FEMA-450-1.pdf

ERRATA FOR THE 2003 NEHRP RECOMMENDED PROVISIONS FOR SEISMIC REGULATIONS FOR NEW BUILDINGS AND OTHER STRUCTURES June 2006 Table of Contents, pages XIV XV, Change the page numbers of Sec. 14.2.5 through 14.4.7 to read as follows: 14.2.5 Structural analysis procedure selection 241 14.2.6 Seismic weight 241 14.2.7 Rigid nonbuilding structures .241 14.2.8 Minimum base shear 241 14.2.9 Fundamental period.241 14.2.10 Vertical distribution of seismic forces 242 14.2.11 Deformation requirements 242 14.2.12 Nonbuilding structure classification .242 14.3 NONBUILDING STRUCTUTRES SIMILAR TO BUILDINGS .242 14.3.1 Electrical power generating facilities242 14.3.2 Structural towers for tanks and vessels .242 14.3.3 Piers and wharves243 14.3.4 Pipe racks 243 14.3.5 Steel storage tanks.243 14.4 NONBUILDING STRUCTURES NOT SIMILAR TO BUILDINGS244 14.4.1 General244 14.4.2 Earth retaining structures.244 14.4.3 Stacks and chimneys .244 14.4.4 Amusement structures.244 14.4.5 Special hydraulic structures 245 14.4.6 Secondary containment systems .245 14.4.7 Tanks and vessels245 Chapter 4 Sec. 4.3.3.2, page 66, Add the word “not” to the last sentence after item No. 4 4.3.3.2 Seismic Design Categories D, E, and F. For structures assigned to Seismic Design Category D, E, or F, shall be permitted to be taken as 1.0, provided that at each story resisting more than 35 percent of the base shear in the direction of interest the seismic-force-resisting system meets the following redundancy requirements: 1. Systems with braced frames: Removal of an individual brace, or connection thereto, would not result in more than a 33 percent reduction in story strength, nor create an extreme torsional irregularity (plan structural irregularity Type 1b). 2. Systems with moment frames: Loss of moment resistance at the beam-to-column connections at both ends of a single beam would not result in more than a 33 percent reduction in story strength, nor create an extreme torsional irregularity (plan structural irregularity Type 1b). 3. Systems with shear walls or wall piers: Removal of a shear wall or wall pier with a height-to- length-ratio greater than 1.0 within any story, or collector connections thereto, would not result in more that a 33 percent reduction in story strength, nor create an extreme torsional irregularity (plan structural irregularity Type 1b). 4. All other systems: No requirements. For structures not meeting items 1,2,3, and 4 above permitting equal to 1.0, shall be taken as 1.3. Exception: The structure shall be permitted to be designed using a taken as 1.0, provided that at each story that resists more than 35 percent of the base shear the seismic force-resisting system is regular in plan with at least two bays of primary seismic force- resisting elements located at the perimeter framing on each side of the structure in each orthogonal direction. The number of bays for a shear wall shall be calculated as the length of wall divided by the story height. Chapter 6 Sec. 6.1.1, page 111, Add the following qualifiers. 6.1.1 Scope. This chapter establishes minimum design criteria for nonstructural components that are permanently attached to structures and for their supports and attachments Exception: The following nonstructural components are exempt from the requirements of this section: 1. Architectural components in Seismic Design Category B other than parapets supported by bearing walls or shear walls provided that the component importance factor (Ip) is equal to 1.0. 2. Mechanical and electrical components in Seismic Design Category B. 3. Mechanical and electrical components in Seismic Design Category C provided that the component importance factor (Ip) is equal to 1.0. 4. Mechanical and electrical components in Seismic Design Categories D, E, and F where the component importance factor (Ip) is equal to 1.0 and either both of the following conditions apply: a. Flexible connections between the components and associated ductwork, piping, and conduit are provided, or and b. Components are mounted at 4 ft (1.22 m) or less above a floor level and weigh 400 lb (1780 N) or less. 5. Mechanical and electrical components in Seismic Design Categories D, E, and F where the component importance factor (Ip) is equal to 1.0 and both of the following conditions apply: a. Flexible connections between the components and associated ductwork, piping, and conduit are provided, and b. The components weigh 20 lb (95N) or less or, for distribution systems, weighing 5 lb/ft (7 N/m) or less. Design Chapter 14 Sec. 14.4.7.1 , Page 245, Remove the Importance Factor (I) from , paragraph 3. a, b (Equation 14.4-1), and c. 14.4.7.1 Design basis. Tanks and vessels storing liquids, gases, or granular solids shall satisfy the analysis and design requirements set forth in the applicable references as indicated in Table 14.1-1 and the additional requirements of these Provisions including the following: 1. Damping for the convective (sloshing) force component shall be taken as 0.5 percent unless otherwise define in an adopted reference or other approved standard. 