Roesler J.R.,University of Illinois at Urbana - Champaign |
Cervantes V.G.,Naval Facilities Engineering Service Center |
Amirkhanian A.N.,University of Illinois at Urbana - Champaign
International Journal of Pavement Engineering | Year: 2012
A new concept for designing concrete pavements by optimising the slab geometry in order to reduce the slab thickness as well as to minimise the mechanical load transfer devices has recently been proposed. Theoretically, the reduced slab size lowers the load and curling-induced tensile stresses and concomitantly a thinner concrete slab can be constructed. Full-scale test sections were constructed and tested under accelerated pavement loading conditions to validate this design concept hypothesis. The design and concrete material factors studied in this research were concrete thickness of 9, 15 or 20cm; granular or asphalt concrete base layer; and plain or fibre-reinforced concrete (FRC). A methodology was presented to convert the channelised traffic loading to equivalent single axle loads (ESALs) so that comparisons could be made between the various test sections. The accelerated pavement testing showed that shorter slab sizes can sustain a significant number of overloads and greater number of ESALs before developing cracking relative to standard jointed concrete pavements. The most prevalent distress observed was corner cracking which occurred twice as much as longitudinal cracks, whereas only 3 out of 46 cracking distresses were transverse cracks. The 20cm concrete slabs on granular base did not experience fatigue cracking for trafficking up to 51 million ESALs. The 15cm concrete slabs on granular base began cracking on an average of 11 million ESALs. As expected, the concrete slabs on asphalt base resisted a significant larger number of ESALs relative to the same concrete thickness on granular base. The cracking performance of the 9cm concrete slabs on granular base varied with the stiffness of the soil. For the 9cm slab thickness, structural fibres provided a longer fatigue life and extended service life relative to the plain concrete slabs. Finally, the smaller slab sizes maintained a medium-to-high load transfer efficiency over the accelerated loading period for all slab thicknesses without the development of any faulting. As expected, these slab systems resulted in higher deflections, and, therefore, the granular base and subgrade layers as well as lateral drainage system must be designed and specified to reduce the rate of permanent deformation and minimise the possibility of support erosion. © 2012 Copyright Taylor and Francis Group, LLC.
Dave E.V.,University of Illinois at Urbana - Champaign |
Ahmed S.,University of Illinois at Urbana - Champaign |
Buttlar W.G.,University of Illinois at Urbana - Champaign |
Bausano J.,Naval Facilities Engineering Service Center |
Lynn T.,APAC Central Inc.
Asphalt Paving Technology: Association of Asphalt Paving Technologists-Proceedings of the Technical Sessions | Year: 2010
This paper describes a comprehensive investigation of strain tolerant type reflective crack relief interlayer systems through fundamental laboratory testing, computer aided design, and accelerated pavement testing. One of the widely used methods to control the reflection of cracks from underlying, cracked pavement into a new asphalt overlay involve the use of conventionally paved 'interlayers' that tolerate the very high tensile and shear strain that exists above cracks and joints in the underlying pavement. While these systems often slow down the rate of reflective cracking relative to untreated control sections in the field, when cracks do appear they are often offset from the location of the underlying discontinuity. A recently completed study sponsored by the National Science Foundation led to the development of a new fracture test (ASTM D7313-07b - the Disk-Shaped Compact Tension Test for Asphalt Concrete) and new techniques for finite element modeling of fracture in asphalt overlay systems. After successful validation of these tools on three field projects, it was decided to conduct further validation using the Advanced Transportation Loading System or ATLAS device and to experiment with new overlay configurations. A large experimental matrix was used to select promising interlayer materials and pavement layer and joint configuration details using finit e element analysis. A 500 ft(165 m) test pavement was constructed, instrumented, and tested in the cold of winter in 2008. This paper describes this comprehensive investigation, the new test sections developed, the types of distress observed under accelerated loading, and how the results were used to validate a new mechanistic analysis and design tool. Moreover, significant new insights towards the mechanisms and prevention of reflective cracking were obtained and have been summarized.
