San Antonio, TX, United States

Protection Engineering Consultants, LLC

www.protection-consultants.co
San Antonio, TX, United States
SEARCH FILTERS
Time filter
Source Type

Naito C.,Lehigh University | States J.,Structural Engineer in Training | Jackson C.,Air Force Research Lab | Bewick B.,Protection Engineering Consultants, LLC
Journal of Materials in Civil Engineering | Year: 2014

To address the ever-increasing quantity of scrap tires produced in the United States, a study is conducted on the use of crumb rubber in concrete for enhancement of structures against blast effects. Crumb-rubber concrete (CRC) is produced by replacing a volume percentage of the traditional coarse and/or fine aggregate with crumb-rubber particles. Crumb rubber is produced in various gradations from used vehicle tires. The research program characterizes the mechanical properties of CRC and provides an assessment of the capability of CRC in providing flexural resistance for structural applications. The experimental and analytical investigation found the following four results: (1) crumb rubber replacement of coarse and fine aggregate is done at a cost premium of approximately 0.75 times the replacement percentage (2) the addition of crumb rubber results in a decrease in unit weight, compression strength, splitting tensile strength, and elastic modulus, which are linearly related to the addition of rubber; (3) the modulus of rupture was not sensitive to replacement of up to 40% rubber aggregate; and (4) flexural failure modes occur at lower demand levels due to the use of rubber replacement. The reductions are consistent with the material property conclusions previously discussed. © 2014 American Society of Civil Engineers.


Naito C.,Lehigh University | States J.,GAI Consultants Inc. | Jackson C.,Applied Research Associates Inc. | Bewick B.,Protection Engineering Consultants, LLC
Journal of Materials in Civil Engineering | Year: 2014

To address the ever-increasing quantity of scrap tires produced in the United States, a study is conducted on the use of crumb rubber in concrete for use in structures against near-field blast and ballistic demands. Crumb rubber concrete (CRC) is produced by replacing a volume percentage of the traditional coarse and/or fine aggregate with crumb rubber particles. Crumb rubber is produced in various gradations from used vehicle tires through a variety of shredding processes. The influence of crumb rubber on the constitutive and structural performance of concrete under quasi-static loading has been examined in past research. CRC has been shown to have decreased strength and stiffness while still being a useable structural material. This research study examines the use of CRC for the specialized application of blast and ballistic protection. The program characterizes resistance of CRC to contact and near-contact high explosive detonations, and examines depth of penetration, and perforation using V50 methods. The results of the experimental and analytical investigation found that (1) the addition of crumb rubber results in decreased resistance to ballistic demands and near-field blast loads, (2) the reduction is less than that estimated by accepted predictor methods, and (3) when normalized by weight rather than thickness, the use of CRC results in an improvement in resistance to ballistic and near-field blast demands. © 2014 American Society of Civil Engineers.


Williamson E.B.,University of Texas at Austin | Bayrak O.,University of Texas at Austin | Davis C.,Protection Engineering Consultants, LLC | Daniel Williams G.,University of Texas at Austin
Journal of Bridge Engineering | Year: 2011

Guidelines for the design of critical bridge components subjected to blast loads are currently not available to the general bridge engineering community. Historically, however, transportation assets have proven to be attractive targets for terrorists because of their open access, utilization by large numbers of people, symbolic importance, and significance to commerce, in addition to a host of other reasons. To improve the current state of practice, the National Cooperative Highway Research Program sponsored a research project to investigate the response of reinforced concrete bridge columns subjected to blast loads. Part I of this manuscript details the unique experimental program carried out to assess the effects of different design parameters on overall performance under these types of loads. In the current paper, results from the test program are analyzed to identify the design parameters that most significantly influence the performance of blast-loaded reinforced concrete bridge columns. Using the scaled standoff distance as the primary variable to assess threat severity, three separate blast design categories are recommended. © 2011 American Society of Civil Engineers.


Williamson E.B.,University of Texas at Austin | Bayrak O.,University of Texas at Austin | Davis C.,Protection Engineering Consultants, LLC | Williams G.D.,University of Texas at Austin
Journal of Bridge Engineering | Year: 2011

Statistical data from past terrorist attacks show that transportation infrastructure has been widely targeted, and a significant percentage of the attacks against transportation structures have been directed towards bridges. Recent threats to bridges in the United States validate this concern and have attracted the attention of the bridge engineering community. To address these concerns, the National Cooperative Highway Research Program sponsored a research project to investigate the response of critical bridge components subjected to blast loads. This paper includes a description of an experimental research program on ten different half-scale column designs in which the design parameters that have the greatest impact on the performance of blast-loaded bridge columns were evaluated. Interpretation of the test results and guidelines for the blast-resistant design of reinforced concrete bridge columns are provided in the companion paper written by the writers. © 2011 American Society of Civil Engineers.


Marchand K.A.,Protection Engineering Consultants, LLC | Stevens D.J.,Protection Engineering Consultants, LLC
Journal of Performance of Constructed Facilities | Year: 2015

Methods for the assessment of structural designs or existing structural systems for susceptibility to disproportionate (progressive) collapse and prescriptive methods intended to mitigate or decrease the likelihood of progressive (disproportionate) collapse are approaching adolescence as compared to the age and maturity of other engineering design standards and approaches. U.S., British, and Eurocode standards such as ASCE-7, BS EN 1991-1-7, 2006, and Eurocode 1: Actions on structures first established design philosophies and some prescriptive approaches, while later U.S. guidelines and IBC code provisions have attempted to fill in the gaps with refined prescriptive methods or detailed static and dynamic analysis approaches. The U.S. Department of Defense (DoD) and the U.S. General Services Administration (GSA) have published design and analysis guidelines in recent years. The DoD guidelines have been updated three times since inception, and GSA guidance is currently being updated to take advantage of the DoD improvements through adaptation of DoD methods within GSA applicability requirements. Additionally, the Structural Engineering Institute (SEI) in the United States has focused on the efforts of several technical experts within their Disproportionate Collapse Mitigation Standards Committee. This paper provides updates on the steadily converging approaches and documents. Specifics of analysis approach updates as well as design philosophy and applicability direction are presented and discussed. © 2015 American Society of Civil Engineers.


