22 Dec 2022

2021 Guided Wave Inspection of California Department of Water Resources Tainter Gate Post-Tensioned Trunnion Anchor Rods: Oroville Dam

Abstract: The Engineering and Test Branch within the Division of Operations and Maintenance of the California Department of Water Resources (DWR) and U.S. Army Corps of Engineers (USACE), Sacramento District, tasked the Sensor Integration Branch (SIB) at the Engineer Research and Development Center (ERDC) to perform nondestructive testing (NDT) on the trunnion anchor rods at Oroville Dam through the use of ultrasonic guided waves. This is the fourth year of this NDT. The results of the testing are presented along with qualitative analysis in determining whether a rod is intact or compromised. Analysis is based upon the expected results from other rods at the site, knowledge of rod response at other sites, data gathered from the trunnion rod research test bed at ERDC, and comparison to the previous year’s effort.

30 Nov 2022

Risk-Based Prioritization of Operational Condition Assessments: Methodology and Case Study Results

Abstract: USACE operates, maintains, and manages more than $232 billion of the Nation’s water resource infrastructure. USACE uses the Operational Condition Assessment (OCA) to allocate limited resources to assess condition of this infrastructure in efforts to minimize risks associated with performance degradation. The analysis of risk associated with flood risk management (FRM) assets includes consideration of how each asset contributes to its associated FRM watershed system, understanding the consequences of the asset’s performance degradation, and a determination of the likelihood that the asset will perform as expected given the current OCA condition ratings of critical components. This research demonstrates a proof-of-concept application of a scalable methodology to model the probability of a dam performing as expected given the state of its gates and their components. The team combines this likelihood of degradation with consequences generated by the application of designed simulation experiments with hydrological models to develop a risk measure. The resulting risk scores serve as an input for a mixed-integer optimization program that outputs the optimal set of components to conduct OCAs on to minimize risk in the watershed. This report documents the results of the application of this methodology to two case studies.

30 Nov 2022

Numerical Analysis of Dike Effects on the Mississippi River Using a Two-Dimensional Adaptive Hydraulics Model (AdH)

Abstract: This report describes the hydraulic effects of dikes on water surface elevation (WSE) and velocities in the Mississippi River near Vicksburg, MS, from Interstate 20 to Highway 80 using a previously calibrated 2D Adaptive Hydraulics numerical model. Dike heights and their associated hydraulic roughness values were varied to quantify the overall effects of adjustments to dike fields. Steady flows characterized as low, medium, and high conditions were simulated. The WSE and velocity difference plots were generated to illustrate the hydraulic effects on the river under all scenarios discussed above. Overall, the dike adjustments had negligible impacts on WSEs and showed minimal effects on velocities on a system wide scale.

19 Aug 2022

The Old River, Mississippi River, Atchafalaya River, and Red River (OMAR) Technical Assessment

NOTE: The Old River, Mississippi River, Atchafalaya River, and Red River (OMAR) Technical Assessment is a 9-volume series of reports that was produced under the direction of the Mississippi River Geomorphology & Potamology Program. An abstract from the main report, Volume 1, is listed below, along with the individual volume titles and links to the relevant reports. ABSTRACT: This is the main report of Old River, Mississippi River, Atchafalaya River, and Red River (OMAR) Technical Assessment. The primary objective of the OMAR Technical Assessment was to conduct a comprehensive evaluation that aimed to understand the impacts of former and potential changes to the system in the vicinity of the Old River Control Complex (ORCC) over time, the water and sediment delivery regime at the ORCC, and the effects to the river system surrounding the ORCC. Scenarios evaluated in this technical assessment were designed to investigate potential system responses to a wide range of possible operational alternatives and identify knowledge gaps in current understanding of system behavior. This report summarizes and synthesizes the individual reports detailing the investigations into specific aspects of the ORCC and the surrounding region.

4 Apr 2022

Risk-Based Prioritization of Operational Condition Assessments: Jennings Randolph Case Study

Abstract: The US Army Corps of Engineers (USACE) operates, maintains, and manages over $232 billion worth of the Nation’s water resource infrastructure. Using Operational Condition Assessments (OCA), the USACE allocates limited resources to assess asset condition in efforts to minimize risks associated with asset performance degradation, but decision makers require a greater understanding of those risks. The analysis of risk associated with Flood Risk Management assets in the context of its associated watershed system includes understanding the consequences of the asset’s failure and a determination of the likelihood that the asset will perform as expected given the current OCA ratings of critical components. This research demonstrates an application of a scalable methodology to model the probability of a dam performing as expected given the state of its subordinate gates and their components. The research team combines this likelihood with consequences generated by the application of designed simulation experiments with hydrological models to develop a measure of risk. The resulting risk scores serve as an input for an optimization program that outputs the optimal set of components to conduct OCAs on to minimize risk in the watershed. Proof-of-concept results for an initial case study on the Jennings Randolph Dam are provided.

