24 Aug 2023

Geomorphic Metrics Used in FluvialGeomorph

Abstract: FluvialGeomorph (FG) is a geographic information system-based geomorphic analysis toolkit that analyzes high-resolution terrain data to provide river-reach assessments for watershed studies. This report demonstrates the utility of FG to identify physical stream channel characteristics that are used to determine channel stability. The FG toolbox is a remote-sensing approach based on lidar data, designed to measure channel, floodplain, valley, and watershed metrics necessary for watershed assessments. Currently, channel slope and cross-sectional analysis and planform metrics are being evaluated with existing lidar data from different hydrophysiographic regions within the United States. Recent study areas include the Northwest, Southwest, South, Midwest, and upper Midwest of the United States.

18 Aug 2023

Unmanned Ground Vehicle (UGV) Path Planning in 2.5D and 3D

Abstract: Herein, we explored path planning in 2.5D and 3D for unmanned ground vehicle (UGV) applications. For real-time 2.5D navigation, we investigated generating 2.5D occupancy grids using either elevation or traversability to determine path costs. Compared to elevation, traversability, which used a layered approach generated from surface normals, was more robust for the tested environments. A layered approached was also used for 3D path planning. While it was possible to use the 3D approach in real time, the time required to generate 3D meshes meant that the only way to effectively path plan was to use a preexisting point cloud environment. As a result, we explored generating 3D meshes from a variety of sources, including handheld sensors, UGVs, UAVs, and aerial lidar.

17 Aug 2023

A/E/C Graphics Standard: Release 2.2

Abstract: The A/E/C Graphics Standard Release 2.2 has been developed by the Computer-Aided Design/Building Information Modeling Technology Center to document how proper hand-drafting practices can be achieved in advanced modeling. It is through the collection and documentation of these practices that consistent models and drawings shall be achieved throughout the US Army Corps of Engineers (USACE), as well as other federal agencies. In the collection of these practices, various historical USACE District drafting manuals were consulted and compared against practices contained in industry and national standards, with consideration toward whether software can achieve those practices. The documentation of these practices will help to achieve both clear and aesthetically pleasing construction documents.

15 Aug 2023

Dynamic Material Properties of Grade 50 Steel: Effects of High Strain Rates on ASTM A992 and A572 Grade 50 Steels

Abstract: Uniaxial tensile tests were conducted on American Society for Testing Materials International (ASTM) A992 and A572 Grade 50 steels at increasing strain rates to determine the material strength properties of structural members subjected to dynamic loadings. The increase in dynamic yield strength and ultimate tensile strength was determined to update design criteria within UFC 3-340-02, which are currently limited to ASTM A36 and A514 steels. The proposed updates will provide the necessary information required to design blast-resistant structures utilizing modern-day structural steels. The dynamic material properties determined by high-rate tensile tests were compared to static values obtained from ASTM E8 standard tensile tests. The comparisons were used to calculate dynamic increase factors (DIFs) for each steel at strain rates from 2E-3 to 2E0 inch/inch/second. The experiments revealed that the A992 steel exhibited an increase in yield strength up to 45% and ultimate tensile strength up to 20% as strain rate increased over the range tested. The A572-50 steel exhibited a similar increase in yield strength up to 35% and ultimate tensile strength up to 20%. The DIF design curves developed during this research will allow engineers to more efficiently design structural steel components of hardened structures for the protection of our nation’s critical infrastructure.

14 Aug 2023

Technology Transfer: Converting Multizone HVAC Systems from Constant to Variable Volume

Abstract: This project promotes awareness and facilitates implementation of a low-cost controls retrofit for multizone air handling systems as an interim solution for energy efficiency that accrues savings while delaying system replacement. Implementation tools support technology evaluation and rapid implementation. Products include the following: fact sheet, technical note, pitch briefing, scoping guide, savings estimator, procurement package templates, commissioning guide, and on-line training. Multiple outreach activities occurred including presentations, journal articles, and contacting potentially interested parties.

