•Experimental tests on multi-storeys full-scale infilled RC frames with different infill-to-structure connection.•Pseudo-dynamic tests at increasing intensity to characterize the frame response and ...the related damage states.•Comparison with available fragility functions at building and frame level.•Non-linear numerical model to capture the global and local response.
Field surveys showed that the fabrication of infill, with particular emphasis on the connection with the surrounding reinforced concrete (RC) frame, may have a significant influence on the global response, earthquake damage and on the actions transmitted to the surrounding RC members.
This study reports and discusses the outcomes of an experimental program on three two-storeys full-scale infilled RC frames varying the concrete strength and infill-to-structure connection. The specimens were subjected to pseudo-dynamic tests at increasing intensity to characterize the frame response and the related damage states. The results showed that the strength and stiffness of the frame increase by increasing the infill-to-structures connection. The enhanced connection allows to have a better loading transfer from the structure to the infill with a strength increase ranging between 10% and 30%. This resulted in a reduction of the displacement demand and in an increase of the shear force transmitted to the top of the column. The results are compared with the damage observed during post-earthquake field survey at building level and with available fragility functions showing a good matching. A non-linear FEM model is proposed to capture the lateral response of the tested frames and the results are compared and discussed. The comparison outlines the reliability of a three-strut model to accurately reproduce the infill response and the shear actions transmitted at the top of the columns.
In this paper, empirical fragility curves for reinforced concrete buildings are derived, based on post-earthquake damage data collected in the aftermath of earthquakes occurred in Italy in the period ...1976–2012. These data, made available through an online platform called Da.D.O., provide information on building position, building characteristics and damage detected on different structural components. A critical review of this huge amount of data is carried out to guarantee the consistency among all the considered databases. Then, an in-depth analysis of the degree of completeness of the survey campaign is made, aiming at the identification of the Municipalities subjected to a partial survey campaign, which are discarded from fragility analysis. At the end of this stage, only the Irpinia 1980 and L’Aquila 2009 databases are considered for further elaborations, as fully complying with these criteria. The resulting database is then integrated with non-inspected buildings sited in less affected areas (assumed undamaged), to account for the negative evidence of damage. The PGA evaluated from the shakemaps of the Italian National Institute of Geophysics and Volcanology (INGV) and a metric based on six damage levels according to EMS-98 are used for fragility analysis. The damage levels are obtained from observed damage collected during post-earthquake inspections through existing conversion rules, considering damage to vertical structures and infills/partitions. The maximum damage level observed on vertical structures and infills/partitions is then associated to the whole building. Fragility curves for two vulnerability classes, C2 and D, further subdivided into three classes of building height, are obtained from those derived for specific structural typologies (identified based on building height and type of design), using their frequency of occurrence at national level as weights.
Lenvatinib is a multi-kinase inhibitor approved for patients with radioactive iodine (RAI)–resistant differentiated thyroid cancer (DTC). Before the drug approval from the Italian National Regulatory ...Agency, a compassionate use programme has been run in Italy. This retrospective study aimed to analyse data from the first series of patients treated with lenvatinib in Italy.
The primary aim was to assess the response rate (RR) and progression-free survival (PFS). Secondary end-points include overall survival (OS) and toxicity data.
From November 2014 to September 2016, 94 patients were treated in 16 Italian sites. Seventeen percent of patients had one or more comorbidities, hypertension being the most common (60%). Ninety-eight percent of patients were treated by surgery, followed by RAI in 98% of cases. Sixty-four percent of patients received a previous systemic treatment. Lenvatinib was started at 24 mg in 64 subjects. Partial response and stable disease were observed in 36% and in 41% of subjects, respectively; progression was recorded in 14% of patients. Drug-related side-effects were common; the most common were fatigue (13.6%) and hypertension (11.6%). Overall, median PFS and OS were 10.8 months (95% confidence interval CI, 7.7–12.6) and 23.8 months (95% CI, 19.7–25.0) respectively.
Lenvatinib is active and safe in unselected, RAI-refractory, progressive DTC patients in real-life setting. RR and PFS seem to be less favourable than those observed in the SELECT trial, likely due to a negative selection that included heavily pretreated patients or with poor performance status.
