Effect of vertical ground motions on the structural response of highway bridges

The Multidisciplinary Center of Earthquake Engineering Research (MCEER) is a national center of excellence in advanced technology applications that is dedicate to the reduction of earthquake losses nationwide. Headquartered at the University at Buffalo, State University of New York, the Center was originally established by the National Science Foundation in 1986, as the National Center for Earthquake Engineering Research (NCEER). Response spectrum analyses are perfomed on all six bridges usinga all of the above ground motion parameters for the cases of (a) two-component horizontal only input and (b) three-component input. Results for the two cases are compared. The accuracy of these resultus is validated by linear time history analyses of three bridges using spectrum compatible records. The additional effect of including the vertical component of motion is presented as a ratio of the dead-load only response. Records with early-arriving short period motion in the vertical component are shown to produce similar structural response to records that do not have these caracteristics. Results from response spectrum analyses using vertical spectrum with a spectral amplitude 2/3 of the horizontal spectrum showed that the response can be up to 40 greater or less than those from empirical vertical spectra