Assessment of long-term structural movements in a historic cliffside construction through Lomb-Scargle spectral analysis of unevenly spaced time records: the Punta Begoña Galleries (Getxo, Spain)

Abstract Long-term monitoring of structural movements in historic buildings and heritage sites allows assessing their stability recognizing damages that require intervention. The Punta Begoña Galleries, built the earlier part twentieth century, present pioneering techniques use reinforced concrete building construction. They stand directly over a coastal cliff, recovery requires first to guarantee stability, while maintaining patrimonial values. Thus, with goal analyzing global as well extent observed damages, we implemented motion network includes three boreholes for extensometric control, an inclinometer, five crack gauges (crackmeters). This was complemented recording hydrometeorological variables at surface four piezometers. spectral analysis signals performed by introducing Lomb-Scargle (LS) periodogram, which is particularly well-suited unevenly spaced time series. allowed us differentiate reversible seasonal elastic components records recognize irreversible long-term plastic displacements, highlight sectors active instability. In our case, identified are related two local problems support. Even though component displacement after sinusoidal detrending small (with maximums up 0.12 mm/year), it does imply dynamic deformation, calls need adopt stabilization measures.