Precast Concrete

L’articolo riporta una serie di riflessioni dedicate all’accezione dei termini “costo” e “qualità” in relazione dell’edilizia dedicata al Social Housing dai programmi di ricostruzione postbellica al periodo attuale. Ciò avviene anche in riferimento all’esigenza di sostenibilità del costruito studiata durante il Workshop della laurea magistrale in costruzione tenutosi nel giugno 2010.

SUMMARY Existing reinforced concrete structures stock is wide and also includes buildings with precast elements, being largely used since Fifties primarily to satisfy needs of the manufacture and tertiary purposes. Their diffusion has been supported by flexibility of structural net dimensions and by the economy and efficiency of the constructional process. From a structural point of view, the evaluation of their seismic efficiency represents a very current problem, not only because of peculiarity and complexity of some structural ...

In the present paper, a numerical and experimental study about creep and shrinkage behavior of a high strength self-compacting concrete is performed. Two new creep and shrinkage prediction models based on the comprehensive analysis on the available models of both conventional concrete and self-compacting concrete are proposed for high strength self-compacting concrete structures. In order to evaluate the predictability of the proposed models, an experimental program was carried out. A concrete which develops 60 MPa within 24 h was used to obtain experimental results. Several specimens were loaded: (i) at different ages and (ii) with different stress-to-strength ratios. Deformation in non-loaded specimens was also measured to assess shrinkage. All specimens were kept under constant stress during at least 600 days in a climatic chamber with temperature and relative humidity of 208C and 50%, respectively. Results showed that the new models were able to predict deformations with good ac...

The paper describes an analysis and detailed design of the 470 m long D4 motorway bridge in the Slovak capital Bratislava. This bridge is a part of 2 932.50 m long D4 motorway crossing of the Danube River and its surrounding areas. The 210 m long main span of the post-tensioned three span box girder bridge is the longest span which has ever been built in Slovakia. The Ministry of Transportation and Construction of the Slovak Republic requirement was to cross all future rowing tracks by a single span. The depth of the cross section varies from 4.39 m at span to 13.09 m at piers. 35 m wide cross section carries 4-lane carriageway, median, sidewalk and cycling path. The central part of carriageway is built by the balanced cantilever method. The overhangs carrying outer lanes are built by wing traveller machine and supported by the precast struts. The bridge is currently under construction as a part of PPP project of Bratislava ring road (the motorway D4 Bratislava, Jarovce - Bratislava...

This paper describes the design of the Fulton Road Bridge segmental concrete arches. The posttensioning concept, superstructure-arch interaction considerations, effective length k factor for moment magnification, and construction sequence analysis methods used for design are discussed.

Building System(IBS) in some of the project. The most two earlier building which using IBS was Pekeliling Flat in Kuala Lumpur and Rifle Range Flat in Penang. Consequently, following the year after 1960's there are lots of construction development in Malaysia using IBS system in most of the low cost high rise residential building. With the aim to reduce the number of the unskilled foreign labor, Malaysia had encouraged local contractor to used the IBS system. Unfortunately, there are lots of problem in maintenance which affected the building quality and operation when a building was built using the IBS system. Thus, factor which will affect the quality of the IBS precast building should be identify in order to produce a better quality and operation of the IBS building. This particular study will fully focus in low practicing of the civil and construction criteria for precast concrete in IBS building. This two particular main criteria will be seriously analysis and find out the factor which will create the building maintenance issues. This study is importantly to find out the factor which leads to building maintenance in civil and construction for IBS precast building. Eventually from the analysis, hopefully the factor affecting the quality of the IBS precast building will be identify and a good propose of solution which can increase the quality and operation of the IBS building.

Road Barrier merupakan suatu alat yang digunakan untuk membuat batas jalan atau sebagai pembagi jalan / pengaman jalan. Biasanya road barrier digunakan di jalan alternatif maupun jalan utama. Pembatas jalan ini sangat dibutuhkan untuk menghindari suatu kemacetan. Road Barrier ini juga dapat digunakan untuk memberi tuntunan arus atau pembatas jalan untuk lokasi yang tidak dapat dilewati. Material yang digunakan untuk membuat road barrier salah satunya adalah beton.

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In the early morning hours of May 16, 1968, the occupant of apartment 90 on the 18th floor of the 22-story Ronan Point apartment tower, in London, lit a match to brew her morning cup of tea. The resulting gas explosion initiated a partial collapse of the structure that killed four people and injured 17 (one of whom subsequently died). On investigation, the apartment tower was found to be deeply flawed in both design and construction. The existing building codes were found to be inadequate for ensuring the safety and integrity of high-rise precast concrete apartment buildings. The Larsen-Nielson building system, intended for buildings with only six stories, had been extended past the point of safety. The tower consisted of precast panels joined together without a structural frame. The connections relied, in large part, on friction. The apartment tower lacked alternate load paths to redistribute forces in the event of a partial collapse. When the structure was dismantled, investigators found appallingly poor workmanship at the critical connections between the panels. Subsequently, building codes in many countries have adopted structural integrity or "robustness" provisions that may be directly traced to the Ronan Point collapse.

Abstract: Cement industry contributes to 5% of global CO2 emissions. To mitigate pollution, there is a need of CO2 sequestration into stable forms. Present research focusses on CO2 being channelized towards an important construction practice. This paper summarizes the potential of CO2 absorption in concrete. To verify CO2 absorption in concrete, an artificial CO2 environment for curing of concrete cubes using dry ice was created. Considering concrete of M20 grade, a comparative experimental study of water cured concrete cubes, CO2 cured concrete cubes, for penetration (using phenolphthalein indicator), and compressive strength was carried out. The result analysis of the tests indicated that CO2 cured concrete cubes showed 22.125% higher compressive strength than water cured concrete cubes and CO2 penetration of 13.5 mm after 2 hours. The rate of CO2 penetration and strength gain in concrete was found to be rapid in the early hours. It is shown that CO2 can prove to be a useful resou...