2. Impulsive and convective components may be combined by taking the square root of the sum of the squares of the components. 3. Vertical earthquake effects shall be considered in accordance with the applicable approved standard. If the approved standard permits the user the option of including or excluding the vertical earthquake effects, to comply with these Provisions, they shall be included. For tanks and vessels not covered by an approved standard, the forces due to the vertical acceleration shall be defined as follows: a. Hydrodynamic vertical and lateral forces in tank walls: The increase in hydrostatic pressures due to the vertical excitation of the contained liquid shall correspond to an effective increase in density, L, of the stored liquid equal to 0.2SDS I L. b. Hydrodynamic hoop forces in cylindrical tank walls: In a cylindrical tank wall, the hoop force per unit height, Nh, at level y from the base, associated with the vertical excitation of the contained liquid, shall be computed in accordance with Eq. 14.4-1 0.2 hDSNSI =()() 2Li L y HD . (14.4-1) where: Di = inside tank diameter (ft) HL = liquid height inside the tank (ft). y = distance from base of the tank to level being investigated (ft). L = unit weight of stored liquid (lb/ft3) c. Vertical inertia forces in cylindrical and rectangular tank walls: Vertical inertia forces associated with the vertical acceleration of the structure itself shall be taken equal to 0.2SDS I W. Program on Improved Seismic Safety Provisions of the National Institute of Building Sciences 2003 Edition NEHRP RECOMMENDED PROVISIONS FOR SEISMIC REGULATIONS FOR NEW BUILDINGS AND OTHER STRUCTURES (FEMA 450) Part 1: Provisions The Building Seismic Safety Council (BSSC) was established in 1979 under the auspices of the National Institute of Building Sciences as an entirely new type of instrument for dealing with the complex regulatory, technical, social, and economic issues involved in developing and promulgating building earthquake hazard mitigation regulatory provisions that are national in scope. By bringing together in the BSSC all of the needed expertise and all relevant public and private interests, it was believed that issues related to the seismic safety of the built environment could be resolved and jurisdictional problems overcome through authoritative guidance and assistance backed by a broad consensus. The BSSC is an independent, voluntary membership body representing a wide variety of building community interests. Its fundamental purpose is to enhance public safety by providing a national forum that fosters improved seismic safety provisions for use by the building community in the planning, design, construction, regulation, and utilization of buildings. See the back of the Commentary volume for a full description of BSSC activities. 2003 BSSC BOARD OF DIRECTION Chairman Charles Thornton, Chairman/Principal, Thornton-Tomasetti Group, Inc., New York, New York Vice Chairman David Bonneville, Degenkolb Engineers, San Francisco, California Secretary Charles Carter, Chief Structural Engineer, American Institute of Steel Construction, Chicago, Illinois Ex-Officio William W. Stewart, Stewart-Schaberg Architects, Clayton, Missouri (representing the American Institute of Architects) Members J. Gregg Borchelt, Vice President, Brick Industry Association, Reston, Virginia Edwin Dean, Nishkian Dean, Portland, Oregon Bradford K. Douglas, Director of Engineering, American Forest and Paper Association, Washington, D.C. Henry Green, Executive Director, Bureau of Construction Codes and Fire Safety, State of Michigan, Department of Labor and Economic Growth, Lansing, Michigan (representing the National Institute of Building Sciences) H.S. Lew, Senior Research Engineer, National Institute of Standards and Technology, Gaithersburg, Maryland (representing Interagency Committee on Seismic Safety in Construction) Joseph Messersmith, Coordinating Manager, Regional Code Services, Portland Cement Association, Rockville, Virginia (representing the Portland Cement Association) Jim Rinner, Project Manager II, Kitchell CEM, Sacramento, California James Rossberg, Manager, Technical Activities for the Structural Engineering Institute, American Society of Civil Engineers, Reston Virginia Jeffery Sciadone, Associate Director, of Engineering, Institute of Business and Home Safety, Tampa, Florida W. Lee Shoemaker, Director, Engineering and Research, Metal Building Manufacturers Association, Cleveland, Ohio Howard Simpson, Simpson Gumpertz and Heger, Arlington, Massachusetts (representing National Council of Structural Engineers Associations) Charles A. Spitz, Architect/Planner/Code Consultant, Wall New Jersey (representing the American Institute of Architects) BSSC STAFF Claret M. Heider, Vice President for BSSC Programs