Gates/Bulkheads - Revision history

Mpollei@gfnet.com at 21:05, 18 July 2023

2023-07-18T21:05:26Z

← Older revision		Revision as of 21:05, 18 July 2023
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	\| [[Image:tainter1.jpg\|350px\|x350px\|link=On-Demand Webinar: Introduction to Spillway Gates]]		\| [[Image:tainter1.jpg\|350px\|x350px\|link=On-Demand Webinar: Introduction to Spillway Gates]]
	\|-		\|-
	\|style="text-align:center; font-size:90%;"\| Learn more about gates from this [[On-Demand Webinar: Introduction to Spillway Gates\|On-Demand Webinar]]		\|style="text-align:center; font-size:90%;"\| Image Source: [https://commons.wikimedia.org/wiki/File:Rapel_Dam_Tainter_Gate_2009.jpg Wikimedia]
			Learn more about gates from this [[On-Demand Webinar: Introduction to Spillway Gates\|On-Demand Webinar]]
	\|}		\|}

Mpollei@gfnet.com at 16:47, 11 July 2023

2023-07-11T16:47:16Z

← Older revision		Revision as of 16:47, 11 July 2023
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	<noautolinks>==Best Practices Resources==</noautolinks>		<noautolinks>==Best Practices Resources==</noautolinks>
	{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations)\|Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), USBR~~, 2022~~]]		{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations)\|Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), USBR]]
	{{Document Icon}} [[Design Standards No. 6: Hydraulic and Mechanical Equipment (Ch. 6: Bulkhead Gates and Stoplogs) \| Design Standards No. 6: Hydraulic and Mechanical Equipment (Ch. 6: Bulkhead Gates and Stoplogs), USBR~~, 2018~~]]		{{Document Icon}} [[Design Standards No. 6: Hydraulic and Mechanical Equipment (Ch. 6: Bulkhead Gates and Stoplogs) \| Design Standards No. 6: Hydraulic and Mechanical Equipment (Ch. 6: Bulkhead Gates and Stoplogs), USBR]]
	{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE~~, 1980~~]]		{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE]]

	==Trainings==		==Trainings==

Rmanwaring at 20:48, 19 December 2022

2022-12-19T20:48:16Z

← Older revision		Revision as of 20:48, 19 December 2022
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	''' ''Gate Passageway Requirements:'' ''' "Normally, when reservoir outlet flows require regulation, the following are provided:		''' ''Gate Passageway Requirements:'' ''' "Normally, when reservoir outlet flows require regulation, the following are provided:
	*Two or more gate passages such that if one passage is inoperative, a reasonable flow regulation as pertains to project purposes is obtained.		*Two or more gate passages such that if one passage is inoperative, a reasonable [[Flow Regulation\|flow regulation]] as pertains to project purposes is obtained.
	*Emergency gate provision (tandem or transferable) for each service gate passage so that if a service gate is inoperative in any position, closure of the gate passage can be made with the emergency gate for any pool level.		*Emergency gate provision (tandem or transferable) for each service gate passage so that if a service gate is inoperative in any position, closure of the gate passage can be made with the emergency gate for any pool level.

	*Bulkhead provisions for each gate passage for inspection and maintenance of the service and emergency gates. At a minimum, the bulkheads must be capable of being installed at the lowest pool elevation that has a reasonable frequency and length of occurrence sufficient for inspection and repair purposes." <ref name="EM 1110-2-1602">[[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| EM 1110-2-1602 ~~Hydraulic Design of Reservoir Outlet Works~~, USACE, 1980]]</ref>		*Bulkhead provisions for each gate passage for inspection and maintenance of the service and emergency gates. At a minimum, the bulkheads must be capable of being installed at the lowest pool elevation that has a reasonable frequency and length of occurrence sufficient for inspection and repair purposes." <ref name="EM 1110-2-1602">[[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE, 1980]]</ref>

	''' ''Gate Slots:'' ''' "The guide slots of rectangular gates produce a discontinuity in sidewalls which may cause [[cavitation]], unless specially designed. It has been common practice to use metal-liner plates downstream from the gate slots to protect the concrete from the erosive action of cavitation." <ref name="EM 1110-2-1602"/>		''' ''Gate Slots:'' ''' "The guide slots of rectangular gates produce a discontinuity in sidewalls which may cause [[cavitation]], unless specially designed. It has been common practice to use metal-liner plates downstream from the gate slots to protect the concrete from the erosive action of cavitation." <ref name="EM 1110-2-1602"/>

Rmanwaring: /* Best Practices Resources */

2022-12-13T23:38:00Z

Best Practices Resources

← Older revision		Revision as of 23:38, 13 December 2022
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	As a result of varying [[Purposes of Dams\|purposes of dams]], as well as the unique site conditions that accompany each particular dam, there are a wide variety of types of gates or bulkheads. Some of the most common types include vertical lift gates, roller gates, hinged or flap gates, or tainter or radial gates. In the design process of a gated spillway system, it is necessary to weigh the advantages and disadvantages of using each type of gates in the particular operating conditions expected at the dam.		As a result of varying [[Purposes of Dams\|purposes of dams]], as well as the unique site conditions that accompany each particular dam, there are a wide variety of types of gates or bulkheads. Some of the most common types include vertical lift gates, roller gates, hinged or flap gates, or tainter or radial gates. In the design process of a gated spillway system, it is necessary to weigh the advantages and disadvantages of using each type of gates in the particular operating conditions expected at the dam.

