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H2020 Research Infrastructures, Grant/Award Number: 730900, This paper reports on a series of shaking table tests on a full-scale flat-bottom steel silo filled with soft wheat, characterized by aspect ratio of around 0.9. The specimen was a 3.64-m diameter and 5.50-m high corrugated-wall cylindrical silo. Multiple sensors were used to monitor the static and dynamic response of the filled silo system, including accelerometers and pressure cells. Numerous unidirectional dynamic tests were performed consisting of random signals, sinusoidal inputs, and both artificial and real earthquake records. The objectives of this paper are (i) to provide a general overview of the whole experimental campaign and (ii) to present selected results obtained for the fixed-base configuration. The measured data were processed to assess the static pressures, the dynamic overpressures (related to the effective mass) and the accelerations of monitored points on the silo wall, and to identify the basic dynamic properties (fundamental frequency of vibration, damping ratio, dynamic amplification factors) of the filled silo. Themain findings are discussed and compared with the predictions given by available theoreticalmodels and code provisions. It is found that the fundamental frequency slightly decreases with increasing acceleration, while it slightly increases with increasing compaction of the granular material. For close-to-resonance input, the dynamic amplification (in terms of peak values of accelerations) increases along the height of the silo wall up to values of around 1.4 at the top surface of the solid content. The dynamic overpressures appear to increase with depth (differently from the EN1998-4 expectations), and to be proportional to the acceleration., H2020 Research Infrastructures 730900

Recent destructive earthquakes in China (Sichuan, 2008 and Yushu, 2010), Japan (Tohoku, 2011) and Italy (Emilia, 2012) highlighted the social and the political consequences of seismic risk due especially to industrial facilities. More precisely, critical interactions between the supporting structure and process components reveal to be extremely vulnerable in a seismic scenario and capable to lead serious damage of process equipment and potential release of hazardous substances. This latter circumstance, underestimated by current codes, in addition to loss of production, pose a serious danger to humans and the surrounding environment. Based on these premises, the SPIF project — Seismic Performance of Multi-Component Systems in Special Risk Industrial Facilities — was proposed within the framework of the European H2020 - SERA funding scheme. In greater detail, the goal of the project is the investigation of both the seismic behavior and the dynamic interactions of a representative industrial substructure equipped with complex process technology by means of shaking table tests. A full-scale mock-up composed by two single-bay moment resisting frames with three floors equipped with tanks, flanges, pipes, cabinet etc. was built and tested using a unidirectional shaking table activated with several earthquake levels. More precisely, the salient features investigated by shaking table testing are: i) the interaction between a primary moment resisting frame steel structure and secondary process components that influence the performance of the whole system; ii) input and system modelling capable to faithfully reproduce the seismic response of SPIF tested structure. The comprehensive testing campaign demonstrated a clear dynamic interaction between the primary steel structure and secondary process units that emphasizes the need of further investigations and studies.

This paper presents the preliminary results of a series of shaking-table tests on a full-scale flat-bottom manufactured steel silo filled with a granular material. A 3.64 m-diameter 5.5 m-height cylindrical silo has been tested in fixed-base and isolated-base configurations. The isolators put between the table and the r.c. plate are Curved Surface Sliders friction pendulum devices. Mono-axial shaking-table tests have been performed using random signals, low-frequency sinusoidal inputs and earthquake records (both artificial and real). The results are relevant to: the identification of the basic dynamic properties (frequency, damping ratio, amplification) of the grain-silo system, the experimental assessment of the static pressure (during filling phase) and seismic dynamic over-pressures and the effectiveness of the isolation system at the base of the silo.

