P1: JsYASCE003-11.tex ASCE003/SIE-v1.cls September 29, 2005 17:5Chapter 11SEISMIC DESIGN CRITERIA11.1 GENERAL11.1.1 Purpose. Chapter 11 presents criteria for the design andconstruction of buildings and other structures subject to earth-quake ground motions. The specified earthquake loads are basedupon post-elastic energy dissipation in the structure, and becauseof this fact, the requirements for design, detailing, and construc-tion shall be satisfied even for structures and members for whichload combinations that do not contain earthquake loads indicatelarger demands than combinations that include earthquake loads.Minimum requirements for quality assurance for seismic force-resisting systems are set forth in Appendix 11A.11.1.2 Scope. Every structure, and portion thereof, includingnonstructural components, shall be designed and constructed toresist the effects of earthquake motions as prescribed by the seis-mic requirements of this standard. Certain nonbuilding structures,as described in Chapter 15, are also within the scope and shall bedesigned and constructed in accordance with the requirementsof Chapter 15. Requirements concerning alterations, additions,and change of use are set forth in Appendix 11B. Existing struc-tures and alterations to existing structures need only comply withthe seismic requirements of this standard where required by Ap-pendix 11B. The following structures are exempt from the seismicrequirements of this standard:1. Detached one- and two-family dwellings that are locatedwhere the mapped, short period, spectral response accelera-tion parameter, SS,isless than 0.4 or where the Seismic De-sign Category determined in accordance with Section 11.6is A, B, or C.2. Detached one- and two-family wood-frame dwellings notincluded in Exception 1 with not more than two stories,satisfying the limitations of and constructed in accordancewith the IRC.3. Agricultural storage structures that are intended only forincidental human occupancy.4. Structures that require special consideration of their re-sponse characteristics and environment that are not ad-dressed in Chapter 15 and for which other regulations pro-vide seismic criteria, such as vehicular bridges, electri-cal transmission towers, hydraulic structures, buried utilitylines and their appurtenances, and nuclear reactors.11.1.3 Applicability. Structures and their nonstructural compo-nents shall be designed and constructed in accordance with therequirement of the following sections based on the type of struc-ture or component:a. Buildings: Chapter 12b. Nonbuilding Structures: Chapter 15c. Nonstructural Components: Chapter 13d. Seismically Isolated Structures: Chapter 17e. Structures with Damping Systems: Chapter 1811.1.4 Alternate Materials and Methods of Construction.Alternate materials and methods of construction to those pre-scribed in the seismic requirements of this standard shall not beused unless approved by the authority having jurisdiction. Sub-stantiating evidence shall be submitted demonstrating that theproposed alternate, for the purpose intended, will be at least equalin strength, durability, and seismic resistance.11.2 DEFINITIONSThe following definitions apply only to the seismic requirementsof this standard.ACTIVE FAULT: Afault determined to be active by theauthority having jurisdiction from properly substantiated data(e.g., most recent mapping of active faults by the United StatesGeological Survey).ADDITION: An increase in building area, aggregate floor area,height, or number of stories of a structure.ALTERATION: Any construction or renovation to an existingstructure other than an addition.APPENDAGE: An architectural component such as a canopy,marquee, ornamental balcony, or statuary.APPROVAL: The written acceptance by the authority havingjurisdiction of documentation that establishes the qualification ofa material, system, component, procedure, or person to fulfill therequirements of this standard for the intended use.ATTACHMENTS: Means by which components and theirsupports are secured or connected to the seismic force-resistingsystem of the structure. Such attachments include anchor bolts,welded connections, and mechanical fasteners.BASE: The level at which the horizontal seismic ground mo-tions are considered to be imparted to the structure.BASEMENT: A basement is any story below the lowest storyabove grade.BASE SHEAR: Total design lateral force or shear at the base.BOUNDARY ELEMENTS: Diaphragm and shear wallboundary members to which the diaphragm transfers forces.Boundary members include chords and drag struts at diaphragmand shear wall perimeters, interior openings, discontinuities, andreentrant corners.BOUNDARY MEMBERS: Portions along wall and di-aphragm edges strengthened by longitudinal and transverse re-inforcement. Boundary members include chords and drag strutsat diaphragm and shear wall perimeters, interior openings, dis-continuities, and reentrant corners.BUILDING: Any structure whose intended use includes shel-ter o