Naval Facilities Engineering Command Research Articles

Evaluation of the Static Design Procedure in the Canadian Foundation Engineering Manual for Piles in Cohesionless Soil

Piles provide a convenient solution for heavy structures, where the foundation soil bearing capacity, or the tolerable settlement may be exceeded due to the applied loads. In cohesionless soils, the two frequently used pile installation methods are driving and drilling (or boring). This paper reviews the results of a large database of pile load tests of driven and drilled piles in cohesionless soils at various locations worldwide. The load test results are compared with the static analysis design method for single piles recommended in the Canadian Foundation Engineering Manual (CFEM) and other codes and standards such as the American Association of State Highway and Transportation Officials, Federal Highway Administration, American Petroleum Institute, Eurocode, and the Naval Facilities Engineering Command. An improved pile design procedure is proposed linking the pile design coefficients (β) and (Nt) to the friction angle of the soil, rather than employing the generalized soil type grouping scheme previously used in the CFEM. This improvement included in the new version of the CFEM 2021 produces a more unified value of the pile capacity calculated by different designers, reducing the obtained design capacity discrepancies.

Comparing abundance estimates from closed population mark-recapture models of endangered adult Atlantic sturgeon

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 39:63-76 (2019) - DOI: https://doi.org/10.3354/esr00957 Comparing abundance estimates from closed population mark-recapture models of endangered adult Atlantic sturgeon J. E. Kahn1,2,*, C. Hager3, J. C. Watterson4, N. Mathies3, K. J. Hartman2 1National Marine Fisheries Service, Office of Protected Resources, Silver Spring, Maryland 20910, USA 2Division of Forestry and Natural Resources, West Virginia University, Morgantown, West Virginia 26506-6125, USA 3Chesapeake Scientific, Williamsburg, Virginia 23185, USA 4U.S. Department of the Navy, Naval Facilities Engineering Command, Atlantic Norfolk, Virginia 23508, USA *Corresponding author: jason.kahn@noaa.gov ABSTRACT: Atlantic sturgeon Acipenser oxyrinchus oxyrinchus were listed as 5 distinct population segments under the US Endangered Species Act in 2012. At that time, only 2 abundance estimates of the Atlantic sturgeon population were available: one from commercial fisheries landings in the Hudson River ending in 1995 and one from mark-recapture research in the Altamaha River, Georgia, in 2004 and 2005. In 2013, we verified spawning in the York River, Virginia, system and initiated a multiple-year mark-recapture study focusing on spawning-run abundance. We used a Schumacher-Eschmeyer model and Program CAPTURE to produce estimates of annual spawning abundances from 2013 to 2018. The Schumacher-Eschmeyer estimates of spawning-run abundance with 95% confidence intervals from 2013 to 2018 were 75 (31-190), 157 (115-244), 184 (150-238), 222 (137-576), 212 (157-328), and 145 (89-381), respectively. Because Atlantic sturgeon do not spawn every year, the trends in estimates do not suggest a recovering or declining population, but rather variability in proportions of the adult population that return to spawn each year. The estimates produced in Program CAPTURE using M0 (null), Mt (Chao Mt and Darroch), Mh (Chao Mh and Jackknife), and Mth (Chao Mth) models all produced similarly reliable estimates. The models that consider a behavioral response to initial capture (Mb, Mbh, and Mtb) failed to produce reliable estimates for this data, likely because as an endangered species, the dataset for Atlantic sturgeon was sparse. The Jackknife equation (model Mh) was the most precise every year with reliable accuracy and therefore is recommended. KEY WORDS: Anadromous · Conservation · Endangered species · Fish · Mark-recapture · Monitoring · Native fish · Population ecology · Population modeling Full text in pdf format Supplementary material PreviousNextCite this article as: Kahn JE, Hager C, Watterson JC, Mathies N, Hartman KJ (2019) Comparing abundance estimates from closed population mark-recapture models of endangered adult Atlantic sturgeon. Endang Species Res 39:63-76. https://doi.org/10.3354/esr00957 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 39. Online publication date: June 06, 2019 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2019 Inter-Research.

