Catalog Record

Data and Report from S&T Project 19170: Uplift Pressures at Spillway Joints

Hydraulic jacking has caused catastrophic spillway chute failures in recent years, including at Oroville Dam in 2017 and on the fifth drop structure of the St. Mary Canal on Reclamation’s Milk River Project (Montana) in 2020. Void development beneath spillways is a frequent issue on Reclamation projects and hydraulic jacking failure modes are commonly considered in Reclamation risk analysis studies. This project reanalyzed laboratory tests performed ca. 1976 and 2007 to develop improved predictive relationships for uplift pressure at sealed joints (no foundation drainage) with varying geometries. Uplift pressures were related to mean channel velocity, estimated boundary layer velocities, and the dimensionless ratio of gap width to joint offset height. New laboratory testing performed in 2021 led to a better understanding of the role of boundary layer velocity profiles in the generation of uplift pressure and developed the first experimentally validated relationships for predicting flow rates through open joints. These findings will aid spillway designers and risk assessment teams considering spillway slab anchors and foundation drainage systems.
Generation Effort S&T Project 19170: Uplift Pressures at Spillway Joints
Themes Infrastructure and Assets
Tags Spillway, Uplift, Hydraulic Impacts, Hydraulic Jacking, Boundary Layer
Reclamation Project
Reclamation Program Science and Technology Program

Location Information

Location Description The Technical Service Center Hydraulics Lab is a 54,000 square foot indoor lab facility that is used to perform physical hydraulic model studies with flow capacities up to 60 cfs and 600 ft of pressure head, with fixed and variable-slope flumes and a low-ambient pressure chamber. The Hydraulic Investigations & Laboratory Services staff apply hydraulic modeling, analysis, and laboratory and field measurements expertise to the solution of water resources, hydraulics, and fluid mechanics problems. The TSC Hydraulics Lab is located at the Denver Federal Center, 6th and Kipling, Building 56, Denver, Colorado 80225-0007.
Location Tags Denver Federal Center
Location Parent
State(s) Colorado
Unified Region(s) Upper Colorado Basin
Timezone MT
Elevation 5,619 ft
Vertical Datum NAVD88
Coordinates (lat, long) See Location Details
Horizontal Datum WGS84