiative
2010
48.0’ Span
16 Arches
Hermon, ME – Tom Frost Memorial Bridge
Snowmobile/Pedestrian Bridge
2010
44.5’ Span
3 Arches
Fitchburg, MA
MA DOT Accelerated Bridge Program
2011
37.5’ Span
15 Arches
Caribou, ME – Farm Access Overpass
Maine Composite Bridge Initiative
2011
54.0’ Span
22 Arches
Pinkham’s Grant, NH
State Bridge Program
2011
24.5’ Span
6 Arches
Bridges in design in ME, MI, proposals
submitted in 11 states
Key Stats
Design Options - Headwalls
Multiple options to meet the Engineering, Economic, and Aesthetic
requirements of the site
• FRP Panel Walls
–
–
–
–
MSE or Through-Tied Configurations
Compatible with skewed bridges
Lightweight, easy to install
Durable, and cost competitive
• Concrete – Precast or CIP
–
–
–
–
MSE, Through-Tied, or Gravity
PC Panel, PCMG Units, Cast-in-place
Versatile design options
More conventional aesthetic
Headwall Options for Test-Level 4 Design
• Wall-mounted Barriers
– Precast or CIP Gravity Wall
– Precast Panel MSE Walls
McGee Bridge Replacement Example – 28’ Span
CONSTRUCTION SEQUENCE
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Demo. existing steel bridge
Excavate for footings
Drill bedrock, form footings
Arch installation
Pour concrete footings
Install composite decking
Fill arches with concrete
Erect composite headwalls
Pour deck concrete
Backfill bridge, install geogrid
Finish grading
Guardrails and cleanup
12 Days Total Construction Time
Low Bid Against Steel, Concrete, Wood
A note on footings
Steel H-piles
Royal River Bridge, Auburn, ME
Spread Footings
Perkins Bridge, Belfast, ME
Caribou Connector Bridge
Key Metrics
• Span – 54’-2”
• Rise – 12’-0½”
• Rise/Span – 22%
• Skew – 30 deg
• 22 – 15” Diameter Arches
• Arch weight ~300lb each
• Precast Concrete MSE
Headwalls/Wingwalls
Caribou Connector Bridge
Caribou Connector Bridge
How we got here- “Bridges to the future, now”
Maine’s Composites Initiative
• Six bridges in two years
• Variety of bridges to best gage
how system fit’s into Maine’s
bridge inventory
• 28-55’ spans
• Stream/road crossing
• Foundation types
• Headwall designs
Also being used in:
• Massachusetts
• New Hampshire
• Michigan
• Proposals in 11 states & 3
countries outside the US
FHWA’s Public Interest Finding:
• Allows for federal funding on projects where aspects deviate from typical
requirements, when in the interest of the public. i.e. in cases of “Cost-Effectiveness
or System Integrity…” [FHWA]
• Simple application process – approval from FHWA in as little as 2 days
[FHWA Contract Administration Core Curriculum Manual, Section 3.C,
http://www.fhwa.dot.gov/construction/cqit/findings.cfm]
Design-Build - Detail-Build - Value Engineering
Performance Testing: Arch Testing
Load-Deflection Response of Concrete-Filled FRP Tubular Arch
80
70
Applied Load (kip)
60
50
40
30
HL-93 Design Load Equivalent
20
10
0
0
1
2
3
4
5
6
7
Vertical Deflection at Crown (in)
Initial Static Test to Failure
Post-Failure Behavior
8
9
10
National Recognition for Bridge-in-a-Backpack
AASHTO TIG - 2011 Focus Technology
2010 Award for Composites Excellence
Most Creative Application
American Society of Civil Engineers
2011 Charles Pankow Award for
Innovation
Engineering Excellence Award
Royal River Bridge, Auburn, ME
(Along with Maine DOT & Kleinfelder |SEA)
Product featured in:
Engineering News Record,
The NY Times,
Concrete International,
Popular Science,
Popular Mechanics,
The Boston Globe
Summary and Quick Facts on CFFT Arch Bridges
Innovative Product Application
• Rapid fabrication our facility or option to
fabricate at/near jobsite
• Hybrid composite-concrete system
improves material performance
• Steel free superstructure
• Reduced carbon footprint
Performance Tested
• Design/tested to exceed AASHTO load
requirements
• Superior redundancy – safe system
• Corrosion resistant materials
• Field load testing indicates even greater
levels of safety
Cost Effective and Fast Installation
• Light weight product– reduces equipment
transportation needs
• Erected with a small crew, no skilled labor
• Performs up to 2x lifespan of conventional
materials
• Accelerated Bridge Construction
• Rapid design, fabrication, and delivery
What can AIT do for you?
• Structural Design
– AIT’s engineers design the composite arch bridge superstructure
– AIT can design the bridge substructure, internally or with consultants
– Optimization to maximize efficiency of structure
• Supply
– AIT supplies a complete engineered bridge system
– Packages: arches/decking, modular FRP headwalls
– Installation Oversight
Daniel Bannon
Structural Engineer
Jonathan Kenerson
Manufacturing Manager