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The track structure has an effect on the dynamic characteristics of the bridge structure, which makes the seismic response of the bridge structure complicated. In this paper, an assessment method is proposed to evaluate the seismic risk of bridge structure, including over-limit risk and over-limit scale. Based on a newly proposed simplified model with high accuracy and high computational efficiency, a total of 3000 calculation conditions are analyzed and the sample stability of response is validated to ensure the reliability of the seismic risk analysis. The seismic risks in the longitudinal direction of the track-bridge model are compared with that of the trackless model, and the influence of the constraint effect of China Railway Track System II ballastless track structure on the seismic risk of the structure is obtained. The influence of the number of spans and PGA on track constraints is also revealed. The analysis results, based on a large number of samples, show that although track constraints can reduce the seismic risk of some phenomenon, such as girders' collision, the expected enhancement of longitudinal seismic safety of the system cannot be guaranteed in general, especially when the number of spans is large. However, it is noted that the track constraint can effectively control the over-limit scale of the system, which can reduce the expected repair cost after an earthquake. Therefore, it can be considered that the positive effect of the track constraints is more significant in economy than in structural safety when the bridge is subjected to a longitudinal earthquake excitation. [ABSTRACT FROM AUTHOR]

Despite significant research advances on the seismic response analysis, there is still an urgent need for validation of numerical simulation methods for prediction of earthquake response and damage. In this respect, seismic monitoring networks and proper modelling can further support validation studies, allowing more realistic simulations of what earthquakes can produce. This paper discusses the seismic response of the "Pietro Capuzi" school in Visso, a village located in the Marche region (Italy) that was severely damaged by the 2016–2017 Central Italy earthquake sequence. The school was a two-story masonry structure founded on simple enlargements of its load-bearing walls, partially embedded in the alluvial loose soils of the Nera river. The structure was monitored as a strategic building by the Italian Seismic Observatory of Structures (OSS), which provided acceleration records under both ambient noise and the three mainshocks of the seismic sequence. The evolution of the damage pattern following each one of the three mainshocks was provided by on-site survey integrated by OSS data. Data on the dynamic soil properties was available from the seismic microzonation study of the Visso village and proved useful in the development of a reliable geotechnical model of the subsoil. The equivalent frame (EF) approach was adopted to simulate the nonlinear response of the school building through both fixed-base and compliant-base models, to assess the likely influence of soil–structure interaction on the building performance. The ambient noise records allowed for an accurate calibration of the soil–structure model. The seismic response of the masonry building to the whole sequence of the three mainshocks was then simulated by nonlinear time history analyses by using the horizontal accelerations recorded at the underground floor as input motions. Numerical results are validated against the evidence on structural response in terms of both incremental damage and global shear force–displacement relationships. The comparisons are satisfactory, corroborating the reliability of the compliant-base approach as applied to the EF model and its computational efficiency to simulate the soil–foundation–structure interaction in the case of masonry buildings. [ABSTRACT FROM AUTHOR]

The companion paper by Rota and Rosti (Bull Earthq Eng, 2017) illustrates a methodology for comparing PSH results with historical macroseismic observations at different scales, in terms of mean damage. This paper presents examples of application of the methodology, at the different considered scales, to the South-East quarter of France. This moderate seismicity region is characterised by a long history of civilization, which makes macroseismic observations available for a long time span, although they are highly approximated measures of the seismic action and they are affected by significant uncertainties. The first scale of application presented is at a single site, i.e. the city of Annecy. This example shows that, despite the seismic history of this city is characterised by a significant number of macroseismic observations spanning over a long time period, they mostly consist of very low intensity values and hence the comparison at a single site is not very meaningful. Therefore, the comparison is carried out on a set of seven aggregated sites, well distributed in the region of interest, providing interesting results and suggesting the opportunity of extending the comparison at an even larger scale. The comparison at the regional scale also allows some interesting observations, although it is obviously able to only provide general (average) indications on the PSH results. These comparisons were aimed at showing the applicability of the proposed methodology, pointing out advantages and drawbacks of the different application scales. [ABSTRACT FROM AUTHOR]

According to the United Nations Office for Disaster Risk Reduction cities must take measures to anticipate disasters and mitigate their impact, protecting homes and cultural heritage, minimizing losses due to earthquakes and other threats. After the recent earthquakes in historical city centres, the evaluation of the seismic risk, even in regions of low or moderate seismicity, is imperative, being damage assessment and loss estimation essential for its reduction. In this paper the seismic risk analysis of the residential buildings in the Ciutat Vella District in Valencia, with great historical and architectural value, is presented. The vulnerability of Ciutat Vella has been assessed with the Vulnerability Index Method establishing the seismic quality of the residential buildings according to their structural typology, conservation status, age and geometry; identifying the most vulnerable buildings. Damage probability matrices have been obtained for the deterministic and probabilistic earthquake scenarios, estimating for each of them, the seismic risk in terms of direct social and economic losses, mapping the results using a GIS system tool. Results confirm that the vulnerability of the building stock in Ciutat Vella is high being the seismic risk significant. In the event of an earthquake, many residential buildings included in the Catalogue of Listed Buildings of the Special Protection Plan of Ciutat Vella will be damaged. The detailed analysis of the most vulnerable buildings will provide, in future research works, criteria for intervention to enhance their structural seismic response, safeguarding the architectural heritage and contributing to the reduction of human and material losses. [ABSTRACT FROM AUTHOR]

