Seismic Performance of Strengthened Slab-Column Connections in a Full-Scale Test

Funding Information: The SlabSTRESS (Slab Structural RESponse for Seismic European Design) experimental campaign is part of the Transnational Access activities of the SERA (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe) project. This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 730900. Publisher Copyright: © 2022 The Author(s). Published with license by Taylor & Francis Group, LLC.Strengthening of flat slab-column connections to resist imposed lateral drifts is often required for older reinforced concrete structures in which the flat slabs were typically designed to resist gravity load only or have been designed for less stringent requirements. The complex stress state around the columns means that strong experimental evidence is required for the repair and strengthening techniques to be adopted with confidence in practice. Although a significant amount of research has been devoted to strengthening of slab-column connections, a series of limitations still remain. A thorough literature review revealed that only relatively thin and isolated specimens have been tested under seismic-type loading and realistic strengthening scenarios. To overcome these limitations, a full-scale two-story flat slab building specimen was tested at the European Commission’s Joint Research Centre–ELSA Laboratory in Ispra, Italy. This paper describes and analyzes the results obtained from the last of a series of phases, on repaired and strengthened internal and external slab-column connections using post-installed bolts. Compared with previous tests, the full-scale building specimen has a thicker slab (200 mm), realistic slab continuity conditions and the connections were strengthened after they suffered damage from gravity loading and previous lateral loading phases. The results show that post-installed bolts are efficient even under the described conditions (i.e. damaged and repaired specimens with realistic thickness), and punching shear failure was prevented in the strengthened connections.publishersversionepub_ahead_of_prin

Deformation capacity evaluation for flat slab seismic design

The authors acknowledge the dedicated and careful work carried out by the Associate Editor and Reviewers whose constructive criticism contributed to a very significant improvement of the quality of the paper. Authors wish to dedicate this work to the memory of their co-author Prof. Ion Radu Pascu, UTCB Bucharest, who passed away on June 10, 2021. Publisher Copyright: © 2021, The Author(s).In flat-slab frames, which are typically designed as secondary seismic structures, the shear failure of the slab around the column (punching failure) is typically the governing failure mode which limits the deformation capacity and can potentially lead to a progressive collapse of the structure. Existing rules to predict the capacity of flat slab frames to resist imposed lateral displacements without losing the capability to bear gravity loads have been derived empirically from the results of cyclic tests on thin members. These rules account explicitly only for the ratio between acting gravity loads and resistance against concentric punching shear (so-called Gravity Shear Ratio). Recent rational models to estimate the deformation capacity of flat slabs show that other parameters can play a major role and predict a significant size effect (reduced deformation for thick slabs). In this paper, a closed-form expression to predict the deformation capacity of internal slab-column connections as a function of the main parameters is derived from the same model that has been used to develop the punching shear formulae for the second generation of Eurocode 2 for concrete structures. This expression is compared to an existing database of isolated internal slab-column connections showing fine accuracy and allowing to resolve the shortcomings of existing rules. In addition, the results of a testing programme on a full-scale flat-slab frame with two stories and 12 columns are described. The differences between measured interstorey drifts and local slab rotations influencing their capacity to resist shear forces are presented and discussed. With respect to the observed deformation capacities, similar values are obtained as in the isolated specimens and the predictions are confirmed for the internal columns, but significant differences are observed between internal, edge and corner slab-column connections. The effects of punching shear reinforcement and of integrity reinforcement (required according to Eurocode 2 to prevent progressive collapse after punching) are also discussed.publishersversionpublishe

The effect of sodium‐glucose co‐transporter 2 inhibitors on outcomes after cardiac resynchronization therapy

