786 resultados para Pile caps


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This work presents a comparative analysis about the behaviour of pile caps supported by 3 piles subjected to axial loading. Piles with 20 cm and 30 cm diameters were analysed. The main reinforcement was maintained in all the specimens, however, the arrangement of the secondary reinforcement varied. The main reinforcement consisted of steel bars connecting the piles. The secondary reinforcement was made up of: (a) bars going through the piles and through the projection of the column, (b) bars forming a network, and (c) vertical and horizontal stirrups. The main objective was the observation of the pile cap behaviour regarding the cracks and the modes of rupture. The real scale specimens were subjected to experimental tests until failure by rupture. Instruments were placed with the aim to obtain the displacement of the bases, the strains in the main and secondary reinforcement bars, in the compression struts, in the lower and upper nodal zones and in the sides of the caps. None of the caps reached failure by rupture with a load less than 1.12 times the theoretical load. The specimens ruptured due to the cracking of the compression strut and/or the yielding of the reinforcement bars in one direction.

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The present research studies the behavior of reinforced concrete locking beams supported by two capped piles with the socket embedded; used as connections for pre-cast concrete structures. The effect provoked by locking the beam on the pile-caps when supported by the lateral socket walls was evaluated. Three-dimensional numerical analyses using software based on the finite element method (FEM) were developed considering the nonlinear physical behavior of the material. To evaluate the adopted software, a comparative analysis was made using the numerical and experimented results obtained from other software. In the pile caps studied, a variation in the wall thickness, socket interface, strut angle inclination and action on beam. The results show that the presence of a beam does not significantly change pile cap behavior and that the socket wall is able to effectively transfer the force from the beam to the pile caps. By the tensions on the bars of longitudinal reinforcement, it was possible to obtain the force on the tie and the strut angle inclination before the collapse of models. It was found that the angles present more inclinations than those used in the design, which was made based on a strut-and-tie model. More results are available at http://www.set.eesc.usp.br/pdf/download/2009ME_RodrigoBarros.pdf

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A large percentage of pile caps support only one column, and the pile caps in turn are supported by only a few piles. These are typically short and deep members with overall span-depth ratios of less than 1.5. Codes of practice do not provide uniform treatment for the design of these types of pile caps. These members have traditionally been designed as beams spanning between piles with the depth selected to avoid shear failures and the amount of longitudinal reinforcement selected to provide sufficient flexural capacity as calculated by the engineering beam theory. More recently, the strut-and-tie method has been used for the design of pile caps (disturbed or D-region) in which the load path is envisaged to be a three-dimensional truss, with compressive forces being supported by concrete compressive struts between the column and piles and tensile forces being carried by reinforcing steel located between piles. Both of these models have not provided uniform factors of safety against failure or been able to predict whether failure will occur by flexure (ductile mode) or shear (fragile mode). In this paper, an analytical model based on the strut-and-tie approach is presented. The proposed model has been calibrated using an extensive experimental database of pile caps subjected to compression and evaluated analytically for more complex loading conditions. It has been proven to be applicable across a broad range of test data and can predict the failures modes, cracking, yielding, and failure loads of four-pile caps with reasonable accuracy.

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This work presents a comparative analysis about the behaviour of pile caps supported by 3 piles subjected to axial loading. Piles with 20 cm and 30 cm diameters were analysed. The main reinforcement was maintained in all the specimens, however, the arrangement of the secondary reinforcement varied. The main reinforcement consisted of steel bars connecting the piles. The secondary reinforcement was made up of: (a) bars going through the piles and through the projection of the column, (b) bars forming a network, and (c) vertical and horizontal stirrups. The main objective was the observation of the pile cap behaviour regarding the cracks and the modes of rupture. The real scale specimens were subjected to experimental tests until failure by rupture. Instruments were placed with the aim to obtain the displacement of the bases, the strains in the main and secondary reinforcement bars, in the compression struts, in the lower and upper nodal zones and in the sides of the caps. None of the caps reached failure by rupture with a load less than 1.12 times the theoretical load. The specimens ruptured due to the cracking of the compression strut and/or the yielding of the reinforcement bars in one direction.

