|TO:||All Design Section Staff|
|DATE:||December 11, 1997|
|SUBJECT:||Seismic Retrofit of Columns|
Reference is made to Section 5.5.2 (B,3.) of the Bridge Design Manual. This section indicates that "existing columns should be considered for retrofitting". Currently, our funding program for seismic retrofit is limited. We need to dedicate all available seismic retrofit program funds to correcting the highest priority deficiency (currently single column piers). Therefore, only single column piers supporting an existing bridge (at sites where EPA is 0.1 or greater) should be retrofitted as part of a bridge widening project that includes additional substructures.
This column retrofit policy will be in effect until all existing single column piers (at sites where EPA is 0.1 or greater) are retrofitted or seismic retrofit funding increases.
cc: M. M. Lwin, 7340
E. H. Henley, 7340