investigation of the bridge's design codes through near fault'searthquakes

viewpoints of various design codes about vertical component of ground motions is reviewed. design codes that have been reviewed in this study are: iranian codes for seismic design of roads and railway's bridges, caltrans ,euro code8, aashto, aashto seismic isolation guide specifications, aashto lrfd bridge design specifications, asce, ibc2012  and ubc 97. then a database consists of 31 near fault earthquake records is gathered and individual and mean and mean +/- standard deviation response spectra plotted for selected 31 earthquakes and by comparison with standard spectra's is showed that usual assumption that vertical component spectrum equal to 2.3 horizontal spectrum isn't correct in short period regions.