Presentation Transcript
Wooden Bridges for Today: Wooden Bridges for Today
New Hampshire’s Transportation Heritage: New Hampshire’s Transportation Heritage Swift River Bridge,
Albany, NH Recently refurbished by
NH Department of Transportation
New Hampshire’s Transportation Heritage: New Hampshire’s Transportation Heritage Newport, NH
Railroad Bridge (Carol Harootian, photo)
NH Bridges in Trouble: NH Bridges in Trouble Concrete deteriorates
Steel rusts
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
NH Bridges in Trouble
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
NH Bridges in Trouble
The Usual Route : The Usual Route
Typical reinforced concrete and steel bridge in need of total replacement
A Road Less Traveled : A Road Less Traveled New Boston, NH
Lyndeborough Road
Completed August 2000
Installed by New Boston Highway Crew
A Road Less Traveled : A Road Less Traveled
Completed 1993
New Boston, NH
Depot Street
Near Town Center
A Road Less Traveled : A Road Less Traveled Designed and constructed by Arnold M. Graton Associates, Inc. Newport, NH
Corbin Bridge, 1994
A Road Less Traveled : 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
A Road Less Traveled : 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
A Road Less Traveled : A Road Less Traveled Gilford, NH
Tannery Hill Bridge
Pedestrian bridge
Built in early 1990’s by a volunteer crew
New Technology Helps a Traditional Material : New Technology Helps a Traditional Material Types of Bridges:
Glue lamination
Nail lamination or doweled
Stress lamination
New Technology Helps a Traditional Material : New Technology Helps a Traditional Material EPA-approved
Preservation & Protection Options
Creosote
Pentachlorophenal
Copper naphthenate
Chromated copper arsenate
Glue Laminated Bridge: Glue Laminated Bridge
1990 –Glu-laminated bridge in New Hampton, NH. Bridge from Laminated Concepts, Elmira, NY.
Glue Laminated Bridge: Glue Laminated Bridge
New Boston Lyndeborough Road Bridge, August 2000 Modern Glu-laminated bridge by Laminated Concepts, Inc.
Nail Laminated Bridge: Nail Laminated Bridge Jefferson Notch Road, 1990
Wheeler Bridge Company
Nail Laminated Bridge: Nail Laminated Bridge Bartlett, NH
1990 Agent for town was Bergeron Engineering, North Conway, NH
Stress Laminated Bridge: Stress Laminated Bridge Chichester, NH
1990
Constructed of southern yellow pine.
Treated with Pentachlorophenal.
Stress Laminated Bridge: Stress Laminated Bridge Chichester, NH, 1990
Constructed of southern yellow pine.
Treated with Pentachlorophenal
Stressing rods compress individual planks together with pressure
Stress Laminated Bridge: Stress Laminated Bridge North Weare, NH
1991
Constructed with local wood material Designed and constructed by Kent Ruesswick of Canterbury, NH
Other Wooden Transportation Structures: 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
Slide24: Why wooden bridges? The public
demands a safe and efficient transportation system
Traffic increases through ‘80’s and ‘90’s
Engineers and community leaders
must find new ways to upgrade bridges with fewer resources
Slide25: Why wooden bridges? Hundreds of bridges in NH need replacing
Aesthetics & appearance
Ease of construction
Slide26: Why wooden bridges? Performance
When properly treated
Cost
Cost competitive, especially when life cycle and maintenance costs are included.
Slide27: 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
Slide28: Why wooden bridges?
Why not?