ABSTRACT
The 2014 New York City Building Code (NYCBC) provides seismic spectral response acceleration coefficients for Site Class B corresponding to the Maximum Considered Earthquake (MCE), and site coefficients as a function of site class and spectral acceleration. The design spectral response acceleration parameters adjusted for different site class conditions can be calculated accordingly for specific project sites. However, the NYCBC design parameters are generic for entire NYC area and in some cases site specific seismic studies may be required or preferred. For example, if the subsurface conditions indicated Site Class F, a site-specific study is required per the Code. In addition, site-specific study is performed for some projects to reduce analysis and construction costs. The approaches to perform site specific seismic studies are presented including seismic field testing to measure shear wave velocity, developing design seismic soil profiles using field testing results, and site-specific ground motion analyses to obtain a design acceleration response spectrum in accordance with the applicable provisions of ASCE 7-10 and NYCBC, using the dynamic soil properties developed. Three case studies in the metropolitan New York City area, including Site Class D, E, and F, are selected to demonstrate how performing site-specific seismic studies can be cost efficient solutions for projects to potentially reduce site classification, spectral acceleration, dynamic loads, thus reduce design and construction costs.