	“Gated [[spillways]] include drop inlet, free overfall, ogee crest, side-channel and bathtub, tunnel inlet, various shaped weirs, and orifice. These control structures are associated with regulated releases and suited for service, auxiliary, and [[Emergency Spillways\|emergency spillways]]. The most frequently used gates include radial gates, drum gates, wheel-mounted gates, and crest gates. Examples of these gated spillways include:		“Gated [[spillways]] include drop inlet, free overfall, ogee crest, side-channel and bathtub, tunnel inlet, various shaped [[weirs]], and orifice. These control structures are associated with regulated releases and suited for service, auxiliary, and [[Emergency Spillways\|emergency spillways]]. The most frequently used gates include radial gates, drum gates, wheel-mounted gates, and crest gates. Examples of these gated spillways include:

	*'' '''Gated drop inlet spillway:''' '' This type of control structure is mostly associated with a service spillway with radial gates. An example of a gated drop inlet spillway is Reclamation’s Gibson Dam (concrete). Other examples include the service spillways with ring gates at Reclamation’s Hungry Horse and Owyhee Dams (both concrete).		*'' '''Gated drop inlet spillway:''' '' This type of control structure is mostly associated with a service spillway with radial gates. An example of a gated drop inlet spillway is Reclamation’s Gibson Dam (concrete). Other examples include the service spillways with ring gates at Reclamation’s Hungry Horse and Owyhee Dams (both concrete).
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	<br/>		<br/>

	==Best Practices Resources==		<noautolinks>==Best Practices Resources==</noautolinks>
	{{Document Icon}}[[~~Hydraulic~~ Design ~~of Reservoir~~ Outlet Works ~~(EM 1110-2-1602~~)\|~~Hydraulic~~ Design ~~of Reservoir~~ Outlet Works ~~(EM 1110-2-1602) (U.S. Army Corps of Engineers~~)]]		{{Document Icon}} [[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations)\|Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), USBR, 2022]]
	{{Document Icon}}[[Design Standards No. 6: Hydraulic and Mechanical Equipment (Ch. 6: Bulkhead Gates and Stoplogs)\|Design Standards No. 6: Hydraulic and Mechanical Equipment (Ch. 6: Bulkhead Gates and Stoplogs) ~~(Bureau of Reclamation)~~]]		{{Document Icon}} [[Design Standards No. 6: Hydraulic and Mechanical Equipment (Ch. 6: Bulkhead Gates and Stoplogs) \| Design Standards No. 6: Hydraulic and Mechanical Equipment (Ch. 6: Bulkhead Gates and Stoplogs), USBR, 2018]]
	{{Document Icon}}[[Design ~~Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General~~ Outlet Works ~~Design Considerations~~)\|Design ~~Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General~~ Outlet Works ~~Design Considerations)~~ (~~Bureau of Reclamation~~)]]		{{Document Icon}} [[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602), USACE, 1980]]

	==Trainings==		==Trainings==
	{{Video Icon}} [[On-Demand Webinar: Introduction to Spillway Gates]]		{{Video Icon}} [[On-Demand Webinar: Introduction to Spillway Gates]]

Grichards at 22:50, 2 December 2022

2022-12-02T22:50:15Z

Grichards at 22:48, 2 December 2022

2022-12-02T22:48:55Z

← Older revision		Revision as of 22:48, 2 December 2022
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	==Components of Gates/Bulkheads==		==Components of Gates/Bulkheads==
	While there are many different types and sizes of gates and bulkheads, they often share similar components. These can include gate slots, gate recesses, gate seats, passageway liners, and air vents. Additionally, it is often required to design and construct redundant systems with at least two gates to allow for partial [[operation]] of the system in an emergency should one of the gates become inoperable.		While there are many different types and sizes of gates and bulkheads, they often share similar components. These can include gate slots, gate recesses, gate seats, passageway liners, and air vents. Additionally, it is often required to design and construct redundant systems with at least two gates to allow for partial [[operation]] of the system in an emergency should one of the gates become inoperable.

	''' ''Gate Passageway Requirements:'' ''' "Normally, when reservoir outlet flows require regulation, the following are provided:		''' ''Gate Passageway Requirements:'' ''' "Normally, when reservoir outlet flows require regulation, the following are provided:
	*Two or more gate passages such that if one passage is inoperative, a reasonable flow regulation as pertains to project purposes is obtained.		*Two or more gate passages such that if one passage is inoperative, a reasonable flow regulation as pertains to project purposes is obtained.
	*Emergency gate provision (tandem or transferable) for each service gate passage so that if a service gate is inoperative in any position, closure of the gate passage can be made with the emergency gate for any pool level.		*Emergency gate provision (tandem or transferable) for each service gate passage so that if a service gate is inoperative in any position, closure of the gate passage can be made with the emergency gate for any pool level.
	*Bulkhead provisions for each gate passage for inspection and maintenance of the service and emergency gates. At a minimum, the bulkheads must be capable of being installed at the lowest pool elevation that has a reasonable frequency and length of occurrence sufficient for inspection and repair purposes." <ref name="EM 1110-2-1602">[[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| EM 1110-2-1602 Hydraulic Design of Reservoir Outlet Works, USACE, 1980]]</ref>		*Bulkhead provisions for each gate passage for inspection and maintenance of the service and emergency gates. At a minimum, the bulkheads must be capable of being installed at the lowest pool elevation that has a reasonable frequency and length of occurrence sufficient for inspection and repair purposes." <ref name="EM 1110-2-1602">[[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| EM 1110-2-1602 Hydraulic Design of Reservoir Outlet Works, USACE, 1980]]</ref>

	''' ''Gate Slots:'' ''' "The guide slots of rectangular gates produce a discontinuity in sidewalls which may cause [[cavitation]], unless specially designed. It has been common practice to use metal-liner plates downstream from the gate slots to protect the concrete from the erosive action of cavitation." <ref name="EM 1110-2-1602"/>		''' ''Gate Slots:'' ''' "The guide slots of rectangular gates produce a discontinuity in sidewalls which may cause [[cavitation]], unless specially designed. It has been common practice to use metal-liner plates downstream from the gate slots to protect the concrete from the erosive action of cavitation." <ref name="EM 1110-2-1602"/>