Past earthquakes demonstrated the high vulnerability of industrial facilities equipped with complex process technologies leading to serious damage of the process equipment and multiple and simultaneous release of hazardous substances in industrial facilities. Nevertheless, the design of industrial plants is inadequately described in recent codes and guidelines, as they do not consider the dynamic interaction between the structure and the installations and thus the effect of seismic response of the installations on the response of the structure and vice versa. The current code-based approach for the seismic design of industrial facilities is considered not enough for ensure proper safety conditions against exceptional event entailing loss of content and related consequences. Accordingly, SPIF project (Seismic Performance of Multi-Component Systems in Special Risk Industrial Facilities) was proposed within the framework of the European H2020 - SERA funding scheme (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe). The objective of the SPIF project is the investigation of the seismic behaviour of a representative industrial structure equipped with complex process technology by means of shaking table tests. The test structure is a three-story moment resisting steel frame with vertical and horizontal vessels and cabinets, arranged on the three levels and connected by pipes. The dynamic behaviour of the test structure and of its relative several installations is investigated. Furthermore, both process components and primary structure interactions are considered and analyzed. Several PGA-scaled artificial ground motions are applied to study the seismic response at different levels. After each test, dynamic identification measurements are carried out to characterize the system condition. The contribution presents the experimental setup of the investigated structure and installations, selected measurement data and describes the obtained damage. Furthermore, important findings for the definition of performance limits, the effectiveness of floor response spectra in industrial facilities will be presented and discussed.

Past earthquakes demonstrated the high vulnerability of industrial facilities equipped with complex process technologies leading to serious damage of process equipment and multiple and simultaneous release of hazardous substances. Nonetheless, current standards for seismic design of industrial facilities are considered inadequate to guarantee proper safety conditions against exceptional events entailing loss of containment and related consequences. On these premises, the SPIF project -Seismic Performance of Multi-Component Systems in Special Risk Industrial Facilities- was proposed within the framework of the European H2020 SERA funding scheme. In detail, the objective of the SPIF project is the investigation of the seismic behaviour of a representative industrial multi-storey frame structure equipped with complex process components by means of shaking table tests. Along this main vein and in a performance-based design perspective, the issues investigated in depth are the interaction between a primary moment resisting frame (MRF) steel structure and secondary process components that influence the performance of the whole system; and a proper check of floor spectra predictions. The evaluation of experimental data clearly shows a favourable performance of the MRF structure, some weaknesses of local details due to the interaction between floor crossbeams and process components and, finally, the overconservatism of current design standards w.r.t. floor spectra predictions.

Relationships between seismic action, system response and relevant damage levels in industrial plants require a solid background both in experimental data, due to the high level of non-linearity and seismic input. Besides, risk and fragility analyses depend on the adoption of a huge number of seismic records usually not available in a site-specific analysis. In order to manage these issues and to gain knowledge on the definition of damage levels, limit states and performance for major-hazard industrial plant components, we present a possible approach for an experimental campaign based on a real prototype industrial steel structure. The investigation of the seismic behaviour of the reference structure will be carried out through shaking table tests. In particular, tests are focused on structural or process-related interactions that can lead to serious secondary damages as leakage in piping systems or connections with tanks and cabinets. The aforementioned test program has been possible thanks to the adoption of: i) a number of artificial spectrum-compatible accelerograms; ii) a ground motion model (GMM) able to generate a suite of synthetic time-histories records for specified site characteristic and earthquake scenarios. More precisely, GMM model parameters can be identified by matching the statistics of a target-recorded accelerogram to the ones of the model in terms of faulting mechanism, earthquake magnitude, source-to-site distance and site shear-wave velocity. As a result, the stochastic model, based both on these matched parameters and on filtered white-noise process, can generate the ensemble of synthetic ground motions capable of capturing the main features of real earthquake ground motions, including intensity, duration, spectral content and peak values. Moreover, the synthetic records are selected to target specific damages and limit states in industrial components. Finally, by means of the combination of artificial and synthetic accelerograms, a seismic vulnerability assessment of both the whole structure and relevant industrial components can be carried out.

Extensive damage to school buildings has been observed during past earthquakes in Italy, with the 2002 Molise earthquake resulting in the complete collapse of a school building, leading to ...

The present paper focuses on the use of Unmanned Aerial System (UAS), commonly known as drones, for the fast mapping of medium to large areas in an emergency response scenario, for example after a seismic event. The information obtained by processing the aerial acquired data (generally images) provide a significant contribution not only in supporting the Search and Rescue (SAR) activities, when timeliness is crucial, but also in the framework of debris volume assessment, exterior safety inspection of critical infrastructures and post-event reconnaissance and reconstruction activities. Within the context of coordinated flight planning for emergency aerial photogrammetry (involving the use of commercial multi-rotor UAS fleets), an operative strategy is proposed in order to address several critical aspects, frequently faced in particular when mapping large areas. The results and the lessons learned from an in-situ implementation of the presented procedure are also reported.

