Soil‐structure interaction for bridges with backwalls : FE‐analysis using PLAXIS

Sammanfattning: Bro 2004, BV Bro and the Eurocodes give guidelines for how to consider earth pressure induced by change in temperature and braking forces when designing backwalls. In this thesis those demands are investigated using PLAXIS for evaluation of the earth pressure. The results show that the model in PLAXIS corresponds quite well with the conventions in Bro 2004 and that modelling in PLAXIS gives reliable results. The demand in Bro 2004 that backwalls always shall be designed for passive earth pressure has been found to be pessimistic. In case of long bridges and short backwalls passive earth pressure is most often reached but for shorter bridge lengths in combination with longer backwalls this is almost never the case. It was also found that PLAXIS is sensitive and that the structure of the model and the choice of input are essential. A model in PLAXIS doesn’t make the design more effective but it may be a good tool for analysing the effect of the earth pressure combined with other effects such as the patterns for displacement as well as moment- and force distributions.