Prediction of Seismic Site Coefficients for Northeast Arkansas (NEA)

Abstract

AbstractAbout 25% of bridges in Craighead County, a part of Northeast Arkansas (NEA) in the United States of America, are in a poor condition. The NEA region is situated within a major seismic zine called the New Madrid Seismic Zone (NMSZ). In recent years, several new bridges have been proposed for new highways or improvement of existing highways within this zone. With the existing vulnerability due to the presence of the nearby active fault and higher seismic design force requirements, future investment in the repairment of bridges and new construction are critical issues. The main objectives of this study are to estimate seismic site coefficients for this zone by ground response analysis and compare them with coefficients recommended by researchers and agencies such as the American Association of State Highway Official (AASHTO). The shear wave velocity profiles (SWVP) of this zone have been collected from historical construction projects in the NEA and Mississippi Embayment (ME) areas. The seismic hazard analysis (SHA) has been carried out for different locations within this zone. Using a unified 1-D (one-dimension) equivalent linear (EQL) and nonlinear (NL) site response analyses platform called DEEPSOIL (Version 7.0), a series of ground response analyses has been carried out to evaluate possible variabilities of SWVPs, dynamic soil properties, and SHA results. Finally, seismic acceleration site coefficients have been estimated for selected locations within this zone. The findings of this study are expected to help the city and state highway design engineers to calculate design forces for existing and new bridges that will lead to the avoidance of expensive field investigations.KeywordsEarthquakeSite coefficientSeismic hazardDEEPSOILShear wave velocityGround response analysis