Design of Shake Table Tests of Multi-Leaf Masonry Walls Before and After Retrofitting

A significant proportion of the built heritage in historic centres is constituted by rubble stone masonry structures. Collapses by leaf separation and disaggregation observed after earthquakes highlight their dramatic vulnerability, especially under out-of-plane loads. Nevertheless, their dynamic response still needs to be fully investigated and their capacity may be overestimated by assessment approaches based on rigid-body mechanics. Effective retrofitting solutions are also needed to protect human lives and safeguard the built heritage, while ensuring the conservation of its architectural value. This paper describes the design of a shake table investigation on stone masonry walls, whose materials and arrangement reproduce those surveyed in the villages of central Italy struck by the 2016-2017 earthquake sequence. The test setup was conceived to induce out-of-plane vertical bending under earthquake base motion and investigate the dynamic response of multi-leaf rubble stone masonry and the gain in seismic capacity that can be achieved with mortar-based composite reinforcements, designed to prevent the leaf separation and disaggregation of the wall without compromising its fair face

Investigation of Rubble-Masonry Wall Construction Practice in Latium, Central Italy

The 2016-2017 Central Italy seismic sequence severely affected existing unreinforced-masonry constructions in four regions. Those in Latium region proved the most prone to fragmentation because of an unfortunate combination of undressed natural stone units and very low lime content in mortar. Within the framework of a research project funded by the regional government, shake table tests are planned to investigate masonry disintegration as well as possible intervention techniques, as described in a companion paper. All specimens will have natural stone units retrieved from the debris in Collespada, a settlement of the municipality of Accumoli, one of the most affected by the seismic sequence. To push further the representativeness of the specimens with respect to field conditions, wall geometry, masonry fabric and mortar recipe are carefully designed. The wall thickness will be approximately equal to 0.5 m, close to average thickness surveyed in the area. Following the survey of several vertical sections of actual masonry walls, the specimens will present unconnected external leaves with a limited nucleus. Based on tests on mortar sampled from collapsed buildings, mortars will be prepared by a part of natural lime every nine parts of sand. Shear tests on sampled mortar delivered apparent cohesion and friction coefficient that are used as preliminary values of a finite-discrete element model, which can account for masonry fragmentation in dynamic non-linear analyses. The numerical model was tested under the envisioned sequence of records, belonging to the Amatrice station and related to the East component, approximately fault normal, of the two main seismic events, 24 August and 30 October, 2016

Design, testing and prototyping of a software programmable I2C/SPI IP on AMBA bus

While power consumption and area occupation are always critical constrains in System-on-Chip design, at the same time high communication flexibility is required, due to proliferation of communication protocols. In this work a novel architecture for an I2C/SPI interface for APB AMBA bus is presented, showing how it is possible to merge flexibility and reduced area occupation. Large part of this work is centered on the testing and FPGA prototyping of this IP. CMOS synthesis results on 0.18 μm standard cell library are also presented

Dynamic identification of the so-called Temple of Minerva Medica: comparison of different instrumentations and methods for mutual validation of the results.

Dynamic monitoring is a well-established technique used to gain information on the global health of constructions. In particular, ambient vibration tests have achieved important results in the dynamic characterization of modal parameters. Several techniques and instrumentations are currently available, however the accuracy of these results is often unquestioned. The mutual validation between different modal analysis techniques is an important procedure to assess the reliability of the results. In the present paper the ambient vibration tests performed on the so-called ‘Temple of Minerva Medica’ in Rome considering different techniques and instrumentations will be described and compared. While it is referred to as the Temple of Minerva Medica, the structure is actually a ruined decagonal nymphaeum in opus latericium that dates to the 4th century AD. Today, the construction is located between the main central train station (Roma Termini) and the local tram way. Ambient vibration data were acquired during different campaigns [1] to characterize the effects of the vibrations and the modal parameters of the structure. This work deals with the data collected on the 11th of July 2019 within the project “Tecnologie per il miglioramento della Sicurezza e la ricostruzione dei centri Storici in area sismica” coordinated by DTC Lazio (Distretto Tecnologico beni e attività culturali). The instrumentation comprised of several seismographs equipped with triaxial velocimeters and piezoelectric accelerometers. A variety of techniques were applied to process the acquired vibration data in order to extract the modal parameters of the studied structure including PolyMAX, FDD, EFDD, CC-SSI, HVSR and FRF. Comparison of the modal parameters obtained by each different technique was considered to provide indications on the reliability of the instruments