Steel dam, academically known as bottom-hinge flap gate, is a new type of hydraulic structure suitable for river regulation. It mainly consists of the gate body, drive shaft, hydraulic system, and civil engineering structure. In July 2008, the Chinese Society for Electrical Engineering and the China Society for Hydropower Engineering held a technical appraisal meeting in Hangzhou, confirming its bidirectional water retention, stepless water regulation, and hidden flood control functions. Key technologies include ultra-long drive shaft support and hydraulic synchronous control, first applied in the Shanghai Suzhou Creek Estuary Sluice Project.
This gate is suitable for river channels 10-100 meters wide with water level differences of 1-7 meters. Its main structure is divided into movable parts, embedded fixed parts, and hoisting equipment. Based on morphology, it can be classified into types such as plane gates and radial gates. Made of steel materials, it operates faster than rubber dams and offers superior aging resistance. By regulating water levels, it can create artificial waterfall landscapes. Technologically, the hydraulic drive system enables 0-90 degree gate operation. Combined with cast steel hinge seats and self-lubricating bearings, durability is enhanced. Some improved models use crank arm structures to reduce bottom shaft torque, supporting single-span applications exceeding 60 meters.