Design of Movable Bridges

When constructing bridges over navigable waters of other waterways, it is required that free navigation to be ensured with a view to future development. These requirements are met by providing adequate bridge clearances which depend on the class of the river. Construction of a bridge with a movable span is a possible solution of the task related to the problem of crossing a waterway. The height of other spans of the bridge may only slightly exceed the calculated navigation horizon level. In some cases, this problem may be solved by construction of a subfluvial tunnel. When constructing the movable bridges, a certain technological sequence in spanning the bridge must be observed in order to ensure uninterrupted navigation: a span structure should be installed after the movable span has been completed or the movable span should be installed during an inter-navigation period.