Earthquake-resistant construction is expensive, especially in a place like the New York metropolitan area. A health care client was looking for the most cost-effective design for a critical care facility while incorporating the appropriate degree of earthquake resistance.
In seismically active areas, including the NY metro area, there is a tendency to overconstruct. This is particularly true in the Meadowlands which is mostly “made land,” built-up with old, and often uncontrolled, fill on top of organic saltmarsh deposits. A significant thickness of these low-stiffness materials can amplify even low-levels of earthquake shaking and cause considerable damage. Site-specific data from several seismic analyses was provided to the client, which helped inform design and construction decisions. This resulted in considerable savings as the building was designed for exactly the degree of shaking and amplification that could be expected at this site.
RETTEW performed a complete seismic hazard analysis, including a refraction microtremor (ReMi) and Multispectral Analysis of Surface Waves (MASW) survey, to develop shear-wave velocity profiles and identify the correct International Building Code seismic site classification. We also performed a Probabilistic Seismic Hazard Analysis (PSHA) and Deterministic Seismic Hazard Analysis (DSHA), giving the architects and structural engineers the most probable horizontal ground acceleration parameters for the Maximum Considered Earthquake (MCE), as well as an analysis of the liquefaction potential for the soil and fill layers beneath the proposed building. RETTEW’s analysis not only helped our client make informed decisions to ensure structural integrity of the new critical care facility during future earthquake events, but also eliminated unnecessary construction costs that may have been incurred without these data.