	''' ''Gate Recess:'' ''' "Hydraulically operated control gates recess into bonnets and cable-suspended gates into wet wells. The necessary dimensional clearances for gate operation are usually based on mechanical and [[structural]] requirements rather than hydraulic. The primary hydraulic consideration is the relative upstream and downstream clearance at the roof recess when the gate passage is operated at part gate opening. The upstream clearance at the roof should be appreciably larger than the downstream clearance to assure maintenance of a hydrostatic head in the well or bonnet for gate [[stability]]. If the downstream clearance exceeds the upstream clearance the gate well can be sucked dry and the gate may float or catapult or oscillate under certain operating conditions." <ref name="EM 1110-2-1602"/>		''' ''Gate Recess:'' ''' "Hydraulically operated control gates recess into bonnets and cable-suspended gates into wet wells. The necessary dimensional clearances for gate operation are usually based on mechanical and [[structural]] requirements rather than hydraulic. The primary hydraulic consideration is the relative upstream and downstream clearance at the roof recess when the gate passage is operated at part gate opening. The upstream clearance at the roof should be appreciably larger than the downstream clearance to assure maintenance of a hydrostatic head in the well or bonnet for gate [[stability]]. If the downstream clearance exceeds the upstream clearance the gate well can be sucked dry and the gate may float or catapult or oscillate under certain operating conditions." <ref name="EM 1110-2-1602"/>

	''' ''Gate Seats:'' ''' "In general, the gate seat is flush with the floor of the gate passage." <ref name="EM 1110-2-1602"/>		''' ''Gate Seats:'' ''' "In general, the gate seat is flush with the floor of the gate passage." <ref name="EM 1110-2-1602"/>

	''' ''Steel Liners:'' ''' "Steel liners in concrete conduits have been used where experience indicates cavitation is likely to occur such as downstream from control gates and valves where a high-velocity jet occurs. For head above 150 feet, no liner should be required. If a liner is necessary, it should not terminate at a monolith joint or in a transition." <ref name="EM 1110-2-1602"/>		''' ''Steel Liners:'' ''' "Steel liners in concrete conduits have been used where experience indicates cavitation is likely to occur such as downstream from control gates and valves where a high-velocity jet occurs. For head above 150 feet, no liner should be required. If a liner is necessary, it should not terminate at a monolith joint or in a transition." <ref name="EM 1110-2-1602"/>

	''' ''Air Vents:'' ''' "Control valves and gates that are located a considerable distance upstream from the exit (i.e., do not discharge into the atmosphere) require air vents. An air vent is required for each service gate. Air vents are not required for emergency gates when those gates are located immediately upstream of air-vented service gates. Extreme caution must be observed if the emergency gate is used for regulation. Air demand will create very low pressures in the service gate recess. The attendant conditions must be carefully analyzed to prevent damage and/or danger to personnel." <ref name="EM 1110-2-1602"/>		''' ''Air Vents:'' ''' "Control valves and gates that are located a considerable distance upstream from the exit (i.e., do not discharge into the atmosphere) require air vents. An air vent is required for each service gate. Air vents are not required for emergency gates when those gates are located immediately upstream of air-vented service gates. Extreme caution must be observed if the emergency gate is used for regulation. Air demand will create very low pressures in the service gate recess. The attendant conditions must be carefully analyzed to prevent damage and/or danger to personnel." <ref name="EM 1110-2-1602"/>

Grichards at 22:47, 2 December 2022

2022-12-02T22:47:36Z

← Older revision		Revision as of 22:47, 2 December 2022
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	While there are many different types and sizes of gates and bulkheads, they often share similar components. These can include gate slots, gate recesses, gate seats, passageway liners, and air vents. Additionally, it is often required to design and construct redundant systems with at least two gates to allow for partial [[operation]] of the system in an emergency should one of the gates become inoperable.		While there are many different types and sizes of gates and bulkheads, they often share similar components. These can include gate slots, gate recesses, gate seats, passageway liners, and air vents. Additionally, it is often required to design and construct redundant systems with at least two gates to allow for partial [[operation]] of the system in an emergency should one of the gates become inoperable.

	“''Gate Passageway Requirements.'' Normally, when reservoir outlet flows require regulation, the following are provided:		''' ''Gate Passageway Requirements:'' ''' "Normally, when reservoir outlet flows require regulation, the following are provided:
	*Two or more gate passages such that if one passage is inoperative, a reasonable flow regulation as pertains to project purposes is obtained.		*Two or more gate passages such that if one passage is inoperative, a reasonable flow regulation as pertains to project purposes is obtained.
	*Emergency gate provision (tandem or transferable) for each service gate passage so that if a service gate is inoperative in any position, closure of the gate passage can be made with the emergency gate for any pool level.		*Emergency gate provision (tandem or transferable) for each service gate passage so that if a service gate is inoperative in any position, closure of the gate passage can be made with the emergency gate for any pool level.
	*Bulkhead provisions for each gate passage for inspection and maintenance of the service and emergency gates. At a minimum, the bulkheads must be capable of being installed at the lowest pool elevation that has a reasonable frequency and length of occurrence sufficient for inspection and repair purposes. ~~All judgement factors involved in the above should be fully discussed in the design memorandum presentation.~~		*Bulkhead provisions for each gate passage for inspection and maintenance of the service and emergency gates. At a minimum, the bulkheads must be capable of being installed at the lowest pool elevation that has a reasonable frequency and length of occurrence sufficient for inspection and repair purposes." <ref name="EM 1110-2-1602">[[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| EM 1110-2-1602 Hydraulic Design of Reservoir Outlet Works, USACE, 1980]]</ref>

