ACI 370R-2014 Report for the Design of Concrete Structures for Blast Effects.pdf

1、Report for the Design of Concrete Structures for Blast EffectsReported by ACI Committee 370ACI 370R-14First Printing: July 2014Errata as of: October 12, 2015ISBN: 978-0-87031-898-6Report for the Design of Concrete Structures for Blast EffectsCopyright by the American Concrete Institute, Farmington H

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11、gether in the annually revised ACI Manual of Concrete Practice (MCP).American Concrete Institute38800 Country Club DriveFarmington Hills, MI 48331Phone: +1.248.848.3700Fax: +1.248.848.3701www.concrete.orgThis report addresses the design of structures to resist blast effects due to explosions. It des

12、cribes the state of the practice for the guidance of structural engineers charged with the design of civil facilities that may be subjected to blast loads. This report addresses the steps commonly followed in this practice, including determination of the threat, calculation of structural loads, beha

13、vior of structural systems, design of structural elements, design of security windows, design of security doors, and design of utility openings. These steps can applied to the design of new structures or to the retrofitting of existing structures.Keywords: blast; blast analysis; blast-resistant buil

14、dings; blast-resistant design; ductility; dynamics; explosions; retrofit for blast; shock; overpressure.Eric B. Williamson*, Chair William L. Bounds*, SecretaryACI 370R-14Report for the Design of Concrete Structures for Blast EffectsReported by ACI Committee 370Adeola K. Adediran*Abi Assadi*Darrell

15、D. Barker*Bal K. Cherwoo*Savita GoelDavid KerinsTheodor Krauthammer*Paul F. Mlakar*Madhav G. Nene*Barendra K. Talukdar*Joseph W. Tedesco*James W. Wesevich*Stanley C. WoodsonDavid Z. Yankelevsky*William H. Zehrt, Jr.*Consulting MembersQuentin A. BakerEve E. HinmanSam A. KigerJaap WeerheijmACI Committ

16、ee Reports, Guides, and Commentaries are intended for guidance in planning, designing, executing, and inspecting construction. This document is intended for the use of individuals who are competent to evaluate the significance and limitations of its content and recommendations and who will accept re

17、sponsibility for the application of the material it contains. The American Concrete Institute disclaims any and all responsibility for the stated principles. The Institute shall not be liable for any loss or damage arising therefrom.Reference to this document shall not be made in contract documents.

18、 If items found in this document are desired by the Architect/Engineer to be a part of the contract documents, they shall be restated in mandatory language for incorporation by the Architect/Engineer.ACI 370R-14 was adopted and published June 2014.Copyright 2014, American Concrete Institute.All righ

19、ts reserved including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by electronic or mechanical device, printed, written, or oral, or recording for sound or visual reproduc-tion or for use in any knowledge or retrieval system or d

20、evice, unless permission in writing is obtained from the copyright proprietors.*Contributed to the writing of the report.CONTENTSCHAPTER 1INTRODUCTION, p. 11.1Overview of report, p. 21.2Background and history, p. 2CHAPTER 2NOTATION AND DEFINITIONS, p. 32.1Notation, p. 32.2Definitions, p. 4CHAPTER 3D

21、ESIGN PHILOSOPHY, p. 53.1Explosions and fragments, p. 53.2Threat scenario, p. 63.3Protection criteria, p. 63.4Balanced design, p. 73.5Global design, p. 73.6General principles of structural design, p. 73.7Analysis and design, p. 83.8Energy absorption, p. 93.9Ductility, p. 93.10Damage control, p. 93.1

22、1Construction, p. 103.12Cost effectiveness, p. 103.13Decision making, p. 10CHAPTER 4GENERAL PLANNING AND DESIGN METHODOLOGY, p. 104.1Applications, p. 104.2Objectives of blast-resistant design, p. 114.3Hazard assessment and risk analysis, p. 114.4Planning, p. 124.5Structural design process, p. 12CHAP

23、TER 5BLAST LOAD PREDICTION, p. 135.1Blast load basics, p. 135.2Explosion sources, p. 145.3Load prediction methods, p. 175.4High explosives, p. 175.5Bursting pressure vessels, p. 191CHAPTER 1INTRODUCTIONThe design of concrete structures for blast resistance has been of great interest to the military

24、and other federal agencies for several decades. In addition, certain specialized segments within the engineering community have also had to consider blast loads on structures as a result of potential accidents. For example, the petrochemical industry has designed for blast resistance in their facili

25、ties for many years. Even though there is considerable history in the design of structures to resist blast effects resulting from accidents or intentional acts, it is only recently that the general structural engineering community has shown a strong interest in the response of structures subjected t

26、o explosions and other high-rate loading phenomena, such as impact.Following the attacks on the World Trade Center in New York and the Pentagon in Washington, DC, on September 11, 2001, the vulnerability of the nations infrastructure to terrorism became a top priority for many state and federal gove

27、rnment agencies as well as private consulting engineers. Though the significance of these attacks greatly increased engineering interest in the design of structures to resist extreme loads, statistics show that US interests have been targeted by terrorists with increasing frequency during the last s

28、everal decades (U.S. Department of State, 2003), leading to significant financial and personal losses. As a result, the engineering community has learned important lessons that have allowed for improved methods of analysis and design to be developed. For example, lessons learned from the Oklahoma Ci

