Comportamento flessionale di nodi esterni in calcestruzzo fibrorinforzato

SOMMARIO – Si presenta un macro modello di tipo reticolare in grado di riprodurre il comportamento in presenza di taglio e momento di nodi esterni trave-colonna di telai in calcestruzzo fibrorinforzato con fibre di acciaio
uncinato ed ordinario. Il caricamento del sistema è di tipo monotono come nel caso dell’analisi di pushover. Il modello considera la presenza di armature orizzontali e verticali della regione nodale e tiene in conto delle modalità
di rottura legate allo snervamento delle barre e allo schiacciamento delle regioni compresse in regime di sforzi pluriassiali. Il modello include le deformazioni flessionali della trave e della colonna in presenza di sforzo normale costante e restituisce la risposta del sistema colonna-nodo-trave (sub-assembralggio) tramite le curve carico-freccia all’estremità della semitrave. Per i singoli costituenti (trave, colonna e nodo) si è considerata la prima fessurazione, lo snervamento e lo schiacciamento delle regioni compresse e si sono fornite precise indicazioni sulla sequenza degli eventi che come è noto sono di fondamentale importanza per lo sviluppo di un progetto plastico che rispetti la gerarchia delle resistenze. Con l’uso del modello il controllo della gerarchia delle resistenze avviene a livello sezionale (lo snervamento delle barre deve avvenire prima dello schiacciamento delle regioni compresse) o di macro elemento (nella regione nodale lo snervamento delle staffe precede la crisi dei puntoni) e dell’intero elemento
sub-assemblaggio trave debole, colonna forte e nodo sovraresistente.
La risposta ottenuta con i modello proposto è in buon accordo con le risposte sperimentali disponibili in letteratura (almeno in termini di resistenza del sub-assemblaggio). Il modello è stato ulteriormente validato con analisi
numeriche agli elementi finiti condotte con il codice ATENA-2D. Le analisi numeriche sono state condotte utilizzando per il calcestruzzo fibroso adeguate leggi costitutive proposte dagli autori ed in grado di cogliere gli effetti
di softening e di resistenza residua a trazione legati alla presenza di fibre. Ulteriori sviluppi del modello saranno indirizzati a includere gli effetti di sfilamento delle barre d’armatura della trave e del conseguente degrado delle
tensioni d’aderenza per effetto di carichi monotonici e ciclici.

SUMMARY – A softened strut-and-tie macro model able to reproduce the flexural behavior of external beam-tocolumn joints with the presence of horizontal and vertical steel bars, including softening of compressed struts and yielding of main and secondary steel bars, is presented, to be used for the pushover analysis. The model proposed is able to calculate also the flexural response of fibrous reinforced concrete (FRC) beam-to-column sub-assemblages in term of a multilinear load-deflection curves. The model is able to take into account of the tensile behavior of main bars embedded in the surrounding concrete and of the softening of the compressed strut, the arrangement and percentage of the steel bars, the percentage and the geometry of steel fibers. First cracking, yielding of main steel and crushing of concrete were identified to determine the corresponding loads and displacement and to plot the simplified monotonic load-deflection curves of the sub-assemblages subjected in the column to constant vertical
load and at the tip of the beam to monotonically increasing lateral force. Through these load-delfection curves the component (beam, joint and column) that first collapse can be recognized and the capacity design can be verified.
The experimental results available in the literature are compared with the results obtained through the proposed model. Further, a validation of the proposed model is numerically made by using a non linear finite element program (ATENA-2D) able to analyze the flexural behavior of sub-assemblages.

Young people's self-reported experiences of sexual exploitation and sexual violence: a view from Northern Ireland

The issue of young people’s experiences of sexual exploitation and sexual violence has received increasing political and media attention within recent years. However, whilst many studies have identified this to be an emerging issue of concern, the collation of prevalence data on the extent of these issues is still very much in its infancy. In this article we report on the findings of a large-scale project on the sexual exploitation of young people, undertaken in Northern Ireland from 2009 to 2011. The article primarily explores young people’s self-reported experiences of sexual violence and exploitation, collated from their responses to a module of questions placed in the 2010 Young Life and Times Survey. The quantitative dataset from the survey covers both prevalence of sexually exploitative experiences and young people’s reports about the type of individuals perpetrating these incidents. This dataset is illustrated and contextualised with reference to the qualitative findings from interviews with young people and professionals conducted as part of the wider sexual exploitation study. The article concludes with a consideration of the implications of the findings, with particular reference to the need for further preventative work in this field.