Dynamic response of ground floor slab due to friedlander local load

Blast load is one of the common phenomena that may heavily damage a building. As a dynamic force, blast loads require further studies. The effect of blast loads on ground floor slab is studied in this paper. Dynamic responses are affected by many factors, such as shear modulus, soil stiffness modulus, and slab thickness. In this study, blast load is modeled in accordance to Friedlander local load, including its negative phase. Although being smaller in amplitude, negative phase causes larger deflections as shown in some previous studies. The Cubic Negative Phase equation used in modeling the Friedlander local load is recommended by Naval Facilities Engineering Command Design Manual 2.08. A number of variations on loading positions, slab thickness, and damping ratios are made to observe the change in its dynamic responses. The result of the study shows that the addition of slab thickness and damping ratio helps reduce the absolute maximum deflection, while the further the local load is located, the larger deflections are caused.

Field Demonstration of a Novel Reversible SOFC System for Islanded Microgrid Energy Storage

The high cost and energy security of importing fuel to islanded grids and communities has led to a growing need to generate power onsite with alternative and renewable energy technologies while reducing logistics costs of importing electrical power. The ability to provide independence, endurance, reliability, and resilience of power compels both remote and critical infrastructure loads to integrate greater capabilities into their microgrid systems. However, grid operators are being faced with the challenges of variability and intermittent energy production from renewables. Therefore, energy storage has become a critical component to balance micro and utility grids, improve efficiency, reduce fuel consumption, enable localized grid independent energy secure power in cases of emergencies or unreliable traditional grid use, and provide critical power in the event of power outages. There has been particular interest in reversible solid oxide fuel cells (RSOFCs) in the energy sector for electricity, energy storage, grid stabilization and improvement to power plant system efficiency due to favorable thermodynamic efficiencies of high temperature steam electrolysis. With funding from Naval Facilities Engineering Command and Expeditionary Warfare Center (NAVFAC EXWC), Boeing’s Advanced Technologies Program, using Sunfire fuel cell technology, has developed the largest ever fully integrated grid tied RSOFC system that uses sunlight and sea water to generate and store energy with no logistical tail. In this system, excess grid energy or curtailed power generated by renewables is sent to the system operating in electrolysis mode to produce H2. The H2 is stored and then used in the system’s fuel cell mode to provide supplemental power to the grid during peak hours or as needed. The system was designed to run off of sea water for cooling and water feed for electrolysis via an internal desalination unit or via the water recycle system. As part of this program, Boeing has developed a H2 storage and compression system, power distribution system, and master controller to interface with the fuel cell subsystem developed by Sunfire. Previous results showed that the system exceeded expectations with an electrolysis efficiency of > 80% LHV and an overall system efficiency of 60% LHV with compression and liquid water feed. The system has been shipped to Pearl Harbor on the island of Oahu, Hawaii to undergo a 6 month demonstration in the field on a working island microgrid. The intent of this demonstration is to validate the opportunity to insert reversible fuel cell systems with greater power generation (e.g. up to 1 MW) into microgrids on both remote islands and expeditionary applications. This paper will discuss test results and challenges of demonstrating a RSOFC system in island microgrid environments. It will also discuss how the RSOFC system fits into the overall microgrid concept for NAVFAC and helps to address a logistic free hydrogen economy in remote areas.

Field Demonstration of a Novel Reversible SOFC System for Islanded Microgrid Energy Storage

Boeing has developed a 50 kWDC reversible solid oxide fuel cell (RSOFC) system that uses sunlight and sea water to generate and store energy with no logistical tail. In this system, renewable energy is sent to the system operating in electrolysis mode to produce H2. The H2 is stored and then used in the system’s fuel cell mode to provide power to the grid. As part of this program, Boeing has developed a H2 storage and compression system, power distribution system, and master controller to interface with the fuel cell subsystem developed by Sunfire. The system was shipped to Pearl Harbor as part of a 6 month field demonstration supported by the Naval Facilities Engineering Command and Expeditionary Warfare Center (NAVFAC). This paper will discuss the demonstration of the RSOFC system in island microgrid environments and how it helps to address a logistic free hydrogen economy in remote areas.

