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.

12 May 2021

Wintertime Snow and Precipitation Conditions in the Willow Creek Watershed above Ririe Dam, Idaho

ABSTRACT:  The Ririe Dam and Reservoir project is located on Willow Creek near Idaho Falls, Idaho, and is important for flood risk reduction and water supply. The current operating criteria is based on fully storing a large winter runoff event. These winter runoff events are generally from large storm events, termed atmospheric rivers, which produce substantial precipitation. In addition to the precipitation, enhanced runoff is produced due to frozen soil and snowmelt. However, the need for additional water supply by local stakeholders has prompted the U.S. Army Corps of Engineers to seek to better understand the current level of flood risk reduction provided by Ririe Dam and Reservoir.  Flood risk analysis using hydrologic modeling software requires quantification of the probability for all of the hydrometeorologic inputs. Our study develops the precipitation, SWE, and frozen ground probabilities that are required for the hydrologic modeling necessary to quantify the current winter flood risk.

12 May 2021

Classical and Innovative Methods of Fatigue and Fracture Repairs in Navigation Steel Structures

Abstract: Most of the hydraulic steel structures (HSS) in the U.S. have reached or have past their design life, which leads to unsatisfactory performance. Welded connections with low fatigue resistance, poor weld quality, unanticipated structural behavior, or unexpected loading due to the deterioration of the design boundary conditions are the causes of fatigue cracking. The purpose of this report is to identify and evaluate the traditional and new methods used for fatigue and fracture repairs in navigation steel structures to restore their load carrying capacity and fatigue and fracture resistance. The final objective was to generate a guidance report comprising of recommended and more efficient repair methods for the different fatigue limit states observed in navigation steel structures.

4 May 2021

Investigating the USACE Operational Condition Assessment Process Current and Future

Abstract: The US Army Corps of Engineers operates, maintains, and manages more than $232 billion worth of the Nation’s water resource infrastructure and relies on the Operational Condition Assessment (OCA) process to determine the condition of the assets and their components. The sheer number of components, all of equal OCA scheduling priority, creates challenges in ensuring that assessments are conducted in a timely manner and that data generated are of sufficient quality to inform resource allocation decisions. This research applied methods from systems design to determine the OCA system “as-is” state and create a stakeholder-informed vision of a “to-be” state that addresses current system challenges. To meet its objective of providing current assessments of asset condition, the OCA system must provide four high-level functions: provide access to asset data, conduct assessments, determine asset risk, and prioritize and schedule assessments. The development of capabilities to provide these functions will facilitate the achievement of the OCA system to-be vision: a consistent view of asset condition and risk across the enterprise.

26 Apr 2021

Automated Construction of Expeditionary Structures (ACES): Materials and Testing

Abstract: Complex military operations often result in U.S. forces remaining at deployed locations for long periods. In such cases, more sustainable facilities are required to better accommodate and protect forward-deployed forces. Current efforts to develop safer, more sustainable operating facilities for contingency bases involve construction activities that require a redesign of the types and characteristics of the structures constructed, that reduce the resources required to build, and that decrease the resources needed to operate and maintain the completed facilities. The Automated Construction of Expeditionary Structures (ACES) project was undertaken to develop the capability to “print” custom-designed expeditionary structures on demand, in the field, using locally available materials with the minimum number of personnel. This work investigated large-scale automated “additive construction” (i.e., 3D printing with concrete) for construction applications. This report, which documents ACES materials and testing, is one of four technical reports, each of which details a major area of the ACES research project, its research processes, and its associated results. There major areas include System Requirements, Construction, and Performance; Energy and Modeling; Materials and Testing; Architectural and Structural Analysis.

22 Apr 2021

Estimating Bridge Reliability by Using Bayesian Networks

Abstract: As part of an inspection, bridge inspectors assign condition ratings to the main components of a bridge’s structural system and identify any defects that they observe. Condition ratings are necessarily somewhat subjective, as they are influenced by the experience of the inspectors. In the current work, procedures were developed for making inferences on the reliability of reinforced concrete girders with defects at both the cross section and the girder level. The Bayesian network (BN) tools constructed in this work use simple structural mechanics to model the capacity of girders. By using expert elicitation, defects observed during inspection are correlated with underlying deterioration mechanisms. By linking these deterioration mechanisms with reductions in mechanical properties, inferences on the reliability of a bridge can be made based on visual observation of defects. With more development, this BN tool can be used to compare conditions of bridges relative to one another and aid in the prioritization of repairs. However, an extensive survey of bridges affected by deterioration mechanisms is needed to confidently establish valid relationships between deterioration severity and mechanical properties.

1 Sep 2020

PUBLICATION NOTICE: Water Security Scenarios: Planning for Installation Water Disruptions

Abstract: The Army’s critical missions are at risk from interruption of water supplies. Sufficient amounts of high- quality potable water are a resource without substitute. The Army’s Installation Energy and Water Security Policy establishes requirements for installations to sustain critical mission capabilities and to mitigate risks posed by energy and water disruptions that affect installations; this includes coordinating vulnerability and risk assessments of potential disruptions and implementing adequate responses to mitigate identified risks. Resilient installations will develop storage capacity to forestall water shortages and will also have short- and long-term plans to help the installation recover from events and forestall progressing to more severe deficits. This project supports compliance with the water security policy by exploring the range of conditions and responses possible across installations. Multiple scenarios were developed to explore how a 14-day interruption in water supply might affect an installation and to provide preliminary guidance to help installations develop strategies to address water disruptions to critical missions drawing from existing processes used in mission assurance. Researchers investigated types of installations and classes of scenarios most relevant to installation water security planning and explored several scenarios to provide a framework to helps installations advance their water resilience and security planning.