Connection Of Use Research Articles

Experimental investigation using demountable steel-concrete composite reduced web section (RWS) connections under cyclic loads

This paper presents an experimental study of demountable steel-concrete composite reduced web section (RWS) connections for use in seismic areas. Four composite connection specimens were subjected to sagging and hogging moments to investigate the performance of RWS connections under reversible actions. For such purpose, a single web opening was created near the beam-column joint. Focus was made on the effects of perforation location and composite beam-slab action induced by bolted shear studs within the protected zone. Results indicate that employing RWS connections for seismic retrofit is a viable solution capable of achieving a performance similar to that observed for RBS connections in new buildings. Notably, a Vierendeel Mechanism is formed, allowing for plasticity development in the beam. All RWS connections were capable of achieving an interstory drift larger than 4%, thereby complying with the performance targets set by ANSI/AISC 358-16, ANSI/AISC 341-16 and EC8. Moreover, the deformation of beam-slab shear-transfer bolts was small enough to allow for disassembly after the tests, indicating that the proposed solution could enable reuse and post-earthquake retrofitting.

P005 Decolonizing measures of sleep and wellbeing to assess the outcomes of a MĀORI-led sleep intervention in Aotearoa whānau (New Zealand families).

Abstract Introduction The creation of culturally relevant questionnaires is an important step towards decolonizing research methodologies to ensure that they are appropriate for use in diverse populations. Our team aimed to develop and test a new questionnaire about sleep, wellbeing and whānau connection for use in Aotearoa whānau with 0-2 year old infants. Methods Our ethnically diverse research team co-designed with relevant communities a new 56-item questionnaire. Some items were adapted from existing questionnaires, with others newly developed through a Māori worldview. The new questionnaire was disseminated online for testing by caregivers of 0-2 year old children. Quantitative and qualitative findings about, and associations between three dimensions of children’s sleep health and caregiver and whānau wellbeing and connection, were examined to determine their acceptability as key outcome measurements for an upcoming trial. Results 957 caregivers completed the new questionnaire. Small, yet consistent positive associations were observed between children’s sleep quality, and caregivers’ perceptions of children’s sleep, and caregiver wellbeing, whānau wellbeing, and connection. Conversely, children’s nocturnal sleep duration was not related to caregiver or whānau wellbeing or connection. Only 14% of caregivers found questions about their perception of their children’s sleep difficult to answer. Qualitative feedback indicated that questions about wellbeing and connection were culturally relevant and acceptable to diverse whānau. Discussion Caregiver perception of children’s sleep, children’s sleep quality, caregiver wellbeing, whānau wellbeing and connection can be measured in a culturally relevant manner when a collaborative team work together to create, and consciously decolonize, new and existing questionnaire items.

Understanding the complexity, patterns, and correlates of alcohol and other substance use among young people seeking help for mental ill-health

PurposeUse of alcohol and other substances is a multifaceted issue impacting young people across multiple life domains. This paper aims to elucidate patterns of substance use and associated demographic and clinical factors among young people seeking treatment for their mental health.MethodsYoung people (12–25 years old) were recruited from five youth-specific primary mental health (“headspace”) services in Australia. Self-reported substance use and harms in the past 3 months were measured using WHO-ASSIST. Network analyses were conducted to evaluate interrelationships between use and harms associated with different substances. Subgroups were then identified based on whether participants reported using high centrality substances, and associated demographic and clinical factors were assessed with multinomial logistic regression.Results1107 youth participated. 70% reported use of at least one substance in the past 3 months, with around 30% of those reporting related health, social, legal or financial problems. Network analysis highlighted substantial interconnections between use and harm indicators for all substances, with amphetamine-type stimulants (ATS) and cannabis being high central substances. Higher levels of substance use and harms were reported in subgroups with ATS or cannabis use and different risk factors were associated with these subgroups.ConclusionsFindings highlight the importance of screening for substance use in youth primary mental healthcare settings, offering a key opportunity for early intervention. Clinicians should be aware of the inner connections of use and harms of different drugs and the role of cannabis and amphetamine use as a marker for more substance use profiles.