Grant
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 69.97K | Year: 2010

Protection Engineering Consultants (PEC) will employ state-of-the-art numerical modeling and simulation (M&S) tools and techniques to assess the performance of armored tactical vehicles when subjected to land mines and improvised explosive devices (IEDs). PEC will identify the key technical issues, such as material models, human surrogate models, and explosive/soil interaction, and will develop and demonstrate successful approaches for each topic. These approaches will be combined into an overall modeling and analysis procedure that is demonstrated through application to a generic armored tactical vehicle subjected to a realistic explosive threat. The key metrics will be the predicted occupant injuries, overall vehicle response, and local deformations and motion. This procedure will be applied to actual vehicles in Phase II and the entire process will be transitioned to the Navy. The final product will allow the Navy and other DoD activities to successfully and reliably assess the effects of design changes that are proposed for reducing injuries and improving vehicle performance in land mine and IED attacks.


Grant
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 150.00K | Year: 2013

CTH is an expert level High Performance Computing (HPC) code developed by Sandia National Laboratories (SNL) to model a wide range of shock wave propagation and material motion phenomena. SNL continues to develop the technical capabilities of CTH, and, as a result, CTH is considered one of the most powerful Eulerian codes available. However, the user interface has not evolved and text-based input decks must be created by hand to generate and execute the models and to post-process the results. This method of input generation requires the user to develop an expert level understanding of syntax for both CTH and Spymaster (post- processing code for CTH) and offers no debugging capabilities prior to model execution. Protection Engineering Consultants (PEC) proposes to develop four improvements to facilitate the accessibility and applicability of CTH by industry and government users. We will develop: 1) a pre-processor for creating, visualizing, and modifying the models; 2) a post-processor that allows the user to easily access and manipulate the results; 3) a debugging and execution capability, and 4) a parametric analysis and optimization capability in Phase II. Commercial Applications: By reducing the complexity of model development and data extraction, the tremendous capabilities of CTH will be more accessible to industry and government. The addition of an optimization and probabilistic capability will allow engineers and modelers to more efficiently achieve successful designs. The resulting software package will be marketed to current and new users and should increase the usage of this powerful tool.


Grant
Agency: Department of Defense | Branch: Defense Threat Reduction Agency | Program: SBIR | Phase: Phase I | Award Amount: 149.77K | Year: 2013

Protection Engineering Consultants (PEC) proposes to develop a coarse-grain neural network modeling approach for efficient simulation of shock propagation through geological media including soil-structure interaction. In the coarse-grain approach, fast-running computational elements are developed which are an order of magnitude larger than typical FE elements, and the elements are driven by neural network-based equations as opposed to physics-based equations. Typically FRMs cannot extrapolate to problems beyond the boundaries of the data set used to develop the models. Moreover, the size of the data set required increases geometrically with the number of independent variables needed as input variables to the FRMs. A more robust approach will help to increase the applicability of the developed FRM, while still maintaining the requirement for rapid execution of the problem. The coarse-grain neural network modeling approach is a novel approach to develop a tool that is versatile and still retains the FRM requirement of rapid execution.


Grant
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase II | Award Amount: 699.92K | Year: 2013

Protection Engineering Consultants (PEC) will use the results of the Phase I numerical analyses of armored tactical vehicles subjected to landmine detonation to further explore, develop, and validate state-of-the-art numerical modeling and simulation (M&S) tools and techniques. In Phase I, PEC identified the key technical issues, which include the high loading rate behavior of materials and bolted and welded connections, human surrogate modeling, and load predictions for landmines. These issues will be examined in more detail, through a combination of experimental and analytical approaches. The resulting data and improved models will be combined into an overall modeling and analysis procedure that is applied to two vehicles designated by the sponsor. Live fire and field data for these vehicles will be obtained and used to modify and validate the modeling procedures. The key metrics will be the occupant injuries, overall vehicle response, and local deformations. The entire modeling process will be transitioned to the Marine Corps, through development of training materials such as reports, computer exercises, and tutorials. The final product will allow the Marine Corps and other DoD activities to successfully assess the effects of design changes for reducing injuries and improving vehicle performance in land mine attacks.


Grant
Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase I | Award Amount: 99.51K | Year: 2015

To protect the mounted warfighter from the effects of landmines, a LOw TRavel Isolated Floor (LOTRIF) system will be developed to reduce injures from the specified blast-generated vehicle accelerations, within a 2 to 4-in stroke. Maneuver accelerations, operational requirements, space claim, weight and cost will also be considered. To accomplish this goal, Protection Engineering Consultants, LLC (PEC) has teamed with GS Engineering, Inc. (GSE) to propose an innovative research and development effort for enhanced lower leg protection, based on crushable glass foam technology, which PEC has recently used for developing aircraft arrestor beds. LOTRIF will include a floating floor panel and edge-support compactors as well as mechanically optimized chassis attachments. As described in the proposal, materials and components will be evaluated, potential designs of the system will be developed and initial proof-of-principle testing will be performed. GSE will help commercialize the final LOTRIF system design.

Loading Protection Engineering Consultants, LLC collaborators
Loading Protection Engineering Consultants, LLC collaborators