•Patients with metastatic differentiated thyroid cancer (DTC) have poor survival rate.•Lenvatinib improved clinical outcomes in patient with metastatic radioactive iodine-refractory DTC.•Lenvatinib is active and safe, even in a real-life patient population.•Older patients show survival benefit from lenvatinib, without safety concern.
AbstractAvailable capacity models for the assessment of seismic capacity of RC columns are mainly based on experimental tests under axial load and uniaxial bending. Furthermore, experimental tests ...have been mainly performed on columns representative of new constructions. To analyze the effects of biaxial bending on the seismic performances of existing RC columns with design characteristics nonconforming to present day seismic codes and practices, this paper presents the results of a first stage of tests on RC columns under both axial load and biaxial bending, which effectively simulate the seismic actions. In particular, this paper presents results of four tests on full-scale square columns reinforced with plain bars subjected to constant axial load and biaxial cyclic actions. Two different cyclic displacement paths were investigated: horizontal displacements with an inclination angle of 45 or 30°, with respect to the cross-section principal axes. The influence of biaxial bending actions on the global behavior of existing RC columns in terms of stiffness, strength, deformation capacity, and the effects of different horizontal displacements orientation on their performances are herein investigated and discussed; the comparison with experimental outcomes provided by uniaxial bending tests on companion specimens are also presented. Experimental findings showed that biaxial bending actions affect columns rotational capacity more than strength. The rotational capacity reduction because of biaxial bending actions, even if more significant than the flexural capacity reduction, is not currently taken into account in the available seismic guidelines related to existing RC buildings.
► We have designed and performed an experimental campaign on RC beam–column joints. ► We carefully analyze and compare four tests on joints with different design levels. ► Influence on collapse ...mechanism of axial load on the column is clearly pointed out. ► Experimental–numerical comparisons are made through a detailed F.E.M. ► Numerical analyses allow to better understand damage and collapse mechanisms.
The paper is focused on the analysis of some test results obtained in the framework of a wide experimental program on RC beam–column joints carried out at the Laboratory of Structures of the University of Basilicata in Potenza, Italy. Specifically, cyclic tests on full-scale joint specimens having different earthquake resistant design levels were performed, applying different values of axial force. Test results relevant to 4 specimens have been analyzed and compared with the results of numerical simulations based on an accurate finite element modeling using the DIANA code at the Structural Engineering Dept. of the University of Naples. Experimental results show how the value of the axial load acting on the column can change the collapse mode, spreading damage from the beam to the joint panel. Moreover, a collapse mode due to the failure of beam longitudinal rebars, sometimes neglected in structural codes, has been observed. Numerical simulations were used to evaluate the stress distribution in the joint panel as a function of the axial load and to quantify the beam rebar deformations. The reasons for the specimens’ global failure and, specifically, for that of the beam longitudinal rebars were identified and highlighted through a comparison with the experimental results.
AbstractCapacity models to assess structural safety are primarily based on experimental outcomes typical of new constructions. In order to analyze deformation and strength mechanisms of members that ...do not comply to current seismic codes and practices, an experimental investigation was undertaken on full-scale columns reinforced with deformed or plain rebars. The experiments involved eight tests under monotonic or cyclic actions on square or rectangular reinforced concrete columns designed according to provisions, construction practice, and material properties enforced between the 1940s and 1970s. Experimental outcomes allowed pointing out global and local behavior of RC columns typically found in existing constructions, in which both plain and deformed bars can be found. Theoretical plastic rotation capacities provided by the proposed supplement to the current ASCE standard are discussed in this paper and compared to those experimentally obtained. The results indicate that predicted plastic rotations corresponding to significant loss of lateral-force capacity are very conservative if compared with experimental outcomes. This seems especially clear in the case of columns reinforced with plain rebars. For these columns, the contribution of the base rotation on the global deformation mechanism is considerable.
•Simplified analytical method for the seismic fragility assessment of Reinforced Concrete buildings.•Mechanical interpretation of Damage States defined according to EMS-98 scale.•Influence of infills ...on structural response and seismic damage to Reinforced Concrete buildings.•Building stock data provided by field survey and other sources.•Seismic vulnerability assessment at urban scale.
