Wooden Bridges for Today

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Wooden Bridges for Today

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New Hampshires Transportation Heritage
Swift River Bridge, Albany, NH
Recently refurbished by NH Department of
Transportation
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New Hampshires Transportation Heritage
Newport, NH Railroad Bridge
(Carol Harootian, photo)
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NH Bridges in Trouble
Concrete deteriorates Steel rusts
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NH Bridges in Trouble

• 10 years ago over 50 of the bridges in NH were
  listed as being structurally deficient,
  functionally obsolete, or red listed.
• State of New Hampshire Ten Year Transportation
  Improvement Program for 2001-2010, August 1999

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NH Bridges in Trouble

• Of 1,959 state owned bridges, 311 red listed or
  structurally deficient or obsolete.
• Of 1,556 non-state owned bridges, 653 either red
  listed or structurally deficient or obsolete.
• State of New Hampshire Ten Year Transportation
  Improvement Program for 2001-2010, August 1999

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The Usual Route

• Typical reinforced concrete and steel bridge in
  need of total replacement

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A Road Less Traveled

• New Boston, NH
• Lyndeborough Road
• Completed August 2000
• Installed by New Boston Highway Crew

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A Road Less Traveled
New Boston, NH Depot Street Near Town Center

• Completed 1993

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A Road Less Traveled
Newport, NH Corbin Bridge, 1994

• Designed and constructed by Arnold M. Graton
  Associates, Inc.

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A Road Less Traveled

• Plymouth, NH
• Smith Bridge

Strongest covered bridge in the world 176-foot
span Under construction, 2001
Designed and constructed by Stan Graton II, 3-G
Construction, Ashland, NH
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A Road Less Traveled

• Plymouth, NH Smith Bridge

250,000 board feet of timber First covered bridge
using glue lamination technology Timbers supplied
by Unadilla Laminated Products, NY
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A Road Less Traveled

• Gilford, NH
• Tannery Hill Bridge
• Pedestrian bridge
• Built in early 1990s by a volunteer crew

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New Technology Helps a Traditional Material

• Types of Bridges
• Glue lamination
• Nail lamination or doweled
• Stress lamination

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New Technology Helps a Traditional Material

• EPA-approved
• Preservation Protection Options
• Creosote
• Pentachlorophenal
• Copper naphthenate
• Chromated copper arsenate

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Glue Laminated Bridge
1990 Glu-laminated bridge in New Hampton, NH.
Bridge from Laminated Concepts, Elmira, NY.
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Glue Laminated Bridge
New Boston Lyndeborough Road Bridge, August 2000
Modern Glu-laminated bridge by Laminated
Concepts, Inc.
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Nail Laminated Bridge

• Jefferson Notch Road, 1990
• Wheeler Bridge Company

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Nail Laminated Bridge

• Bartlett, NH
• 1990

Agent for town was Bergeron Engineering, North
Conway, NH
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Stress Laminated Bridge
Chichester, NH 1990 Constructed of southern
yellow pine. Treated with Pentachlorophenal.
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Stress Laminated Bridge
Chichester, NH, 1990 Constructed of
southern yellow pine. Treated with
Pentachlorophenal Stressing rods compress
individual planks together with pressure
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Stress Laminated Bridge
North Weare, NH 1991 Constructed with local
wood material
Designed and constructed by Kent Ruesswick of
Canterbury, NH
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Other Wooden Transportation Structures
Timber bin retaining wall, Campton, NH Bin wall
system is also suitable for bridge abutments
Constructed with eastern hemlock, commercially
treated with chromated copper arsenate
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Why wooden bridges?
The public demands a safe and efficient transpor
tation system Traffic increases through 80s
and 90s Engineers and community leaders must
find new ways to upgrade bridges with fewer
resources
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Why wooden bridges?
Hundreds of bridges in NH need replacing Aestheti
cs appearance Ease of construction
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Why wooden bridges?
Performance When properly treated Cost Cost
competitive, especially when life cycle and
maintenance costs are included.
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Why wooden bridges?
Maintenance Long life cycle with fewer
maintenance requirements Not susceptible to salt
corrosion Potential new markets for NH
wood Potential new secondary manufacturing
industry for NH
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Why wooden bridges?

Why not?