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Glendale, CA, United States

Crawford J.E.,Karagozian and Case, Inc.
Canadian Journal of Civil Engineering

Protective design has become a chief concern in the design of some bridges and buildings, particularly related to the requirement that such facilities offer protection from accidental or malicious explosions. In this paper, the enhancement of the blast-resistance capability of reinforced concrete columns using FRP (fiber-reinforced plastic) is examined as a key element in upgrading the protective design of existing buildings and bridges. In this paper, the basic behaviors that need to be considered in blast effects analysis of RC columns for vehicle bomb threats are described. The ability of FRP to address these sorts of risks is shown through the analysis and test results presented. Three crucial points are made: (1) FRP offers a remarkable capability to enhance the blast resistance of existing RC columns, (2) assessing the residual capacity of large columns struck by a blast loading involves consideration of the effects of material damage, and (3) physics-based material models are often needed to capture the concrete behaviors engendered by intense blast loads. © 2013 Published by NRC Research Press. Source

Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase II | Award Amount: 749.48K | Year: 2012

ABSTRACT: This proposal is for a 24-month Phase II project to develop innovative High-Fidelity Physics-Based (HFPB) Fast-Running Models (FRMs) that simulate the interaction of weapons with structural components of buildings and predict their secondary debris and air blast into adjoining spaces. As stated in Air Force Topic AF103-131, the disintegration of overloaded walls and slabs generates two important secondary effects that can be lethal to personnel, equipment, and structural components located in adjoining rooms; the first is secondary debris from fragmentation of the wall/slab component and the second is secondary air blast that can, in many circumstances, interact with the disintegrating wall and project blast and dynamic pressure loadings. Current HFPB FRMs that are used to predict weapons effectiveness or assess human or building lethality do not account for these effects. This can have negative impacts on collateral damage estimation and weaponeering activities. The DoD needs a new generation of FRMs to improve their prediction capabilities in these areas. BENEFIT: Given the generality of the analysis and fast-running modeling technology proposed, many non-military applications are possible. One possibility is enhanced risk analysis tools for accidental blast responses of civil structures. K & C has already marketed some of our FRM codes and engineering services to government and commercial clients. Other potential customers include the Department of State, the Secret Service, DHS, DDESB, FAA, GSA, and all agencies for which consideration of multiple threats is of interest. The general ability to consider the damage imparted to a component either by successive applications of a single type of threat (e.g., blast) or a combination of threats (e.g., blast followed by a high-energy impact load) is going to be of interest to many who need to consider the risks associated with multiple hazards. This capability, for example, would interest first responders and could be included in DHS programs for developing rapid assessment tools to evaluate the safety of structures that have been involved in situations involving multiple hazards.

Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase II | Award Amount: 749.92K | Year: 2016

US Naval ships such as the LPD 17 San Antonio class vessels require transparent armored windows (TAW) in the Pilot House and several control/conflagration stations. The current TAW design used aboard these ships is more than 20 years old and it has several design flaws that adversely affect life span, mission readiness, and replacement cost.There is an expressed need in the US Navy to develop a next-generation TAW that addresses these flaws and significantly enhances readiness, increases the life span of the windows, and reduces operational and maintenance costs. Karagozian and Case (K&C) is developing concept designs to overhaul the TAW system on LPD 17 Class ships using advanced materials and processes as well as an improved mounting system. The K&C concept for a next-generation TAW adopts the use of specialty glasses in a very limited but effective manner that improves performance while avoiding production size issues and cost increases. The next-generation designs are based on mature technologies that are producible and can be transitioned to the warfighter at the end of the Phase II effort for production and full scale testing aboard a Navy ship.

Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 149.98K | Year: 2015

ABSTRACT:Karagozian and Case, Inc. (K&C) proposes to develop a Rigid-Body Off-Axis Ordnance Shock And Tail-Slap Environment Replicator (ROOSTER) concept which can induce peak accelerations over 10,000 g for sustained periods of at least 5 ms to sub-scale non-inventory warheads in order to replicate the harsh and complex deceleration environment experienced by ordnance during penetration. The concept takes advantage of the known strengths of at least two different types of dynamic loaders to accelerate a pseudo-static test penetrator, and a proven approach to subsequently arrest it. The concept consists of three key elements, each targeting an essential component of the required acceleration response. The first is an impact-driven loader that acts to generate the desired peak accelerations over a very short time-frame. The second element, adds a second dynamic loader that acts on the test penetrator over a much longer duration. The loaders used for this element leverages strain-energy or fast-acting hydraulically-driven loaders, which are far more effective during this time-frame. The final essential component consists of an arrestment basin, which acts to catch and decelerate the test article, since the test apparatus will send it traveling at significant velocities.BENEFIT:The proposed test fixture closely mimic the penetration phenomenology providing realistic axial accelerations on the penetrator body and can also induce realistic lateral accelerations by a simple modification of the test setup. This test fixture will enable the Air Force to adequately test the next generation of fuzing technologies which are needed to meet increasingly challenging requirements, for enhanced penetration capabilities. Furthermore, the ability to model high-velocity impact scenarios will provide opportunities to test and enhance the protection of storage for hazardous/nuclear waste, especially during transit.

Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 149.98K | Year: 2015

ABSTRACT:The overall goal for this project is to demonstrate the feasibility of a methodology to develop advanced cumulative-damage models that predict time-dependent reinforced concrete (RC)-bunker wall deflection, spalling, breach, secondary debris generation, and the incremental wall damage state from multiple weapon detonations. This effort builds on previous work conducted by K&C and ACTA in (1) analytically modeling the behaviors of walls to multiple hits and (2) developing a High Fidelity Physics Based (HFPB) fast-running model (FRM) for modeling cumulative damage resulting from multi-hits scenarios. In this proposal an advanced cumulative damage FRM (ACD-FRM), incorporating the complicated physics involved in multiple loadings leading to local and global failure of RC components will be developed. The methodology proposed to develop the ACD-FRM is general in nature and can be readily extended to other structural components or systems and for loadings other than blast and fragmentation. The broad methodology developed under this effort will provide a rational approach for the stochastic consideration of accumulated or cyclic damage and has broad applicability across a range of industries where consideration of accumulated damage and the associated requirements for repair, maintenance and replacement is critical, such as the energy, utility and transportation industries.BENEFIT:As a science and engineering consulting company actively involved in a multitude of government and private industries including building construction, defense, anti-terrorism, petrochemical plant safety, and nuclear plant and infrastructure safety, K&C is in an excellent position to market, commercialize, and transition the technologies developed under this project. These clients, especially related to their overseas operations, have particular concerns related to the risks engendered by blast and fragmentation loading as well as cumulative damage effects. The U.S. defense community is another clear market for this technology, which also has interest in the resilience of structures and having the ability to evaluate the effects of cumulative damage. In this regard, the stochastic approach to be taken to modeling cumulative damage will be especially of interest since the probability of a particular outcome in a cumulative damage targeting problem should reflect the uncertainties involved if it is to be useful.

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