29、ty bombing in 1995 and the U.S. embassy attacks in Tanzania and Nairobi in 1998 shaped present design guidelines for prevention of progressive collapse.While the field of blast- and impact-resistant design is not as mature as other fields, such as seismic-resistant design, historical events such as

30、those described are important to note because they help shape current practice and research interests. Just as the field of seismic-resistant design has advanced by learning lessons from past incidents, engineers working in protective design can similarly benefit from being aware of historical event

31、s and corresponding data. Although such information is typically outside the scope of work routinely undertaken by design engineers, awareness of these issues is important for understanding potential threats and associated loads that may result. While historical data can be used with reasonable conf

32、idence for predicting natural loads such as earthquakes and floods, the same claim cannot be made for man-made loads associated with potential terrorist threats. Thus, the intent of the discussion herein is to bring awareness to engineers and designers that many factors can influence the loads to wh

33、ich a structure may potentially be subjected, and it is only through awareness and consideration of the factors that affect the threat environment that engineers can estimate design loads.1.1Overview of reportGiven the trends in terrorism and the required protection of building occupants at petroche

34、mical facilities, it is clear that structural engineers must be able to design structures 5.6Vapor cloud explosions, p. 195.7Load on structures, p. 20CHAPTER 6TYPES OF STRUCTURES, p. 236.1Building functions and physical characteristics, p. 236.2Building types and configurations, p. 256.3Blast resist

35、ance capabilities of structural systems, p. 27CHAPTER 7MATERIAL CHARACTERISTICS, p. 287.1Strain-rate dependency of concrete, p. 287.2Factors contributing to strain rate dependency, p. 287.3Constitutive models for concrete, p. 307.4Strain-rate-dependent constitutive equations for concrete, p. 327.5St

36、rain rate effects in metals, p. 337.6Application to blast assessment and design, p. 35CHAPTER 8STRUCTURAL ANALYSIS, p. 368.1Introduction and background, p. 368.2Computational support capabilities, p. 378.3Single degree-of-freedom (SDOF) computational approaches, p. 388.4Intermediate approximate comp

37、utational approaches, p. 418.5Advanced approximate computational approaches, p. 438.6Structural assessment support tools, p. 448.7Application examples, p. 458.8Conclusions and recommendations, p. 46CHAPTER 9DESIGN OF REINFORCED CONCRETE COMPONENTS, p. 479.1Introduction, p. 479.2Design safety factor,

38、 p. 479.3Reinforced concrete design, p. 489.4Development of reinforcing bars, p. 509.5Construction details and procedures, p. 509.6Masonry construction, p. 51CHAPTER 10BLAST HARDENING RETROFIT CONCEPTS FOR EXISTING BUILDINGS, p. 5210.1Strengthen existing building components, p. 5210.2Employ addition

39、al components, p. 56CHAPTER 11DESIGN OF BLAST-RESISTANT ANCILLARY OPENINGS, p. 5711.1General considerations, p. 5711.2Materials, p. 6011.3Design issues, p. 6211.4Specification, p. 65CHAPTER 12REFERENCES, p. 66American Concrete Institute Copyrighted Material www.concrete.org2 REPORT FOR THE DESIGN OF

40、 CONCRETE STRUCTURES FOR BLAST EFFECTS (ACI 370R-14)to resist the blast effects due to explosions. Drawing on research and engineering practice, the goal of this document is to compile essential information on the design of concrete structures to resist blast effects. Information is gathered from re

41、search reports, military design guidelines (when publicly available), and expertise from the petrochemical industry to provide a thorough introduction to the design of concrete structures to resist blast effects.Several of the chapters in this report address topics that are nonstructural. When desig

42、ning for blast effects, engineers must take into consideration that the loads that act on structures are strongly dependent on the distance between the structures and potential blast locations. In addition, there is a chapter on windows and openings because glass fragments from a blast typically con

43、tribute to injuries and fatalities. Thus, in designing structures to provide a safe environment for the inhabitants, structural engineers must consider other design issues that fall outside of their usual responsibilities when designing structures for more typical loads. Accordingly, it is important

44、 that engineers become familiar with these topics and play an active role in the decision-making process used to site buildings and select a faade system, doors, and windows.Providing standoff is often the most cost-effective solution for mitigating the hazards associated with a blast load. In many

45、cases, however, it may not be possible to provide sufficient standoff distance for a structure to eliminate the need for considering structural response to blast effects. Under these conditions, structural hardening is likely required. If consideration is given to structural modifications during the

46、 design stage, the costs of hardening can be minimized, and the aesthetic impact on the structure under consideration can, in many cases, be completely eliminated. As a retrofit, structural hardening can be expensive, although necessary for the safety of a building and its occupants. To address thes

47、e design challenges, significant guidance is provided in this document on the selection of structural systems for blast resistance, methods of analysis, and design considerations. In addition, an entire chapter is dedicated to describing methods of retrofitting structures to achieve adequate blast r

48、esistance.Although this report provides great breadth in the topics it addresses, it is not intended to be a stand-alone volume for practicing engineers. The purpose of this report is to provide a well-organized introduction that will serve as a starting point for identifying key issues associated w

49、ith the design of concrete structures to resist blast effects. For engineers looking to familiarize themselves with this topic, it will serve as a concise guide. If more detailed information is needed, an extensive list of references has been provided.1.2Background and historyTo develop an appreciation of the extent to which terrorists have targeted U.S. assets, it is helpful to review several previous events. The events described in the following are not intended to be an exhaustive list of attacks against U.S