DEVELOPMENT OF UNITED-STATES SEISMIC CODES

This paper aims to clarify for design engineers the basis on which sei smic lateral loads are established in US codes. The particular empiric al seismic response spectra recommended in the AISC seismic provisions will be discussed. Such curves give the base shear coefficients for v arious buildings as a function of their natural period. The relationsh ips of seismic code provisions to the actual behavior of buildings dur ing an earthquake is presented. A brief comparison of lateral load pro visions in the US and those of Canada, Japan and Europe follows. For e ngineers unfamiliar with seismic design, the various technical terms u sed in earthquake engineering are introduced and defined.