Eagle River Timber Bridge

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Eagle River Timber Bridge
Eagle River Timber Bridge.JPG
Other name(s) Eagle River Bridge
Carries Automobiles
Crosses Eagle River
Locale Eagle River, Michigan
ID number 42142021000B050[1]
Material Wood and steel
Total length 152 feet (46 m)[2]
Width 35 feet (11 m)[1]
Height 50 feet (15 m)[2]
Longest span 79 feet (24 m)[a]
Construction begin 1988
Opened 1990
Daily traffic 849 (in 2007)[1]
Preceded by Lake Shore Drive Bridge
Coordinates 47°24′45″N 88°17′49″W / 47.4125°N 88.297°W / 47.4125; -88.297Coordinates: 47°24′45″N 88°17′49″W / 47.4125°N 88.297°W / 47.4125; -88.297

The Eagle River Timber Bridge is a wooden arch bridge carrying highway M-26 over the Eagle River in Eagle River, Michigan. It opened in 1990 as a replacement for the historic Lake Shore Drive Bridge that runs parallel to it.

History[edit]

Construction on the bridge began in 1988.[1][3] The quantity of wood used was equivalent to three or four average-size houses.[2] The bridge opened for highway M-26 traffic in 1990, at which point the neighboring Lake Shore Drive Bridge was restricted to pedestrian use.[4]

On August 26, 1992, the bridge was entered into the 1992 Timber Bridge Design and Construction Award Competition.[5] It was awarded first place in the "Long Span Vehicular Bridges" category.[6]

Design[edit]

The bridge is primarily constructed of wood joined together with steel connectors. It is supported by two adjacent arches: one spans 74 feet (23 m) and the other 79 feet (24 m). Each arch is constructed from two curved sections joined together by a crown hinge. The road deck is made of wood and covered by an asphalt road surface.[2]

All the timber members were glue-laminated and pressure treated with preservative pentachlorophenol in oil. Any wooden portions which were cut or drilled also had an application of copper naphthenate. The steel pins in the hinges at the crown and abutments were chrome plated to reduce friction and prevent corrosion. All other steel was hot-dipped galvanized, given a tie-coat, and covered by epoxy and a top coat of brown urethane, a system designed to provide thirty years of protection.[2]

Bridge maintenance consists of reapplying preservative to all wooden members and any necessary tightening of bolts.[2]

Notes[edit]

  1. ^ One arch spans 74 feet (23 m), the other spans 79 feet (24 m).[2]

References[edit]

  1. ^ a b c d Conro, Steve (October 9, 2011). "Eagle River Bridge". BridgeHunter.com: Historic Bridges of the US. Retrieved January 1, 2012. 
  2. ^ a b c d e f g Ness, Brian (June 1991). "The Eagle River Timber Bridge". Mates (54). Retrieved January 1, 2012. 
  3. ^ Staff (October 1, 2011) (PDF). Highway Bridge Report (Report). Michigan Department of Transportation. p. 61. http://mi.gov/documents/mdot/MDOT_HighwayBridgeReport_July31-10_CountyB_335026_7.pdf. Retrieved January 1, 2012.
  4. ^ Staff. "Lake Shore Drive Bridge". State Historic Preservation Office. Michigan State Housing Development Authority. Retrieved December 31, 2011. 
  5. ^ Bukoski, Glenn (November 1992). "1992 Member Bridge Award Competition". Mates (69). Retrieved January 1, 2012. 
  6. ^ "Timber Bridge Design Awards Announce" (PDF). Crossings. Timber Bridge Information Resource Center. February 1994. p. 2. Retrieved January 2, 2012. 

Further reading[edit]