Analysis of the Seismic Site Effects along the Ancient Via Laurentina (Rome)

This paper presents an evaluation of the Local Seismic Response (LSR)
along the route of the ancient Roman road Via Laurentina, which has
been exposed in several areas of southwest Rome over the last decade
during the construction of new buildings and infrastructures. It is
an example of LSR analysis applied to ancient and archaeological
sites located in alluvial valleys with some methodological inferences
for the design of infrastructure and urban planning. Since the ancient
road does not cross the alluvial valley (namely the Fosso di Vallerano
Valley) normal to its sides, it was not possible to directly perform
2D numerical modelling to evaluate the LSR along the road route.
Therefore, outputs of 2D numerical models, obtained along three cross
sections that were normal oriented respect to the valley, were projected
along the route of the Via Laurentina within a reliable buffer attributed
according to an available high-resolution geological model of the
local subsoil. The modelled amplification functions consider physical
effects due to both the 2D shape of the valley and the heterogeneities
of the alluvial deposits. The 1D and 2D amplification functions were
compared to output that non-negligible effects are related to the narrow
shape of the fluvial valley and the lateral contacts between the
lithotecnical units composing the alluvial fill. The here experienced
methodology is suitable for applications to the numerical modelling of
seismic response in case of linear infrastructures (i.e., roads, bridges,
railways) that do not cross the natural system along physically characteristic
directions (i.e. longitudinally or transversally).