The C1 wedge connection in towers for wind turbine structures, tensile behaviour of a segment test

This paper shows a part of the analysis of the development of the second generation of the C1 wedge connections for use in offshore wind turbine supporting towers. The novelty of this connection is that bolt failure is avoided under static and fatigue loads. This study aims to investigate the tensile behaviour of the connection by combining the findings of experiments and finite element (FE) analysis. Two specimens subjected to uniaxial and cyclic tensile loading tested until failure are used for illustration. Advanced quasi-static FE analysis results, considering the most detailed geometry and using an explicit dynamic solver, are compared to the experimental results. The FE analysis results agree well with the experimental results. Based on the FE model, a parametric study is carried out to analyse the influence of the bolt grade, friction coefficient between contact surfaces, and preloading force level on mechanical behaviour. Failure modes, bolt force development, and the evolution of gap opening between contacted segments are analysed. Results demonstrate that the tensile fracture of the C1 wedge connection mainly appears in the lower segment. All the investigated parameters have a negligible effect on the connection's ultimate resistance and failure mode. However, the friction coefficient between contact surfaces and bolt preload level significantly affects the connection's local deformation capacity and the response of the bolt stress range. The FE simulation provides practical guidance for designing this connection without bolt failure.

A Lego‐like steel‐framed system for standardization and serial production

AbstractA Lego‐like steel‐framed structural system has been developed within the frame of an RFCS project, REDUCE, to facilitate 1) deconstruction of composite structures, 2) circularity at structure and element levels, and 3) serial production in construction by promoting a greater standardization of structural elements. The system utilizes innovative demountable shear connections for composite flooring solutions with precast concrete elements, and adjustable steel connections for use in both beam‐to‐beam and beam‐to‐column connections. The first use case of the structural system has been realized in the Petite Maison project which is a demonstration project for circularity and contributes to the event ESCH2022. Each construction element is linked to a digital database and remains available for future reuse, as a result of the plug‐and‐play, demountable and robust features of the developed system. This paper presents the proposed demountable system, the results from experiments and finite element analyses on the behaviour of shear connections, composite beams, and steel connections, and indicates the analysing methods for structural engineers to open a pathway for full implementation of the structures built into digital tools, fabrication, and construction.

Determination of load transfer characteristics to connections between cold-formed steel truss and supporting system

PurposeRecently, the utilization of cold-formed steel (CFS) roof truss systems and different types of other combination structural support systems, such as concrete or hot-rolled steel support, becomes more frequently used. This paper aims to identify the load transfer characteristics of three different design details for cold-formed truss to supporting system connections and to propose simplified modelling approach for practices.Design/methodology/approachSimplification modelling of connection design could be proposed for practical purpose based on the load transfer characteristics obtained from detailed study using finite element method. A cold-formed roof truss system with connection is modelled using line elements. However, the supporting system is not modelled in this work. Three types of connection involve, which are five pieces of CFS L-angle brackets, one-piece of CFS L-angle brackets and three types of bolts connection are modelled.FindingsThe results of analysis show that the connections located on the loaded side experienced higher reactions than those far from loaded side. From the result, it is also found that the option of “Fixed But” support condition in STAAD.Pro with translational degree of freedom being restrained is the most suitable way to represent the CFS L-angle brackets design for Type 1 connection for use in truss modelled using line elements.Originality/valueSuch increase in usage necessitates an appropriate connection detailing depending on the behaviour of the connection.

Cyclic Behavior of DuraFuse Frames Moment Connections

Most special moment frames (SMF) rely on beam yielding to reach drifts of 0.04 rad and beyond. In contrast, DuraFuse Frames (DFF) incorporate a fuse plate that acts as the yielding element. Nine full-scale DFF specimens were tested using AISC 341, Seismic Provisions for Structural Buildings, Chapter K, to prequalify the DFF connection for use in SMF and inclusion in AISC 358, Prequalified Connections for Special and Intermediate Steel Moment Frames for Seismic Applications. Eight specimens were tested with the standard protocol and exceeded the qualification criteria. The other specimen completed a custom protocol representing three maximum credible earthquakes (MCE) in sequence. The experiments demonstrated that the stiffness of the DFF connection is sufficient to classify the connection as fully restrained (FR).

Experimental study on two innovative ductile moment-resisting precast concrete beam-column connections

The use of precast concrete elements in construction leads to increased output quality, better product control, cost savings, and reduced construction time. The main problem of precast concrete structures is the improper performance of connections under lateral loads. In the present study, the aim is to improve the behavior of precast connections under cyclic loading. Two new beam-column precast connections with steel profiles as corbel with high-strength bolt fasteners are developed. Those connections have been designed to be used in intermediate moment frames in regions with high seismic risk. The advantage of these connections is the elimination of the need for remarkable concrete formwork, temporary supports, and low demand for in-situ concrete during construction and providing the possibility of construction progress on the floors in parallel. For studying the seismic performance of proposed connections, six specimens including four precast and two monolithic connections with different rebar ratios were made. The specimens were subjected to a horizontal displacement-control cyclic loading to obtain the load-displacement curves. The maximum lateral strength, ductility, strength degradation, stiffness reduction, and energy dissipation of precast connections were evaluated and compared with the in-situ connections. The ultimate strength and ductility of the precast connections were similar to the in-situ specimens, and proposed connections showed good cyclic behavior. The strength degradation and stiffness deterioration of precast connections were more than the in-situ connection, and the energy dissipation of them was less than monolithic connections. According to the analysis results, the performance of the proposed connections is acceptable and satisfies the criteria of the connections for use in areas with high seismicity.

