30 Oct 2024

Development of an Inertial Profiler Specification for Airfield Pavement Construction

Abstract: The US Army Engineer Research and Development Center (ERDC) developed a test method and specification for measuring the smoothness of newly constructed airfield pavements using the inertial profiler. The limitations inherent in the currently accepted measurement system, the California-type profilograph, are detailed in this report. The effort detailed herein draws attention not only to the superior repeatability of the inertial profiler but also to the device’s ability to report true surface profile more accurately than the California-type profilograph. Correlations were drawn between the two devices with high (greater than 0.8) goodness-of-fit, and recommendations were made pertaining to the use of inertial profilers in place of California-type profilographs. These recommendations were not only founded on the data collected and analyzed in this effort but are also consistent with the current state of practice for other federal agencies, such as the Federal Aviation Administration and the Federal Highway Administration.

29 Oct 2024

Influence of Fines Content on the Progression of Backward Erosion Piping

Abstract: Backward erosion piping is a form of internal erosion that endangers the structural stability of levees and dams. Understanding the factors that influence this form of erosion can result in improved risk assessment and more appropriate modifications to new and existing structures. Historically, it has been assumed that the presence of silt size particles would reduce the gradient required for erosion. This study investigated the influence of fines content on backward erosion piping through a series of laboratory experiments on silty sands. Laboratory results show that as the fines content increased in the samples, so too did the gradient required to produce and progress piping to failure. The results indicate that a new factor is needed to properly account for silt content in backward erosion piping (BEP) risk assessment of silty sands.

9 Oct 2024

Unified Facilities Criteria and Unified Facilities Guide Specifications for Sustainable Military Construction : Concrete, Asphalt, Wood, and Life-Cycle Assessment Perspectives

Abstract: Construction materials such as concrete, asphalt, and wood are essential components for Department of Defense (DoD) Military Construction (MILCON) and construction for contingency operations around the world. From housing facilities, to airfields, to magazines and hardened structures, each of these materials fulfill numerous Army building applications. However, greenhouse gas (GHG) emissions stemming from the manufacturing, application, maintenance, and disposal of concrete and steel exact a significant climate burden. Thus, due to their pervasive use and commodity status, the advancement of sustainable concrete, asphalt, and wood materials are a critical driver for GHG mitigation. This report communicates a first step toward decarbonization-focused updates to UFC and UFGS by outlining major specifications related to concrete, asphalt, and wood with near- and long-term strategies to facilitate modernization. The Engineer Research and Development Center (ERDC) is poised to make a significant impact on the identification and integration of sustainable materials to meet regulatory goals for the re-duction of GHG emissions in MILCON. New guidance will be integrated into UFC and UFGS by leveraging unique re-search, development, test, and evaluation (RDT&E) capabilities in materials science, life-cycle assessment, and federal relationships with discipline working groups

7 Oct 2024

Seismic analysis for Pohnpei Island, Federated States of Micronesia

Abstract: The purpose of this study was to determine the seismic hazards that can affect Pohnpei Island and provide estimates of the ground motion parameters. The primary parameters are peak ground acceleration (PGA), pseudo-spectral acceleration (PSA), and velocity. These values were determined both probabilistically and deterministically to illustrate the overall seismic hazard to Pohnpei Island. A review was conducted of the technical literature to determine geologic studies that have been performed for characterization of the island’s volcanism, stratigraphy, and tectonism. This report is a desktop study that examines the tectonism of the region, the geology of the island, its geologic history, and its seismic record. No liquefaction areas or tsunami hazards were identified by researchers on the island.

7 Oct 2024

Full-Scale Evaluation of Saltwater Concrete for Airfield Pavement Construction and Repair

Abstract: The US Navy has a need to rapidly construct concrete facilities onshore to support contingency operations. Mixing water for concrete is typically specified to be freshwater; however, in many scenarios there are limited amounts of freshwater available for construction. Thus, use of readily available saltwater would be advantageous. This project’s objective was to evaluate the suitability of saltwater as a replacement for freshwater for producing concrete airfield pavement under relevant operational scenarios. Three full-scale test sections were constructed, and performance was evaluated in the context of relatively short design life requirements. First, direct comparison slabs of freshwater and saltwater concrete were constructed and exposed to ambient environmental conditions for one year; periodic concrete strength measurements were made. Next, 8 in. thick and 11 in. thick saltwater concrete pavements were constructed then subjected to P-8 aircraft accelerated loading. Finally, four airfield damage repair techniques were executed using saltwater and subjected to accelerated P-8 aircraft loading. Saltwater concrete performance was found to be similar to freshwater concrete for all scenarios investigated. The overall conclusion was that saltwater can be used in place of freshwater for concrete airfield pavement construction and repair for short- to medium-term use (1–2 yr) with no meaningful impact to mission requirements.

