Ricerc@Sapienza

The seismic analysis of bridges needs to account for the effects of soil-structure interaction with methods that strike a reasonable balance between completeness and reliability of the numerical soil-structure interaction models. In view of this, focusing on the marked influence that the behaviour of the abutments can have on the seismic performance of the whole bridge, this study presents an identification procedure of the dynamic response bridge abutments.

Under the large forces transmitted by a bridge structure during an earthquake, a bridge abutment may undergo significant displacements deriving from the mobilisation of both the soil and the structural strength. In some cases a controlled yielding of the abutment may produce favourable effects, dissipating seismic energy and limiting the seismic actions into the superstructure. In fact, the bridge design could explicitly account for dissipative features of the soil-abutment system, allowing a certain amount of irreversible displacements compatible with a prescribed performance level.

This paper presents a coupled numerical modelling of the soil-structure interaction for a multi-span girder bridge, inspired by a case study in Italy, to analyse the importance of the local dynamic response of the abutments in the seismic performance of the bridge. The full soil-bridge model was implemented in the analysis framework OpenSees, describing the mechanical behaviour of the foundation soils by means of an advanced constitutive model calibrated against experimental data.