Aims: The trials upon which recommendations for the use of cardiac resynchronization therapy (CRT) in heart failure used optimal medical therapy (OMT) before sodium‐glucose co‐transporter 2 inhibitors (SGLT2i). Moreover, the SGLT2i heart failure trials included only a small proportion of participants with CRT, and therefore, it remains uncertain whether SGLT2i should be considered part of OMT prior to CRT. Methods and results: We compared electrocardiogram (ECG) and echocardiographic responses to CRT as well as hospitalization and mortality rates in consecutive patients undergoing implantation at a large tertiary centre between January 2019 to June 2022 with and without SGLT2i treatment. Three hundred seventy‐four participants were included aged 74.0 ± 11.5 years (mean ± standard deviation), with a left ventricular ejection fraction (LVEF) of 31.8 ± 9.9% and QRS duration of 161 ± 29 ms. The majority had non‐ischaemic cardiomyopathy (58%) and were in NYHA Class II/III (83.6%). These characteristics were similar between patients with (n = 66) and without (n = 308) prior SGLT2i treatment. Both groups demonstrated similar evidence of response to CRT in terms of QRS duration shortening, and improvements in LVEF, left ventricular end‐diastolic inner‐dimension (LVIDd) and diastolic function (E/A and e/e′). While there was no difference in rates of hospitalization (for heart failure or overall), mortality was significantly lower in patients treated with SGLT2i compared with those who were not (6.5 vs. 16.6%, P = 0.049). Conclusions: We observed an improvement in mortality in patients undergoing CRT prescribed SGLT2i compared with those not prescribed SGLT2i, despite similar degrees of reverse remodelling. The authors recommend starting SGLT2i prior to CRT implantation, where it does not delay implantation

Testing of a full-scale flat slab building for gravity and lateral loads

Full-scale testing of a two-storey flat slab structure is reported, undertaken in the SlabSTRESS research project; the construction and testing were planned and carried out at the ELSA laboratory of the European Commission’s Joint Research Centre. The dimensions are three bays by two, spans 4.5 and 5 m, slab thickness 0.2 m, interstorey height 3.2 m. Two different longitudinal reinforcement details were considered; welded studs shear reinforcement was provided only in the second floor slab. The testing program included seismic tests for service and ultimate actions, using the pseudodynamic technique with virtual walls. To this aim a building structure was designed with primary walls and the flat slab frame as secondary element. Cyclic loading tests followed up to ultimate drift capacity of the structure. The sequence of tests included strengthening of a set of damaged connections using bolted bars in holes drilled through the slab, followed by cyclic testing to failure. The instrumentation was provided for the global response and the connections with local rotations in the columns and slab; cracking around the columns was measured with through-crack sensors; a measurement system for internal forces and moments was included within the columns. The results show the response with deformations and damage for the different loading conditions up to failure. The results obtained on a full-scale structure extend and confirm the knowledge in the literature, mainly based on isolated connections and/or small-scale samples

Flat slab response for seismic and cyclic actions prediction with numerical models

As an outcome of a recent European research project, the modelling of the response of flat slab structures for seismic and cyclic loading was the object of a blind competition. No other blind tests are available in the literature on this topic. The test results concern a full-scale, two-storey, three-by two bay reinforced concrete flat slab frame. The seismic tests were carried out using a hybrid pseudo-dynamic test up to the ULS design excitation. The cyclic test reached a drift capacity of 2.5% and 6% in two concatenated tests. A synthesis of the models of three participants is provided, with one 3D NLFE (Nonlinear finite element) models and two slab and frame models. The CSCT (Critical Shear Crack Theory) model included in the fib MC2010 was adopted in the two latter to predict punching failure. The results are presented and discussed. Conclusions are drawn on research developments and practical approaches

Clinical outcomes in individuals at clinical high risk of psychosis who do not transition to psychosis: a meta-analysis

