After the 2010 Chilean Earthquake, buildings design code was upgraded in topics related to spectrum design and soil classification; however, the bridge's code was not. The main target of this research is to propose a Ground Motion Prediction Equation (GMPE) in order to predict seismic intensity in Chile and to analyze the current spectrum design of the Road Manual code and use on it to evaluate the Seismic Risk Inform. I use an existing Japanese GMPE (Dr. KATAOKA Shojiro from NILIM) but modified by Chilean records using modification factors. These modification factors multiply the parameter “b” inside the original GMPE and become the geometric mean value (ratio between observed acceleration response spectrum over predicted acceleration response spectrum) to one (1). The results show excellent performance of GMPE Modified. Also, it shows that the peak of acceleration response spectrum and acceleration value at 1 second period of the current spectrum design for bridges must be examined.
Keywords: Ground Motion Prediction Equation (GMPE), Seismic Intensity, Bridge Spectrum Design, PGA.