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BRIDGES Engineer-It Class Summer 2004 History Primitive Peoples: Logs Slabs of Rocks Intertwined Vines or Ropes Roman Empire—First Great Bridge Builders Timber Truss Bridges Masonry Arch Bridges Europeans Followed HRE Until Iron and Steel Use Nineteenth Century— Modern Long Bridges
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BRIDGES Engineer-It Class Summer 2004
History • Primitive Peoples: • Logs • Slabs of Rocks • Intertwined Vines or Ropes • Roman Empire—First Great Bridge Builders • Timber Truss Bridges • Masonry Arch Bridges • Europeans • Followed HRE Until Iron and Steel Use • Nineteenth Century— • Modern Long Bridges • Moveable Bridges
View under RainbowBridge, a massive sandstone bridge in Natural Bridges National Monument, Utah, includes a dried up streambed. "RainbowBridge, Utah."
LOG BRIDGE Members of a Denver and Salt Lake Railroad Company (D&SL) survey crew pose on a logbridge over the Colorado River in Gore Canyon (Grand County), Colorado.
View of a settlement in (probably) Utah; shows a logbridge, a stream, and houses. People sit on a porch; a United States flag waves from a pole.
U.S. Army soldiers from the Ohio Engineers, building a small log bridge over a ditch, at Fort Sheridan, Illinois
LOG BRIDGE View of hot springs site enclosed by stone and wooden frame buildings, Hot Sulphur Springs, CO
COVEREDBRIDGE • Bridges. Old covered bridge, Jackson River, Va.
CONSTRUCTION • Must carry own weight and weight of traffic • Must withstand force of high winds • Must consider effects of contraction and/or • Expansion due to temperature changes • Most common materials • Wood—temporary • Steel—for long, strong spans • Reinforced concrete—attractive designs but difficult to work with on large bridges • Prestressed concrete—stronger than reinforced, cheaper than steel
TYPES OF BRIDGES • Fixed • Moveable • Other
FIXED • Beam or Girder • Two parallel beams w/ flooring supported by piers • Span can be supported by trestle • Used for hwy over/underpasses or small stream crossings • Example—Covered Bridge
Cars on a suspension bridge over a river, possibly in Colorado.
FIXED • Truss • Beam bridge strengthed by trusses (structural spts joined to form triangles with tie rods) • Lighter than ordinary beam sections of equal length • Useful for longer bridges
View west of an iron trussbridge crossing the Colorado River on the Denver and Rio Grande Railroad Montrose line at Grand Junction, Colorado; people and horses are on a sand bar.
View of the bridge crossing the White River at Meeker, CO on the Mesa and Flag Creek road.
White Water Creek Bridge, Spanning White Water Creek, Bernard vicinity, Dubuque County, IA
Truss Bridge View of a trestle bridge that crosses Arastra Gulch near Silverton (San Juan County), Colorado.
Jefferson Barracks BridgeLocation: Mississippi River, Jefferson Barracks, Missouri
FAI 24 Bridge Over the Ohio RiverPaducah, Kentucky www.modjeski.com/projects/ servproj/paducah.htm
FIXED • Arch • One or more arches • Masonry, reinforced concrete or steel • Roadway on toop of arches or suspended by cables • Spans can be longer than beam or truss
Old stone bridge at Bull Run Battlefield. Manassas, Virginia.