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Blast Mitigation for Structures: 1999 Status Report on the DTRA/TSWG Program 4 Technology Transfer BACKGROUND One part of the committee's charge was to recommend a strategy for technology transfer for advances identified by the BMSP in engineering, architectural, and building practices, disaster preparedness and recovery, and emergency medical services. The need for information on blast-resistant design and improved dissemination of information cuts across disciplines and levels of technical expertise, and the field of earthquake engineering can provide many models that can be adapted to meet this need. This chapter describes a recommended strategy for the BMSP to develop an action plan; DTRA to form partnerships among federal agencies, the academic community, and professional organizations; and to begin the process of technology transfer. As a first step, a workshop on technology transfer for the mitigation of blast effects should be scheduled this year. NEEDS OF THE ENGINEERING COMMUNITY In light of the continuing focus on blast effects as a design consideration, engineers, who may not be specialists in blast engineering, are likely to be called upon increasingly to participate in the design process. These engineers will need better information than is currently available to enable them either to develop blast-resistant designs or to serve in an advisory capacity to building owners. Professional societies may consider certifying engineers in blast-resistant design, much as they do for engineers specializing in earthquake-resistant design. Necessary information will include generic blast loads for various charge weights/shapes and standoff distances, structural design procedures, and detailing requirements. Although much of this information is already available in various manuals and technical documents produced by the military and other organizations (e.g., Design and Analysis of Hardened Structures to Conventional Weapons Effects [U.S. Army et al., 1997], Structures to Resist the Effects of Accidental Explosions [U.S. Army, 1990], and Design of Structures to Resist Nuclear Weapons Effects [ASCE, 1985]), its distribution is generally limited to government agencies and their contractors, and it can not always be easily applied to civilian structures. These manuals do provide an excellent starting point, however, for generic guidance on blast-resistant design. The military has attempted to address conventional construction in Estimating Damage to Structures from Terrorist Bombs, Field Operations Guide (USACE, 1999), but this is more of a vulnerability assessment than a design tool. The recently released report By the American Society of Civil Engineers (ASCE), Structural Design for Physical Security: State of the Practice (ASCE, 1999), is another important source of technical information. Related guidance documents include Minimum Design Loads for Buildings and Other Structures (ASCE, 1996) and Recommended Lateral Force Requirements and Commentary (SEAOC, 1996), both of which describe seismic loads and design approaches (the former addresses dead and live loads, as well as soil, flood, wind, snow, rain, ice, and earthquake loads, singly and in combination) and
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Blast Mitigation for Structures: 1999 Status Report on the DTRA/TSWG Program could serve as models for transferring current knowledge and advances in blast-resistant design as they become available. Structural systems to resist the forces of high winds and tornadoes are discussed at length in Minimum Design Loads for Buildings and Other Structures, (ASCE, 1996). Although the potential benefits of main wind-force resisting systems, such as cross-bracing and shear walls, for improving blast resistance have not received as much attention as seismic improvements, the wind-engineering community could provide valuable insights into improved multihazard building performance. Blast-related information for nonengineers would appeal to a wide audience. This information could clear up some of the confusion about the effects of explosions and blast effects on structures, the benefits of setbacks, the cost and effectiveness of mitigation measures, and so on. A series of briefing papers published by the Applied Technology Council (ATC) and the Structural Engineers Association of California (SEAOC) on seismic design and construction (ATC and SEAOC, 1998) could serve as a model for a similar series on blast-resistant design published as part of the BMSP. BUILDING CODES AND STANDARDS The committee believes that provisions for blast-resistant design are not likely to be incorporated into model building codes in the foreseeable future. Although bombing attacks have serious consequences, the probability that a civilian building will be the target of a terrorist bombing is relatively low. Therefore, public support for blast-resistance requirements in all construction is also low, and building owners are reluctant to pay the additional costs of designing and maintaining blast-resistant features. The committee believes that a general market demand or some economic motivation, such as reduced insurance rates, will be necessary before commercial developers will act voluntarily. Without strong financial or regulatory incentives, blast-resistant design features are not likely to become common practice unless they provide more readily acceptable (and understandable) multihazard mitigation