Analysis of Jerk as a novel tree-fails hazard index: A case study applied to tree monitoring in the archaeological park of the Colosseum in Rome (Italy)

Abstract

This study shows the implementation of a new risk assessment monitoring tool, to be applied to prevent trees failure and significant damage to people and structures, in an urban archaeological site i.e. the Colosseum's Archaeological Park in Rome. Here, a network of ten TreeSavers has been recently installed to allow real-time continuous static and dynamic monitoring of the trees. These data, also linked with readings collected from a local weather station, are transmitted to an online data storage i.e. the cloud to be post-processed. The objective, in this post-processing phase, is that the online data storage system effectively works in autolearning capabilities to “become experts” in risk assessment and thus preventing dangerous situations. In this study we present the preliminary data, analyzed by relating the maximum acceleration on x-, y- and z-axis with maximum wind speed and gust events. The risk analysis was performed considering the Drag Coefficient CD and the Jerk values. The first represents the drag force generated on plants; the second describes the effect of accelerations on rigid bodies. This study has deepened the understanding of Jerk, as a novel hazard index, able to categorize the effect of accelerations on trees under dynamic wind loads for hazard control and prediction of the tree fails. Jerk has the potentiality to be an effective tool for early warning alarm which may reduce the risk of falling of trees with consequent reduction of damage to people and structures, especially in the urban archaeological sites.