Design and Construction of Gravity Dams: Difference between revisions
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[[Category:Gravity Dams]] | |||
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| [[Image:GravityDamUplift1.png|350px|x350px|link=https://damfailures.org/lessons-learned/concrete-gravity-dams-should-be-evaluated-to-accommodate-full-uplift/]] | |||
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|style="text-align:center; font-size:90%;"| Learn more about the need to consider uplift pressure when designing a gravity structure at [https://damfailures.org/lessons-learned/concrete-gravity-dams-should-be-evaluated-to-accommodate-full-uplift/ DamFailures.org] | |||
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“Basically, gravity dams are solid concrete structures that maintain their stability against design loads from the geometric shape and the mass and strength of the concrete. Generally, they are constructed on a straight axis, but may be slightly curved or angled to accommodate the specific site conditions. Gravity dams typically consist of a nonoverflow section(s) and an overflow section or spillway. The two general concrete construction methods for concrete gravity dams are conventional placed mass concrete and roller-compacted concrete (RCC)”.<ref name="USACE Gravity Dam Design">[[Gravity Dam Design (EM 1110-2-2200) | EM 1110-2-2200 Gravity Dam Design, USACE, 1995]]</ref> | “Basically, [[Gravity Dams|gravity dams]] are solid concrete structures that maintain their [[stability]] against design loads from the geometric shape and the mass and strength of the concrete. Generally, they are constructed on a straight axis, but may be slightly curved or angled to accommodate the specific site conditions. [[Gravity Dams|Gravity dams]] typically consist of a nonoverflow section(s) and an overflow section or spillway. The two general concrete [[construction]] methods for concrete [[Gravity Dams|gravity dams]] are conventional placed [[Mass Concrete|mass concrete]] and roller-compacted concrete (RCC)”.<ref name="USACE Gravity Dam Design">[[Gravity Dam Design (EM 1110-2-2200) | EM 1110-2-2200 Gravity Dam Design, USACE, 1995]]</ref> | ||
==Conventional Concrete Dams== | |||
= | “Construction procedures include batching and mixing, and transportation, placement, [[vibration]], cooling, curing, and preparation of horizontal construction joints between lifts. The large volume of concrete in a gravity dam normally justifies an onsite batch plant, and requires an aggregate source of adequate quality and quantity, located at or within an economical distance of the project… The concrete is placed in lifts of 5- to 10-foot depths. Each lift consists of successive layers not exceeding 18 to 20 inches. Vibration is generally performed by large one-man, air-driven, spud-type vibrators”.<ref name="USACE Gravity Dam Design" /> | ||
==Roller-Compacted Concrete (RCC) Gravity Dams== | |||
“The design of RCC [[Gravity Dams|gravity dams]] is similar to conventional concrete structures. The differences lie in the construction methods, concrete mix design, and details of appurtenant structures. Construction of an RCC dam is a relatively new and economical concept. Economic advantages are achieved with rapid placement using construction techniques that are similar to those employed for [[Embankment Dams|embankment dams]]. RCC is a relatively dry, lean zero slump concrete material containing coarse and fine aggregate that is consolidated by external vibration using vibratory rollers, dozer, and other heavy equipment. In the hardened condition, RCC has similar properties to conventional concrete. For effective consolidation, RCC must be dry enough to support the weight of the construction equipment, but have a consistency wet enough to permit adequate distribution of the past binder throughout the mass during the mixing and vibration process and, thus, achieve the necessary compaction of the RCC and prevention of undesirable segregation and voids".<ref name="USACE Gravity Dam Design" /> | |||
== | ==Examples== | ||
{{Website Icon}} [https://damfailures.org/lessons-learned/concrete-gravity-dams-should-be-evaluated-to-accommodate-full-uplift/ Learn more about the need to consider uplift pressure (DamFailures.org)] | |||
