Global ETD Search

361	Rehabilitation of Exterior RC Beam-Column Joints using Web-Bonded FRP Sheets Mahini, Seyed Saeid Unknown Date (has links) In a Reinforced Concrete (RC) building subjected to lateral loads such as earthquake and wind pressure, the beam to column joints constitute one of the critical regions, especially the exterior ones, and they must be designed and detailed to dissipate large amounts of energy without a significant loss of, strength, stiffness and ductility. This would be achieved when the beam-column joints are designed in such a way that the plastic hinges form at a distance away from the column face and the joint region remain elastic. In existing frames, an easy and practical way to implement this behaviour following the accepted design philosophy of the strong-column weak-beam concept is the use a Fibre Reinforced Plastic (FRP) retrofitting system. In the case of damaged buildings, this can be achieved through a FRP repairing system. In the experimental part of this study, seven scaled down exterior subassemblies were tested under monotonic or cyclic loads. All specimens were designed following the strong-column weak-beam principal. The three categories selected for this investigation included the FRP-repaired and FRP-retrofitted specimens under monotonic loads and FRP-retrofitted specimen under cyclic loads. All repairing/retrofitting was performed using a new technique called a web-bonded FRP system, which was developed for the first time in the current study. On the basis of test results, it was concluded that the FRP repairing/retrofitting system can restore/upgrade the integrity of the joint, keeping/upgrading its strength, stiffness and ductility, and shifting the plastic hinges from the column face toward the beam in such a way that the joint remains elastic. In the analytical part of this study, a closed-form solution was developed in order to predict the physical behaviour of the repaired/retrofitted specimens. Firstly, an analytical model was developed to calculate the ultimate moment capacity of the web-bonded FRP sections considering two failure modes, FRP rupture and tension failure, followed by an extended formulation for estimating the beam-tip displacement. Based on the analytical model and the extended formulation, failure mechanisms of the test specimens were implemented into a computer program to facilitate the calculations. All seven subassemblies were analysed using this program, and the results were found to be in good agreement with those obtained from experimental study. Design curves were also developed to be used by practicing engineers. In the numerical part of this study, all specimens were analysed by a nonlinear finite element method using ANSYS software. Numerical analysis was performed for three purposes: to calculate the first yield load of the specimens in order to manage the tests; to investigate the ability of the web-bonded FRP system to relocate the plastic hinge from the column face toward the beam; and to calibrate and confirm the results obtained from the experiments. It was concluded that numerical analysis using ANSYS could be considered as a practical tool in the design of the web-bonded FRP beam-column joints. Reinforced concrete Reinforcement Bar strong-column weak-beam principal Exterior Beam-Column Joints Core Small scale modelling Experimental Test set-up Control Plain specimen Rehabilitation Retrofitting retrofitted Repair Repaired Repairing Strengthening Controlling Relocating Plastic hinge Pre-cracking Cracking Crushing Post-cracking Crack Cracked Penetration Damaged Pre-cracked Web-Bonded Wrapping De-bonding Fibre Reinforced Plastic FRP Sheets Composite Confinement Monotonic loads Cyclic loading Loads Displacement control Load control Regime Phase Loading sequence Procedure Available ductility factor Curvature ductility factor Ultimate First yield Flexural yielding Strength Moment Stiffness Failure mechanism Modes Sudden Brittle failure Measured beam-tip displacement Deflection Numerical analysis ANSYS Solid65 Solid45 Link8 Non-linear Finite Element (FE) Convergence criteria Analytical Closed from FRP rupture tension failure Compression failure Minimum thickness Maximum thickness Compressive Tensile Steel Ratio Design charts Effective Moment of Inertia Compatibility Strain Stress
