Engineering Geological and Geophysical Studies Supporting Finite Element Analysis of Historical Buildings after Dynamic Identification

Abstract

Resonance frequencies of a masonry bell tower were estimated by means of ambient noise measurements and compared with those computed by using fixed base, Winkler, and FE numerical, including subsoil. Given the geological complexity that characterizes the subsurface of the analyzed area, despite the presence of massive volcanic outcrops near the bell tower, we carried out a geophysical characterization of the subsoil by using active and passive seismic surveys. These surveys have identified a soft substrate underneath the construction; for this reason, the dynamic identification of the tower was performed, including the interaction with the soil. The resonance frequencies of the masonry bell tower computed by the models are very similar to those obtained using ambient noise. Results suggest that building resonance frequencies, estimated by ambient noise surveys, can be used because of their reliability especially when quick analyses are required at historical buildings located in seismically active areas needing plan actions to reduce their vulnerability. Moreover, such analyses, being performed on samplings acquired within the structure, allow for estimating its dynamic response, taking into account the effect of subsurface characteristics as well.