Dynamic modeling of Mataquito Bridge affected by liquefaction - induced lateral spreading

Abstract

The Mataquito Bridge is located at the north of the M_w 8. 8 Maule earthquake epicenter and it was selected for this study because clear evidence of liquefaction induced lateral spreading was detected at the site and the data available was enough to generate a numerical model. The numerical model was developed in the geotechnical software FLAC and includes advanced soil constitutive models, such as PM4SAND and UBCHYST, which are validated in dynamic condition. Furthermore, the soil-structure interaction is considered with the pile elements available in FLAC, via shear and normal springs. The acceleration history applied in the dynamic condition was registered in Rapel station. The calibration process considered in this research was conducted with SPT results and geotechnical correlations. Several numerical models were solved to obtain the parameters included in the soil constitutive models and in the pile coupling springs. The results include pile lateral displacement and the bending moments due to the earthquake. The residual lateral displacements are about 10 cm and concentrated at the top of the pile. Besides, the pore water pressure increased during the seismic motion and the liquefaction was reached before the peak acceleration.