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A dynamic testing system consisting of a totally independent mechanical laboratory has been designed and constructed at the EUCENTRE Foundation. The results of a first experimental trial with the aim of checking the reliability of the system apparatus when stressed by imposing a series of dynamic loading histories on a real-scale two-storey tridimensional frame are presented. Particular care was devoted to equipment and its functioning, reliability of the digital controller, actuator response, and matching between reference input and feedback signal. Furthermore, a brief description regarding the behavior of the tridimensional frame and the experimental results is added. [ABSTRACT FROM AUTHOR]

Various papers have presented different methods for computations of mechanics and kinematics of discrete structural systems. However, little has been done in comparing and benchmarking the seismic response from two different discrete-system-models with experiments. This paper presents a detailed seismic performance comparison between two models—level set discrete element method (LS-DEM) and Logiciel de Mécanique Gérant le Contact (LMGC90), calibrated with shake table experiments conducted on four concrete-block configurations. Theories of both models are thoroughly explained and compared. The simulation results are benchmarked against experimental data. Finally, the principal results and significance of this benchmarking effort is discussed. [ABSTRACT FROM AUTHOR]

This paper presents the results of an experimental program involving shake table testing of two full-scale reinforced concrete frame buildings. These tests were conducted to investigate the effectiveness and reliability of a newly proposed servo-hydraulic Active Mass Damper (AMD) that can be designed to enhance the target seismic performance of a building at multiple earthquake intensity levels. The two nominally identical case-study buildings were intentionally designed to exhibit a "soft story" mechanism at the first level when subject to ground shaking of sufficient intensity, but one was equipped with the newly proposed AMD, installed on the roof. The two specimens were then subject to the same loading protocol consisting of a ground shaking sequence of varying intensity, with the seismic input consisting of a selected natural ground motion.The experimental results demonstrated that the proposed AMD is extremely effective at enhancing building seismic performance. Specifically, the AMD provided peak displacement reductions in the order of 70% and was shown capable of absorbing more than 60% of the total input energy. As a consequence, the un-retrofitted structure suffered nontrivial structural and non-structural damage, while the AMD-retrofitted building remained virtually undamaged at all shaking intensities considered. [ABSTRACT FROM AUTHOR]

Damage to devices installed in electric substations, which have shown vulnerable behaviour under strong earthquakes in the last decades, may endanger power delivery in the emergency phases during and after an earthquake. Within seismic risk assessment of power networks, the definition of the fragility functions of electric equipment is paramount. However, in the current literature the availability of such fragility models for some specific electric substation components, including instrument transformers, is relatively limited, this being the reason behind the deployment of the current experimental and numerical research endeavour. Two voltage transformers and two current transformers having different system voltage levels (respectively in the high voltage HV and extra-high voltage EHV ranges) were subjected to shake table tests, and the experimental results were used to calibrate the corresponding 3D numerical models developed in OpenSees. A number of nonlinear dynamic analyses carried out within a multiple-stripe analysis (MSA) framework allowed the derivation of 16 fragility curves for the four transformers in both stand-alone and elevated/supported configurations, considering also two different soil types. Based on the derived curves, one of the voltage transformers is expected to experience light or negligible damage due to earthquake shaking, owing to its high resonance frequencies (and hence stiffness), whilst the remaining three devices may suffer moderate damage under medium to strong shaking intensities; however, their seismic risk is in effect mitigated by the presence of the typically employed supporting column. Comparison against models available in the literature lent valuable reassurance on the adequacy of the employed methodology and the reliability of the derived fragility curves. [ABSTRACT FROM AUTHOR]

Real-Time Dynamic Hybrid Test (RTDHT) is a promising experimental testing technique, which combines numerical simulation and experimental testing of physical specimen in a complementary and efficient way. However, taking advantage of both numerical and experimental capabilities requires facing issues related to both environments. In this article, the design and implementation of a RTDHT hardware and software architecture is presented. Issues related both to the numerical model and to the experimental setup are discussed; this is done from a general perspective, as well as referring to a base isolated structure which represents the implemented case study. [ABSTRACT FROM AUTHOR]

Real-Time Dynamic Hybrid Test (RTDHT) is a promising experimental testing technique, which combines numerical simulation and experimental testing of physical specimen in a complementary and efficient way. However, taking advantage of both numerical and experimental capabilities requires facing issues related to both environments. In this article, the design and implementation of a RTDHT hardware and software architecture is presented. Issues related both to the numerical model and to the experimental setup are discussed; this is done from a general perspective, as well as referring to a base isolated structure which represents the implemented case study. [ABSTRACT FROM AUTHOR]

The purpose of the research was to study the response of existing constructions, designed for gravity loads only in the South of Italy, more precisely in the Sicily Region. The building is an existing two-story reinforced concrete structure, built in the '80s. In order to design the test, numerical study on the structure has been conducted, using information reported on original design drawings or derived by in situ geometric and material investigation. A number of numerical models and pushover analyses of the structure have been carried out, in order to account for the uncertainties related to possible different responses. The numerical analyses aimed at estimating the capacity of the structure in terms of both force and displacement, the ductility reserve, and the most likely sequence of formation of plastic hinges. The pseudo-static cyclic test was designed to push and pull the building in one direction at increasing displacement levels, up to a drift of about 2%. At the end of the test, the infill panels were completely collapsed. Beams, columns, and joints showed plastic hinges and shear failures in different parts of the structure, with spread spalling of the concrete. Numerical and experimental results were found in fair agreement. [ABSTRACT FROM AUTHOR]