28 Mar 2022

2020 Guided Wave Inspection of California Department of Water Resources Tainter Gate Post-Tensioned Trunnion Anchor Rods: Oroville Dam

Abstract: The Engineering and Test Branch within the Division of Operations and Maintenance of the California Department of Water Resources (DWR) and U.S. Army Corps of Engineers (USACE), Sacramento District, tasked the Sensor Integration Branch (SIB) at the Engineer Research and Development Center (ERDC) to perform non-destructive testing (NDT) on the trunnion anchor rods at Oroville Dam through the use of ultrasonic guided waves. This is the third year of this NDT. The results of the testing are presented along with qualitative analysis in determining whether a rod is in-tact or compromised. Analysis is based upon the expected results from other rods at the site, knowledge of rod response at other sites, data gathered from the trunnion rod research test bed at the ERDC, and comparison to the previous year’s effort.

1 Oct 2021

Acoustic Nondestructive Testing and Measurement of Tension for Steel Reinforcing Members

Abstract: Many concrete structures contain internal post-tensioned steel structural members that are subject to fracturing and corrosion. The major problem with conventional tension measurement techniques is that they use indirect and non-quantitative methods to determine whether there has been a loss of tension. We have developed an acoustics-based technology and method for making quantitative tension measurements of an embedded, tensioned steel member. The theory and model were verified in the laboratory using a variety of steel rods as test specimens. Field tests of the method were conducted at three Corps of Engineers dams, located in Oklahoma, Georgia, and Illinois. Measurements of the longitudinal and shear velocity were able to be made on rods up to 50 ft long. Not all rods of this length were able to be measured and the quality and consistency of the signal varied. There were fewer problems measuring the longitudinal velocity than shear velocity. While the tension predictions worked in the laboratory tests, the tension could not be accurately calculated for any of the field sites. This is because we were not able to obtain the longitudinal or shear velocities in an unstressed state or precise measurements of the longitudinal and shear velocities due to the lack of knowledge of the precise length of the rods in the tensioned state.

15 Jun 2021

Red River Structure Physical Model Study: Bulkhead Testing

Abstract: The US Army Corps of Engineers, St. Paul District, and its non-federal sponsors are designing and constructing a flood risk management project that will reduce the risk of flooding in the Fargo-Moorhead metropolitan area. There is a 30-mile long diversion channel around the west side of the city of Fargo, as well as a staging area that will be formed upstream of a 20-mile long dam (referred to as the Southern Embankment) that collectively includes an earthen embankment with three gated structures: the Diversion Inlet Structure, the Wild Rice River Structure, and the Red River Structure (RRS). A physical model has been constructed and analyzed to assess the hydraulic conditions near and at the RRS for verification of the structure’s flow capacity as well as optimization of design features for the structure. This report describes the modeling techniques and instrumentation used in the investigation and details the evaluation of the forces exerted on the proposed bulkheads during emergency operations for the RRS.

3 Jun 2021

Finite element analysis of quoin block deterioration and load transfer mechanisms in miter gates: pintle and pintle connections

Abstract: The U.S. Army Corps of Engineers (USACE) currently operates and maintains approximately 193 commercially active lock sites with 239 locks and dams spanning nearly 12,000 miles. These networks of water channels are used to transport 600 million tons of domestic cargo, generating $405 billion in revenue annually. Nearly 60% of these structures in operation are over 50 years old and have reached design life. A failure of the miter gates could result in a major negative impact on the economy and on the ability to maintain flood control. Administrators need recommendations to better prioritize maintenance and repair of the USACE miter gates. This work investigated the influence of miter gate’s quoin block degradation on load transfer to the pintle and/or pintle connections. Results of finite element analysis are reported for the quoin block degradation simulated levels of 0%, 25%, 50%, and 75%. The parametric study shows the overstressed regions are the pintle neck and bolt-hole regions. To improve pintle designs so they may better mitigate detrimental environmental based deterioration effects, this work recommends (1) increasing the thickness of the bolt-hole connection region and (2) adding ribbing reinforcement around the neck area of the pintle.

14 May 2021

Hydraulic Dike Effects Investigation on the Mississippi River: Natchez to Baton Rouge

Abstract: This report documents an investigation of the hydraulic effects of dikes on water levels in the Mississippi River between Natchez, MS, and Baton Rouge, LA, conducted for the U.S. Army Corps of Engineers, Mississippi Valley Division, Vicksburg, MS. The investigation was conducted using a previously calibrated Natchez-to-Baton Rouge Adaptive Hydraulics numerical model. The objectives were to alter roughness and height variables associated with the dikes and overbanks encompassed in the numerical model and evaluate their effects on water surface elevations. Steady flow simulations were simulated for 12 May 2011 to investigate the variation in model results during the peak of the 2011 flood on the Mississippi River.