Experimental study of grouted sleeve connections under bending for steel modular buildings

In steel modular buildings, both inter- and intra-module connections can attract bending moment under the action of lateral loads. The moment is distributed in accordance with the relative stiffness ratios among the structural components and hence the connections should have sufficient flexural resistance and stiffness relative to the connecting members to be classified as a rigid connection. Typically, intra-module connections (beam-column joints within a module) are designed as full-strength rigid connections, while the inter-module connections are normally designed as pin-connected for fast-track construction. This paper proposes the use of grouted sleeve connection which does not require bolting or welding to achieve fast-track construction of modular buildings. An experimental programme is carried to investigate two types of inter-module connections, shear-keyed grouted sleeve versus slot-hole grouted sleeve, under flexural loading to evaluate their structural performance in terms of strength, stiffness, and ductility. The results showed that both connections have adequate moment resistance and ductility to resist bending and they can be classified as partial strength rigid connection for use in braced steel modular buildings. An analytical model, based on EN1992-1-1, is proposed to predict the moment resistance of the connection for the purpose of design.

Methods for flexibility determination of bolted joints: empirical formula review

In this work, a comparative analysis of existing methods for determining the compliance of mechanical joints such as ‘composite-composite’ and ‘composite-metal’ is performed. Polymer composite materials are widely used in modern aircraft industry. As a result, it is necessary to take into account the characteristics of joints of composite aggregates with composite and metallic ones. Considering the compliance of connections in the global finite element models of structural units of aircraft allows increasing the accuracy of calculations. The use of empirical formulae can significantly reduce time and labour costs in calculating the compliance of bolted connections for use in global finite element models. In this paper we review and analyse the existing empirical dependencies. Calculation of rigidity and compliance of single-shear ‘composite-composite’ and ‘composite-metal’ joints by finite element method for small, medium and large membrane thicknesses is carried out, and the results are compared with the calculations using empirical formulae. As a result of the analysis for medium and small thicknesses it is proposed to determine the value of bolted joint flexibility by the empirical formula Boeing 1, and for large thicknesses of connecting membranes it is proposed to use empirical formula Huth.

Low-rise steel moment-resisting frames with novel re-centering beam-to-column connections: connection modelling and system performance evaluation

This research focused on a new type of re-centering beam-to-column connection for use in low-rise steel moment-resisting frames (MRFs). A new material model was first developed and validated to accurately, conveniently, and efficiently simulate the nonlinear behavior of the critical components of the connection. To demonstrate its potential, a representative low-rise MRF previously investigated was revisited and re-designed with the considered re-centering connection. Specifically, the re-centering beam-to-column connections in the re-designed system are controlled to have the same flexural resistances as the corresponding ones in the original system under the connection rotation angle of 0.025 rad. Computer simulations were conducted to compare different aspects the original and re-designed systems under the design basis earthquake level excitations. It was found that the re-designed system is overall superior to the original one based on a comprehensive performance measure established in this research that considers the peak transient and residual inter-story drift angles as well as the peak base shear demand. Moreover, compared with the original system, the re-designed system was found to have similar seismic demands on the acceleration-sensitive or velocity-sensitive nonstructural components but larger seismic demands on the displacement-sensitive nonstructural components. Accordingly, the displacement-sensitive nonstructural components should be designed with caution in the low-rise MRF with the re-centering beam-to-column connections.

Depicting the Ecosystems of Support and Financial Sustainability for Five College Promise Populations

The college promise movement is aimed toward making the attendance and completion of college affordable for eligible Americans in hundreds of local communities and states throughout the United States. Many college promise programs are designed with the intent of enabling students to start and complete college degree and/or postsecondary certificate programs without taking on unmanageable college debt. Two significant issues were examined at the June 2019 symposiumDepicting the Ecosystem of Support and Financial Sustainability for Five College Promise Populations, sponsored by Educational Testing Service (ETS) and the College Promise Campaign with the generous support of the ECMC Foundation and the Strada Education Network. First, how would college promise programs be enhanced if they were reconceived with a deeper understanding and intent to accommodate the diversity within the postsecondary student population (traditional‐aged students, adults, undocumented students, veterans, and justice‐involved students)? Second, how could extant and new funding models be aligned to leverage the financial support needed to develop and implement these subpopulation‐targeted ecosystem designs? The symposium united the higher education community with scholars, policy makers, student representatives and other stakeholders to develop comprehensive ecosystems of support for these five subpopulations as they make their way to, through and beyond college. Additional aims were (a) to identify the cross‐group connections for use and adaptation in local communities and states and (b) to explore the variety, and knitting together, of funding opportunities for program supports.