{{Website Icon}} [https://damfailures.org/case-study/st-francis-dam-california-1928// Learn from the critical oversights that led to the failure of St. Francis Dam (DamFailures.org)] | |||
<noautolinks>==Best Practices Resources==</noautolinks> | |||
{{Document Icon}}[[Gravity Dam Design (EM 1110-2-2200)|Gravity Dam Design (EM 1110-2-2200) (U.S. Army Corps of Engineers)]] | |||
{{Document Icon}}[[Engineering Guidelines for the Evaluation of Hydropower Projects: Chapter 3- Gravity Dams|Engineering Guidelines for the Evaluation of Hydropower Projects: Chapter 3- Gravity Dams (Federal Energy Regulatory Commission)]] | |||
{{Document Icon}}[[Design Criteria for Concrete Arch and Gravity Dams (EM 19)|Design Criteria for Concrete Arch and Gravity Dams (EM 19) (Bureau of Reclamation)]] | |||
{{Document Icon}}[[Design of Gravity Dams|Design of Gravity Dams (Bureau of Reclamation)]] | |||
==Trainings== | ==Trainings== | ||
{{Video Icon}}[[On-Demand Webinar: Concrete | {{Video Icon}} [[On-Demand Webinar: Introduction to Concrete Gravity Dams]] | ||
{{Video Icon}} [[On-Demand Webinar: Rehabilitation of Concrete Dams]] | |||
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Latest revision as of 22:40, 26 January 2023
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| Learn more about the need to consider uplift pressure when designing a gravity structure at DamFailures.org |
“Basically, gravity dams are solid concrete structures that maintain their stability against design loads from the geometric shape and the mass and strength of the concrete. Generally, they are constructed on a straight axis, but may be slightly curved or angled to accommodate the specific site conditions. Gravity dams typically consist of a nonoverflow section(s) and an overflow section or spillway. The two general concrete construction methods for concrete gravity dams are conventional placed mass concrete and roller-compacted concrete (RCC)”.[1]
Conventional Concrete Dams
“Construction procedures include batching and mixing, and transportation, placement, vibration, cooling, curing, and preparation of horizontal construction joints between lifts. The large volume of concrete in a gravity dam normally justifies an onsite batch plant, and requires an aggregate source of adequate quality and quantity, located at or within an economical distance of the project… The concrete is placed in lifts of 5- to 10-foot depths. Each lift consists of successive layers not exceeding 18 to 20 inches. Vibration is generally performed by large one-man, air-driven, spud-type vibrators”.[1]
Roller-Compacted Concrete (RCC) Gravity Dams
“The design of RCC gravity dams is similar to conventional concrete structures. The differences lie in the construction methods, concrete mix design, and details of appurtenant structures. Construction of an RCC dam is a relatively new and economical concept. Economic advantages are achieved with rapid placement using construction techniques that are similar to those employed for embankment dams. RCC is a relatively dry, lean zero slump concrete material containing coarse and fine aggregate that is consolidated by external vibration using vibratory rollers, dozer, and other heavy equipment. In the hardened condition, RCC has similar properties to conventional concrete. For effective consolidation, RCC must be dry enough to support the weight of the construction equipment, but have a consistency wet enough to permit adequate distribution of the past binder throughout the mass during the mixing and vibration process and, thus, achieve the necessary compaction of the RCC and prevention of undesirable segregation and voids".[1]
Examples
Learn more about the need to consider uplift pressure (DamFailures.org)
Learn from the critical oversights that led to the failure of St. Francis Dam (DamFailures.org)
Best Practices Resources
Gravity Dam Design (EM 1110-2-2200) (U.S. Army Corps of Engineers)
Design Criteria for Concrete Arch and Gravity Dams (EM 19) (Bureau of Reclamation)
Design of Gravity Dams (Bureau of Reclamation)
Trainings
On-Demand Webinar: Introduction to Concrete Gravity Dams
On-Demand Webinar: Rehabilitation of Concrete Dams
Citations:
Revision ID: 6469
Revision Date: 01/26/2023