In the last decades, particular attention has been paid to the seismic vulnerability of existing reinforced concrete buildings designed for gravity loads only. Such buildings, designed before the introduction of capacity design in modern seismic codes, are very common, particularly in seismic prone countries of the Mediterranean area. Due to poor detailing and lacking of capacity design principles, high vulnerability has been highlighted in several past studies. In this article, inadequate seismic response and peculiar damage pattern are investigated by means of shake table tests performed on a 1:2 scaled 3-story infilled prototype. Particular attention is given to the role of beam-column joints and frame-panel interaction. The effectiveness of the EC8-based assessment approach is then evaluated; both linear and nonlinear numerical models, with different levels of sophistication, have been implemented in order to explore their behavioral aspects.

This paper describes a state-space partitioned algorithm for real-time hybrid simulation. The state-space modeling is proposed to represent nonlinear numerical substructures. The effectiveness of the proposed method is demonstrated for a virtual bridge case study equipped with seismic isolation devices.

Extensive damage to school buildings has been observed during past earthquakes in Italy, with the 2002 Molise earthquake resulting in the complete collapse of a school building, leading to numerous casualties. In this paper, data provided by instruments installed in a number of school buildings throughout Italy from both ambient vibration and triggered dynamic vibration following the 2016 Central Italy earthquake are compared with predictions of numerical models. This comparison of predicted and measured structural response characteristics is investigated to provide practicing engineers with further insight into and validation of the accuracy of typical modeling techniques compared with instrumented responses of numerous different building typologies subjected to different dynamic excitations. Initial comparisons demonstrate reasonable agreement between the numerically predicted modes of vibration and natural frequencies from ambient vibration measurements, with further numerical parametric studies exhibiting improved matching. Additional comparative analyses are considered to discuss the potential impacts on the seismic assessment of existing structures within a performance-based seismic assessment framework.

Nowadays base isolation represents one of the most effective solutions for seismic protection of both building and bridge structures. Thanks to the provided low stiffness and the high dissipation capacity, a significant reduction of internal forces induced in the superstructure can be obtained, with limited increased displacement demands. However, for bridge structures, the definition of the layout for anti-seismic devices can strongly affect the overall response of the system, due to the interaction between properties of each isolator and stiffness characteristics of piers. Precisely, the topography of the bridge site may lead to relatively high vertical supporting elements. Such elements would not take advantage of an additional isolation layer: thus, the displacement seismic demand of the deck can be directly accommodated through the flexural deformation of tall elements. On the other hand, isolators on short piers are generally needed, in order to avoid unexpected brittle shear failures.In the present endeavour a simplified optimization procedure is proposed for the most efficient definition of the seismic isolation system for existing bridges retrofit. The response of a case study structure has been assessed for the calibration of the implemented parameters, through Non- Linear Time History Analyses, by applying spectrum-compatible natural records. Finally, a framework for hybrid simulations with sub-structuring has been considered, aiming at evaluating the effectiveness of the presented design strategy, by means of an experimental validation.

Extensive damage to school buildings has been observed during past earthquakes in Italy, with the 2002 Molise event resulting in the complete collapse of a school building leading to numerous casualties. As part of a wider project in Italy to assess the seismic risk in school structures, six school buildings of various construction typologies were surveyed and instrumented to validate detailed numerical models of typical school structures located throughout Italy.

Remote sensing is proving very useful for identifying damage and planning support activities after an earthquake has stricken. Radar sensors increasingly show their value as a tool for damage detection, due to their shape-sensitiveness, their extreme versatility and operability, all weather conditions. The previous work of our research group, conducted on 1-m resolution spotlight images produced by COSMO-SkyMed, has led to the discovery of a link between some selected texture measures, computed on radar maps over single blocks of an urban area, and the damage found in these neighbourhoods. Texture-to-damage correlation was used to develop a SAR-based damage assessment method, but significant residual within-class variability makes estimations sometimes unreliable. Among the possible remedies, the injection of physical vulnerability data into the model was suggested. The idea here is to do so while keeping all the sources of data in the EO domain, by estimating physical vulnerability from the observation of high-resolution optical data on the area of interest. Although preliminary results seem to suggest that no significant improvement can be directly obtained on classification accuracy, there appears to be some link between estimated damage and estimated accuracy on which to build a more refined version of the damage estimator.

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.