Aims: The clinical outcomes of individuals at clinical high risk of psychosis (CHR-P) who do not transition to psychosis are heterogeneous and inconsistently reported. We aimed to comprehensively evaluate longitudinally a wide range of outcomes in CHR-P individuals not developing psychosis. Methods: "Preferred Reporting Items for Systematic reviews and Meta-Analyses" and "Meta-analysis Of Observational Studies in Epidemiology"-compliant meta-analysis (PROSPERO: CRD42021229212) searching original CHR-P longitudinal studies in PubMed and Web of Science databases up to 01/11/2021. As primary analysis, we evaluated the following outcomes within CHR-P non-transitioning individuals: (a) change in the severity of attenuated psychotic symptoms (Hedge's g); (b) change in the severity of negative psychotic symptoms (Hedge's g); (c) change in the severity of depressive symptoms (Hedge's g); (d) change in the level of functioning (Hedge's g); (e) frequency of remission (at follow-up). As a secondary analysis, we compared these outcomes in those CHR-P individuals who did not transition vs. those who did transition to psychosis at follow-up. We conducted random-effects model meta-analyses, sensitivity analyses, heterogeneity analyses, meta-regressions and publication bias assessment. The risk of bias was assessed using a modified version of the Newcastle-Ottawa Scale (NOS). Results: Twenty-eight studies were included (2756 CHR-P individuals, mean age = 20.4, 45.5% females). The mean duration of follow-up of the included studies was of 30.7 months. Primary analysis: attenuated psychotic symptoms [Hedges' g = 1.410, 95% confidence interval (CI) 1.002-1.818]; negative psychotic symptoms (Hedges' g = 0.683, 95% CI 0.371-0.995); depressive symptoms (Hedges' g = 0.844, 95% CI 0.371-1.317); and functioning (Hedges' g = 0.776, 95% CI 0.463-1.089) improved in CHR-P non-transitioning individuals; 48.7% remitted at follow-up (95% CI 39.3-58.2%). Secondary analysis: attenuated psychotic symptoms (Hedges' g = 0.706, 95% CI 0.091-1.322) and functioning (Hedges' g = 0.623, 95% CI 0.375-0.871) improved in CHR-P individuals not-transitioning compared to those transitioning to psychosis, but there were no differences in negative or depressive symptoms or frequency of remission (p > 0.05). Older age was associated with higher improvements of attenuated psychotic symptoms (β = 0.225, p = 0.012); publication years were associated with a higher improvement of functioning (β = -0.124, p = 0.0026); a lower proportion of Brief Limited Intermittent Psychotic Symptoms was associated with higher frequencies of remission (β = -0.054, p = 0.0085). There was no metaregression impact for study continent, the psychometric instrument used, the quality of the study or proportion of females. The NOS scores were 4.4 ± 0.9, ranging from 3 to 6, revealing the moderate quality of the included studies. Conclusions: Clinical outcomes improve in CHR-P individuals not transitioning to psychosis but only less than half remit over time. Sustained clinical attention should be provided in the longer term to monitor these outcomes

Probability of Transition to Psychosis in Individuals at Clinical High Risk: An Updated Meta-analysis

Estimating the current likelihood of transitioning from a clinical high risk for psychosis (CHR-P) to psychosis holds paramount importance for preventive care and applied research

Longitudinal outcome of attenuated positive symptoms, negative symptoms, functioning and remission in people at clinical high risk for psychosis:a meta-analysis