benefits. Damage-resistant/injury-preventive designs that can be effective against multiple hazards, such as earthquakes, fire, wind, and floods (which are much more likely to occur than bomb blasts), will be easier to promote and justify for a wider potential market. A larger market would, in turn, make the manufacture and distribution of materials and technology to meet these design specifications more economically attractive. In light of the lack of public awareness of the nature of the threat and the lack of a consensus on what to do about it, guidance on building collapse and building code requirements would be valuable. The phenomenom of progressive collapse is not well understood, despite the widespread recognition that most catastrophic building failures involve building collapse. Although building codes admonish designers to ensure that collapses do not occur, they do not provide guidance on how this can or should be accomplished. Because preventing collapse is a key factor in reducing fatalities in the event of a terrorist bombing, suggested design approaches to reduce the likelihood of progressive collapse would serve the BMSP's purposes and be of immense value to the structural engineering community. Guidelines for applying building codes would also be helpful. Building Code Requirements for Structural Concrete and Commentary (ACI, 1999) devotes an entire chapter to special provisions for seismic design, including the detailing of reinforcing steel in concrete construction and the applicability of different structural frames. This document could serve as a vehicle for conveying similar provisions for blast-
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Blast Mitigation for Structures: 1999 Status Report on the DTRA/TSWG Program resistant designs that have been verified through the BMSP. However, resistance to dynamic loads of the three moment frames specified in Building Code Requirements for Structural Concrete and Commentary (i.e., normal, intermediate, and special) differs markedly. Therefore, building frames selected without taking dynamic forces imposed by natural hazards (e.g., earthquakes or extreme winds) into account will also be less likely to resist blast loads. Therefore, in addition to addressing specific code provisions, for the benefit of those seeking guidance in blast-resistant design, the BMSP's technology transfer strategy should also describe when and how the provisions should be applied. The International Building Code has replaced the three model building codes followed in the United States, (i.e., the Uniform Building Code, Building Officials and Code Administrators National Code, Standard Building Codes). Although a single building code would appear to make it easier for the BMSP to evaluate commercial building codes, the three codes will remain in force in many jurisdictions for several years. Therefore, additional evaluations may be required. In addition to the commercial building codes, the BMSP should also be aware of several other documents that address dynamic effects. For example, Japan and New Zealand have developed extensive codes, procedures, and construction methods for structures subjected to earthquake motions. Furthermore, the design of mechanical, electrical, and other elements, especially those relating to physical security, fire, and life safety must also be addressed. Therefore, the BMSP should evaluate mechanical, electrical, and codes by other groups, such as the National Fire Protection Association, the Nuclear Regulatory Commission, the American Society of Mechanical Engineers, and the Institute of Electrical and Electronic Engineers. New editions of these documents are released every few years, and the design community must be kept aware of the continuous evolution of this body of knowledge. Revisions to the documents include both new requirements and changes to existing methods, based on evaluations of ongoing research. The earthquake engineering field provides an excellent example of this evolutionary process. Beginning in 1959, seismic risk and design requirements were based on the Blue Book published by the Structural Engineers Association of California (SEAOC, 1996). The Applied Technology Council (ATC), which was established after the Sylmar earthquake in 1971, published Tentative Provisions for the Development of Seismic Regulations for Buildings in 1978 (ATC, 1982), under the sponsorship of the National Science Foundation (NSF) and the National Bureau of Standards (now the National Institute of Standards and Technology [NIST]). The promulgation of seismic design requirements was taken over by the Federal Emergency Management Agency (FEMA), which in 1997 issued the National Earthquake Hazards Reduction Program Guidelines for Seismic Rehabilitation of Buildings and Commentary (FEMA, 1997a) and National Earthquake Hazards Reduction Program Recommended Provisions for Seismic Regulations for New Buildings and Other Structures and Commentary (FEMA, 1997b). Recent versions of the Uniform Building Code have included recommendations from the Blue Book (as revised), as well as work sponsored by NIST and FEMA and performed by ATC, the Building Seismic Safety Council (BSSC), and other organizations. The array of publications and activities in the earthquake field have been facilitated by the Earthquake Engineering Research Institute (EERI) and the earthquake engineering research centers sponsored by the NSF, under the auspices of the National Earthquake Hazard Reduction Program (NEHRP).
