The other lost bridge was the Four Bears Bridge at the City of Elbowood, which is located about 40 miles down river of the New Town area. This bridge opened on June 14, 1934 as the fourth bridge built across the Missouri River in North Dakota. This bridge was different from most of the through truss bridges that had been built up to that time. The War Department requested wider clearance between bridge piers than what the Pennsylvania style through truss bridge spans were suitable for. The new design was a single huge truss that spanned across four bridge piers as one truss. This truss was 1,425 feet long. It also had a small 190 foot long through truss approach span.
The building of the Garrison Dam spelled doom for these two bridges. Buy the time the dam was finished and Lake Sakakawea filled, these bridges would be flooded under between a dozen and a hundred feet of water. The Verendrye Bridge was simply demolished. The Four Bears Bridge, however, had the potential for reused. The fact that it needed fewer piers than the older style humpback truss bridges was a key factor since piers would be very expensive in the deep waters of Lake Sakakawea.
A new design was completed for a bridge to be located at New Town, a new city established on the Fort Berthold Indian Reservation to house folks who were displaced when dozens of other smaller towns were flooded up by the Garrison Dam, including Elbowood and Sanish. Engineers would build four new piers at the center of the lake. The truss section of the Four Bears Bridge would be floated 40 miles up stream and installed on new piers near New Town. Long sections of top deck truss sections were installed on both ends of the truss to connect the truss section to the bluffs on each side of the lake. The project was completed in 1955. Work had to wait for the Garrison Dam to be closed off and the lake started to fill in order for there to be the water depth needed to move the truss structure. The result was a 4,483 foot long bridge with a 1,425 foot central truss structure. It was 20 feet wide, and stood 44 feet above the lake when the lake was at its nominal level of 1,838 feet of elevation.
The relocated Four Bears Bridge started to show its age in the 1990s as traffic increased due to the nearby casino, and ever heavier truck traffic took its toll on the bridge. As a result, the state decided to build a new bridge. Construction on the new Four Bears Bridge started in April 2003. The bridge was to be a precast segmented concrete box girder that was held together by post-tensioned cables that run though the bridge structure. The bridge required 482 of these precast segments, to be used to build 13 spans of 316 feet each, and 2 spans of 196 feet each, for an overall bridge length of 4,500 feet.
The piers are interesting on the new bridge. Ice is a big factor, and some extreme forces could potentially hit the bridge if the ice on the lake goes out during high water in the spring. To protect against these forces, cone-shaped concrete piers 39 feet in diameter were built. The side walls of the cones are set at 65-degrees, which will deflect ice upwards, reducing the stress on the piers. The piers are each supported by 13 or 14 pilings driving into the riverbed between 90 and 160 feet. The piers range from 45 feet to 73 feet, and the bridge ranges in thickness from 8 feet to 17 feet, placing the roadway as high as 90 feet above the water.
The Four Bears Bridge are named after two Indian chiefs, both of whom are named Chief Four Bears. One is from the Mandan Tribe, the other from the Hidatsa Tribe. The bridge is decorated with a series of 10-foot diameter medallions that represent the heritage of the three tribes that live on the reservation (Arikara, Hidatsa, and Mandan).
The old Four Bears Bridge was removed after the new bridge opened. Two small sections of the bridge were preserved, along with sections of the old bridge piers, and they are set up in a display on the west end of the new bridge in the parking lot of the casino. The two sections can be seen in the bottom two photos. Note that these photos were taken a bit after sunset, so they are a bit dark.
