Numerical investigation on the seismic performance of a RC framed building equipped with a novel Prestressed LEad Damper with Straight Shaft

This study aims at assessing the use of a novel damper, which is called the Prestressed LEad Damper with Straight Shaft (or PSLED), for the seismic rehabilitation of RC framed buildings. This device provides high energy dissipation by the friction activated between a lead core and a shaft and achieves a high specific output force by preloading the lead during the assembly. In order to show the effectiveness of the PS-LED device for the retrofit of existing buildings, a RC structure designed according to past codes that ignored seismic actions is retrofitted with the PS-LED system considering two different damage targets: (i) in the first case, the structure is retrofitted in order to behave elastically under the design earthquake; (ii) in the second case, a partially dissipative behavior of the structure is conceived, with activation of plastic hinges, and limited and reparable damage. In order to assess the suitability of the design procedure, non-linear static analyses are performed on the upgraded building, showing a satisfactory agreement between the seismic performance and the design target. Non-linear dynamic analyses are further carried out considering a suite of bidirectional artificial ground motions with response spectra matching on average the target spectrum according to the Italian Building Code for the life-safety limit state. Finally, a comparison is performed between the performances of the building retrofitted with the PS-LED device and the building retrofitted with a conventional steel hysteretic damper (SHD), demonstrating that the PS-LED, thanks to its superior damping capacity, limits the increase in internal forces that usually affects frames equipped with SHDs, reducing the need of local strengthening of the columns and foundations and consequently the total cost of the seismic rehabilitation

Implementing clinical guidelines in an organizational setup

Outcomes research in healthcare has been a topic much addressed in recent years. Efforts in this direction have been supplemented by work in the areas of guidelines for clinical practice and computer-interpretable workflow and careflow models.In what follows we present the outlines of a framework for understanding the relations between organizations, guidelines, individual patients and patient-related functions. The derived framework provides a means to extract the knowledge contained in the guideline text at different granularities, in ways that can help us to assign tasks within the healthcare organization and to assess clinical performance in realizing the guideline. It does this in a way that preserves the flexibility of the organization in the adoption of the guidelines

Friction of Polymers Sliding on Smooth Surfaces

Friction plots of polymers sliding on smooth metal surfaces are generally characterized by two regions of distinct dependency on the normal load, with low sensitivity at low stress levels followed by a sharp change in the rate of decrease of friction with increasing pressure at levels above the plastic flow limit of the polymer. A simplified model is proposed to describe this behavior which accounts for the effect of the normal load on the growth of the real contact area and the shear stress at the interface between the polymer and the mating surface. The model has a wide generality when expressed in terms of dimensionless variables, allowing to rationalize the friction behavior of different polymers within a single framework

Patients’ involvement in e-health services quality assessment: A system for the automatic interpretation of SMS-based patients’ feedback

AbstractPurposeEffective communication between patients and health services providers is a key aspect for optimizing and maintaining these services. This work describes a system for the automatic evaluation of users’ perception of the quality of SmsCup, a reminder system for outpatient visits based on short message service (SMS). The final purpose is the creation of a closed-loop control system for the outpatient service, where patients’ complaints and comments represent a feedback that can be used for a better implementation of the service itself.MethodsSmsCup was adopted since about eight years by an Italian healthcare organization, with very good results in reducing the no-show (missing visits) phenomenon. During these years, a number of citizens, even if not required, sent a message back, with comments about the service. The automatic interpretation of the content of those SMS may be useful for monitoring and improving service performances.Yet, due to the complex nature of SMS language, their interpretation represents an ongoing challenge. The proposed system uses conditional random fields as the information extraction method for classifying messages into several semantic categories. The categories refer to appreciation of the service or complaints of various types. Then, the system analyzes the extracted content and provides feedback to the service providers, making them learning and acting on this basis.ResultsAt each step, the content of the messages reveals the actual state of the service as well as the efficacy of corrective actions previously undertaken. Our evaluations showed that: (i) the SMS classification system has achieved good overall performance with an average F1-measure and an overall accuracy of about 92%; (ii) the notification of the patients’ feedbacks to service providers showed a positive impact on service functioning.ConclusionsOur study proposed an interactive patient-centered system for continuous monitoring of the service quality. It has demonstrated the feasibility of a tool for the analysis and notification of the patients’ feedback on their service experiences, which would support a more regular access to the service

SAFOTEB project: towards new approaches for the reliability assessment of existing prestressed bridge

This paper presents the structure of new collaborative research project entitled SAFOTEB “A reviewed SAfety FOrmat for structural reliability assessment of post-TEnsioned concrete Bridges”. The research aims at assessing the reliability of the current safety format and developingspecific suggestions for existing concrete bridges with post-tensioned cables. To date, no European code provides specific guidance for such a purpose. Indeed, the status of conservation and possible de-fects of the cables may be hidden, enlarging the uncertainties in the structural assessment of such constructions. The basic steps of the research are: (i) defini-tion of the probabilistic models for the main variables concerning the assessment of existing post-tensioned prestressed concrete bridges; (ii) reliability assessment and calibration of updated safety coefficients for the partial factors method; (iii) evaluation of the residual life and model updating through real-time continuous monitoring systems. The full procedure will be applied on existing casestudy structures used as benchmarks. The project is funded by FABRE, an Italian re-search consortium composedbyuniversities and research institutions aimed at the evaluation and monitoring of bridges, viaducts, tunnels and other structures