Rowell S.P.,U.S. Army |
Hager K.P.,Naval Facilities Engineering Service Center
Structures Congress 2010 | Year: 2010
Criteria for designing hardened, heavily-reinforced concrete structures to resist blast effects from accidental explosions are defined by Unified Facilities Criteria 3-340-02 formerly Army Technical Manual TM 5-1300 (Departments of the Army, Navy, and Air Force. 1990). Lap splicing of the required steel reinforcing bars is the current practice in the construction of these reinforced concrete structures. Lap splicing of reinforcing bars often creates congested areas within the formwork that limit working space and hinder proper placement of concrete. In 1971, a limited number of splice types were tested at the ERDC (formerly Waterways Experiment Station) to investigate their performance under dynamic load conditions (Flathau 1971). Subsequently, several types of mechanical couplers have been tested and validated for developing the strength of reinforcing steel for cyclic loading and strain rates expected during earthquakes. The ERDC recently conducted a series of high strain-rate tests on five different types of American Concrete Institute 318 type II mechanical couplers, used for splicing of flexural reinforcing steel, to obtain their measured performance when loaded at high strain-rates. This paper compares the performance of the different types of mechanical couplers to control bars tested at the same high strain rates, and evaluates their performance to meet the service requirements of UFC 3-340-02. © 2010 American Society of Civil Engineers.
Nordkam D.,U.S. Navy |
Varnava B.,Naval Facilities Engineering Service Center |
Miller M.,U.S. Army |
Hoffard T.,Naval Facilities Engineering Service Center
Ultrapure Water | Year: 2010
Reverse osmosis (RO) desalination has become the benchmark for the shipboard production of freshwater since its introduction the Navy in the late 1980s. The NSRO system includes a series of single-use, disposable string-wound cartridge filters for removal of entrained suspended solids in the incoming seawater that could foul or plug the RO membranes. The development during the pilot test program of a novel flush procedure that would remove entrained solids from the membrane was vital to the successful long-term, low-maintenance operation of this MF system. A portion of filtered seawater was supplied to the automated electrolytic chlorine generation system, which produced the chlorinated solution used in flushing the MF membrane modules. Fabrication and factory testing of the EUWP Generation 2 demonstration plant was completed in November 2007. Aggressive chemical cleaning of a membrane-based filtration system is required when the pressure difference between feed seed and filtrate side of the membrane approaches a manufacturer's specified limit.
Breakah T.M.,Iowa State University |
Bausano J.P.,Naval Facilities Engineering Service Center |
Williams R.C.,Iowa State University |
Vitton S.,Michigan Technological University
International Journal of Pavement Engineering | Year: 2011
The development of the Mechanistic-Empirical Pavement Design Guide (MEPDG) provides an opportunity to simulate the performance of pavements. This paper considers the impact of fine aggregate on the predicted performances of pavements by simulating the performance differences between pavement mixes prepared with different sources of fine aggregate with different gradations using the MEPDG. A natural and four manufactured sands from parent material consisting of dolomite, limestone, traprock (TR) and a glacial gravel (GG), and five gradations were utilised in this study. This resulted in 19 different sand/stone combinations being tested for dynamic modulus to enable level 1 analysis in the MEPDG. The results indicate that the fine aggregate angularity (FAA) test adequately ranks aggregates from the same source, but does not appropriately rank aggregates from different sources. TR and GG were identified as the best performers within the investigated aggregate sources and that the FAA, aggregate source and gradation are not significant in determining mixture performance. © 2011 Taylor & Francis.
Malvar L.J.,Naval Facilities Engineering Service Center |
Magallanes J.M.,Karagozian and Case, Inc. |
Wu Y.,Karagozian and Case, Inc.