Characterization and optimization of a steel beam to RC wall connection for use in innovative hybrid coupled wall systems

Steel-concrete hybrid solutions with replaceable fuses as coupling elements and appropriately detailed composite connections have shown their efficiency to design safe and easily repairable earthquake-resisting structures. In this general framework, the behavior of a possible steel to concrete composite connection to be used in a recently suggested Hybrid Coupled Wall (HCW) system, consisting of a reinforced concrete shear wall coupled with steel side columns via dissipative steel shear links, is studied in this paper. The steel shear links are bolted to a steel profile either partly embedded or passing through the RC wall. The connection zone is designed in such a way that the damage always occurs in the steel shear links (fuses) prior to any damage in the RC wall in general and in the connection zone in particular. The emphasis lies therefore on the characterization of a suitable “steel link + embedded composite connection within the RC wall” configuration and on the evaluation of an appropriate embedment length allowing the concentration of seismic damage to the replaceable steel links. To this purpose, two joint configurations are designed based on a capacity-based approach, namely “partly embedded” and “completely passing through” steel beam, and are examined through detailed FE analyses. A parametric study is carried out to provide sufficient insight into the system in terms of strength, stiffness and local bearing strength, in view of validating the proposed design procedure.

Ciclo de Modelagem associado à automatização de experimentos com o Arduino: uma proposta para formação continuada de professores

Este artigo discute a implementação do ciclo de Modelagem de Hestenes associado à automatização de atividades experimentais com a plataforma de prototipagem Arduino. Além das metodologias imbricadas com elementos tecnológicos, buscamos uma constante reflexão sobre o papel das atividades práticas e a participação do aluno durante o processo de ensino e de aprendizagem. Partindo de demandas do ensino de Física e recorrendo à modelização como uma estratégia metodológica com suas ferramentas inerentes, e, finalmente, convergindo às próprias realidades a partir da contextualização e extrapolação dos modelos propostos. Como aplicação, apresentamos um relato de experiência de um curso de extensão universitária, destinado aos professores de Física da educação básica e estudantes de licenciatura. Em decorrência, destacamos que os participantes do curso de extensão apresentaram, ao longo dos encontros, maior reconhecimento sobre a importância da atuação discente em todas as etapas do ciclo de Modelagem, inclusive durante o próprio planejamento da prática experimental. Eles ainda indicaram como satisfatória a junção das ferramentas tecnológicas com a dinâmica do ciclo de Modelagem, bem como possível a implementação em suas práticas experimentais já consolidadas.

LED Flat Panel Capable of Seamless Connection for Use in Lighting

LED Flat Panel Capable of Seamless Connection for Use in Lighting

Performance Evaluation of Transverse High-Performance Concrete Closure Pour Connection for Use in Modular Bridge Construction

Because of the potential for concrete crushing, the negative moment transfer mechanism of the transverse connections above the pier support is still a point of concern. The objective of this study was to evaluate the behavior of a transverse closure pour connection used for the constructed Little Silver Creek Bridge in Iowa and to validate its adequacy for modular bridge application. To evaluate the need for the complicated compression block, two transverse connection specimens with and without the compression block were designed, fabricated, instrumented, and tested under a negative bending moment. Finite element models were established to further understand the specimens’ performance, and hand calculations were performed to estimate their moment capacity. No significant difference was found between the crack patterns of the two specimens, and the diaphragm concrete tended to crush in the bottom regardless of the configuration. The established finite element models were sufficient at representing the structural behavior of the two transverse connection specimens. The connection with a compression block had higher yield and ultimate moment capacity than the connection without a compression block. To design both types of connections according to the classic theory of reinforced concrete design, an effective width equal to the width of the steel girder bottom flange and the centroid of the compression force at the bottom of the steel girder bottom flange can be assumed for the connections with and without a compression block, respectively. Hand calculations reasonably estimated the moment capacity of the two specimens, and the two connections were safe under the codified, factored loads.