[EN] Background: Little is known about clinical outcomes other than transition to psychosis in people at Clinical High-Risk for psychosis (CHR-P). Our aim was to comprehensively meta-analytically evaluate for the first time a wide range of clinical and functional outcomes beyond transition to psychosis in CHR-P individuals. Methods: PubMed and Web of Science were searched until November 2020 in this PRISMA compliant metaanalysis (PROSPERO:CRD42020206271). Individual longitudinal studies conducted in individuals at CHR-P providing data on at least one of our outcomes of interest were included. We carried out random-effects pairwise meta-analyses, meta-regressions, and assessed publication bias and study quality. Analyses were twotailed with a=0.05. Findings: 75 prospective studies were included (n=5,288, age=20.0 years, females=44.5%). Attenuated positive symptoms improved at 12 (Hedges’ g=0.753, 95%CI=0.495-1.012) and 24 (Hedges’ g=0.836, 95%CI=0.463- 1.209), but not 36 months (Hedges’ g=0.315. 95%CI=-0.176 0.806). Negative symptoms improved at 12 (Hedges’ g=0.496, 95%CI=0.315 0.678), but not 24 (Hedges’ g=0.499, 95%CI=-0.137 1.134) or 36 months (Hedges’ g=0.033, 95%CI=-0.439 0.505). Depressive symptoms improved at 12 (Hedges’ g=0.611, 95%CI=0.441 0.782) and 24 (Hedges’ g=0.583, 95%CI=0.364 0.803), but not 36 months (Hedges’ g=0.512 95%CI=-0.337 1.361). Functioning improved at 12 (Hedges’ g=0.711, 95%CI=0.488 0.934), 24 (Hedges’ g=0.930, 95%CI=0.553 1.306) and 36 months (Hedges’ g=0.392, 95%CI=0.117 0.667). Remission from CHRP status occurred in 33.4% (95%CI=22.6 44.1%) at 12 months, 41.4% (95%CI=32.3 50.5%) at 24 months and 42.4% (95%CI=23.4 61.3%) at 36 months. Heterogeneity across the included studies was significant and ranged from I2=53.6% to I2=96.9%. The quality of the included studies (mean§SD) was 4.6§1.1 (range=2-8). Interpretation: CHR-P individuals improve on symptomatic and functional outcomes over time, but these improvements are not maintained in the longer term, and less than half fully remit. Prolonged duration of care may be needed for this patient population to optimize outcomes.There was no funding source for this stud

MEDICAL SCIENCE. GISSI-2: A factorial randomised trial of alteplase versus streptokinase and heparin versus no heparin among 12 490 patients with acute myocardial infarction

A multicentre, randomised, open trial with a 2 x 2 factorial design was conducted to compare the benefits and risks of two thrombolytic agents, streptokinase (SK, 1\ub75 MU infused intravenously over 30-60 min) and alteplase (tPA, 100 mg infused intravenously over 3 h) in patients with acute myocardial infarction admitted to coronary care units within 6 h from onset of symptoms. The patients were also randomised to receive heparin (12 500 U subcutaneously twice daily until discharge from hospital, starting 12 h after beginning the tPA or SK infusion) or usual therapy. All patients without specific contraindications were given atenolol (5-10 mg iv) and aspirin (300-325 mg a day). The end-point of the study was the combined estimate of death plus severe left ventricular damage. 12 490 patients were randomised to four treatment groups (SK alone, SK plus heparin, tPA alone, tPA plus heparin). No specific differences between the two thrombolytic agents were detected as regards the combined end-point (tPA 23\ub71%; SK 22\ub75%; relative risk 1\ub704, 95% Cl 0\ub795-1\ub713), nor after the addition of heparin to the aspirin treatment (hep 22\ub77%, no hep 22\ub79%; RR 0\ub799, 95% Cl 0\ub791-1\ub708). The outcome of patients allocated to the four treatment groups was similar with respect to baseline risk factors such as age, Killip class, hours from onset of symptoms, and site and type of infarct. The rates of major in-hospital cardiac complications (reinfarction, post-infarction angina) were also similar. The incidence of major bleeds was significantly higher in SK and heparin treated patients (respectively, tPA 0\ub75%, SK 1\ub70%, RR 0\ub757, 95% Cl 0\ub738-0\ub785; hep 1\ub70%, no hep 0\ub76%, RR 1\ub764, 95% Cl 1\ub709-2\ub745), whereas the overall incidence of stroke was similar in all groups. SK and tPA appear equally effective and safe for use in routine conditions of care, in all infarct patients who have no contraindications, with or without post-thrombolytic heparin treatment. The 8\ub78% hospital mortality of the study population (compared with approximately 13% in the control cohort of the GISSI-1 trial) indicates the beneficial impact of the proven acute treatments for AMI. \ua9 1990