Comparison of pedotransfer functions for the determination of saturated hydraulic conductivity coefficient

Abstract On one hand, direct methods of measurement of saturated hydraulic conductivity coefficient are time consuming, and on the other hand, laboratory methods are cost consuming. That is why the popularity of empirical methods has increased. Their main advantages are speed of calculations and low costs. Comparison of various empirical methods (pedotransfer functions) for the determination of saturated hydraulic conductivity coefficient was the purpose of this work. The methods used were Shepard’s, Hazen’s, USBR (United States Bureau of Reclamation), Saxton et al.’s, Kozeny–Carman’s, Krüger’s, Terzaghi’s, Chapuis’s, Sheelheim’s, Chapuis’, and NAVFAC (Naval Facilities Engineering Command) methods. Calculations were carried out for the soil samples of differential texture. The obtained results shows the methods used for the determination of permeability coefficient differ considerably. Mean values obtained by analysed methods fluctuated between 0.0006 and 12.0 m·day−1. The results of calculations by the chosen methods were compared with the results of the laboratory method. The best compatibility with laboratory method was obtained by using the Terzaghi method.

A Crusade on HSP Amber High Mast Yields Green with Plasma

Naval Facilities Engineering Command Northwest (NAVFAC NW) Public Works Department (PWD) Everett recently completed a lighting replacement project at Naval Station (NS) Everett, Washington, utilizing a utility energy service contract (UESC) with Bonneville Power Administration (BPA). The project replaced 74 high pressure sodium (HPS) light fixtures with modern energy saving, light-emitting plasma (LEP) fixtures atop 80-foot light poles along the piers and wharf at NS Everett. The no-glare LEP bulbs last twice as long while using less than half the power of their HPS predecessors. This project was completed at a cost of $160,000 and will result in cost avoidances in annual operating and maintenance of over $16,000, with a payback under 10 years. This UESC-financed and executed project saves one percent of the total shore energy consumption cost. Through similar efficiency projects and energy conservation efforts, NS Everett has reduced power usage by 16 percent in the past year and 40 percent since 2003.

COMPUTATION OF BLAST LOADING FOR A MULTI STOREYED FRAMED BUILDING

The number and intensity of domestic and international terrorist activities have heightened our concerns towards the safety of our infrastructure systems. Due to different accidental or intentional events, related to important structures all over the world, explosive loads or blast loads have received considerable attention in recent years. The development in this field is made mostly through publication of the U.S. Army Corps of Engineers, Naval Facilities Engineering Command (NAVFAC), and Air Force Civil Engineer Support Agency. In India also, the guidelines for the blast loading are published in IS 4991. In the present study, blast pressures for different weights of surface blast or TNT and varying stand-off distances are computed for a multi-storeyed framed building adopting wave scaling laws given by U.S Army technical manual (UFC3-340-02). Blast pressures for different cases are computed using correlation between blast pressure and blast scaled distance based on charts given in U.S manual. Time history loading is also obtained with parameters of reflected total over pressure and duration of positive phase of blast.

Ecological restoration in a cultural landscape: conservationist and Chagossian approaches to controlling the 'coconut chaos' on the Chagos Archipelago.

The citation BWoods andMoriarty 2001^ that appears on page 1 and page 2 of the original publication has beenmisprinted as BWoods 2999.^ The sentences should read: Page 1, second column, lines 14–18: BThis allows for definitions of species as more or less native than other species, and for the recognition of changes over time such that a species may adapt or evolve in a process of ‘naturalisation’ in its new habitat from alien to native (Woods and Moriarty 2001: 176).^ Page 2, first column, lines 3–6: BConsequently, the removal of invasive species might facilitate invasion by other more aggressive alien species and may harm native wildlife that utilises alien hosts (Woods and Moriarty 2001: 183).^ The sentence on page 3, second column, lines 25–29 contains erroneously inserted B260.^ The sentence should read: BIn 2005, the US Navy reported on rat and cat control programmes at the military base on Diego Garcia, and proposed extending rat eradication measures to the entire island (US Naval Facilities Engineering Command (Pacific Division) 2005: Appendix I-2).^ The sentence on page 3, second column, lines 2–5 contains misprinted phrase Bcoconcxut crab.^ The sentence should read: BChagos islanders ate coconut crabs and the meat and eggs of green sea turtles and a range of ground-nesting birds, and green sea turtles and hawksbill turtles were exported to Mauritius for their meat and shells respectively (Frazier 1980: 343).^ The Publisher regrets the mistakes.

