This work is based on the assumption that a resistivity meter can effectively monitor water saturation in earth levees and can be used as a warning system when saturation exceeds the expected seasonal maxima. We performed time-lapse ERT measurements to assess the capability of this method to detect areas where seepage is critical. These measurements were also very useful to design a prototype monitoring system with remarkable savings by customizing the specifications according to field observations. The prototype consists of a remotely controlled low-power resistivity meter with a spread of 48 stainless steel 20 × 20 cm plate electrodes buried at half-meter depth. We deployed the newly-designed permanent monitoring system on a critical levee segment. A weather station and an ultrasonic water level sensor were also installed in order to analyse the correlation of resistivity with temperature, rainfalls and water level seasonal variations. The preliminary analysis of the monitoring data shows that the resistivity maps follow a very reasonable trend related with the saturation/drying cycle of the levee caused by the seasonal variations of the water level in the irrigation channel. Sharp water level changes cause delayed and smooth resistivity variations. Rainfalls and, to a lesser extent, temperature seem to have an influence on the collected data but effects are apparently negligible beyond 1 m depth. The system is currently operating and results are continuously monitored.

The earthquake occurred on the 6th of April 2009 in the Abruzzo Region of Italy, seriously hit the Cultural Heritage (C.H.) patrimony with major destructive effects on L'Aquila, a city of 70,000 inhabitants with the size and the historical and strategic importance of the Region capital. The emergency activities to protect the C.H. have been developed on two parallel levels: (1) survey and assessment of damages, (2) implementation of temporary safety measures. The organization of the emergency actions was managed by a centralized structure, the so called Function 15 "Protection of Cultural Heritage", that coordinated the surveys of protected buildings and the design and implementation of temporary safety measures. This allowed the cooperation among different involved subjects (Ministry of Cultural Heritage officers, experts on structural engineering, architects and historians from Universities and private offices and fire brigade teams). The first level of the operating process was carried out on site by expert teams filling up dedicated survey forms for churches and palaces, developed by 123 106 Bull Earthquake Eng (2011) 9:105-138 Heritage); the forms were based on the standardization of damage survey allowing for its immediate interpretation. The second level was based on the past experience in the field of temporary safety measures; the idea was to provide a technical and scientific support in order to assist the work of fire brigade, highly experienced professionals in the "emergency" field. After the first emergency phase the damages of the most important buildings were more carefully investigated and the possible damage progression constantly monitored. The paper presents the case of the Spanish Fortress in L'Aquila, severely damaged by the earthquake; the description concerns the definition of the damages and the interpretation of the activated collapse mechanisms. Finally the design of the provisional strengthening interventions and the on site diagnostic investigations are presented.

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The 19th century restoration works of the Basilica of Sant'Andrea in Mantua consisted of important modifications of pronaos and facade. According to historical documents, the use of metal reinforcements was planned to tie the facade with the counter-facade but designs and details are missing and since no external evidences of the tie-rods can be observed, the existence of these reinforcements was a fundamental open issue. The problem has been recently addressed with a GPR survey. Some tie-rods have been confirmed. The location of some of them has been problematic because of plaster decorations that reduced the survey area to narrow corridors. The dual-polarization was a benefit because some reinforcements, oriented parallel to the survey corridor, were detected only by the parallel-broadside polarization. In addition, for the exact location of these elements, 3D migration was needed because the reflection was generated out-of-plane. Some other unexpected reinforcements were also detected within the counter-facade wall. The complex geometry of these reinforcements was finally understood by composing the results of GPR investigations on orthogonal faces of the counter-facade. However, a tricky question arose on one side of the wall where an unexpected anomaly in GPR response seemed to reveal the presence of an additional set of metal bars. Again the dual-polarization was essential to exclude this misinterpretation and to understand the real origin of these unexpected signals

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Erosional voids developing around concrete-lined tunnels can compromise the safety of the surrounding areas, as well as of the tunnels themselves. In this study, ground penetrating radar (GPR) was used to assess the condition of a water tunnel built to channel a river under a mountain road. The tunnel is lined with 60–80 cm thick concrete and has a semicircular cross-section with a diameter that varies between 3 m and 4 m. The concrete structure has been damaged from erosion beneath the concrete floor, creating a sequence of pools and waterfalls, which further extend the erosive action below the floor and side walls.