Impact Assessment of Infrastructures Exposure to Weak Motion Vibrations in Arequipa, Peru

Abstract

Being an important economic and industrial hub, Arequipa is the second most populous city in Peru, with over one million inhabitants. Within its metropolitan area, high-amplitude vibrations are generated by heavy construction machinery as well as by urban and commercial transportation. These vibrations pose a potential risk of damage to both urban and archaeological infrastructures. To assess possible structural impacts, vibration measurements were collected at significant sites and analyzed according to the DIN 4150- 3 standard. Ground vibrations attenuation was evaluated using the Levenberg-Marquardt inversion method. Regression adjustment models were developed, and the analysis of geometric and material damping coefficients was automated with the application of neural network algorithms, in areas with lower data density. The results indicate that vibrations caused by heavy machinery can damage sensitive or residential structures, as the peak particle velocity (PPV) exceeded 20 mm/s in these cases. However, for sources such as vehicular traffic on bridges and railway transport, the PPV only exceeded 10 mm/s. Attenuation analysis revealed that maximum particle velocity decreases with increasing distance from the source, and that the strongest damping occurs in the vertical component. Geometric damping (γ) values ranged from 0.1 to 1.65, and material damping (α) values ranged from 0.001 to 0.03 for the various sources evaluated. In cohesive soils, wave propagation is faster, which reduces tension in the foundations, whereas in sandy-silty soils, slower propagation increases the tension transmitted to the foundations. This research also aims to lay the foundation for the development of Peruvian regulations framework to assess structural damage caused by anthropogenic vibrations, since there are no existing regulations governing these effects on buildings. This study can help propose guidelines for the city of Arequipa.