Seismic actions induced by cladding panels on precast concrete frame structures

The strong earthquakes occurred in Southern Europe in the last decade pointed out a poor seismic performance of the connection system of the cladding of precast industrial structures. The cladding of these buildings usually consists of sandwich concrete panels of remarkable mass, connected to the frame structure with mechanical devices. The estimation of the out-of-plane seismic action on these connections is a key step for their correct proportioning. However, the formulation currently provided in the Eurocode 8 for the estimation of the seismic action on non-structural elements was calibrated with different objectives. Furthermore, given there is no in-plane structure-panel interaction, a quote of the panel mass is lumped in correspondence of their connection for a correct proportioning of the frame structure. The designers need to make assumptions on both aspects that often bring to remarkably different solutions. The paper presents a consistent dynamic formulation of the problem of the vibration of rigid bodies connected with cantilever columns. The solution brings to closed-form equations to evaluate the exact out-of-plane action on the connections and the correct amount of panel mass to be lumped

Dynamic Response of Cantilever Retaining Walls Considering Soil Non-Linearity

For many decades the analysis of earth retaining structures under dynamic or seismic conditions has been carried out by means of standard limit equilibrium (Coulomb, M-O) or elastic methods (Wood, Veletsos and Younan). These approaches are simplified, as they make use of considerable approximations which are often applicable only under particular conditions. A different and perhaps more realistic approach is possible using established computer codes, which integrate numerically the governing equations of the soil and wall media. Since these problems may involve significant levels of strain in the backfill, material non-linearity should be taken into account to realistically simulate the response of the system. In the herein-reported study, a parametric analysis is carried out through the finite-difference code FLAC 5.0. Starting from simple cases involving elastic response, and moving gradually towards more realistic conditions, salient features of the dynamic wall-soil interaction problem are addressed. The case of non-linear hysteretic behaviour of soil and flexibility of wall is considered at a second stage. Results indicate that with increasing levels of acceleration, there is a clear transition from elastic behaviour (in which the aforementioned V-Y type methods are applicable), to plastic behaviour in which M-O methods are thought to be more suitable under pseudo-static conditions. The results of the parametric analyses are reported in terms of pertinent normalized parameters, to provide a general framework for the assessment of wall-soil dynamic interaction under strong seismic excitation

New Target Genes for the Peroxisome Proliferator-Activated Receptor-γ (PPARγ) Antitumour Activity: Perspectives from the Insulin Receptor

The insulin receptor (IR) plays a crucial role in mediating the metabolic and proliferative functions triggered by the peptide hormone insulin. There is considerable evidence that abnormalities in both IR expression and function may account for malignant transformation and tumour progression in some human neoplasias, including breast cancer. PPARγ is a ligand-activated, nuclear hormone receptor implicated in many pleiotropic biological functions related to cell survival and proliferation. In the last decade, PPARγ agonists—besides their known action and clinical use as insulin sensitizers—have proved to display a wide range of antineoplastic effects in cells and tissues expressing PPARγ, leading to intensive preclinical research in oncology. PPARγ and activators affect tumours by different mechanisms, involving cell proliferation and differentiation, apoptosis, antiinflammatory, and antiangiogenic effects. We recently provided evidence that PPARγ and agonists inhibit IR by non canonical, DNA-independent mechanisms affecting IR gene transcription. We conclude that IR may be considered a new PPARγ “target” gene, supporting a potential use of PPARγ agonists as antiproliferative agents in selected neoplastic tissues that overexpress the IR

Analytical and finite element modelling of the elastic–plastic behaviour of metallic strands under axial–torsional loads

In this work a new formulation for modelling the elastic–plastic behaviour of metallic strands subjected to axial–torsional loads is presented. Simple and accurate cross sectional constitutive equations a rederived, fully accounting for the evolution of plastic deformations in the wires, starting from a description of the internal structure of the strand. The proposed approach is suitable both for straightforward analytical calculations as well as for implementation into finite elements for the large-scale structural analyses of cable structures. A full three-dimensional(3D) finite element(FE) model, based on a parametric description of the strand internal geometry, is also developed. The results of both the FE model and the analytical formulation are validated with reference to a well-documented physical testing campaign and a well-established linearly elastic literature model. Additional analyses are then performed to carefully assess the validity of the proposed mechanical formulation, for a wide range of strand construction parameters, by means of systematic comparisons against the results of the 3DFE modeland of a recent linearly elastic literature model

Dynamic load tests on the North-South axis cable-stayed bridge with a non-symmetric central pylon.