Measurements of the peak pressure and sound exposure level from underwater explosions

There is an interest by the Navy to determine the sound field produced by underwater explosions to minimize the impact on marine life during training exercises. This work presents measurements of underwater explosions collected 7 km off the coast of Virginia in shallow water (depth 14 m) with sound speed conditions considered approximately iso-speed. Explosive charges with TNT equivalent weight 0.1 to 6.0 kg (W) were deployed at approximately mid-water and bottom depths. Acoustic data were recorded using a 9 element vertical line array at range 430 m and single-element autonomous systems at ranges 170, 430, and 950 m. The peak pressures and sound exposure levels (SEL) are calculated from the data; at 430 m peak pressures as high as 220 dB re 1 μPa and SEL as high as 190 dB re 1 μPa2 s were measured. The peak pressures are compared to semi-empirical equations that are functions of range and W to the one-third power, such as Arons [J. Acoust. Soc. Am. 26, 343-346 (1954)], and both the peak pressures and SEL are compared to simulations obtained using the parabolic wave equation. [Research supported by Naval Facilities Engineering Command.]

Comparative Bearing Capacity Analysis of Spread Footing Foundation on Fractured Granites

It is evident from several studies that ultimate bearing capacities calculated by traditional methods are conservative and subjective. For large civil structures founded on spread footings, cost-effective and safer foundation could be achieved by adopting optimum ultimate bearing capacity values that are based on an objective and pragmatic analysis. There is a pressing need to modify the existing methods for accurate estimation of the bearing capacities of rocks for spread footings. In practice, foundation bearing capacities of rock masses are often estimated using the presumptive values from Building Officials Code Administrators, National Building Code, and methods adopted by the American Association of State Highway and Transportation Officials. However, the estimated values are often not realistic, and site-specific analyses are essential. In this study, geotechnical reports and drill-log data from successful geotechnical design projects founded on a wide range of granites in eastern Tennessee were consulted. Different published methods were used to calculate ultimate bearing capacity of rock mass. These methods included Peck, Hansen and Thornburn, Hoek and Brown, Army Corps of Engineers, Naval Facilities Engineering Command, and Terzaghi's general bearing capacity equations. Wide variation was observed in the calculated ultimate bearing capacity values, which ranged over about two orders of magnitude. Only two of the methods provided realistic results when validated with plate-load test data from similar rocks.

Developing a Business Case Using Whole Building Performance Measurement

ABSTRACT Since 1998, the U.S. Navy's Naval Facilities Engineering Command (NAVFAC) has had a policy for incorporating sustainable design principles into new building construction. The policy states it is the intent of NAVFAC to accomplish this within the given budget constraints and while meeting customer requirements. Programming a building using a first cost approach instead of a life cycle cost approach is one of the biggest challenges for integrating sustainable design into Navy projects. Due to this hurdle, an attempt to develop a Navy-specific business case was undertaken. Through this process, it was discovered that consistent data were not being collected for all applicable Navy buildings. Therefore, the current business case information being used by the Navy is the conglomeration of existing business case analysis in the literature. Although this business case information is useful, there is still a need for collecting and analyzing the Navy business case. To develop the Navy-specific business case, NAVFAC is developing program metrics to capture the status of buildings in the design and construction phase, and started to collect whole building cost and performance data for 14 buildings (7 sustainably designed and 7 traditionally designed buildings) to capture data on the existing inventory of sustainably designed buildings. Performance measurement data are being collected on water, energy, operations and maintenance, waste generation, purchasing, occupant satisfaction, and transportation. The building cost and performance data will be collected for a minimum of 12 months. Both of these data collection and analysis efforts have offered lessons learned that will be shared alongside the current Navy business case information.

The effects of helicopter noise on the reproductive success of the coastal California gnatcatcher

Our laboratory conducted a five‐year study on the potential effects of helicopter noise on the reproductive success of the coastal California gnatcatcher (Polioptila californica californica) on Marine Corps Air Station Miramar (MCAS Miramar) in Southern California. Seven‐hundred twenty‐one nests were monitored for reproductive success, predation, noise levels, and habitat quality. An array of Larson‐Davis sound level meters was used to monitor habitat on MCAS Miramar for a total of 6,176 days during 620 runs at 328 locations. Most sites were exposed to noise in excess of 60 dBA SPL for less than 5% of the monitoring period, but some nests experienced levels in excess of 70 dBA for more than 20% of the time. Statistical models of nest success, nest site selection, and number of fledges per pair showed that the factors best predicting reproductive success were measures of suitable nesting habitat, not noise levels. Helicopter and other noise sources did not affect the reproductive success of gnatcatchers. [Supported by the Marine Corps Air Bases Western Area and the Naval Facilities Engineering Command, SW.]