	"''Gate Slots.'' The guide slots of rectangular gates produce a discontinuity in sidewalls which may cause [[cavitation]], unless specially designed. It has been common practice to use metal-liner plates downstream from the gate slots to protect the concrete from the erosive action of cavitation.		''' ''Gate Slots:'' ''' "The guide slots of rectangular gates produce a discontinuity in sidewalls which may cause [[cavitation]], unless specially designed. It has been common practice to use metal-liner plates downstream from the gate slots to protect the concrete from the erosive action of cavitation." <ref name="EM 1110-2-1602"/>

	"''Gate Recess.'' Hydraulically operated control gates recess into bonnets and cable-suspended gates into wet wells. The necessary dimensional clearances for gate operation are usually based on mechanical and [[structural]] requirements rather than hydraulic. The primary hydraulic consideration is the relative upstream and downstream clearance at the roof recess when the gate passage is operated at part gate opening. The upstream clearance at the roof should be appreciably larger than the downstream clearance to assure maintenance of a hydrostatic head in the well or bonnet for gate [[stability]]. If the downstream clearance exceeds the upstream clearance the gate well can be sucked dry and the gate may float or catapult or oscillate under certain operating conditions.		''' ''Gate Recess:'' ''' "Hydraulically operated control gates recess into bonnets and cable-suspended gates into wet wells. The necessary dimensional clearances for gate operation are usually based on mechanical and [[structural]] requirements rather than hydraulic. The primary hydraulic consideration is the relative upstream and downstream clearance at the roof recess when the gate passage is operated at part gate opening. The upstream clearance at the roof should be appreciably larger than the downstream clearance to assure maintenance of a hydrostatic head in the well or bonnet for gate [[stability]]. If the downstream clearance exceeds the upstream clearance the gate well can be sucked dry and the gate may float or catapult or oscillate under certain operating conditions." <ref name="EM 1110-2-1602"/>

	"''Gate Seats.'' In general, the gate seat is flush with the floor of the gate passage.		''' ''Gate Seats:'' ''' "In general, the gate seat is flush with the floor of the gate passage." <ref name="EM 1110-2-1602"/>

	"''Steel Liners.'' Steel liners in concrete conduits have been used where experience indicates cavitation is likely to occur such as downstream from control gates and valves where a high-velocity jet occurs. For head above 150 feet, no liner should be required. If a liner is necessary, it should not terminate at a monolith joint or in a transition.		''' ''Steel Liners:'' ''' "Steel liners in concrete conduits have been used where experience indicates cavitation is likely to occur such as downstream from control gates and valves where a high-velocity jet occurs. For head above 150 feet, no liner should be required. If a liner is necessary, it should not terminate at a monolith joint or in a transition." <ref name="EM 1110-2-1602"/>

	"''Air Vents.''		''' ''Air Vents:'' ''' "Control valves and gates that are located a considerable distance upstream from the exit (i.e., do not discharge into the atmosphere) require air vents. An air vent is required for each service gate. Air vents are not required for emergency gates when those gates are located immediately upstream of air-vented service gates. Extreme caution must be observed if the emergency gate is used for regulation. Air demand will create very low pressures in the service gate recess. The attendant conditions must be carefully analyzed to prevent damage and/or danger to personnel." <ref name="EM 1110-2-1602"/>
	*Control valves and gates that are located a considerable distance upstream from the exit (i.e., do not discharge into the atmosphere) require air vents. An air vent is required for each service gate. Air vents are not required for emergency gates when those gates are located immediately upstream of air-vented service gates. Extreme caution must be observed if the emergency gate is used for regulation. Air demand will create very low pressures in the service gate recess. The attendant conditions must be carefully analyzed to prevent damage and/or danger to personnel.
	*The size of air vents can be determined as per HDC 050-2n which assumes that the maximum air demand occurs at a gate opening of 80 percent fully open and the maximum air velocity in the vent does not exceed 150 fps. It is further suggested that air vents be designed so that the head loss through the vent not exceed 0.5 to 1.0 feet of water (i.e., air vent outlet pressure head of -0.5 to -1.0 feet of water). Although air vents are usually designed assuming incompressible flow, high-velocity local flow should be checked to determine if flow is incompressible.
	*Air vent passages should use generous bend radii and gradual transitions to avoid losses and, particularly, excessive noise.
	*Air vent intakes should be so located that they are inaccessible to the public and they should be protected by grills. The intake entrance average velocity should not exceed 30 fps.
	*Interconnected air vents (one main vertical stem manifolded to vent more than one gate) should be avoided; but if they are necessary, the connections should be above the maximum possible elevation of the pressure grade line at the air vent exit opening to prevent crossflow of water.
	*The air vent exit portal should be designed to assure spread of air across the full width of the conduit. The air vent should terminate into a plenum located in the conduit roof and immediately downstream of the gate. The plenum should extend across the full width of the conduit and should be vaned so that the air flow is evenly distributed”.<ref name="EM 1110-2-1602"~~>[[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| EM 1110-2-1602 Hydraulic Design of Reservoir Outlet Works, USACE, 1980]]<~~/~~ref~~>

	==Types of Gates/Bulkheads==		==Types of Gates/Bulkheads==
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	#[[O&M of Gates/Bulkheads]]		#[[O&M of Gates/Bulkheads]]
	<br/>		<br/>

	==Best Practices Resources==		==Best Practices Resources==
	{{Document Icon}}[[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602)\|Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) (U.S. Army Corps of Engineers)]]		{{Document Icon}}[[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602)\|Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) (U.S. Army Corps of Engineers)]]

Grichards at 22:40, 2 December 2022

2022-12-02T22:40:53Z

← Older revision		Revision as of 22:40, 2 December 2022
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	As a result of varying [[Purposes of Dams\|purposes of dams]], as well as the unique site conditions that accompany each particular dam, there are a wide variety of types of gates or bulkheads. Some of the most common types include vertical lift gates, roller gates, hinged or flap gates, or tainter or radial gates. In the design process of a gated spillway system, it is necessary to weigh the advantages and disadvantages of using each type of gates in the particular operating conditions expected at the dam.		As a result of varying [[Purposes of Dams\|purposes of dams]], as well as the unique site conditions that accompany each particular dam, there are a wide variety of types of gates or bulkheads. Some of the most common types include vertical lift gates, roller gates, hinged or flap gates, or tainter or radial gates. In the design process of a gated spillway system, it is necessary to weigh the advantages and disadvantages of using each type of gates in the particular operating conditions expected at the dam.