A simplified analytical method for the seismic fragility assessment of Reinforced Concrete buildings at large scale is presented. The proposed method is based on a simulated design procedure to define the structural model and on non-linear static analysis of a simplified structural model based on Shear-Type assumption to evaluate seismic capacity. Damage States are defined according to the observational-based Damage States provided by the European Macroseismic Scale (EMS-98). Presence of infills is considered, both taking into account their influence on the structural response and evaluating the damage to such non-structural elements. The method is applied to the Reinforced Concrete building stock data provided by the field survey carried out on a city in a high seismic area in Southern Italy, which are illustrated and compared with data from other sources. Uncertainties in seismic demand, material characteristics, and capacity models are taken into account through a Monte Carlo simulation technique. Fragility curves are obtained for each building, leading to the evaluation of annual failure probability at the assumed Damage States. The influence of key parameters in predicting seismic fragility, such as the number of storeys and the age of construction, is illustrated. The spatial distribution of annual failure probability at the different Damage States provides information on areas most prone to seismic risk within the city, depending both on building stock characteristics and on local amplification of seismic hazard due to soil conditions. A comparison with empirical-based fragility curves from literature is also illustrated.
Seismic risk mitigation in urban areas is a very relevant issue in European regions, such as Italy and Greece, characterized by the presence of a large stock of heritage structures. Enhancing the ...knowledge about the dynamics of structures is definitely useful in view of seismic assessment and design of risk mitigation interventions. However, this task can be difficult in the case of heritage structures, since several uncertainties affect material properties and structural patterns. In this paper, the opportunities provided by dynamic identification techniques for the non-destructive evaluation of heritage structures are discussed with focus on an interesting case study. This refers to the characterization of a modern heritage reinforced concrete building as a preliminary step towards seismic assessment. The structure under investigation is the Tower of the Nations, located in the Mostra D'Oltremare urban park in Naples, Italy. The paper shows how the combination of ambient vibration tests and model refinement can represent a valuable tool for an indirect non-invasive structural assessment of historical structures. Their proper analysis and modeling, in fact, is usually very challenging from the scientific and technical viewpoint due to their unique structural configurations, the several modeling uncertainties and the need to keep destructive investigations very limited. In this framework the present paper shows how a rational choice of the updating parameters and of the objective function can support the model optimization taking into account the ultimate objectives of the analysis, namely the setting of a reliable model for the assessment of the seismic performance of the structure in the linear regime. As a result, the paper describes the refinement of the model of the Tower of the Nations, in a way able to minimize the scatter with the experimental data and, at the same time, enhance the accuracy of response spectrum and seismic time-history linear analyses.
•The role of dynamic identification as the NDT method for seismic assessment is analyzed.•Relevance of NDT methods applied to modern heritage buildings is remarked.•An original objective function for seismic analysis oriented model refinement is proposed.•Results of model refinement point out the role of infills and participating masses.•Potential accuracy enhancement of seismic analyses is demonstrated.
In the aftermath of the M
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6.0 August 24, 2016 Central Italy earthquake, the authors carried out a reconnaissance survey in the municipality of Amatrice and gathered extensive photographic evidence ...of damage, with emphasis on 37 reinforced concrete buildings located outside the historical centre. Damage distribution is generally represented by widespread cracking and/or collapse of the masonry infill panels at the lower buildings’ stories. Moreover, damage was observed in the columns due to the interaction with masonry infill panels. Starting from the collected information, POST—a mechanics-based damage prediction model—was applied in order to compare predicted damage distribution and damage observed during the field reconnaissance. The comparison shows an overall good agreement between the results of the POST method and the observed damage with a slightly conservative tendency by POST.
This paper presents the general criteria and implementation of an automatic procedure to evaluate the seismic capacity of existing reinforced concrete (RC) regular buildings. The method represents a ...useful tool in the framework of mechanical based vulnerability assessment methods. In particular, the seismic capacity is retrieved via pushover analyses on a lumped plasticity model for the building. Unlike recent approaches that rely on a single representative structural model for an entire building population, the proposed method allows virtually all the buildings of the population to be analysed in an automatic loop. With the aim of expediting and automatizing the analysis process, a dedicated software was implemented, whose main functions are: identifying possible structural systems compatible with regular building shapes of assigned dimensions and designing its elements in terms of cross-section and reinforcement; constructing the related nonlinear model and performing pushover analyses in order to determine synthetic capacity parameters useful for preliminary vulnerability assessment at a large scale. The software application and potentialities are shown in an example for the generic building of a class.
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