Book Description

One of the goals of the Department of Homeland Security's 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 this edition of the “NEHRP Recommended Provisions for Seismic Regulation of New Buildings and Other Structures” and its “Commentary” (“FEMA 450-2 / Part 2: Commentary”) is a fitting end to the 25th year of the NEHRP and reaffirms FEMA's 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. This 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 “NEHRP Recommended Provisions for Seismic Regulations for New Buildings and Other Structures” (referred to hereinafter as the “Provisions”) present criteria for the design and construction of structures to resist earthquake ground motions. The purposes of these “Provisions” are as follows: 1. To provide minimum design criteria for structures appropriate to their primary function and use considering the need to protect the health, safety, and welfare of the general public by minimizing the earthquake-related risk to life and 2. To improve the capability of essential facilities and structures containing substantial quantities of hazardous materials to function during and after design earthquakes. The design earthquake ground motion levels specified herein could result in both structural and nonstructural damage. For most structures designed and constructed according to these “Provisions,” structural damage from the design earthquake ground motion would be repairable although perhaps not economically so. For essential facilities, it is expected that the damage from the design earthquake ground motion would not be so severe as to preclude continued occupancy and function of the facility. The actual ability to accomplish these goals depends upon a number of factors including the structural framing type, configuration, materials, and as-built details of construction. For ground motions larger than the design levels, the intent of these “Provisions” is that there be a low likelihood of structural collapse. These “Provisions” shall apply to the design and construction of structures—including additions, changes of use, and alterations—to resist the effects of earthquake motions. Every structure, and portion thereof, shall be designed and constructed to resist the effects of earthquake motions as prescribed by these “Provisions.”