Design of Seismic Restrainers for In-Span Hinges

摘要

Using sample WSDOT designs and seismic retrofitting guidelines from WSDOT andCALTRANS, the researchers developed a model of a two-frame bridge with a single in-span hinge. The nonlinear response of the bridge was studied to determine the maximum opening experienced at the in-span hinge and the maximum relative displacements at the abutments. To identify the parameters most important in restrainer design and in predicting the unrestrained maximum relative abutment displacements, the researchers varied eleven parameters. The parametric study identified the parameters that significantly influenced the maxiumum relative hinge displacement (MHRHD) and the maximum relative abutment displacements (MRAD). The ASSHTO empirical seat with width equation and the CALTRANS restrainer design method were compared with the results of nonlinear time history analysis. Using the results of the parametric study, the researchers developed a new restrainer design method that predicted the MRHD much more accurately than the CALTRANS method. The researchers also developed a method for estimating the unrestrained MRAD.