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 Cotter Bridge - Cotter, Arkansas Posted by:  iconions
N 36° 16.035 W 092° 32.676
15S E 540905 N 4013687
The Cotter Bridge, also known as the R.M. Ruthven Bridge and the White River Concrete Arch Bridge, carries the business route of U.S. Route 62 across the White River west of the city of Cotter in Baxter County, Arkansas.
Waymark Code: WMWB0P
Location: Arkansas, United States
Date Posted: 08/05/2017
Views: 2
The Cotter Bridge, also known as the R.M. Ruthven Bridge and the White River Concrete Arch Bridge, carries U.S. Route 62 Business across the White River west of the city of Cotter in Baxter County, Arkansas. Upon completion, the bridge allowed access to a part of the Ozarks previously undiscovered by motorists. Constructed in 1930, it is the only bridge built by the Marsh Engineering Company of Des Moines, Iowa in the state of Arkansas.
Cotter was established in 1905 as a railroad town. The area used a ferry system to cross the vast White River, with the nearest road crossing being 100 miles (160 km) north in Branson, Missouri. The river would rise and fall very quickly, which caused the ferry to be very unreliable. Baxter County residents wanted a bridge, but were opposed to the use of toll to pay for it. Once it became apparent that the federal road U.S. Route 62 would replace Arkansas Highway 12 through the area, bridge interest reached a peak. The federal road would bring an economic boom to the tourist-themed Ozarks that had not been developed, but the funding was still not available due to Arkansas' lack of a central road authority. The state approved the use of toll bridges in 1927, as long as they became free upon payment of the debt. Judge R.M. Ruthven concealed a damning feasibility report from the Highway Commission, which would've resulted in the bridge being built elsewhere. Twenty years later, he allegedly mailed the report to the Commission anyway. President Calvin Coolidge signed the bridge into construction on May 2, 1928, and upon approval by the War Department, the bridge was contracted to James Barney Marsh.
The bridge was contracted to a company from Nashville, Tennessee in 1929, and they used as much local labor as possible. A cable system was used to avoid problems with the mercurial river. The company installed lights, and worked around the clock in order to prevent delays. The bridge was dedicated on November 11, 1930, but for months the residents of Cotter continued to use the free ferry system rather than pay the toll. The Highway Department even had to threaten the community with retracted funding unless the residents began using the bridge.
The Cotter Bridge was once proposed to be replaced, but area residents protested, and instead a new bridge was built north of the area. U.S. Route 62 now runs on the new bridge, where the former alignment of US 62 exists today as U.S. Route 62 Business through downtown Cotter. It was Arkansas' first National Historic Civil Engineering Landmark. In 1990, it was added to the National Register of Historic Places as structure #90000518.
- Wikipedia Entry
Located in the Ozark Mountains of north-central Arkansas, the Cotter Bridge crosses the White River in the White River Valley immediately west of Cotter on U.S. Highway 62. This structure has been identified as a Marsh Rainbow Arch bridge and is constructed of steel and reinforced concrete. Its main spans and approach spans are unaltered and in good condition.
ELABORATION
The Cotter Bridge is a five-span. 1,850-foot Marsh rainbow arch bridge, comprised of five 216-foot concrete arches, an arch viaduct of 132 feet, and 638 feet of deck girder approaches, with a 24-foot-wide roadway. The viaduct is 26 feet from the east abutment and is separated from the five main arches by 141 feet of approach spans. Following the Marsh arch design, concrete was applied over the steel frame, maintaining the basic outine of the structural elements.
Each arch, four angles laced with angles, increases in depth from the crown toward the spring line. Eighteen panels are formed in each arch by hangers and spandrel columns, which are made from four angles with double lacing, resembling an I in cross-section. The hangers, as the name implies, hang from the arch down to the road deck, and the spandrel columns rise from the arch up to the deck. The roadway crosses the arch at the third panel point from either end. Pairs of hangers suspend, and pairs of columns support, the floor girders, which are made from angles and reinforced with steel bars. A two-foot-tall concrete balustrade spans the distance between the hangers.
The two lines of arches are braced laterally above and below the deck. Three lateral struts cross the road at the crown, The struts, four angles joined by double lacing, rise at a five-degree angle from the two arch lines, to meet over the center of the road. Underneath the road, a beam connects the two arch lines near
the springline and angles with lacing cross just above the beam.
The concrete formwork was laid horizontally for most of the bridge. The exception was the placement of the forms along the curve of the arch. Along the arch, the concrete was poured in a sequence to induce the least amount of stress in the steel from the added dead load of the concrete. First the concrete was poured at the haunches and on either side of the crown. The crown and mid-height of the arch were next, and lastly the rest of the arch was covered. Two-inch-thick lumber was used to create a panel along the outer face of each arch. The girders were poured monolithically with the arch. The floor deck was poured before the hangers were covered so that the hangers were carrying the full dead load. Having the steel component of the hangers almost
fully extended reduced the amount of cracking of the concrete cover when tension forces from live load were applied.
- National Register Application Visit Instructions:
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