	“Gated [[spillways]] include drop inlet, free overfall, ogee crest, side-channel and bathtub, tunnel inlet, various shaped weirs, and orifice. These control structures are associated with regulated releases and suited for service, auxiliary, and [[Emergency Spillways\|emergency spillways]]. The most frequently used gates include radial gates, drum gates, wheel-mounted gates, and crest gates. Considerations include a firm foundation (typically rock), high degree of reliability of gate operation, limiting debris blockage potential, and favorable economics. In addition, gated spillways provide increased control of releases for a given reservoir water surface, allowing increased discharge where reservoir storage is limited, and/or to reduce the amount of reservoir water surface rise during a flood event. These considerations would apply to large volume inflows, where there is a relatively small reservoir storage capacity. Examples of these gated spillways include:		“Gated [[spillways]] include drop inlet, free overfall, ogee crest, side-channel and bathtub, tunnel inlet, various shaped weirs, and orifice. These control structures are associated with regulated releases and suited for service, auxiliary, and [[Emergency Spillways\|emergency spillways]]. The most frequently used gates include radial gates, drum gates, wheel-mounted gates, and crest gates. Examples of these gated spillways include:
			*'' '''Gated drop inlet spillway:''' '' This type of control structure is mostly associated with a service spillway with radial gates. An example of a gated drop inlet spillway is Reclamation’s Gibson Dam (concrete). Other examples include the service spillways with ring gates at Reclamation’s Hungry Horse and Owyhee Dams (both concrete).
	*"''Gated drop inlet spillway -'' This type of control structure is mostly associated with a service spillway with radial gates. An example of a gated drop inlet spillway is Reclamation’s Gibson Dam (concrete). Other examples include the service spillways with ring gates at Reclamation’s Hungry Horse and Owyhee Dams (both concrete).~~<ref name="DS14" />~~		*'' '''Gated free overfall spillway:''' '' This type of control structure is mostly associated with a service spillway with roller gates. An example of a gated free overall spillway is Reclamation’s Parker Dam (concrete).
	*"''Gated free overfall spillway -'' This type of control structure is mostly associated with a service spillway with roller gates. An example of a gated free overall spillway is Reclamation’s Parker Dam (concrete). ~~<ref name="DS14" />~~		*'' '''Gated ogee crest spillways:''' '' This type of control structure is associated with a service and auxiliary spillway with gates. Examples of gated ogee crest spillways are Reclamation’s Shasta Dam (concrete) with drum gates and auxiliary spillway with radial gates at Reclamation’s Stewart Mountain Dam (concrete). Other examples include service and [[Emergency Spillways\|emergency spillways]] with radial gates at Reclamation’s Folsom Dam (composite) and the service spillway with fixed-wheel gates at Reclamation’s Keswick Dam (composite).
	*"''Gated ogee crest spillways -'' This type of control structure is associated with a service and auxiliary spillway with gates. Examples of gated ogee crest spillways are Reclamation’s Shasta Dam (concrete) with drum gates and auxiliary spillway with radial gates at Reclamation’s Stewart Mountain Dam (concrete). Other examples include service and emergency spillways with radial gates at Reclamation’s Folsom Dam (composite) and the service spillway with fixed-wheel gates at Reclamation’s Keswick Dam (composite).~~<ref name="DS14" />~~		*'' '''Gated side-channel spillway:''' '' This type of control structure is mostly associated with a service spillway with gates. An example of a gated side-channel spillway is Reclamation’s Arrowrock Dam (concrete), which has drum gates.
	*"''Gated side-channel spillway -'' This type of control structure is mostly associated with a service spillway with gates. An example of a gated side-channel spillway is Reclamation’s Arrowrock Dam (concrete), which has drum gates.~~<ref name="DS14" />~~		*'' '''Gated tunnel inlet spillway:''' '' This type of control structure is mostly associated with a service spillway with gates. An example of a gated tunnel inlet spillway is Reclamation’s Seminoe Dam (concrete) with fixed wheel gates. Other examples include the service spillways with radial gates at Reclamation’s Glen Canyon Dam and the service spillways with drum gates at Reclamation’s Hoover Dam.
	*"''Gated tunnel inlet spillway -'' This type of control structure is mostly associated with a service spillway with gates. An example of a gated tunnel inlet spillway is Reclamation’s Seminoe Dam (concrete) with fixed wheel gates. Other examples include the service spillways with radial gates at Reclamation’s Glen Canyon Dam and the service spillways with drum gates at Reclamation’s Hoover Dam.~~<ref name="DS14" />~~		*'' '''Gated various shaped weir spillway:''' '' This type of control structure is mostly associated with a service spillway with gates. An example of a gated various shaped weir spillway is Reclamation’s Hyrum Dam (embankment) with radial gates.
	*"''Gated various shaped weir spillway -'' This type of control structure is mostly associated with a service spillway with gates. An example of a gated various shaped weir spillway is Reclamation’s Hyrum Dam (embankment) with radial gates.~~<ref name="DS14" />~~		*'' '''Gated orifice spillway:''' '' With this type of control structure, flow is typically released from the spillway by one of two approaches: 1) A free jet is released downstream of the gates and typically is stilled by a plunge pool, 2) Flows will be released to a conveyance feature (such as a chute, conduit, or tunnel) and/or terminal structure."<ref name="DS-14">[[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), Bureau of Reclamation, 2022]]</ref>
	*"''Gated orifice spillway -'' With this type of control structure, flow is typically released from the spillway by one of two approaches:
	**"A free jet is released downstream of the gates and typically is stilled by a plunge pool~~. <ref name="DS14" />~~
	**"Flows will be released to a conveyance feature (such as a chute, conduit, or tunnel) and/or terminal structure.<ref name="DS-14">[[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), Bureau of Reclamation, 2022]]</ref>



