Punching strength is a critical point in the design of flat slabs and due to the lack of a theoretical method capable of explaining this phenomenon, empirical formulations presented by codes of practice are still the most used method to check the bearing capacity of slab-column connections. This paper discusses relevant aspects of the development of flat slabs, the factors that influence the punching resistance of slabs without shear reinforcement and makes comparisons between the experimental results organized in a database with 74 slabs carefully selected with theoretical results using the recommendations of ACI 318, EUROCODE 2 and NBR 6118 and also through the Critical Shear Crack Theory, presented by Muttoni (2008) and incorporated the new fib Model Code (2010).Keywords: flat slab, punching shear, reinforced concrete, codes.O dimensionamento à punção é um ponto crítico no projeto de lajes lisas e devido à falta de um método teórico capaz de explicar este fenômeno a verificação da capacidade resistente de ligações laje-pilar é feita normalmente utilizando-se as recomendações de normas de projeto. Este artigo discute aspectos relevantes do surgimento do sistema de lajes lisas, dos fatores que influenciam na resistência à punção de lajes sem armadura de cisalhamento e faz comparações entre os resultados experimentais de um banco de dados com 74 lajes cuidadosamente selecionadas com resultados teóricos utilizando-se as recomendações das normas ACI 318, EUROCODE 2 e NBR 6118 e também através da Teoria da Fissura Crítica de Cisalhamento, apresentada por Muttoni (2008)
Colorectal cancer (CRC) caused 261,060 deaths in Brazil over a 20-year period, with a tendency to increase over time. This study aimed to verify the sociodemographic factors predicting higher mortality caused by CRC and survival rates. Moreover, we aimed to verify whether the performance of screening, diagnostic and treatment procedures had an impact on mortality. Ecological observational study of mortality due to CRC was conducted in Brazil from 2000–2019. The adjustment variable was age, which was used to calculate the age-standardized mortality rate (ASMR). The exposure variables were number of deaths and ASMR. Outcome variables were age-period-cohort, race classification, marital status, geographic region, and screening, diagnostic, and treatment procedures. Age-period-cohort analysis was performed. ANOVA and Kruskal-Wallis test with post hoc tests were used to assess differences in race classification, marital status, and geographic region. Multinomial logistic regression was used to test for interaction among sociodemographic factors. Survival analysis included Kaplan-Meier plot and Cox regression analysis were performed. Multivariate linear regression was used to test prediction using screening, diagnosis, and treatment procedures. In Brazil, mortality from CRC increased after age 45 years. The highest adjusted mortality rates were found among white individuals and in the South of the country (p < 0.05). Single, married, and widowed northern and northeastern persons had a higher risk of death than legally separated southern persons (p < 0.05). Lower survival rates were observed in brown and legally separated individuals and residents from the North (p < 0.05). An increase in first-line chemotherapy and a decrease in second-line chemotherapy were associated with high mortality in the north (p<0.05). In the south, second-line chemotherapy and abdominoperineal rectal resection were associated with high mortality (p < 0.05). Regional differences in sociodemographic factors and clinical procedures can serve as guidelines for adjusting public health policies.
The use of column capitals is one way to increase the punching strength of slab-column connections. Recommendations presented by codes of practice for defining the geometry and checking the resistance of slab-column connections with capitals are not comprehensive, with few experimental studies available on the topic. This paper discusses important aspects of the historical development of mushroom slabs and also presents experimental results of 4 tests, with 1 test in a reference flat slab and 3 tests in mushroom slabs with circular column capitals. These results are compared with theoretical results estimated using Eurocode 2 (2004) and NBR 6118 (2007). They were also compared with a series of non-linear finite element analysis in order to get insight of the stress distribution and of the failure mechanism of mushroom slabs.Keywords: mushroom slab, punching shear, reinforced concrete, column capitals.O uso de capitéis é uma das formas de se aumentar a resistência à punção de ligações laje-pilar. As recomendações normativas para a definição da geometria e verificação da resistência última de ligações com capitéis são pouco abrangentes, sendo poucas as pesquisas experimentais disponíveis sobre o tema. Este artigo discute aspectos relevantes do desenvolvimento histórico das lajes cogumelo e apresenta resultados de 4 ensaios experimentais, sendo 1 laje lisa de referência e 3 lajes cogumelo com capitéis de seção circular. Estes resultados são comparados com as estimativas das normas EUROCODE 2 (2004) e NBR 6118 (2007) e com modelos numéricos não-lineares a fim de se compreender melhor a distribuição das tensões e o mecanismo de ruptura de lajes cogumelo.Palavras-chave: lajes cogumelo, punção, concreto armado, capitel. Experimental and numerical analysis of reinforced concrete mushroom slabsAnálise experimental e numérica de lajes cogumelo de concreto armado Faculdade de Engenharia Civil, Universidade Federal do Pará, Campus de Tucurui, aaraon@ufpa.br, Tucurui, Pará, Brasil. b Professor, Faculdade de Engenharia Civil, Universidade Federal do Pará, mpina@ufpa.br, Belém, Pará, Brasil. c Professor, Faculdade de Engenharia Civil, Universidade Federal do Pará, denio@ufpa.br, Belém, Pará, Brasil. d Professor, Departamento de Engenharia Civil e Ambiental, Universidade de Brasília, melog@unb.br, Brasília, Distrito Federal, Brasil. Received: 06 Jun 2012 • Accepted: 12 Nov 2012 • Available Online: 05 Apr 2013 Abstract Resumo
Objetivo: Caracterizar os perfis social, clínico e hemodinâmico de pacientes admitidos em Unidade de Terapia Intensiva (UTI) que evoluíram a óbito e verificar a influência na sobrevida. Métodos: Coleta de prontuários de pacientes admitidos na UTI de um Hospital de referência terciária na região amazônica, que evoluíram a óbito (n=200), com análise das variáveis clínicas, sociais e hemodinâmicas e descrição das frequências absoluta e relativa, média, desvio padrão e intervalo de confiança de 95%. Resultados: Características sociais predominantes: idade 20-59 anos (48,5%), sexo masculino (52%), raça/cor pardo (72,5%), profissão empregada doméstica (10,5%), religião católica (6,5%), escolaridade 9 anos (21%) e estado civil solteiro (30%). Características clínicas principais: doenças respiratórias (20,5%), estado grave na admissão (70,5%), coma induzido (42%), acamados (87%), uso de ventilação mecânica invasiva (91%) e média de aspiração brônquica 1,27 ± 0,55 por dia. Complicações clínicas prevalentes: sepse (79,5%), choque (69%) e edema (61%). Uso de sonda vesical (82,5%) e tempo médio de internação 11,81 ± 9,50 dias. As características hemodinâmicas acentuadas foram: creatinina, uréia, lactato e leucócitos. Além disso, observou-se menor sobrevida de indivíduos da raça Branca e com leucocitose admissional. Conclusão: Este estudo auxilia na compreensão do perfil epidemiológico da população local, contribuindo no melhor manejo do paciente crítico. Descritores: Unidade de Terapia Intensiva, Perfil de saúde, Monitorização hemodinâmica, Sobrevida e Morte.
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