26 Sep 2024

A Geospatial Model for Identifying Stream Infrastructure Locations

Abstract: Management of hydraulic infrastructure for flood control, hydropower, navigation, and water supply is a critical component of the Army Dams and Transportation Infrastructure Program (ADTIP). This project provides a tool to locate stream infrastructure using a one-dimensional approach supplemented with geospatial filtering that only needs digital elevation model (DEM) files as primary input. The regions in and around Forts Liberty, Sill, and Cavazos were selected as study areas, and stream networks with corresponding stream elevation profiles were created and searched for elevation changes that met vertical threshold and search window criteria. Recall, Fβ, and a ratio of under to overprediction were used to evaluate performance. The search algorithm generally overpredicts the number of stream infrastructure locations and especially so for large search windows (20 or 25 cells) and small vertical threshold values (5 or 10 m). Overall, it was found that midrange vertical threshold values (2 or 2.5 m with long search windows (20 or 25 cells) with the land cover classification (LCC) check applied yielded results that minimized false negatives and overpredictions. The significance of this tool is that it may reduce costly field investigations, or at least aid in the prioritization of site visits for hydraulic infrastructure managers.

26 Sep 2024

High-Rate Characterization and Modeling of a Hyperelastic Block Copolymer Subjected to Ballistic Impact

Abstract: A polystyrene-polyisobutylene-polystyrene star-block copolymer (PS-PIB-PS) is a thermoplastic elastomer with visco hyperelastic characteristics that displays a high level of toughness and performs well in shock attenuating applications. The research goal is to investigate experimentally and numerically the capacity of PS-PIB-PS to dissipate kinetic energy and examine its deformation and failure modes under impact by spherical steel projectiles at speed ranges of 200–1,700 m/s. First, PS-PIB-PS is characterized using a Split-Hopkinson Pressure Bar to measure high strain rate response and calibrate a hyperelastic material model. Second, ballistics tests are conducted on 12 in. × 12 in. PS-PIB-PS targets with various thicknesses to determine the ballistic limit and residual velocity (Vr) versus impact velocity (Vi) relationship. Finally, ALE3D is used to model the ballistic response and capture the extreme deformation observed during testing. During ballistic impact tests, significant deformation occurred on the backside of polymer targets, followed by perforation of the polymer, culminating with retraction and recovery of the polymer in a self-healing manner. Numerical simulations captured the deformation behavior during impact and predicted the Vr versus Vi response with high accuracy. This research provides a method of modeling hyperelastic materials subjected to ballistic impact and provides a better understanding of energy dissipation of these materials.

25 Sep 2024

Accelerated Concrete Flexural Strengths for Airfield Pavements

Abstract: Mixture-proportioning studies and submittals are an integral part of the pavement design and planning process as outlined in the Unified Facilities Guide Specification 32 13 14.13 for Department of Defense airfield pavements. Many aspects of the required testing are time-consuming due to the duration of the test (e.g., alkali–silica reaction experiments) or to the required concrete age at testing (e.g., compressive or flexural strength testing). Time awaiting testing results often delays projects and adds cost. The objective was to develop an accelerated testing requirement for flexural strength (currently 650 psi or greater at 90 days), thereby reducing the time to pavement acceptance. Potential accelerated testing methodologies were evaluated in a literature review. A statistical analysis generated under a design of experiments protocol determined concrete flexural strength gain and correlation ratios. Results of the statistical analysis showed that a reduced flexural strength of 600 psi could be accepted at 14 days and still reach the minimum flexural strength requirement of 650 psi at 90 days with high certainty (i.e., greater than 95% certainty). Additionally, the results stemming from the design of experiments compared favorably with data gathered from four mixture-proportioning submittals acquired via the Transportation Systems Center.

12 Sep 2024

SEG-2 Viewer MATLAB App User Guide

Purpose: This technical note documents the functionalities of the SEG-2 Viewer and provides a step-by-step user guide for the application. SEG-2 Viewer is a MATLAB app that was developed at the Geotechnical and Structures Laboratory (GSL) of the US Army Engineer Research and Development Center (ERDC) for visualizing and analyzing geophysical data in SEG-2 format.

11 Sep 2024

Helical Anchor Installation with the High Mobility Engineer Excavator: Proof-of-Concept Testing

Abstract: Proof-of-concept testing was conducted to determine the viability of helical anchor installation using the US Army’s High Mobility Engineer Excavator (HMEE). To facilitate the proof-of-concept test, a new hydraulic hose kit was designed that connects the Bridge Supplemental Set (BSS) drive motor to the HMEE’s auxiliary hydraulic system. Additionally, a steel mount was fabricated that provided means to attach the BSS drive motor to the boom of the HMEE. Testing indicated the HMEE can successfully install the BSS anchors with the required hardware, but the vehicle’s large footprint will likely increase the installation time compared to previous methods. Several improvements to the hydraulic hose kit design were identified through the experiment, and guidance was created to facilitate efficient HMEE usage in the future. Once a permanent solution is developed to mount the BSS drive motor to the HMEE, the capabilities of the BSS will be greatly expanded by allowing each Multi-Role Bridge Company to install anchors using multiple vehicle types.