Movable Bridges

ISBN: 9781333751562 出版年：2016 页码：373 Otis Ellis Hovey Forgotten Books

For economy in the cost Of construction, Operation, and mainte nance, the time of Operation Should be made as long as feasible without inconvenience to traffic. The economic importance of allowing a rea sonable time for the operation of the bridge will be appreciated if it is remembered that the power required increases almost in inverse propor tion to the cube of the time for operation.