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Blast Mitigation for Structures: 1999 Status Report on the DTRA/TSWG Program ROLE OF ACADEMIA The BMSP, a DoD research and development program, is not intended to support basic research. Nevertheless, the nature and mechanism of progressive collapse is a topic that merits further study by the academic community. This subject, which has not been addressed at a meaningful level for almost a quarter of a century, could have benefits for mitigating risks from many hazards. Coordinating basic research with the BMSP and ensuring a funding source will require partnerships (e.g., between NSF, the BFRL, DoD, and DTRA). Similar partnerships by NEHRP to leverage funds for earthquake research could provide a model of interagency cooperation and a model for securing congressional support for basic research to address national-level issues. Since the early 1980s, active involvement of academicians in fortification-related research has declined as the result of attrition and reduced research support. The NRC report, Protecting Buildings From Bomb Damage: Transfer of Blast-Effects Mitigation Technology from Military to Civilian Applications states: The committee has found that there are several serious barriers to technology transfer from the military to the civilian sector. The first major barrier is education. The current academic and professional training of architects and engineers does not adequately prepare the design professionals, either technically or philosophically, to incorporate blast-hardening principles in civilian structures. Thus, a strong educational commitment is required by university schools of architecture, construction, and engineering, as well as by professional engineering societies, if the potential for technology transfer is to be realized (NRC, 1995). Universities could provide a significant contribution to technology transfer and closing the training gap by including aspects of blast-resistant design in their structures and structural dynamics curricula, similar to university programs in earthquake-resistant or wind-resistant design. Furthermore, training should be complemented by university involvement in active research related to the improved blast-resistance of structures. University students could be directly involved in blast-related topics through internships with federal agencies, student design competitions for blast-resistant structures, and other mechanisms. Academic involvement in physical and computational research in this area will have the benefit of the focused research that typically occurs in the university environment. The role of academia could also be extended to market research and risk communication related to the promotion of hazard-resistant building design. HANDLING OF SENSITIVE INFORMATION A technology transfer program for mitigating blast effects must be tailored to handle potentially sensitive information. Although the design basis (underlying assumptions of design blast loads and the location and configuration of critical services) for a specific building would be valuable to terrorists, the process used to design the building would not. Plans for buildings, both public and private, which are often available from local building officials to anyone who requests them, could represent a more serious security issue than the widespread dissemination of design guidance. Nevertheless, the committee recognizes that the dissemination of test and analysis data for specific components from the BMSP coupled with detailed structural plans
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Blast Mitigation for Structures: 1999 Status Report on the DTRA/TSWG Program could be a serious security risk. However, realization of the benefits of a wide range of improved techniques, materials, and practices developed by the BMSP will require that the information not be restricted to a narrow group of users. This issue has been addressed by the Blast Mitigation Action Group (BMAG) organized by the U.S. Army Corps of Engineers ERDC to identify and evaluate COTS products. The BMAG web site is password-protected and provides sources of blast-mitigation products and services for both retrofitting and original construction to registered users (BMAG, 2000). The committee supports this excellent initiative and believes that it should be expanded to disseminate information about a broader range of products. A FRAMEWORK FOR TECHNOLOGY TRANSFER The effective transfer of the results of the BMSP will require overcoming many barriers. One way to accelerate this process is to make maximum use of existing institutional infrastructures for disseminating information. These include joint activities with other organizations, such as ACI (especially Committee 370, Short Duration Dynamic and Vibratory Load Effects), the American Institute of Steel Construction (which is considering establishing a committee to address blast effects), and the American Society of Civil Engineers (which has established a committee to develop a standard for blast protection of buildings), to develop model code and standard provisions that would be voluntary in the civil sector but possibly mandatory for select government buildings. Although code- and standard-writing processes are lengthy and involved, the BMSP could provide data and information as it becomes available for possible inclusion in voluntary guidance documents (e.g., detailing methods for reinforcing steel to resist localized and progressive collapse). The participation of the American Institute of Architects will be critical in joint activities; the members of this highly respected organization are in a position to encourage the incorporation of blast-resistant features and designs. The committee believes that the next step for the BMSP should be to convene a formal workshop in 2000 to document information needs and develop a plan of action for technology transfer in the mitigation of blast effects. The BMSP should also increase its efforts to provide continuing outreach to other federal agencies. An organization of the National Research Council, the Federal Facilities Council, was established to address information needs related to the planning, design, construction, operations, maintenance, and management of federal facilities, and could serve as an information portal to federal agencies. The BMSP should also consider sponsoring an annual or biennial conference on blast-mitigation design and engineering. Although these issues are discussed at existing engineering, construction, security, and emergency management conferences, a single, integrated forum could be of enormous benefit in the dissemination of the latest advances in the field and could stimulate the development of new and effective retrofitting concepts for existing structures. Figure 4-1 illustrates the committee's suggested model for a technology transfer strategy for the BMSP.
