Global Stability of a Dam

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Learn more about the need to consider uplift pressure when designing a gravity structure at DamFailures.org

When a dam impounds a body of water, it will experience a load or force commonly referred to as hydrostatic pressure. A variety of other forces such as uplift pressure, earth pressure, silt pressure, wave pressure, wind pressure, ice pressure, seismic acceleration, hydrodynamic pressure, and thermal stress from ambient temperature changes can also act on the dam depending upon site conditions. Global stability refers to the ability of the dam to withstand all design loading conditions with adequate safety margin. This is a function of the geometry and material properties of the dam as well as the magnitude and combination of loads acting on the structure.

While this is imperative for gravity-type dams, global stability must also be demonstrated for appurtenances that impound water. For example, labyrinth spillway weir walls which impound the upper-most portion of a reservoir must be stable under normal and flood loadings. Failure of such a structure would result in the uncontrolled release of a portion of the reservoir. Therefore, they should be designed to gravity dam standards to resist overturning/sliding. This may require supplemental restraint such as grouted anchors due to the relatively low mass of the structure to resist the driving forces imposed by the reservoir.

Required Data

• Material Properties
• Loads / Load Cases

Evaluation Criteria

• Sliding Stability
• Rotational Stability
• Flotation
• Bearing Capacity
• Internal Stability (Stresses)

Types of Analyses

• Linear vs. Non-linear
• Static Analysis
• Dynamic Analysis

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

Design Standards No. 13: Embankment Dams (Ch. 13: Seismic Analysis and Design), USBR

Earthquake Design and Evaluation of Concrete Hydraulic Structures (EM 1110-2-6053), USACE

Stability Analysis of Concrete Structures (EM 1110-2-2100), USACE

Roller-Compacted Concrete (EM 1110-2-2006), USACE

Gravity Dam Design (EM 1110-2-2200), USACE

Arch Dam Design (EM 1110-2-2201), USACE

Sliding Stability for Concrete Structures (ETL 1110-2-256), USACE

Design of Small Dams, USBR

Trainings

On-Demand Webinar: Rehabilitation of Concrete Dams

On-Demand Webinar: Stability Evaluations of Concrete Dams

On-Demand Webinar: Analysis of Concrete Arch Dams

On-Demand Webinar: Introduction to Concrete Gravity Dams

Citations:

Revision ID: 7171
Revision Date: 07/11/2023