	==Life Cycle of Gates/Bulkheads==		==Life Cycle of Gates/Bulkheads==

Grichards at 22:35, 2 December 2022

2022-12-02T22:35:02Z

← Older revision		Revision as of 22:35, 2 December 2022
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	As a result of varying [[Purposes of Dams\|purposes of dams]], as well as the unique site conditions that accompany each particular dam, there are a wide variety of types of gates or bulkheads. Some of the most common types include vertical lift gates, roller gates, hinged or flap gates, or tainter or radial gates. In the design process of a gated spillway system, it is necessary to weigh the advantages and disadvantages of using each type of gates in the particular operating conditions expected at the dam.		As a result of varying [[Purposes of Dams\|purposes of dams]], as well as the unique site conditions that accompany each particular dam, there are a wide variety of types of gates or bulkheads. Some of the most common types include vertical lift gates, roller gates, hinged or flap gates, or tainter or radial gates. In the design process of a gated spillway system, it is necessary to weigh the advantages and disadvantages of using each type of gates in the particular operating conditions expected at the dam.

	“Gated [[spillways]] include drop inlet, free overfall, ogee crest, side-channel and bathtub, tunnel inlet, various shaped weirs, and orifice. These control structures are associated with regulated releases and suited for service, auxiliary, and emergency spillways. The most frequently used gates include radial gates, drum gates, wheel-mounted gates, and crest gates. Considerations include a firm foundation (typically rock), high degree of reliability of gate operation, limiting debris blockage potential, and favorable economics. In addition, gated spillways provide increased control of releases for a given reservoir water surface, allowing increased discharge where reservoir storage is limited, and/or to reduce the amount of reservoir water surface rise during a flood event. These considerations would apply to large volume inflows, where there is a relatively small reservoir storage capacity. Examples of these gated spillways include:		“Gated [[spillways]] include drop inlet, free overfall, ogee crest, side-channel and bathtub, tunnel inlet, various shaped weirs, and orifice. These control structures are associated with regulated releases and suited for service, auxiliary, and [[Emergency Spillways\|emergency spillways]]. The most frequently used gates include radial gates, drum gates, wheel-mounted gates, and crest gates. Considerations include a firm foundation (typically rock), high degree of reliability of gate operation, limiting debris blockage potential, and favorable economics. In addition, gated spillways provide increased control of releases for a given reservoir water surface, allowing increased discharge where reservoir storage is limited, and/or to reduce the amount of reservoir water surface rise during a flood event. These considerations would apply to large volume inflows, where there is a relatively small reservoir storage capacity. Examples of these gated spillways include:

	*"''Gated drop inlet spillway -'' This type of control structure is mostly associated with a service spillway with radial gates. An example of a gated drop inlet spillway is Reclamation’s Gibson Dam (concrete). Other examples include the service spillways with ring gates at Reclamation’s Hungry Horse and Owyhee Dams (both concrete).<ref name="DS14" />		*"''Gated drop inlet spillway -'' This type of control structure is mostly associated with a service spillway with radial gates. An example of a gated drop inlet spillway is Reclamation’s Gibson Dam (concrete). Other examples include the service spillways with ring gates at Reclamation’s Hungry Horse and Owyhee Dams (both concrete).<ref name="DS14" />
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	*"''Gated orifice spillway -'' With this type of control structure, flow is typically released from the spillway by one of two approaches:		*"''Gated orifice spillway -'' With this type of control structure, flow is typically released from the spillway by one of two approaches:
	**"A free jet is released downstream of the gates and typically is stilled by a plunge pool. <ref name="DS14" />		**"A free jet is released downstream of the gates and typically is stilled by a plunge pool. <ref name="DS14" />
	**"Flows will be released to a conveyance feature (such as a chute, conduit, or tunnel) and/or terminal structure.<ref name="~~DS14~~" />		**"Flows will be released to a conveyance feature (such as a chute, conduit, or tunnel) and/or terminal structure.<ref name="DS-14">[[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), Bureau of Reclamation, 2022]]</ref>

Grichards at 22:32, 2 December 2022

2022-12-02T22:32:34Z

@@ Line 38: / Line 38: @@
 ==Types of Gates/Bulkheads==
 As a result of varying [[Purposes of Dams|purposes of dams]], as well as the unique site conditions that accompany each particular dam, there are a wide variety of types of gates or bulkheads. Some of the most common types include vertical lift gates, roller gates, hinged or flap gates, or tainter or radial gates. In the design process of a gated spillway system, it is necessary to weigh the advantages and disadvantages of using each type of gates in the particular operating conditions expected at the dam.
 ==Life Cycle of Gates/Bulkheads==

← Older revision		Revision as of 22:50, 2 December 2022
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	==Components of Gates/Bulkheads==		==Components of Gates/Bulkheads==
	While there are many different types and sizes of gates and bulkheads, they often share similar components. These can include gate slots, gate recesses, gate seats, passageway liners, and air vents. Additionally, it is often required to design and construct redundant systems with at least two gates to allow for partial [[operation]] of the system in an emergency should one of the gates become inoperable.		While there are many different types and sizes of gates and bulkheads, they often share similar components. These can include gate slots, gate recesses, gate seats, passageway liners, and air vents. Additionally, it is often required to design and construct redundant systems with at least two gates to allow for partial [[operation]] of the system in an emergency should one of the gates become inoperable.

