Some trends in the development of gate construction abroad

Abstract

1. Even greater attention is being devoted abroad to an increase of reliability of outlet works and gates as one of the virtually important elements of every dam. For this purpose, types of gates, grooves, and mechanisms already checked in practice are, as a rule, used on newly constructed dams [1, 11, 14], and the main efforts of designers are aimed at improving their designs and layouts on structures [1, 2, 5]; the power supply of the mechanical equipment of important outlets, as a rule, comes from two “alternative” sources, e.g., from the central power supply network plus a standby supply from a local diesel electric plant [6]; redundancy of the most important gate components and mechanisms (electric motors, pumps of the oil-pressure system, balance carriages, etc.) is provided for everywhere [3]; technical innovations find use only after comprehensive model and prototype investigations (see, e.g., the proceedings of the 11th and 13th Congresses on large dams). 2. As a consequence of Sec. 1, a trend toward a substantial reduction of the number of types of gates being used is observed everywhere [2, 4]. Serious attention is being devoted to methods of preventing cavitation and vibration [13–18]. 3. An individual (for each gate) drive (as a rule, electrohydraulic), having a number of operational advantages compared with cranes (high efficiency of gate operation, possibility of automatic or remote control of the gates, etc.), is gaining greater popularity. 4. Reliability factors are taken into account also in the operating instructions [6, 7], which, e.g., stipulate the need for periodic testing of the mechanical equipment (especially before passage of a flood), etc. 5. One of the current trends is the fact that many specialists [1, 11, 14, 15] are presently taking a more cautious approach to the use of gates with high design parameters (area of the outlet being closed and head), considering that failure of a large gate (especially during passage of a flood) substantially reduces the discharge capacity (and, consequently, the reliability) of the dam.