KOKONIS36
Structural
- Oct 28, 2001
- 28
My question is related to the Response modification factors of the foundations of seismic-isolated bridges. According to the AASHTO Guide Specifications for Seismic Isolation Design "the response modification factor for all substructures shall be half of those given in table 3.7 of the AASHTO Standard Specifications, but not less than 1.5.
But, what about foundations of seismically-isolated bridges?
Please note that according to the AASHTO specifications the response modification factor for the foundations of conventional bridges i.e. non-isolated bridges is half the value of the the substructure elements of the nonisolated bridges. For example, if the columns are designed for R=5 their foundations are designed for R=2.5
Consequently, the foundations of the columns of a seismically-isolated bridge should be designed for an R-value equal to 5/2=2.5/2 = 1.25 .Correct? What about piles?(not pile bents)
But, what about foundations of seismically-isolated bridges?
Please note that according to the AASHTO specifications the response modification factor for the foundations of conventional bridges i.e. non-isolated bridges is half the value of the the substructure elements of the nonisolated bridges. For example, if the columns are designed for R=5 their foundations are designed for R=2.5
Consequently, the foundations of the columns of a seismically-isolated bridge should be designed for an R-value equal to 5/2=2.5/2 = 1.25 .Correct? What about piles?(not pile bents)