Performance Evaluation of Longitudinal Ultrahigh-Performance Concrete Closure Pour Connection for Use in Modular Bridge Construction: Pairwise Comparison of Capacity and Ductility at Failure Limit State

Accelerated bridge construction techniques taking advantage of prefabricated bridge elements and high-performance materials are being used more frequently for bridge replacement projects. They result in minimal road closure times and traffic interruption and in the reconstruction of long-lasting highway bridges. Longitudinal closure pour connections are an important deck-level component for modular bridge elements that are heavily stressed by traffic loadings and environmental effects and whose durability is a concern. To address cracking and leakage issues in such connections, the strength and failure modes of the longitudinal ultrahigh-performance concrete (UHPC) closure pour connection between adjacent prefabricated deck units were evaluated. First, specimens with and without a longitudinal UHPC closure pour connection were fabricated, instrumented, and tested. Finite element (FE) models were established to improve understanding of the behavior of the specimens under the loading condition. In addition, strut-and-tie models (STMs) were developed on the basis of FE model predictions to estimate the strength of the specimens. The jointed specimens were found not to have any cracks or leakage at the early stage but had lower cracking loads than did the jointless specimens. The strength and ductility of the jointed specimens were comparable with those of the jointless specimens. On the basis of the FE models and STMs, the ultimate strength of the specimens was accurately predicted.

Doing mental health care integration: a qualitative study of a new work role.

BackgroundMental health care in Australia is fragmented and inaccessible for people experiencing severe and complex mental ill-health. Partners in Recovery is a Federal Government funded scheme that was designed to improve coordination of care and needs for this group. Support Facilitators are the core service delivery component of this scheme and have been employed to work with clients to coordinate their care needs and, through doing so, bring the system closer together.ObjectiveTo understand how Partners in Recovery Support Facilitators establish themselves as a new role in the mental health system, their experiences of the role, the challenges that they face and what has enabled their work.MethodsIn-depth qualitative interviews were carried out with 15 Support Facilitators and team leaders working in Partners in Recovery in two regions in Western Sydney (representing approximately 35 % of those working in these roles in the regions). Analysis of the interview data focused on the work that the Support Facilitators do, how they conceptualise their role and enablers and barriers to their work.ResultsThe support facilitator role is dominated by efforts to seek out, establish and maintain connections of use in addressing their clients’ needs. In doing this Support Facilitators use existing interagency forums and develop their own ad hoc groupings through which they can share knowledge and help each other. Support Facilitators also use these groups to educate the sector about Partners in Recovery, its utility and their own role. The diversity of support facilitator backgrounds are seen as both and asset and a barrier and they describe a process of striving to establish an internally collective identity as well as external role clarity and acceptance. At this early stage of PIR establishment, poor communication was identified as the key barrier to Support Facilitators’ work.ConclusionsWe find that the Support Facilitators are building the role from within and using trial and error to develop their practice in coordination. We argue that a strong organisational hierarchy is necessary for support facilitation to be effective and to allow the role to develop effectively. We find that their progress is limited by overall program instability caused by changing government policy priorities.

Modelling of connection behaviour for progressive collapse analysis

The structural robustness of frame structures depends to a considerable extent on the ability of the connections between the main structural elements to transmit the sorts of loading generated following an initial structural damage while delivering the deformations needed to arrest progressive collapse through dissipation of the collapse energy. Therefore, connection performance is, arguably, the most important feature of the problem and accurate modelling of the connection behaviour under the sorts of conditions experienced during progressive collapse is an essential component for any realistic analysis. Based on the component method principles of EC3 and EC4, a mechanical approach for describing the behaviour of bare steel and composite connections for use in progressive collapse analyses is developed herein. Explicit expressions covering the full range of loading – including interaction between the connection bending moments and beam axial load – and problem variables likely to be encountered in practice are derived. Those expressions can be applied in a step-by-step consideration for tracing connection nonlinear behaviour up to failure. The model is carefully validated against both available tests and results obtained from rigorous numerical analyses.

Monitoring and Management of Source Water Pollution Based on a New Bio-Optoelectronic System in Jinan, China

A new bio-optoelectronic system, which included the behavior (aquatic organism) monitoring system and the water physiochemical factor monitoring system, was developed for the purpose of the management of accidental pollution events in water resource in Jinan, China. The system included a monitoring center and three monitoring stations. Communication between the monitoring stations and the monitoring center was mainly by the General Packet Radio Service network transmission complemented by a dial-up connection for use when this service was unavailable. The results suggested that once an accidental pollution occurred, the system would make a comprehensive evaluation based on the Self-Organising Map analysis on the monitoring data and some decision would be made based on the Emergency Management of Accidental Pollution. As a result, the new bio-optoelectronic system provided an effective approach on the management of accidental pollution events in drinking water supply.