3D numerical characterization of a dissipative connection system for retrofit of prefabricated existing RC sheds

Prefabricated industrial sheds featured a high seismic vulnerability during the 2012 Emilia earthquake (Italy). The buildings typically exhibited a rigid collapse mechanism that was a consequence of the loss of support between columns, beams and roof elements. The study presents a numerical characterization of a novel dissipative connection system (DCS) designed to improve the seismic performance of industrial sheds. The device, which is placed on the top of the columns, exploits the movement of a rigid body on a sloped surface to provide horizontal stiffness and control the lateral displacement of the beam. A 3D finite element model of the prototype is formulated in Abaqus and used to switch the backbone curve from the scaled model to the full-scale device. A parametric study is conducted to evaluate the influence of the slope of the contact surface and the coefficient of friction on the output force of the system. In the second part of the study, non-linear dynamic analyses are performed on a finite element model of a portal frame implementing, at beam-column joints, either the DCS or a pure friction connection. The results highlight the effectiveness of the DCS in controlling beam-to-column displacements, reducing shear forces on the top of columns, and limiting residual displacements that can accrue during ground motion sequence

Assessment of bridge Post‐Tensioning systems using non‐destructive (ND) inspection methods

Reinforced concrete bridges with post-tensioned cables are particularly critical structures, as the degradation of the tendons is not fully detectable through conventional investigation methods and/or through visual inspections, due to the intrinsic nature of the structural typology. After shortly reviewing the main applications of current non-destructive (ND) methods available for investigating the deterioration of tendons and grout, the paper presents a simple procedure to rank these methods through a series of metrics formulated to evaluate the various technologies under four different aspects: accuracy of measurement, ease of use, cost, impact on the operation of the bridge. The procedure has the aim of providing bridge owners with a decision tool which can assist in the selection of the optimal ND technology available to detect a particular strand or grout defec

ASSESSMENT OF THE SHEAR PROPERTIES OF HDRBS UNDER DIFFERENT COMPRESSION LEVELS

Despite it is well known that the shear properties of High Damping Rubber Bearings (HDRBs) are affected by the instantaneous compression load developed during the seismic ground motion, only permissible variations of their design properties with frequency, temperature and ageing are prescribed in the standards while the influence of the compression level is usually disregarded. Within this framework, this research addresses this drawback through both experimental and numerical investigations. In the first part of the study, small scale laminated isolators are tested on a custom biaxial machine in order to assess the secant modulus, and damping factor of the elastomeric compound under different compression levels. In the second part, the same phenomenon is investigated through cyclic shear tests on full scale HDRBs under three different levels of axial load. In the last part, a 3D finite element model of the isolator is eventually formulated in Abaqus FEM software. The mechanical response of the elastomer is simulated by means of a hyperelastic strain energy function combined with a relaxation function. The experimental results highlight the substantial influence of the axial load on the damping capacity of the elastomer, while the shear modulus is less affected. The numerical analyses demonstrate that the vertical – horizontal coupled response of HDRBs can be accurately predicted, within the proposed formulation, with constitutive parameters estimated from simple uniaxial tests

Design and experimental assessment of a novel damper with high endurance to seismic loads

The study presents the design and the experimental characterization of a new energy dissipation device aimed at providing improved resistance to repeated seismic loads. Differently from conventional steel hysteretic dampers, which dissipate energy by yielding of a mild steel core and are noted to suffer low-cycle fatigue, the new damper provides energy dissipation by the friction that is activated between a moving shaft and a lead core prestressed within a tube. The prestress level is controlled during the assembling process, allowing to adjust the axial strength of the damper. Thanks to the ability of lead to restore its properties by static recrystallization taking place immediately after deformation, repeated cycles of loading do not produce damages that may accrue and eventually lead to failure of the device. Moreover, prestressing of the lead core allows to achieve high specific strength (i.e., high force to volume ratio), thereby providing low dimensions which help to reduce the architectural invasiveness. Prototypes of the damper were subjected to the test procedure established in the European standard EN 15129 for Displacement Dependent Devices, fulfilling the relevant requirements. The damper provides a robust and stable response over repeated cycles, characterized by essentially rectangular hysteresis loops with an equivalent viscous damping ratio ξeff of about 55%. Moreover, it shows low sensitivity of mechanical properties on the loading rate and the ability to withstand multiple cycles of motion at the design earthquake displacement without deterioration of performance, demonstrating maintenance-free operation in presence of repeated ground shakes. Its ability to survive several strong motions without being damaged, and its high damping capability coupled to a compact design and low manufacturing cost, are the distinctive features that make it suitable for social housing

Data Quality and Completeness in a Web Stroke Registry as the Basis for Data and Process Mining

Electronic health records often show missing values and errors jeopardizing their effective exploitation. We illustrate the re-engineering process needed to improve the data quality of a web-based, multicentric stroke registry by proposing a knowledge-based data entry support able to help users to homogeneously interpret data items, and to prevent and detect treacherous errors. The re-engineering also improves stroke units coordination and networking, through ancillary tools for monitoring patient enrollments, calculating stroke care indicators, analyzing compliance with clinical practice guidelines, and entering stroke units profiles. Finally we report on some statistics, such as calculation of indicators for assessing the quality of stroke care, data mining for knowledge discovery, and process mining for comparing different processes of care delivery. The most important results of the re-engineering are an improved user experience with data entry, and a definitely better data quality that guarantees the reliability of data analyses