In combination with standard transducers and data acquisition systems, computer vision can be adopted in order to perform the analysis of the behaviour of structures during dynamic tests such as earthquake simulations on shake tables. The paper describes the design and implementation of a machine vision system aimed at providing bi-dimensional position measurement of reflective markers directly placed on test specimens. The developed solution is composed of a scalable set of acquisition units, each consisting of a high definition digital camera and a personal computer. A sequence of images is acquired by the cameras and the position of the markers in the scene is estimated by means of a software application running on the computers. Each unit can perform measurements in a single plane which is defined in a previous calibration phase. The method has many advantages over the most commonly used acquisition devices such as accelerometers and potentiometers: first, the absence of contact between the acquisition device and the tested structure, which allows the non-invasive deployment of an arbitrary number of measurement targets, which is even more important in destructive tests, for preventing the loss of expensive transducers; second, the direct calculation of the position of an object in length units, without the need of post processing like integration and conversion, as required when using accelerometers in shake table tests. Besides, in the selected plane, thanks to the adoption of infrared illumination and filters to reduce environmental lighting interferences, each unit can follow the movements of a large number of markers (up to 50 for each camera in the performed tests) with a precision of around 0.05 mm. On the other hand, the method is by itself unable to overcome problems deriving from the three-dimensional movement of the selected markers. The paper also explains the different approaches and the corresponding results obtained while solving this issue.

Recent events in Italy and in other countries with similar building stock have demonstrated the need of an extensive campaign of assessment to define the seismic risk and outline the intervention policy especially for buildings devoted to public or important functions (hospitals, fire brigade buildings, schools, etc.) and for the infrastructures. Advanced codes of practice, like EC8, or those implementing similar concepts, have introduced in the last years accurate verification procedures based on the mixed use of numerical and experimental investigations, to qualify the level of knowledge of the existing structures first, and to verify the compliance with limit state requirements for seismic loads, second. Since the introduction of the assessment approaches in the codes several applications to real cases have been developed. However, the number of studies carried out to verify their real efficiency is still limited. This would require a more extended campaign of analyses to better validate procedures and safety requirement assumptions. The work presented in this paper aims at contributing to the experimental verification of code assessment approaches in the common case of an irregular multi-storey RC building designed for gravity loads. As required in the assessment procedures, linear and non linear analyses have been applied to determine the performance level of the building at each limit state. Then a dynamic testing campaign has been performed on the advanced testing facility at EUCENTRE in Italy, to directly verify the effects of seismic loading. An innovative system of high definition digital cameras developed at EUCENTRE has allowed the acquisition of a rich base of data in the shaking table tests and a careful comparison of the results in terms of local and global response parameters to those obtained from the code procedures.

With the introduction of higher seismic design forces in the Swiss loading standard of 2003 most unreinforced masonry (URM) buildings fail to satisfy the seismic design check. For this reason, in new construction projects, a number of URM walls are nowadays replaced by reinforced concrete (RC) walls. The lateral bracing system of the resulting structure consists therefore of URM walls and some RC walls which are coupled by RC slabs and masonry spandrels. The same situation characterises a number of seismically retrofitted URM building across Europe in which RC walls are added to the original structure to improve its seismic behaviour. Within the framework of the FP7-SERIES project, a four-storey RC-URM wall structure was tested on the shake table at the EUCENTRE TREES Laboratory (Laboratory for Training and Research in Earthquake Engineering and Engineering Seismology) in Pavia (Italy). The test was conducted at half-scale and is part of a larger research initiative on mixed RC-URM wall systems initiated at EPFL (Ecole Polytechnique Federale de Lausanne, Switzerland). The key objective of the testing campaign was to gain insight into the dynamic behaviour of mixed RC-URM wall structures and to provide input for the definition of a performance-based design approach of such mixed structural system. Multiple shaking at increasing intensity was used to test the dynamic behaviour of the examined building. During the final shaking several of the URM walls lost their axial load bearing capacity, however, the structure did not collapse as it was subjected to uni-directional loading only and the axial load was transferred to the RC walls and the URM walls that were loaded out-of-plane. Random noise vibration tests were performed to monitor the elongation of the natural periods induced by the damage progression. The paper presents details on the structural system and the selected ground motion, the test set-up and the instrumentation. Additionally, initial results of the shake table test are presented with a first interpretation of the observed structural behaviour.