A pre-posterior analysis framework for quantifying the value of seismic monitoring and inspections of buildings

Peer reviewe

The value of visual inspections for emergency management of bridges under seismic hazard

One of the major problems in the aftermath of an earthquake is the management of the emergency inspection operations. Traffic restriction, including limited emergency operations or bridge closure due to safety concerns, may be issued to keep an appropriate level of safety. Visual inspections may be conducted to provide useful information on the damage state of the bridge and support the decision of imposing traffic restriction up to the complete closure of the bridge, or for allowing the immediate use of safe bridges after the event. The cost related to the inspection shall be at least balanced by the uncertainty reduction provided by the inspection data and the benefit is higher when the costs associated with taking a wrong management decision are high, but may be negligible if this is not the case. Practical tools and methods to forecast this benefit before collecting the information exist in classical decision theory, but are seldom applied by engineers. In this paper a framework based on the concept of Value of Information (VoI) from the pre-posterior Bayesian decision analysis is adopted and applied to the case study of a two span reinforced concrete bridge

The benefit of permanent monitoring for seismic emergency management

In this paper, a framework based on Value of Information (VoI) theory from pre-posterior Bayesian decision analysis is applied to the case of post-earthquake emergency management of traffic restrictions for a bridge. The decision context is the following: the operator of a bridge is concerned about the use of the structure in post-earthquake scenarios and wishes to know if it is worth to install a Structural Health Monitoring (SHM) system which gives information about the state of the bridge. The possible choices about traffic restrictions after the seismic event are Open or Close the bridge. The benefit of SHM is computed based on VoI and the influence of significant variables involved in the decisional framework is investigated

Satellite interferometric data for seismic damage assessment

Radar satellites allow the collection of data on large areas without direct access to structures. Thereby, they appear very attractive for Structural Health Monitoring (SHM) purposes. Data collected by satellites can be processed to obtain temporal histories of displacements through which the health state of a monitored system can be potentially identified. However, anomalies in the time histories of displacements are not necessarily due to damage. Environmental phenomena, such as variations in atmospheric temperature, and rain, can modify the behavior of structures without compromising their safety. The impact of these phenomena on the structural response can hinder the identification of anomalies or lead to false alarms if such alterations are misinterpreted as damage. Furthermore, if the monitored system is a historical structure, uncertainties on the structural behavior are inevitably increased during aging. The purpose of this article is to discuss the possibility of identifying damage due to seismic actions considering the impact of variations of environmental factors on the time histories of the displacements retrieved by satellite data. The structural health condition of a historical structure located in the city of Rome (Italy) hit by the October 2016 Central Italy earthquakes is investigated based on interferometric satellite data. The satellite data are acquired by COSMO-SkyMed (CSM) of the Italian Space Agency between 2010 and 2019 and are processed by CNR IREA