104 research outputs found

    Deformation capacity evaluation for flat slab seismic design

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    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

    Establishing urban gardens on vacant land while considering international good practices: a legal case study from Portugal

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    There is a gap in most countries’ legal frameworks regarding their ability to connect vacant land and urban gardens. Hence, research is needed to understand how regulation on vacant land might be designed to promote a more sustainable purpose to it. Urban gardens are a type of urban agriculture that could be potentiated by such regulation. The aim of this paper is to show how that can be done through the Municipal Master Plans (MMP) legal and regulatory framework for the Portuguese case, by reviewing worldwide good practices on vacant land restorations for urban sustainable development. The paper comprises a literature review on good practices adopted in different countries regarding vacant lot restoration. The evaluation of good practices is built on the achievement of the three pillars of sustainability. Five Portuguese MMP were used, as empirical data, to support the design of a new legal and regulatory framework. The goal is to enhance the sustainable destination of vacant land by converting it into urban gardens. The analysis of these MMPs demonstrated that they disregard urban gardens as a tool to promote urban sustainability in spite of global trends to make urban territorial planning and management instruments greener. An additional outcome of this paper is to categorise different types of vacant land in the five municipalities under analysis according to their suitability for urban garden conversion. The design of the legal framework enhancing the conversion of vacant land into urban garden will contribute to the 2030 international agenda goals’ achievement. The proposal would create an innovative legal framework in the case of Portugal that could be replicated by other countries.info:eu-repo/semantics/acceptedVersio

    Ethnographic understandings of ethnically diverse neighbourhoods to inform urban design practice

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    The aim of this paper is to inform urban design practice through deeper understanding and analysis of the social dynamics of public outdoor space in ethnically diverse neighbourhoods. We hypothesise that findings from ethnographic research can provide a resource that improves cultural literacy and supports social justice in professional practice. The primary method is a meta-synthesis literature review of 24 ethnographic research papers, all of which explore some dimensions of public open space use and values in UK urban contexts characterised by ethnic and racial diversity. We summarise thematic understandings and significance of neighbourhood places of shared activity, parks, spaces of passing-by and of retreat. We evaluate the implications for intercultural social dynamics, exploring the spatial and temporal dimensions of conviviality and racism in public open space. We then argue that it is possible to develop principles for urban design practice informed by this work, and propose four for discussion: maximising straightforward participation, legitimising diversity of activity, designing in micro-retreats of nearby quietness and addressing structural inequalities of open space provision. We conclude that ethnographic research can provide detailed insights into the use of the public realm and also inform a more nuanced understanding of outdoor sociality relevant for an increasingly diverse society. The challenge is two-fold: for ethnographers to become less cautious in engaging with decisions and priorities regarding how cities change, and for urban designers to explicitly embed informed understandings of difference into their broad desire for inclusive public space

    Double blind randomized placebo-controlled trial on the effects of testosterone supplementation in elderly men with moderate to low testosterone levels: design and baseline characteristics [ISRCTN23688581]

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    In ageing men testosterone levels decline, while cognitive function, muscle and bone mass, sexual hair growth, libido and sexual activity decline and the risk of cardiovascular diseases increase. We set up a double-blind, randomized placebo-controlled trial to investigate the effects of testosterone supplementation on functional mobility, quality of life, body composition, cognitive function, vascular function and risk factors, and bone mineral density in older hypogonadal men. We recruited 237 men with serum testosterone levels below 13.7 nmol/L and ages 60–80 years. They were randomized to either four capsules of 40 mg testosterone undecanoate (TU) or placebo daily for 26 weeks. Primary endpoints are functional mobility and quality of life. Secondary endpoints are body composition, cognitive function, aortic stiffness and cardiovascular risk factors and bone mineral density. Effects on prostate, liver and hematological parameters will be studied with respect to safety. Measure of effect will be the difference in change from baseline visit to final visit between TU and placebo. We will study whether the effect of TU differs across subgroups of baseline waist girth (< 100 cm vs. ≥ 100 cm; testosterone level (<12 versus ≥ 12 nmol/L), age (< median versus ≥ median), and level of outcome under study (< median versus ≥ median). At baseline, mean age, BMI and testosterone levels were 67 years, 27 kg/m(2 )and 10.72 nmol/L, respectively

    Evaluation of cellular immunity in chronic liver diseases during immunosuppressive treatment

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    The evidence that cell mediated immunological reactions may contribute to the development of Chronic Active Hepatitis (CAH) and Primary Biliary Cirrhosis (PBC) suggests the use of immunosuppressive agents in these disorders. To study the cellular immunity and the response to immunosuppressive therapy in chronic liver disease, the Rosette Inhibition Test (RIT) was employed. This test was applied to evaluate the degree of T lymphocytes sensitization in autoimmune diseases. 53 patients with chronic liver disease were examined: PBC (9), CAH (30) and Chronic persistent Hepatitis (CPH) (13); 14 of these subjects had repeated controls of the RIT during the treatment with cortisone and/or azathioprine. The concentration of antilymphocyte serum causing 25% rosette inhibition relative to control was taken as the end point (MIC = minimal inhibitors concentration). In 22 healthy subjects the range of MIC was 1/14000 to 1/32000; the MIC in patients with CPH fell into the same range. In 80% of CAH and in 77% of PBC the MIC was higher than normal controls, showing a T lymphocytes sensitization. In patients subjected to immunosuppressive therapy the MIC usually changed towards the normal values and in 8 cases became normal after some months of treatment

    Verifica sperimentale di connessioni prefabbricate pilastro-fondazione soggette a carichi ciclici

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    This paper describes the experimental characterization of column-foundation joints in precast concrete elements, in particular regarding cyclic horizontal loads. This issue gains particular interest in case of seismic actions. The work is part of a wider EU research programme called SAFECAST. The tests carried out compare different connection systems: wet joints with expansive grouted mortar connecting the rebars protruding from the column and other mechanical connections. All the connections have been inserted within similar members (columns with a 40x40 section, 2.50 m high with and 1% of longitudinal reinforcement ratio) and tested with a loading protocol with increasing intensity. The columns have been tested under axial compression of 380 kN. The aim of the tests is to measure the final capacity of each joint when subjected to cyclic horizontal loads, assessing its ductility and behaviour in term of extension of plastic hinge, energy dissipation
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