Stoplog consists of several sets of horizontal beams/logs stacked vertically. For narrow openings, the logs span between support slots at the ends of the openings. For wide openings, intermediate removable support posts may be required. They are prevalent in the past because of its low establishment cost, simple erection and easy operation.
However, there are also several drawbacks of this closure system. Since it requires a long lead time to mobilize workers and equipment for installation, it needs an accurate long-range weather forecast to allow for the long lead time. The situation is even worse for wide stoplogs which requires special lifting equipment for installation of intermediate support posts. When compared with time required to close sluice gates, the installation time of stoplogs is much longer. Moreover, a storage building has to be provided to prevent material loss by theft and damage by vandalism.
This question is taken from book named – A Closer Look at Prevailing Civil Engineering Practice – What, Why and How by Vincent T. H. CHU.
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