The seismic Performance-Based Assessment (PBA) of monumental buildings requires to consider safety and conservation objectives, including also the possible presence of artistic assets. In order to face these issues, the case study of the Great Mosque of Algiers is analysed in this paper: in fact, besides to be one of the remaining Almoradiv architecture and the oldest mosque of the city, it is also characterized by the presence of a mihrâb, a decorated arched niche that represents an interesting artistic asset to be included in the PBA. Within this context, particular attention has been paid to the choice of the most reliable modelling strategy for the application of the displacement approach in the PBA procedure, as a function of different possible seismic behaviours. In the case of Great Mosque both the current state of the building and a virtual strengthened condition are analysed. It is worth noting that, while in the current state the seismic behaviour of the asset is well described by a set of macroelements that may be analysed independently (through 2D models), in the second case the strengthening intervention leads to the adoption of a 3D global model (indeed, the roof bracing promotes a 'box-type' behaviour). In the paper, the integrate use of three different modelling strategies of different complexity is discussed: the finite element model, the equivalent frame approach and the macro-block model. The results of nonlinear analyses performed (static and kinematic) constitute the main tool to interpret the seismic response of the asset, perform the PBA and address the choice on the rehabilitation decisions. These latter in this case are mainly affected by the occurrence of too high deformations in local portions of the building, including that in which the artistic asset is located. [ABSTRACT FROM AUTHOR]

According to most of current design standards, the need for high strength and ductility of reinforced concrete frame structures is accomplished utilizing a high amount of transverse reinforcement in beam-column joints. Reinforcement congestion can be overcome by means of Fiber Reinforced Concrete and High Performance Fiber Reinforced Concrete, which are known to improve the structural performance of single structural members or beam-column joints. Through an extended numerical simulation, this paper elaborates the overall benefits of using fiber reinforced concrete materials in critical regions to the seismic behaviour of regular reinforced concrete frame structures. An extensive number of non-linear static and dynamic analyses with distributed plasticity and fibre sections are performed to compare the behaviour of simple reinforced concrete and mixed reinforced concrete/fiber reinforced concrete frames in terms of total base shear and fragility curves and failure mechanisms. Even if execution and technological aspects are beyond the scope of the present work, the use of fiber reinforced concretes in critical regions of mixed frames seems to improve the structural performance of reinforced concrete frames at a global level. [ABSTRACT FROM AUTHOR]

Over the last two decades, seismic ground motion prediction has been significantly improved thanks to the development of shared, open, worldwide databases (waveform and parametric values). Unlike seismic ground motion, earthquake data recorded in buildings are rarely shared. However, their contribution could be essential for evaluating the performance of structures. Increasing interest in deploying instrumentation in buildings gives hope for new observations, leading to better understanding of behavior. This manuscript presents a flat-file containing information on earthquake responses of instrumented buildings. Herein, we present the structure of the NDE1.0 flat-file containing structural response parameters (i.e. drift ratio, peak top values of acceleration, velocity and displacement, pre- and co-seismic fundamental frequencies) computed for several intensity measures characterizing ground motion (i.e. peak ground values of acceleration, velocity and displacement, spectral values, Arias intensity, strong motion duration, cumulative absolute velocity, destructive potential). The data are from real earthquake recordings collected in buildings over the years. Some building, site and earthquake characteristics are also included (i.e. structural design, shear wave velocity, magnitude, epicentral distance, etc.). This 1.0 version contains 8520 strong motion recordings that correspond to 118 buildings and 2737 events, providing useful information for analyses related to seismic hazard, variability of building responses, structural health monitoring, nonlinear studies, damage prediction, etc. [ABSTRACT FROM AUTHOR]

In low-to-moderate seismicity regions such as metropolitan France, characterized by limited strong-motion records in the magnitude-distance range of interest for seismic hazard assessment, the derivation of empirical ground motion prediction equations (GMPEs) is a major challenge. In this study, we take advantage of the RESORCE-2013 database () that contains uniformly processed records for the Pan-European region including relevant number of French records. After discussing the metadata for French events and stations, we first derive a base-case GMPE that is used to investigate the within-event and between-event residuals. The short-period between-event residuals for French (and Swiss) events show larger variability with respect to larger magnitude events in other regions. We show that the between-event residuals are clearly correlated with the stress parameter and that such larger variability can be explained by accounting for stress-parameter scaling. We derive an empirical scaling of ground motion with stress parameter that is consistent across regions and with the scaling predicted by stochastic GMPEs. This suggests that the scaling of ground motion with stress parameter for a given magnitude is largely region independent whereas the absolute stress parameter values may vary regionally. Based on these results we propose to adopt the scaling model as a function of stress parameter and magnitude by Yenier and Atkinson (Bull Seismol Soc Am 105(4):1989-2009, 2015) by adapting the reference stress parameter to our target regions. By accounting for stress parameter scaling in the GMPE we reduce the between-event variability for French and Swiss small-magnitude events. Finally, we investigate the aleatory variability (σ) of the GMPE and its components (τ, ϕ, ϕ). We propose a heteroscedastic σ model to be used when the stress-parameter scaling is not considered in the GMPEs due to lack of information. If enough information on the stress-parameter is available the adjusted GMPE can be applied using a homoscedastic σ. Despite using small events, the ϕ for French stations is found to be consistent with other studies and confirms the stability of ϕ across different regions and datasets. [ABSTRACT FROM AUTHOR]