Geophysical Monitoring of a Field‐Scale Biostimulation Pilot Project

The USGS conducted a geophysical investigation in support of a U.S. Naval Facilities Engineering Command, Southern Division field-scale biostimulation pilot project at Anoka County Riverfront Park (ACP), down-gradient of the Naval Industrial Reserve Ordnance Plant, Fridley, Minnesota. The goal of the pilot project is to evaluate subsurface injection of vegetable oil emulsion (VOE) to stimulate microbial degradation of chlorinated hydrocarbons. To monitor the emplacement and movement of the VOE and changes in water chemistry resulting from VOE dissolution and/or enhanced biological activity, the USGS acquired cross-hole radar zero-offset profiles, travel-time tomograms, and borehole geophysical logs during five site visits over 1.5 years. Analysis of pre- and postinjection data sets using petrophysical models developed to estimate VOE saturation and changes in total dissolved solids provides insights into the spatial and temporal distribution of VOE and ground water with altered chemistry. Radar slowness-difference tomograms and zero-offset slowness profiles indicate that the VOE remained close to the injection wells, whereas radar attenuation profiles and electromagnetic induction logs indicate that bulk electrical conductivity increased down-gradient of the injection zone, diagnostic of changing water chemistry. Geophysical logs indicate that some screened intervals were located above or below zones of elevated dissolved solids; hence, the geophysical data provide a broader context for interpretation of water samples and evaluation of the biostimulation effort. Our results include (1) demonstration of field and data analysis methods for geophysical monitoring of VOE biostimulation and (2) site-specific insights into the spatial and temporal distributions of VOE at the ACP.

Construction Litigation for the U.S. Naval Facilities Engineering Command, 1982–2002

Evaluation of construction claims history can provide an understanding of improvement opportunities in a capital projects portfolio. This study analyzed cases of construction litigation involving the U.S. Naval Facilities Engineering Command (NAVFAC) for the period of 1982–2002, extracted from the historical trial decision record of the Armed Services Board of Contract Appeals (ASBCA). The study provides trend data for all “first time” construction litigation cases brought before the Board over the last 21 years and a total of 666 cases involving NAVFAC construction contracts were identified over this period. The characterization of these cases was accomplished through a review and tabulation of ASBCA identified “primary” causes and a subjective analysis of “root” causes from a random sample extracted from the total population. The random sample data set totals 30 cases and was taken from cases litigated in the last 10 years (1993–2002). Findings and recommendations based on root causes, including specifi...

Predicting the saturated hydraulic conductivity of sand and gravel using effective diameter and void ratio

This paper assesses methods to predict the saturated hydraulic conductivity, k, of clean sand and gravel. Currently, in engineering, the most widely used predictive methods are those of Hazen and the Naval Facilities Engineering Command (NAVFAC). This paper shows how the Hazen equation, which is valid only for loose packing when the porosity, n, is close to its maximum value, can be extended to any value of n the soil can take when its maximum value of n is known. The resulting extended Hazen equation is compared with the single equation that summarizes the NAVFAC chart. The predictive capacity of the two equations is assessed using published laboratory data for homogenized sand and gravel specimens, with an effective diameter d10 between 0.13 and 1.98 mm and a void ratio e between 0.4 and 1.5. A new equation is proposed, based on a best fit equation in a graph of the logarithm of measured k versus the logarithm of d102e3/(1 + e). The distribution curves of the differences “log(measured k) – log(predicted k)” have mean values of –0.07, –0.21, and 0.00 for the extended Hazen, NAVFAC, and new equations, respectively, with standard deviations of 0.23, 0.36, and 0.10, respectively. Using the values of d10 and e, the new equation predicts a k value usually between 0.5 and 2.0 times the measured k value for the considered data. It is shown that the predictive capacity of this new equation may be extended to natural nonplastic silty soils, but not to crushed soils or plastic silty soils. The paper discusses several factors affecting the inaccuracy of predictions and laboratory test results.Key words: permeability, sand, prediction, porosity, gradation curve.

