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On Wednesday March 9, 2016, North Dakota State Geologist Ed Murphy will illustrate some of the ways geology might influence, shape, or even dictate an area’s history. His principal example will be the history of the railroad bridge which crosses the Missouri River between Bismarck and Mandan.
Mr. Murphy’s power-point illustrated discussion will cover a wide range of interrelated factors including the following:
The Bismarck Railroad Bridge was completed in 1882. Although the original bridge spans were replaced in 1905, the original granite piers remain, making them some of the oldest existing structures in the Bismarck-Mandan area. Innovative techniques were used in both bridge design and construction. The bridge’s engineer had the Missouri River narrowed at the bridge site to control the bridge length, forever changing the Missouri River in the Bismarck-Mandan area.
Almost as soon as the bridge was completed, the east pier of the railroad bridge began sliding towards the river. For more than 60 years, the Northern Pacific Railway Company tried to stabilize the pier by various geotechnical methods including sliding the pier back into place, digging a drainage tunnel, and constructing a cofferdam around the pier. Finally, in 1951 the renowned civil engineer Ralph B. Peck was hired to stabilize the pier. At the same time the track on the east side of the bridge was straightened to make it easier for locomotives to negotiate the curve. Although Peck’s solution slowed pier movement it continues to move today, albeit at a slower pace.
Ed Murphy has both a Bachelor’s and a Master’s Degree of Science in Geology from the University of North Dakota. He has worked as a geologist for the North Dakota Geological Survey, Department of Mineral Resources, for 36 years, the last 12 as state geologist. He has published hundreds of maps and reports on various aspects of Williston Basin sedimentology, stratigraphy, and hydrogeology including the environmental impacts oil and gas exploration and development, municipal waste disposal, geohazard inventories, uranium, the Cretaceous/Tertiary Boundary, and economic coal deposits.
The public is invited. Refreshments will be served. Reservations are not required.