Bernard F. Murphy, Director, Special Projects Carita Tanner, Communications/Public Relations Manager Patricia Blasi, Administrative Assistant NEHRP RECOMMENDED PROVISIONS (National Earthquake Hazards Reduction Program) FOR SEISMIC REGULATIONS FOR NEW BUILDINGS AND OTHER STRUCTURES (FEMA 450) 2003 EDITION Part 1: PROVISIONS Prepared by the Building Seismic Safety Council for the Federal Emergency Management Agency BUILDING SEISMIC SAFETY COUNCIL NATIONAL INSTITUTE OF BUILDING SCIENCES Washington, D.C. 2004 ii NOTICE: Any opinions, findings, conclusions, or recommendations expressed in this publication do not necessarily reflect the views of the Federal Emergency Management Agency. Additionally, neither FEMA nor any of its employees make any warranty, expressed or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, product, or process included in this publication. This report was prepared under Contract EMW-2001-CO-0269 between the Federal Emergency Management Agency and the National Institute of Building Sciences. Building Seismic Safety Council activities and products are described at the end of this report. For further information, see the Councils website (www.bssconline.org) or contact the Building Seismic Safety Council, 1090 Vermont, Avenue, N.W., Suite 700, Washington, D.C. 20005; phone 202-289-7800; fax 202-289-1092; e-mail bsscnibs.org. Copies of this report on CD Rom may be obtained from the FEMA Publication Distribution Facility at 1-800-480-2520. Limited paper copies also will be available. The report can also be downloaded in pdf form from the BSSC website at www.bssconline.org . The National Institute of Building Sciences and its Building Seismic Safety Council caution users of these Provisions documents to be alert to patent and copyright concerns especially when applying prescriptive requirements iii PREFACE One of the goals of the Department of Homeland Securitys Federal Emergency Management Agency (FEMA) and the National Earthquake Hazards Reduction Program (NEHRP) is to encourage design and building practices that address the earthquake hazard and minimize the resulting risk of damage and injury. Publication of the 2003 edition of the NEHRP Recommended Provisions for Seismic Regulation of New Buildings and Other Structures and its Commentary is a fitting end to the 25th year of the NEHRP and reaffirms FEMAs ongoing support to improve the seismic safety of construction in this country. Its publication marks the sixth edition in an ongoing series of updating of both the NEHRP Recommended Provisions and several complementary publications. FEMA was proud to sponsor the Building Seismic Safety Council for this project and we encourage the widespread dissemination and voluntary use of this state-of-the-art consensus resource document. The 2003 edition of the NEHRP Recommended Provisions contains several significant changes, including: a reformatting to improve its usability; introduction of a simplified design procedure, an updating of the seismic design maps and how they are presented; a modification in the redundancy factor; the addition of ultimate strength design provisions for foundations; the addition of several new structural systems, including buckling restrained braced frames and steel plate shear walls; structures with damping systems has been moved from an appendix to a new chapter; and inclusion of new or updated material industry reference standards for steel, concrete, masonry, and wood. The above changes are but a few of the 138 ballots submitted to the BSSC member organizations. The number of changes continues to be significant and is a testament to the level of attention being paid to this publication. This is due in large part to the role that the NEHRP Recommended Provisions has in the seismic requirements in the ASCE-7 Standard Minimum Design Loads for Buildings and Other Structures as well as both the International Building Code and NFPA 5000 Code. FEMA welcomes this increased scrutiny and the chance to work with these code organizations. Looking ahead, FEMA is contracting with BSSC for the update process that will lead to the 2008 edition of the NEHRP Recommended Provisions. As is evidenced by the proposed date, this next update cycle will be expanded to a five-year effort to conclude in time to input into the next update of the ASCE-7 standard. This update will include referencing of the ASCE-7 standard to avoid duplication of effort and a significant update and revision to the Commentary along with the normal update of current material and the inclusion of new, state-of-the-art seismic design research results. Finally, FEMA wishes to express its deepest gratitude for the significant efforts of the over 200 volunteer experts as well as the BSSC Board of Directors and staff who made possible the 2003 NEHRP Provisions documents. It is truly their efforts that make these publications a reality. Americans unfortunate enough to experience t