11 Aug 2023

Dredged Material Can Benefit Submerged Aquatic Vegetation (SAV) Habitats

Purpose: This technical note (TN) was developed by the US Army Engineer Research and Development Center–Environmental Laboratory (ERDC-EL) to provide an overview of the ecosystem services delivered by submerged aquatic vegetation (SAV) to estuarine and coastal ecosystems and to describe potential methods for the beneficial use of dredged material (BUDM) to aid in SAV restoration. Although dredging tends to have a negative association with SAV habitats, BUDM may provide an opportunity to expand suitable SAV habitat to areas where depth is the primary limiting factor. Recent in situ observations have shown that SAV has opportunistically colonized several dredged-material placement sites. This TN provides context on BUDM for SAV habitat restoration to encourage increased strategic placement.

11 Aug 2023

International Workshop on Cold Regions Defense Infrastructure: 13–15 September 2022, Hanover, New Hampshire

Abstract: The Inaugural International Workshop on Cold Regions Defense Infrastructure united engineers and scientists of the US Department of Defense with defense representatives from the other nations comprising the International Cooperative Engagement Program for Polar Research (ICE-PPR): Canada, Denmark, Finland, Norway, Sweden, and New Zealand. Through the ICE-PPR Memorandum of Understanding, Project Arrangements (PAs) enable the seven nations to share measurements, models, and access to research sites and facilities. The goal of the workshop was to work as a coherent team to identify needs and develop PAs for three major topic areas: infrastructure, water/wastewater, and energy. Increasing interest in earth’s polar regions necessitates identifying capabilities and gaps for these critical mission-relevant topic areas.

10 Aug 2023

Sensitivity of Simulated Flaw-Height Estimates to Phased Array Scan Parameters

Abstract: Phased array ultrasonic testing (PAUT) is a nondestructive testing (NDT) technique for detecting and sizing flaws in welds. Estimates of flaw size are sensitive to a variety of PAUT scan parameters. In this study, estimates of flaw height are simulated using computer software. The sensitivity of these estimates to selected PAUT scan parameters is analyzed to identify those that have the greatest influence on estimates of flaw height. Understanding how varying different parameters within a phased array instrument affects the accuracy of flaw-height estimates helps to validate PAUT scan procedures and improve flaw-height estimates. For this research, a series of permutations on selected flaws were performed to see how certain parameters affect the accuracy in sizing flaw height. In addition, an analysis on how beam spread leads to flaw sizing inaccuracies was also conducted as part of this work.

9 Aug 2023

Repair of Corroded Steel Girders of Hydraulic Steel Structures (HSS) Using Fiber-Reinforced Polymers (FRP)

Abstract: Although steel hydraulic structures have a protective system to prevent corrosion, this type of deterioration will eventually occur due to the constant exposure to harsh environmental conditions. There are several techniques that can be implemented to repair corroded steel structural elements. This report presents a numerical study to evaluate the mechanical behavior of corroded steel girders used in hydraulic steel structures and to evaluate several carbon fiber–reinforced polymers (CFRP) layups to repair them. The girders were modeled as simply supported with four-point loading boundary conditions. The corrosion deterioration was modeled as loss in section as 10%, 25%, and 40%. The effectiveness of the deterioration was established based on the level of stresses at the steel compared with the undamaged condition after it is strengthened with CFRP. It was found that CFRP repair is more practical for reducing the stresses at the steel in the shear dominated zone if deterioration is below 25%. At the tensile dominated zone, CFRP is effective for reducing the stresses for deterioration below 40%.

8 Aug 2023

Evaluation of Structural and Operational Alternatives to Optimize the Distribution of Water and Sediment in the Passes of the Mississippi River

Abstract: Mississippi River shoaling and dredging processes in the vicinity of Head of Passes and in Southwest Pass were investigated. Existing rates of deposition and dredging were determined using near-daily eHydro bathymetric surveys, National Dredging Quality Management dredge operating data, and geospatial processing steps developed for this study. These surveys provide a means to characterize the highly dynamic and variable sedimentation patterns observed in the navigation channel. The HEC-6T one-dimensional numerical sedimentation model was used to evaluate possible modifications to the distribution of water and sediment in the Mississippi River near Head of Passes in an attempt to reduce shoaling in the navigation channel. The model was used to evaluate the effects of partial closures of several distributaries downstream from Venice and to evaluate the effects of channel widening and channel deepening adjacent to the Hopper Dredge Disposal Area at Head of Passes. In this study, various structural alternatives were compared to a base test that represented existing conditions. Sedimentation and dredging effects were projected 50 years into the future.