Proceedings of the 8th International Conference on Structural Dynamics, EURODYN 2011 | Year: 2011
Results from numerical simulations are presented that investigate the behavior of concrete samples under standard laboratory strength tests. Samples include cylinder and cube specimens in compression and cylinder specimens for the splitting tension test. Each of these tests is commonly used to derive fundamental material properties for concrete, i.e. compressive and tensile strengths. Numerical models are developed for each of these tests using the finite element method and a recent release of the K&C concrete material model. Quasi-static solutions are then obtained using explicit time integration. The results indicate that the strength and failure modes for the compression tests can be highly influenced by the specimen shape and boundary conditions, in particular for the cube test. It is shown that ASTM C 1231 appears to provide the best estimate of compressive strength as a material property. The splitting tensile strength was confirmed to be slightly higher than the input tensile strength, suggesting that the proper material property input should be slightly smaller than the ASTM C 496 value.
Piedmont E.,Naval Facilities Engineering Service Center |
Tehada T.,Naval Facilities Engineering Service Center
NACE - International Corrosion Conference Series | Year: 2010
This presentation will present the current status and findings of a Department of Defense project, Solar Powered Cathodic Protection System. Underwater fuel pipelines traverse Guantanamo Bay, Cuba. Studies indicated that the pipeline was not adequately protected from corrosion. Failure of the pipeline would release fuel into the bay resulting in high cost environmental cleanup and legal fees, damage to the environment, and negative publicity towards the Navy. AC power in the area was recently removed, and this project demonstrates the use of an alternative solar powered CP system.
Malvar L.J.,Naval Facilities Engineering Service Center
Transportation Research Record | Year: 2010
Several accidents involving aircraft punching through airfield pavements prompted the U.S. Navy to develop a technology for void detection. Initially, a successful void detection survey was completed at a naval air station where several voids were generated by leakage of large underground drainpipes. Various methods were used, such as internal videotaping of the pipes, heavy weight deflectometer (HWD) testing, testing with a ground-penetrating radar, and testing with a dynamic cone penetrometer (DCP). A state-of-the-art review was also completed to assess all existing technology applicable to void detection under pavements. However, the optimum technology (visual inspection and testing with an HWD and a DCP) still presented limitations because of the availability and speed of data acquisition, requiring prioritization of the work. A risk analysis was then completed and established work prioritization within each airfield and providing a prioritization of all U.S. Navy and Marine Corps airfield pavements. An interim policy and technical guidance (IP&TG) was issued on March 23, 2000, to establish the void detection methodology developed. This IP&TG was recently updated and included as an appendix in U.S. Department of Defense Unified Facilities Criterion UFC 3-260-03 and routinely applied at all 70 major U.S. Navy and Marine Corps airfields. This paper summarizes the methodology used and presents some recent field cases.
Tufenkjian M.R.,California State University, Los Angeles |
Thompson D.J.,Naval Facilities Engineering Service Center
Proceedings of the International Offshore and Polar Engineering Conference | Year: 2010
Accurate strength characterization of near surface seafloor soils is critical when designing and installing mat foundations and seafloor cable systems. This paper presents the results of an ongoing investigation to assess the merits of using flow penetrometer technology to aid the U.S. Navy's requirements for seafloor characterization in soft sediments. The paper presents the experiences learned from the preparation and consolidation of a large-scale clay specimen and discusses the penetration and extraction resistances measured using ball and cone penetrometers. The undrained shear strengths calculated with the cone, ball, and a vane are evaluated and compared. Copyright © 2010 by The International Society of Offshore and Polar Engineers (ISOPE).
Zueck R.F.,Naval Facilities Engineering Service Center
Proceedings of the International Offshore and Polar Engineering Conference | Year: 2011
Vortex-Induced Vibrations (VIV) are cyclic motions in flexible slender structures that are induced by fluid flow. Nonlinear three-dimensional finite element modeling of the structure is vital for representing VIV. Coupled fluid/structure simulations show that initial state, evolving geometry and changing stiffness of the structure are essential for modeling initiation, evolution and sustainment of VIV. Simulations in a vacuum suggest that some measured VIV phenomena are being improperly attributed to fluid flow. Simulations in fluid confirm the difficulty of suppressing VIV by damping. Copyright © 2011 by the International Society of Offshore and Polar Engineers (ISOPE).