Practice and Policy in the UK with Children and Young People who Display Harmful Sexual Behaviour: An analysis and critical review

This article considers the trajectory and effectiveness of policy, procedures and practice in the UK since the early 1990s in responding to young people who display problematic and harmful sexual behaviours. It draws on data from three publications in which research, policy and practice in the last 20 years have been reviewed. Key themes raised by Masson and Hackett are revisited including: denial and minimisation; terminology and categorisation; similarities with other young offenders; the child protection and youth justice systems; and assessment and interventions. The authors find that there is improvement in recognition of, and practice in response to, this group of young people, but good practice standards are inconsistently applied. With devolution of political powers, Scotland and Northern Ireland are now embarking on a more strategic response than England. The absence of a public debate and prioritising of primary prevention of child sexual abuse is noted.

Provision for young people who have displayed harmful sexual behaviour

Over the past few decades, children and young people who have sexually harmed others have attracted increasing attention from researchers and policy makers. Although it is known that they form a small, but significant group, there are difficulties in gaining a clear indication of incidence since much of the existing research has involved small and heterogeneous samples, many of which were not UK-based and lack of control groups for comparison. Furthermore, many incidents of sexual abuse are likely to go unreported. The nature, extent and significant negative consequences of harmful sexual behaviour for the victims and perpetrators, make this an important issue for policy development and research investigation. Overall, research and knowledge in this important area are still accumulating and much remains to be confirmed. Although recent decades have seen a movement towards greater understanding of the issue of harmful sex behaviour, a gap remains. The purpose of the project was to help address this gap in knowledge.

Impact of abuse and neglect on the health and wellbeing of children:Child sexual abuse

During the past 30 years, the focus on the extent and nature of child abuse and neglect has been coupled with an increasing interest in the impact on children’s development, health and mental wellbeing. Child maltreatment is both a human rights violation and a complex public health issue, likely caused by a myriad of factors that involve the individual, the family, and the community. Child abuse includes any type of maltreatment or harm inflicted upon children and young people in interactions between adults (or older adolescents). Such maltreatment is likely to cause enduring harm to the child.
The different forms of abuse and neglect often occur together in one family and can affect one or more children. These include, in deceasing level of frequency: neglect; physical abuse and non-accidental injury; emotional abuse; and sexual abuse (Cawson et al, 2000; 2002). Recently, bullying and domestic violence have been included as forms of abuse of children.
There is a sizeable body of literature on the relationship between types of child maltreatment and a variety of negative health and mental health consequences. These include biological, psychological, and social deficits (for reviews, see Crittenden, 1998; Kendall-Tackett, 2001; 2003). Aside from the serious physical and health consequences of child maltreatment, several emotional and behavioural consequences for children have been noted in the literature.

Sexual Abuse in Institutional Contexts

This chapter adopts a cross-national comparative perspective on institutional child sexual abuse. It seeks first to provide a critical overview of a range of high profile inquiries and official reviews into allegations of institutional child abuse and the dominant transnational themes arising from them. It also seeks to highlight the dynamics of what I have previously termed 'institutional grooming' (McAlinden, 2006) and the features of the organisational environment which both facilitate institutional child sexual abuse and help mask its discovery or disclosure. In so doing, the analysis examines the tension between what others have termed 'preferential' or 'situational' sexual offending – that is whether offenders deliberately set out to gain employment which affords access to children or whether the motivation to sexually offend only emerges after they become ensconced in an institutional environment. Finally, the article concludes by offering some suggestions for combatting institutional grooming and sexual abuse.

The Sexual Offences (NI) Order 2008 implications for nurses

This article outlines the changes to the definition of sexual offences in Northern Ireland following the implementation of the Sexual offences Northern Ireland Order 2008 in 2009, and its implications for nurses working with sexually active children in a range of clinical settings. The paper outlines the key changes for practice and addresses the needs of children in three different age groups with emphasis on children aged 13-15 years, and reviews mandatory reporting, the differences between the rights of children to consent and confidentiality, developmental sexual experimentation and sexual health promotion. It reviews related policy and guidance and makes clear the differences between sexual abuse and exploitation, and experimentation. It seeks to advise the Safeguarding Committee of the Department of Health Northern Ireland on how best to support nurses working with sexually active children and when this activity should be discussed with line managers and safeguarding specialists or referred to the safeguarding authorities.

Sexual Health and Sexuality Education Needs of Young People in Care: a Survey of Service-provider Perspectives. Report No 1.

Aim: This study aims to describe the sex education and sexual health needs of young people in care, and to explore the degree to which these needs are being met by current provision.As part of the Department for Children and Youth Affairs ‘National Strategy for Data and Research on Children’s Lives, 2011-2016’, the HSE Crisis Pregnancy Programme (CPP) and HSE Children and Families Social Services Care Group have co-commissioned a team of researchers from UCD School of Nursing, Midwifery & Health Systems, Insights Health and Social Research and Queen’s University Belfast to examine the sex education and sexual health needs of young people in care in the Republic of Ireland. The project is supported by a steering group of senior personnel from both partner organisations (CPP and CFS) and external advisors. The study involves data collection with young people, care providers, birth parents and foster parents using a mixed methods approach. Findings from each stage of the study will be combined to inform recommendations for policy and practice.