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The purpose of this report is to build a model that represents, as best as possible, the seismic behavior of a pile cap bridge foundation by a nonlinear static (analysis) procedure. It will consist of a reproduction of a specimen already built in the laboratory. This model will carry out a pseudo static lateral and horizontal pushover test that will be applied onto the pile cap until the failure of the structure, the formation of a plastic hinge in the piles due to the horizontal deformation, occurs. The pushover test consists of increasing the horizontal load over the pile cap until the horizontal displacement wanted at the height of the pile cap is reached. The output of this model will be a Skeleton curve that will plot the lateral load (kN) over the displacement (m), so that the maximum movement the pile cap foundation can reach before its failure can be calculated. This failure will be achieved when the load at that specific shift is equal to 85% of the maximum. The pile cap foundation finite element model was based on pile cap built for a laboratory experiment already carried out by the Master student Deming Zhang at Tongji University. Two different pile caps were tested with a difference in height above the ground level. While one has 0:3m, the other rises 0:8m above the ground level. The computer model was calibrated using the experimental results. The pile cap foundation will be programmed in a finite element environment called OpenSees (Open System for Earthquake Engineering Simulation [28]). This environment is a free software developed by Berkeley University specialized, as it name says, in the study of earthquakes and its effects on structures. This specialization is the main reason why it is being used for building this model as it makes it possible to build any finite element model, and perform several analysis in order to get the results wanted. The development of OpenSees is sponsored by the Pacific Earthquake Engineering Research Center through the National Science Foundation engineering and education centers program. OpenSees uses Tcl language to program it, which is a language similar to C++.

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This metric short course was developed in response to a request from the Office of Bridges and Structures to assist in the training of engineers in the use of metric units of measure which will be required in all highway designs and construction after September 30, 1996 (CFR Presidential Executive Order No. 12770). The course notes which are contained in this report, were developed for a half-day course. The course contains a brief review of metrication in the U.S., metric units, prefixes, symbols, basic conversions, etc. The unique part of the course is that it presents several typical bridge calculations (such as capacity of reinforced concrete compression members, strength of pile caps, etc.) worked two ways: inch-pound units throughout with end conversion to metric and initial hard conversion to metric with metric units throughout. Comparisons of partial results and final results (obtained by working the problems the two ways) are made for each of the example problems.

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Since the beginning of channel straightening at the turn of the century, the streams of western Iowa have degraded 1.5 to 5 times their original depth. This vertical degradation is often accompanied by increases in channel widths of 2 to 4 times the original widths. The deepening and widening of these streams has jeopardized the structural safety of many bridges by undercutting footings or pile caps, exposing considerable length of piling, and removing soil beneath and adjacent to abutments. Various types of flume and drop structures have been introduced in an effort to partially or totally stabilize these channels, protecting or replacing bridge structures. Although there has always been a need for economical grade stabilization structures to stop stream channel degradation and protect highway bridges and culverts, the problem is especially critical at the present time due to rapidly increasing construction costs and decreasing revenues. Benefits derived from stabilization extend beyond the transportation sector to the agricultural sector, and increased public interest and attention is needed.

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We describe in this paper the phenotype-genotype analysis of a Brazilian cohort of patients with cryopyrin-associated periodic syndromes (CAPS). Patient 1 presented with an urticarial rash and recurrent fever exacerbated by cold weather, arthritis, and anterior uveitis, thus, receiving a clinical diagnosis of familial cold autoinflammatory syndrome. CIAS1 sequencing identified the T436I mutation, previously associated to a clinical phenotype of chronic infantile neurological cutaneous and articular/neonatal onset multisystem inflammatory disease. Patient 2 developed a papular exanthema with daily fever shortly after birth, frontal bossing, patellae enlargement, and cognitive and motor impairments. Sequencing identified the exceedingly rare G755R CIAS1 mutation in exon 4. Patient 3 developed skin rash and articular symptoms 6 h after birth, followed by aseptic meningitis. He was found to have the novel C148Y missense mutation in CIAS1. This report expands the spectrum of CIAS1 mutations associated to clinical disease, suggests that the same mutation can be associated with different clinical syndromes, and supports the evidence that CAPS patients should always be screened for mutations outside exon 3.

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This study was carried out with the aim of modeling in 2D, in plain strain, the movement of a soft cohesive soil around a pile, in order to enable the determination of stresses resulting along the pile, per unit length. The problem in study fits into the large deformations problem and can be due to landslide, be close of depth excavations, to be near of zones where big loads are applied in the soil, etc. In this study is used an constitutive Elasto-Plastic model with the failure criterion of Mohr-Coulomb to model the soil behavior. The analysis is developed considering the soil in undrained conditions. To the modeling is used the finite element program PLAXIS, which use the Updated Lagrangian - Finite Element Method (UL-FEM). In this work, special attention is given to the soil-pile interaction, where is presented with some detail the formulation of the interface elements and some studies for a better understand of his behavior. It is developed a 2-D model that simulates the effect of depth allowing the study of his influence in the stress distribution around the pile. The results obtained give an important base about how behaves the movement of the soil around a pile, about how work the finite element program PLAXIS and how is the stress distribution around the pile. The analysis demonstrate that the soil-structure interaction modeled with the UL-FEM and interface elements is more appropriate to small deformations problems.