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Blast Mitigation for Structures: 1999 Status Report on the DTRA/TSWG Program FIGURE 4-1 Model of a technology transfer strategy. CONCLUSION AND RECOMMENDATION Conclusion 10. The barriers to the complete and effective transfer of the results of the BMSP will require considerable time and effort to overcome. A convenient way to reduce the transfer time would be to use existing institutional infrastructures (i.e., building code and standards-writing organizations, professional and technical organizations, universities, and research centers) to disseminate knowledge. Recommendation 10. A workshop to develop a road map for transferring technology for mitigating blast effects should be scheduled as soon as possible. To assist in the ongoing dissemination of information, the Blast Mitigation for Structures Program should consider sponsoring an annual or biennial conference devoted to all aspects of blast-mitigation design, engineering, injury prevention, and rescue and recovery. REFERENCES ACI (American Concrete Institute). 1999. Building Code Requirements for Structural Concrete and Commentary. Farmington Hills, Mich.: American Concrete Institute. ASCE (American Society of Civil Engineers). 1985. Design of Structures to Resist Nuclear Weapons Effects. New York: American Society of Civil Engineers. ASCE. 1996. Minimum Design Loads for Buildings and Other Structures. Reston, Va.: American Society of Civil Engineers. ASCE. 1999. Structural Design for Physical Security: State of the Practice. Reston, Va.: American Society of Civil Engineers.
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Blast Mitigation for Structures: 1999 Status Report on the DTRA/TSWG Program ASCE. 1999. Structural Design for Physical Security: State of the Practice. Reston, Va.: American Society of Civil Engineers. ATC (Applied Technology Council). 1982. Tentative Provisions for the Development of Seismic Regulations for Buildings (ATC-3-06). Redwood City, Calif.: Applied Technology Council. ATC and SEAOC (Applied Technology Council and Structural Engineers Association of California). 1998. Built to Resist Earthquakes: The Path to Quality Seismic Design and Construction. Redwood City, Calif.: Applied Technology Council. BMAG (Blast Mitigation Action Group). 2000. BMAG. Available on line at:http://bmag.nwo.usace.army.mil FEMA (Federal Emergency Management Agency). 1997a. National Earthquake Hazards Reduction Program Guidelines for Seismic Rehabilitation of Buildings and Commentary. Washington, D.C.: Federal Emergency Management Agency. FEMA. 1997b. National Earthquake Hazards Reduction Program Recommended Provisions for Seismic Regulations for New Buildings and Other Structures and Commentary. Washington, D.C.: Federal Emergency Management Agency. NRC (National Research Council). 1995. Protecting Buildings from Bomb Damage: Transfer of Blast-Effects Mitigation Technologies from Military to Civilian Applications. Washington, D.C.: National Academy Press. SEAOC (Structural Engineers Association of California). 1996. Recommended Lateral Force Requirements and Commentary. Sacramento, Calif.: Structural Engineers Association of California. USACE (U.S. Army Corps of Engineers). 1999. Estimating Damage to Structures from Terrorist Bombs, Field Operations Guide. Engineering Technical Letter 1110-3-495. Washington, D.C.: U.S. Army Corps of Engineers. U.S. Army. 1990. Structures to Resist the Effects of Accidental Explosions. TM 5-1300. Washington, D.C.: Department of the Army. U.S. Army, U.S. Air Force, U.S. Navy, and Defense Special Weapons Agency. 1997. Design and Analysis of Hardened Structures to Conventional Weapons Effects. TM 5-855-1/AFPAM 32-1147(I)/NAVFAC P-1080/DAHSCWEMAN-97. Washington, D.C.: U.S. Army Corps of Engineers.
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