362	A Novel Approach to Youth Crime Prevention: Mindfulness Meditation Classes in South African Townships / A Novel Approach to Youth Crime Prevention : Mindfulness Meditation Classes in South African Townships Kneip, Katharina January 2020 (has links) Children growing up in poor areas with high crime rates are shown to easily get involved in violent actions and criminal gangs. In South Africa, despite considerable efforts to reduce youth delinquency, youth crime rates are still disturbingly high – specifically, in the townships of the Cape Flats. This paper points out an important aspect previously unaddressed by most youth crime prevention: the subconscious roots of youth crime. What if we could develop youth crime prevention programs that manage to impact the subconscious behavioral patterns of youth in high crime areas? This paper proposes a promising and cost-effective approach that has great potential to affect multipe causes of crime: mindfulness meditation. Built upon newest findings in Neuroscience, this paper suggests that mindfulness meditation classes are associated with a reduction in aggressive behavior, a risk factor for youth crime, and an increase in self-efficacy, a protective factor. The impact of mindfulness classes at a high school in Khayelitsha, a poor and violent-stricken township of Cape Town, is analyzed. Self-reported aggression and self-efficacy are measured via a psychometric survey questionnaire created from two well-tested and validated scales. Regression analyses of 384 survey answers provided mixed results. Whilst novice meditators were not associated with higher self-efficacy and lower aggression, long-term meditators performed better in several dimensions of self-efficacy and aggression, yet no significant relationship was found. Further research specifically needs to investigate the moderating effect of age (a proxy for psychological development) on meditation. This study aims to bridge the gap between the outdated paradigms of youth crime prevention and ancient wisdom via ground-breaking new evidence from the field of Neuroscience. This study furthermore hopes to point policy makers toward developing new, integrative and sustainable approaches to youth crime prevention – approaches that give back agency to our youth. / <p>Anders Westholm har inget med betygssättningen att göra annat än i rent formellt hänseende (examinator). Det är han som rapporterar in och skriver under men i sak är det seminarieledaren som har beslutet i sin hand. Statsvetenskapliga institutet har som princip att skilja på handledning och examination vilket innebär att handledaren inte får vara seminarieledare. Seminarieledare och personen som satt betygget var i det här fallet Sven Oskarsson: Sven.Oskarsson@statsvet.uu.se</p> Juvenile delinquency youth aggression crime youth crime prevention cost-effective crime prevention crime rates psychometric survey questionnaire psychological scales aggression scale self-efficacy scale regression analysis quantitative study empowerment youth agency youth development development sustainable approach self-development Psychology Social Psychology abuse trauma risk factors protective factors townships poor area violent area Khayelitsha Guguletu Mitchell's Plain Ghetto Africa South Africa Cape Town Cape Flats school mindfulness meditation mindfulness meditation Kabat-Zinn future resilience subconsciousness subconscious brain emotional brain decision making aggression disruptive behavior self-efficacy self-esteem self-regulation emotional regulation subconsciousness subconscious behavioral patterns Neuroscience Political Science Development Studies Peace and Conflict Uppsala Jugendgewalt Jugendkriminalität Jugendaggression Aggressionsbewältigung Gewalt Verbrechensrate Gewaltrate Jugendgewaltprävention Gewaltprävention Survey-Studie Umfrage psychologische Skalen Aggressionsskala Selbstwirksamkeitsskala Regressionsanalyse Quantitative Studie Handlungsfähigkeit Jugend nachhaltig Entwicklungsarbeit Entwicklung Selbstentwicklung Psychologie Sozialpsychologie Missbrauch Trauma Risikofaktor Schutzfaktor Townships Armenviertel Konfliktgebiet Ghetto Cape Town Cape Flats Khayelitsha Südafrika Afrika Schule Primarschule weiterführende Schule Achtsamkeit Meditation Mindfulness Meditation Kabat-Zinn Zukunft Resilienz Aggression Selbstvertrauen Selbstwirksamkeit Selbstbewusstsein Selstregulierung Emotionsregulierung unbewusste Verhaltensmuster Unterbewusstsein Neurowissenschaft Politikwissenschaft Entwicklungsstudien Friedensforschung Uppsala Ungdomskriminalitet brottslighet förebyggande av brott enkätundersökning psykologiska skalor aggressionsskala egeneffektivitetsskala regression kvantitativ ungdomsutveckling utveckling självutveckling psykologi socialpsykologi övergrepp trauma riskfaktorer skyddsfaktorer townships fattiga område kriminellt område Khayelitsha Afrika Sydafrika Kapstaden skola mindfulness meditation mindfulness meditation Kabat-Zinn framtid motståndskraft aggression störande beteende självförmåga självkänsla självreglering emotionell reglering neurovetenskap statsvetenskap utvecklingsstudier fred och konfliktstudier Uppsala Globalisation Studies Globaliseringsstudier

Search results

Rehabilitation of Exterior RC Beam-Column Joints using Web-Bonded FRP Sheets

A Novel Approach to Youth Crime Prevention: Mindfulness Meditation Classes in South African Townships / A Novel Approach to Youth Crime Prevention : Mindfulness Meditation Classes in South African Townships