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OBJETIVO: Avaliar o estado nutricional de pacientes com esquizofrenia, atendidos por um programa de reabilitação social (CAPS). MÉTODOS: Foi realizado um estudo transversal com 40 pacientes com diagnóstico de esquizofrenia, em uso de antipsicóticos, atendidos no CAPS do Hospital de Clínicas de Porto Alegre. Foram verificados medidas antropométricas (peso, estatura, circunferência abdominal, percentual de gordura corporal), pressão arterial e tabagismo. RESULTADOS: A amostra constitui-se de 65% de homens. A média de peso encontrada foi de 75,39 ± 15,73 kg. O índice de massa corporal médio apresentou-se dentro dos parâmetros de sobrepeso (26,76 ± 4,78 kg/m²), sendo 55% dos pacientes com sobrepeso ou obesidade segundo a classificação da OMS/1998. A circunferência abdominal e o percentual de gordura corporal apresentaram-se elevados na maioria dos pacientes (62,5% e 92,5%, respectivamente). Adicionalmente, não houve associação significativa entre IMC e a classificação de antipsicóticos (típicos, atípicos, clozapina). Encontrou-se uma correlação entre o tempo de doença com o percentual de gordura (r = 0,39, p = 0,033) e escolaridade com o peso (r = 0,362, p = 0,046) e IMC (r = 0,372, p = 0,039). Na regressão linear, 13% da variabilidade do percentual de gordura foi explicada pelo tempo de doença (r² = 0,131, B = 0,233, p = 0,049); 13% da variação do peso foi explicada pela escolaridade (r² = 0,131, B = 1,415, p = 0,046) e 13,8% da variação do IMC foi explicada pela escolaridade (r² = 0,138, B = 0,411, p = 0,039). CONCLUSÃO: Os pacientes apresentaram níveis aumentados de circunferência abdominal, percentual de gordura corporal e peso. Aparentemente, o ganho de peso ocorre em todos os pacientes expostos a antipsicóticos, independentemente do tipo de medicação e de resposta clínica, e a qualquer momento ao longo da evolução da doença. Sugere-se que, adicionalmente, a avaliação dos hábitos alimentares e o acompanhamento nutricional desses pacientes, a detecção precoce de alterações associadas à exposição aos antipsicóticos, em especial a obesidade, e o registro de mudanças ao longo do curso da doença e perante exposição a diferentes apresentações, tipos e doses de antipsicóticos sejam essenciais para o entendimento mais preciso do ganho de peso.

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Objetivo Analisar as características sociodemográficas e o padrão de uso de drogas em pacientes dos CAPS-AD de Curitiba, Paraná. Métodos Trata-se de um estudo observacional, transversal e descritivo em uma amostra de 268 indivíduos, 184 em início e 84 no terceiro mês de tratamento. Os questionários foram aplicados no período entre abril e setembro de 2012 e, além das variáveis sociodemográficas pesquisadas, obtiveram-se informações sobre quais substâncias eram utilizadas, tempo e frequência de uso. Para análise dos dados, utilizaram-se os programas Excel e Epi-Info. Médias e testes de qui-quadrado foram utilizados para a comparação dos grupos. Resultados Em ambos os grupos, predominaram sexo masculino, baixa escolaridade, baixa renda, ser da cor branca, residir com familiar ou amigo e possuir moradia própria. As drogas lícitas foram as mais utilizadas, e a maconha foi a droga ilícita mais utilizada na vida. O crack foi a droga mais utilizada no último ano e no último mês. Inalantes e alucinógenos foram os menos utilizados. Pacientes em terceiro mês de tratamento eram significativamente mais velhos, casados, tiveram menor uso na vida e no último mês de maconha, cocaína e crack, faziam uso mais frequente de álcool, e mais de um terço nunca tinha usado droga ilícita na vida. Conclusão Os achados deste estudo podem subsidiar o desenvolvimento de estratégias que possibilitem que grupos vulneráveis possam acessar e se manter em tratamento nos CAPS-AD.

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El projecte té com a objectiu la construcció d’una nau per a ús ramader, concretament per a l’engreix de porcs, així com de les instal•lacions necessàries per a fer-la viable. Aquesta granja d’engreix serà un complement per a l’activitat actual de la finca. L’edificació disposarà, a més de la zona d’estabulació, d'un vestidor amb lavabos i un petit magatzem. Serà necessari disposar de sitges per al pinso, dipòsits d'aigua i bassa de purins. Pel que fa a l'apartat productiu, l'objectiu de l’explotació és l’obtenció d’una producció de 1.000 porcs d’engreix per cicle productiu. Cada any hi haurà 2,5 engreixades, el que representa 2.500 porcs teòrics/any

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A necessidade manifesta de inclusão no processo de produção da vida material através do trabalho, de uma parcela da população usuária de serviço de saúde mental, deu origem a este estudo. Para apreender o significado do trabalho utilizou-se o referencial do materialismo histórico e dialético, fundamentado no conceito de reabilitação psicossocial, e o fez através da análise dos discursos dos usuários. O cenário é o Centro de Atenção Psicossocial Prof. Luis Cerqueira (CAPS). Os resultados indicam a compreensão do trabalho como um instrumento que possibilita aos usuários acessar o campo dos direitos sociais.