DOE Initiatives: Enhancing collaborative decision making between DOE and its regulators

Federal Facilities Environmental JournalVolume 8, Issue 1 p. 115-120 Column DOE Initiatives: Enhancing collaborative decision making between DOE and its regulators Laurie A. Boucher, Laurie A. Boucher: , P. E., initiated the U.S. DOE's “Inter-Agency Partnering Program” in 1995 with the goal of developing stronger partnerships between federal and state agencies. Her primary focus and area of expertise is on effective communication, coordination, and strategic thinking between individuals, divisions, and agencies in order to achieve more creative, cost-effective, and efficient solutions. Previously employed by the Naval Facilities Engineering Command, she worked with EPA and state agencies to reduce CERCLA administrative time frames by over 50 percent. The opinions expressed in this article are those of the author, not those of the Environmental Management Program or DOE.Search for more papers by this author Laurie A. Boucher, Laurie A. Boucher: , P. E., initiated the U.S. DOE's “Inter-Agency Partnering Program” in 1995 with the goal of developing stronger partnerships between federal and state agencies. Her primary focus and area of expertise is on effective communication, coordination, and strategic thinking between individuals, divisions, and agencies in order to achieve more creative, cost-effective, and efficient solutions. Previously employed by the Naval Facilities Engineering Command, she worked with EPA and state agencies to reduce CERCLA administrative time frames by over 50 percent. The opinions expressed in this article are those of the author, not those of the Environmental Management Program or DOE.Search for more papers by this author First published: 10 January 2007 https://doi.org/10.1002/ffej.3330080112 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat Volume8, Issue1Spring 1997Pages 115-120 RelatedInformation

Stability Analysis and Displacement Measurements of Graving Drydock Walls

Maintenance and safety certification of the Navy's graving drydocks are essential in supporting fleet operation and readiness. Thus, structural analyses of graving drydocks are made regularly by the Naval Facilities Engineering Command using a finite element computer program. An analytical method is implemented to evaluate the structural adequacy of existing drydocks which are subjected to static and earthquake loads. The results of the analyses are used in certifying the safety of drydocks. Due to the complexity of the drydock structure, an analysis is begun by setting up structural models which can accurately include structural and geotechnical parameters for finite element numerical analysis. The accuracy of the results can then be checked through a comparison of the different models used in the analysis, and the comparison of field observations made from carefully monitored instrumentation. For example, in order to evaluate a mathematical analysis of the response of a drydock to static and earthquake loads, measurements of the movement of drydock walls in Charleston Naval Shipyard, South Carolina, were made by flooding and draining the drydock during a docking operation. A dial gauge instrument was used to measure the displacement of a wall and a laser electronic distance measuring instrument (EDM) was used to measure the displacement across the width of the dry-dock. The purpose of this paper is to present the drydock wall stability analysis method and to compare the analytical results with the observed wall displacement. Conclusions were derived from the results of the finite element analysis and the measured wall displacement. The results were useful in the structural analyses and safety certification of the graving drydocks.

A 3‐MHz acoustic concentration meter that measures suspended sand

A 3‐MHz acoustic concentration meter (ACM), which measures the intensity of backscattered acoustic energy, has been deployed in the laboratory and in the field in order to estimate the concentration of suspended sand. Techniques for measuring the profile of the concentration of suspended sand close to the seabed with a vertical resolution of about 1 cm are discussed. The scattering characteristics of suspended sand in a laboratory tank were used to provide a method of calibration for the ACM. The dependence of the scattering coefficients upon sediment size was also investigated. The ACM was deployed in the surf zone at Starthope Lane, Prince Edward Island, Canada, in October 1984. In the surf zone, the limitations of such profilometers are (a) air bubbles injected into the water by breaking waves, and (b) the possible variations in sand size with height above the seabed. [Work supported by Naval Facilities Engineering Command.]

CTACTS Charleston Tactical Aircrew Combat Training System

This paper presents an overview of the Ocean Engineering and Construction Project Office (FPO-1) of the Chesapeake Division, Naval Facilities Engineering Command design and construction of eight ocean towers. These towers are for the Charleston Tactical Aircrew Combat Training System (CTACTS). The offshore portion of the CTACTS provides the necessary facilities to accurately monitor and control the training of Navy, Marine Corps, and Air Force pilots, during aerial warfare training exercises. These offshore facilities are located 30 to 72 nautical miles east of northern Georgia in water depths ranging from 81 to 143 feet. In June, 1984, FPO-1 awarded the ocean tower design contract to Brown & Root Development, Inc. The final design was completed in August, 1985 and in January, 1986, FPO-1 awarded a contract to McDermott Marine Construction to fabricate and install the platforms. The installation is scheduled to be completed by mid-September, 1986.