	''' ''Gate Passageway Requirements:'' ''' "Normally, when reservoir outlet flows require regulation, the following are provided:		''' ''Gate Passageway Requirements:'' ''' "Normally, when reservoir outlet flows require regulation, the following are provided:
	*Two or more gate passages such that if one passage is inoperative, a reasonable flow regulation as pertains to project purposes is obtained.		*Two or more gate passages such that if one passage is inoperative, a reasonable flow regulation as pertains to project purposes is obtained.
	*Emergency gate provision (tandem or transferable) for each service gate passage so that if a service gate is inoperative in any position, closure of the gate passage can be made with the emergency gate for any pool level.		*Emergency gate provision (tandem or transferable) for each service gate passage so that if a service gate is inoperative in any position, closure of the gate passage can be made with the emergency gate for any pool level.

	*Bulkhead provisions for each gate passage for inspection and maintenance of the service and emergency gates. At a minimum, the bulkheads must be capable of being installed at the lowest pool elevation that has a reasonable frequency and length of occurrence sufficient for inspection and repair purposes." <ref name="EM 1110-2-1602">[[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| EM 1110-2-1602 Hydraulic Design of Reservoir Outlet Works, USACE, 1980]]</ref>		*Bulkhead provisions for each gate passage for inspection and maintenance of the service and emergency gates. At a minimum, the bulkheads must be capable of being installed at the lowest pool elevation that has a reasonable frequency and length of occurrence sufficient for inspection and repair purposes." <ref name="EM 1110-2-1602">[[Hydraulic Design of Reservoir Outlet Works (EM 1110-2-1602) \| EM 1110-2-1602 Hydraulic Design of Reservoir Outlet Works, USACE, 1980]]</ref>

	''' ''Gate Slots:'' ''' "The guide slots of rectangular gates produce a discontinuity in sidewalls which may cause [[cavitation]], unless specially designed. It has been common practice to use metal-liner plates downstream from the gate slots to protect the concrete from the erosive action of cavitation." <ref name="EM 1110-2-1602"/>		''' ''Gate Slots:'' ''' "The guide slots of rectangular gates produce a discontinuity in sidewalls which may cause [[cavitation]], unless specially designed. It has been common practice to use metal-liner plates downstream from the gate slots to protect the concrete from the erosive action of cavitation." <ref name="EM 1110-2-1602"/>

	''' ''Gate Recess:'' ''' "Hydraulically operated control gates recess into bonnets and cable-suspended gates into wet wells. The necessary dimensional clearances for gate operation are usually based on mechanical and [[structural]] requirements rather than hydraulic. The primary hydraulic consideration is the relative upstream and downstream clearance at the roof recess when the gate passage is operated at part gate opening. The upstream clearance at the roof should be appreciably larger than the downstream clearance to assure maintenance of a hydrostatic head in the well or bonnet for gate [[stability]]. If the downstream clearance exceeds the upstream clearance the gate well can be sucked dry and the gate may float or catapult or oscillate under certain operating conditions." <ref name="EM 1110-2-1602"/>		''' ''Gate Recess:'' ''' "Hydraulically operated control gates recess into bonnets and cable-suspended gates into wet wells. The necessary dimensional clearances for gate operation are usually based on mechanical and [[structural]] requirements rather than hydraulic. The primary hydraulic consideration is the relative upstream and downstream clearance at the roof recess when the gate passage is operated at part gate opening. The upstream clearance at the roof should be appreciably larger than the downstream clearance to assure maintenance of a hydrostatic head in the well or bonnet for gate [[stability]]. If the downstream clearance exceeds the upstream clearance the gate well can be sucked dry and the gate may float or catapult or oscillate under certain operating conditions." <ref name="EM 1110-2-1602"/>

	''' ''Gate Seats:'' ''' "In general, the gate seat is flush with the floor of the gate passage." <ref name="EM 1110-2-1602"/>		''' ''Gate Seats:'' ''' "In general, the gate seat is flush with the floor of the gate passage." <ref name="EM 1110-2-1602"/>

	''' ''Steel Liners:'' ''' "Steel liners in concrete conduits have been used where experience indicates cavitation is likely to occur such as downstream from control gates and valves where a high-velocity jet occurs. For head above 150 feet, no liner should be required. If a liner is necessary, it should not terminate at a monolith joint or in a transition." <ref name="EM 1110-2-1602"/>		''' ''Steel Liners:'' ''' "Steel liners in concrete conduits have been used where experience indicates cavitation is likely to occur such as downstream from control gates and valves where a high-velocity jet occurs. For head above 150 feet, no liner should be required. If a liner is necessary, it should not terminate at a monolith joint or in a transition." <ref name="EM 1110-2-1602"/>

	''' ''Air Vents:'' ''' "Control valves and gates that are located a considerable distance upstream from the exit (i.e., do not discharge into the atmosphere) require air vents. An air vent is required for each service gate. Air vents are not required for emergency gates when those gates are located immediately upstream of air-vented service gates. Extreme caution must be observed if the emergency gate is used for regulation. Air demand will create very low pressures in the service gate recess. The attendant conditions must be carefully analyzed to prevent damage and/or danger to personnel." <ref name="EM 1110-2-1602"/>		''' ''Air Vents:'' ''' "Control valves and gates that are located a considerable distance upstream from the exit (i.e., do not discharge into the atmosphere) require air vents. An air vent is required for each service gate. Air vents are not required for emergency gates when those gates are located immediately upstream of air-vented service gates. Extreme caution must be observed if the emergency gate is used for regulation. Air demand will create very low pressures in the service gate recess. The attendant conditions must be carefully analyzed to prevent damage and/or danger to personnel." <ref name="EM 1110-2-1602"/>

