Seismic displacement demand of bridge’s wall piers controlled by foundation rocking

Applying the effect of soil-structure-interaction on displacement demand of essential structures, like bridges in design or assessment procedures required enormous nonlinear dynamic time history analysis considering rocking and uplifting phenomena in foundations. In conventional bridges with strong wall pier, nonlinear mechanism are controlled by the foundation behavior and geotechnical capacity and in consequence nonlinear sources mainly concentrated in the level of soil and foundation. It is necessary to implement foundation nonlinear behavior in order to utilize linear analysis to determine seismic demand in these types of bridge. Displacement amplification factors mentioned in current codes are not able to consider foundation flexibility, rocking or uplifting phenomena. In this paper in addition to presenting the coefficient derived from solving SDOF system with the potential of rocking -uplifting, a case study bridge is investigated to compare proposed equation with the exact solution and determine their accuracy

Keywords:

Soil-Structure-Interactions , Wall Pier , Displacement Demand , Rocking Motion