10. Fragility Functions of Highway and Railway Infrastructure

The experience of past earthquakes has revealed that highway and railway elements are quite vulnerable to earthquake shaking and induced phenomena such as soil liquefaction or landslide; damages to these elements can seriously affect the transportation of products and people in both short-term (emergency actions) and long-term period. The objective of this chapter is to propose appropriate fragility functions for roadway and railway components other than bridges that are presented separately in Chap. 9. To this end, the main typological features are summarized and a short review of earthquake damages together with damage states definitions are provided for these elements. Fragility curves from literature are collected and reviewed. In some cases these functions are modified and adapted, while in other cases new fragility curves are developed. A general procedure for the derivation of analytical fragility curves that was followed in SYNER-G is described. This approach takes into account the effect of structure geometry, ground motion characteristics, soil conditions and associated uncertainties. New fragility curves are presented for tunnels in soil, embankments, cuttings and bridge abutments based on numerical analyses due to ground shaking. Finally, the proposed fragility functions are summarized and a general scheme to identify the functionality of roadway and railway elements due to different damage levels is outlined.