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	“Gated [[spillways]] include drop inlet, free overfall, ogee crest, side-channel and bathtub, tunnel inlet, various shaped weirs, and orifice. These control structures are associated with regulated releases and suited for service, auxiliary, and [[Emergency Spillways\|emergency spillways]]. The most frequently used gates include radial gates, drum gates, wheel-mounted gates, and crest gates. Examples of these gated spillways include:		“Gated [[spillways]] include drop inlet, free overfall, ogee crest, side-channel and bathtub, tunnel inlet, various shaped weirs, and orifice. These control structures are associated with regulated releases and suited for service, auxiliary, and [[Emergency Spillways\|emergency spillways]]. The most frequently used gates include radial gates, drum gates, wheel-mounted gates, and crest gates. Examples of these gated spillways include:

	*'' '''Gated drop inlet spillway:''' '' This type of control structure is mostly associated with a service spillway with radial gates. An example of a gated drop inlet spillway is Reclamation’s Gibson Dam (concrete). Other examples include the service spillways with ring gates at Reclamation’s Hungry Horse and Owyhee Dams (both concrete).		*'' '''Gated drop inlet spillway:''' '' This type of control structure is mostly associated with a service spillway with radial gates. An example of a gated drop inlet spillway is Reclamation’s Gibson Dam (concrete). Other examples include the service spillways with ring gates at Reclamation’s Hungry Horse and Owyhee Dams (both concrete).

	*'' '''Gated free overfall spillway:''' '' This type of control structure is mostly associated with a service spillway with roller gates. An example of a gated free overall spillway is Reclamation’s Parker Dam (concrete).		*'' '''Gated free overfall spillway:''' '' This type of control structure is mostly associated with a service spillway with roller gates. An example of a gated free overall spillway is Reclamation’s Parker Dam (concrete).

	*'' '''Gated ogee crest spillways:''' '' This type of control structure is associated with a service and auxiliary spillway with gates. Examples of gated ogee crest spillways are Reclamation’s Shasta Dam (concrete) with drum gates and auxiliary spillway with radial gates at Reclamation’s Stewart Mountain Dam (concrete). Other examples include service and [[Emergency Spillways\|emergency spillways]] with radial gates at Reclamation’s Folsom Dam (composite) and the service spillway with fixed-wheel gates at Reclamation’s Keswick Dam (composite).		*'' '''Gated ogee crest spillways:''' '' This type of control structure is associated with a service and auxiliary spillway with gates. Examples of gated ogee crest spillways are Reclamation’s Shasta Dam (concrete) with drum gates and auxiliary spillway with radial gates at Reclamation’s Stewart Mountain Dam (concrete). Other examples include service and [[Emergency Spillways\|emergency spillways]] with radial gates at Reclamation’s Folsom Dam (composite) and the service spillway with fixed-wheel gates at Reclamation’s Keswick Dam (composite).

	*'' '''Gated side-channel spillway:''' '' This type of control structure is mostly associated with a service spillway with gates. An example of a gated side-channel spillway is Reclamation’s Arrowrock Dam (concrete), which has drum gates.		*'' '''Gated side-channel spillway:''' '' This type of control structure is mostly associated with a service spillway with gates. An example of a gated side-channel spillway is Reclamation’s Arrowrock Dam (concrete), which has drum gates.

	*'' '''Gated tunnel inlet spillway:''' '' This type of control structure is mostly associated with a service spillway with gates. An example of a gated tunnel inlet spillway is Reclamation’s Seminoe Dam (concrete) with fixed wheel gates. Other examples include the service spillways with radial gates at Reclamation’s Glen Canyon Dam and the service spillways with drum gates at Reclamation’s Hoover Dam.		*'' '''Gated tunnel inlet spillway:''' '' This type of control structure is mostly associated with a service spillway with gates. An example of a gated tunnel inlet spillway is Reclamation’s Seminoe Dam (concrete) with fixed wheel gates. Other examples include the service spillways with radial gates at Reclamation’s Glen Canyon Dam and the service spillways with drum gates at Reclamation’s Hoover Dam.

	*'' '''Gated various shaped weir spillway:''' '' This type of control structure is mostly associated with a service spillway with gates. An example of a gated various shaped weir spillway is Reclamation’s Hyrum Dam (embankment) with radial gates.		*'' '''Gated various shaped weir spillway:''' '' This type of control structure is mostly associated with a service spillway with gates. An example of a gated various shaped weir spillway is Reclamation’s Hyrum Dam (embankment) with radial gates.

	*'' '''Gated orifice spillway:''' '' With this type of control structure, flow is typically released from the spillway by one of two approaches: 1) A free jet is released downstream of the gates and typically is stilled by a plunge pool, 2) Flows will be released to a conveyance feature (such as a chute, conduit, or tunnel) and/or terminal structure."<ref name="DS-14">[[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), Bureau of Reclamation, 2022]]</ref>		*'' '''Gated orifice spillway:''' '' With this type of control structure, flow is typically released from the spillway by one of two approaches: 1) A free jet is released downstream of the gates and typically is stilled by a plunge pool, 2) Flows will be released to a conveyance feature (such as a chute, conduit, or tunnel) and/or terminal structure."<ref name="DS-14">[[Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations) \| Design Standards No. 14: Appurtenant Structures for Dams (Ch. 4: General Outlet Works Design Considerations), Bureau of Reclamation, 2022]]</ref>