Abstract The new cable-stayed bridge built for the North-South axis road of Bari in order to overpass the railway of RFI and Ferrotramviaria s.p.a. has been recently built and opened to the traffic. The bridge is 626 m long and the central cable-stayed bays have a total length of 225 m. They are supported by cables connected to a central upside down Y-shaped pylon. The peculiarity is that this column is about 60° rotated with respect to the axis of the bridge deck. A dynamic load tests was developed previously to open the bridge to conventional traffic. 26 piezoelectric accelerometers have been utilized in different positions of the cables-stayed bays to record the accelerations produced by environmental forces and by the impact produced by a loaded truck passing over a bump. Operational Modal Analysis has been applied by mean of Artemis software to determine the first fundamental frequencies and the mode shapes. The main frequency of this non-symmetric pylon is the main frequency of all the stayed bridge

Integrated process of images and acceleration measurements for damage detection

The use of mobile robots and UAV to catch unthinkable images together with on-site global automated acceleration measurements easy achievable by wireless sensors, able of remote data transfer, have strongly enhanced the capability of defect and damage evaluation in bridges. A sequential procedure is, here, proposed for damage monitoring and bridge condition assessment based on both: digital image processing for survey and defect evaluation and structural identification based on acceleration measurements. A steel bridge has been simultaneously inspected by UAV to acquire images using visible light, or infrared radiation, and monitored through a wireless sensor network (WSN) measuring structural vibrations. First, image processing has been used to construct a geometrical model and to quantify corrosion extension. Then, the consistent structural model has been updated based on the modal quantities identified using the acceleration measurements acquired by the deployed WSN. © 2017 The Authors. Published by Elsevier Ltd

Italian Version of the Risk Assessment and Prediction Tool: Properties and Usefulness of a Decision-Making Tool for Subjects' Discharge after Total Hip and Knee Arthroplasty

Background: Growing attention is being given to standardized outcome measures to improve interventions for total hip arthroplasty (THA) and total knee arthroplasty (TKA). We culturally adapt and validate the Italian version of the Risk Assessment and Prediction Tool (RAPT-I) to allow its predictive use after THA and TKA. Methods: The RAPT-I was adapted by forward-backward translation, a final review by an expert committee and a test of the pre-final version to establish its correspondence with the original version. The psychometric testing included test-retest reliability (intraclass correlation coefficient, ICC). The RAPT score was used to predict the subjects-destination (<6: rehabilitation unit; 6-9: additional intervention before discharging home; or >9: discharge directly at home) by comparing the actual discharge destination with the predicted destination. The predictive effects of RAPT items on the discharge destination were further described by a logistic regression model (repeated leave-one-out bootstrap procedure). Results: The questionnaire was administered to 78 subjects with THA and 70 subjects with TKA and proven to be acceptable. The questionnaire showed excellent test–retest reliability (ICC = 0.839; with 95% confidence interval (CI) of 0.725–0.934 for THA; ICC = 0.973, with 95% CI of 0.930–0.997 for TKA). The RAPT-I overall predictive validity was 87.2%, and the discharge destination was directly related to living condition (odds ratio (OR) = 2.530), mobility (OR = 2.626) and age (OR = 1.332) and inversely related to gait aids (OR = 0.623) and gender (OR = 0.474). Conclusions: The RAPT-I was successfully adapted into Italian and proven to exhibit satisfactory properties, including predictive validity in determining discharge destination

Analytical modelling of the varying bending stiffness inside the boundary layer of cables

peer reviewedIn the present paper, a novel model for a shallow cable with small bending stiffness subjected to transverse loading conditions is presented. The proposed model is based on a simple yet accurate phenomenological description of the non-linear moment-curvature law of stranded cables. Numerical solutions are first compared to experimental results of the literature, to assess the validity of the proposed formulation. Parametric analyses are then carried out to investigate the effect of different non-dimensional groups controlling the bending stiffness variation within the boundary layers