Este artigo se propõe a destacar aspectos-chave em torno do processo de preservação da obra do arquiteto João Filgueiras Lima (1932-2014), também conhecido como Lelé, no Brasil. No momento em que o Instituto do Patrimônio Histórico e Artístico Nacional (IPHAN) decide iniciar a salvaguarda de seus prédios em Brasília, me parece pertinente levantar questões que remontam às origens de seu envolvimento com a pré-fabricação. Nesse sentido, descobrir como a sequência de falhas atribuíveis a Lelé e sua equipe se tornou um pré-requisito para a pesquisa construtiva do arquiteto é fundamental.
Lelé mostrou que, durante mais de 50 anos dedicados a promover a industrialização da construção no Brasil, os desentendimentos técnicos foram frequentes e decisivos em sua vida profissional. Os fracassos vividos pelo arquiteto durante a construção da Universidade de Brasília (1961-65) – um dos momentos mais significativos da pré-fabricação no Brasil – e depois, durante a ditadura militar (1964-85) – quando se envolveu mais sistematicamente com construtoras e engenheiros – formaram a base de sua capacidade de converter a falta de meios em desafios.
De certa forma, as decisões deliberadas do arquiteto em relação ao método operacional e às diretrizes práticas de sua obra podem apresentar desafios para o poder público interessado nas ações de preservação. Prova disso são os inúmeros edifícios em que os sistemas originais (cobertura, drenagem, ventilação, iluminação, etc.) foram parcial ou totalmente alterados. A questão que se coloca aqui não é se essas mudanças podem ter afetado a funcionalidade ou aparência do edifício, mas como o Instituto do Patrimônio no Brasil poderia aproveitá-las para (re)construir e validar o conhecimento construtivo do arquiteto e, portanto, compartilhar sua maneira de pensar e produzir arquitetura como um objeto técnico, percebida e executada como parte de um processo.

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Preservation challenges of Lelé's rationalized architecture in Brazil

This paper attempts to highlight key aspects around the preservation process of the work of the Brazilian architect João Filgueiras Lima (1932-2014), otherwise known as Lelé, in Brazil. In a moment when the National Historic and Artistic Heritage Institute (Instituto do Patrimônio Histórico e Artístico Nacional, IPHAN) decides to initiate the safeguarding of his buildings in Brasília, it seems pertinent to arise questions that trace back to the origins of his involvement with prefabrication. Therefore, finding out how the sequence of failures attributable to Lelé and his team became a prerequisite for the architect’s constructive research is paramount.
Lelé showed that, during more than 50 years dedicated to promoting building industrialization in Brazil, disagreements were rife and decisive at his professional life. The failures experienced by the architect during the construction of the University of Brasília (1961-65) – one of the most meaningful moments for prefabrication in Brazil – and afterwards – during the military dictatorship (1964-85) when he got involved with building companies and engineers more systematically – formed the basis of his capacity of converting the lack of means into challenges.
In a way, the architect’s combined attitude behavior towards operative-based method and practice guidelines may present challenges for the public power interested in the preservation undertaking. Proof of that are the numerous buildings where the original systems (roof, drainage, ventilation, illumination and so forth) were partially or totally altered. The question arising here is not whether these changes may have affected the building’s functionality, but how the heritage institute in Brazil could take advantage of them to (re)build and validate the architect’s constructive knowledge and, therefore, sharping his way of thinking and producing architecture as a technical object, perceived and performed as part of a process.

A industrialização introduziu novos materiais, processos e métodos de construir que afetaram irreversivelmente e em escala crescente a arquitetura. A prática está essencialmente associada aos conceitos de organização e de fabricação em série, elementos esses que são entendidos a partir de um estudo mais amplo das relações de produção envolvidas e da mecanização dos meios de produção. E foi em concreto armado que a nova arquitetura se expressou em sua absoluta maioria no Brasil. Do período Vargas a Kubistchek e do boom construtivo do pós-guerra, tivemos o início de uma industrialização em um país que saía de um quadro predominantemente agropastoril. É neste cenário ainda incipiente para a pré-fabricação que dois projetos de conjuntos residenciais construídos com estrutura pré-moldada são apresentados.

O primeiro projeto, de 1961, é o Conjunto Residencial da Universidade de São Paulo - CRUSP integrante da Cidade Universitária Armando Salles de Oliveira, em São Paulo. Originalmente formado por doze blocos, foram financiados pelo Fundo de Construção da Universidade de São Paulo – FUNDUSP, com a finalidade de abrigar estudantes de outras cidades que ingressaram na instituição. Projeto de autoria dos arquitetos Eduardo Kneese de Mello, Joel Ramalho Jr. e Sidney de Oliveira, teve sua construção iniciada em março de 1962. Os blocos A, B, C, D, E e F foram inaugurados em maio de 1963, sendo executados em estrutura convencional de concreto e os seis restantes em estrutura pré-moldada no próprio canteiro da obra. Constituindo um dos primeiros casos de construção de grande porte executada neste sistema no Brasil, o CRUSP teve sua importância pelo pioneirismo e pela sistematização das etapas de projeto e execução.

O segundo projeto a ser estudado é dos Edifícios de Apartamentos para Professores, conhecido também como Colina, de autoria do arquiteto João Filgueiras Lima (Lelé). Projetado para o Campus Universitário Darcy Ribeiro da UnB em Brasília no ano de 1962, foi executado em 1963. O conjunto, também construído em estrutura pré-moldada, é formado pelos blocos A, B, C e D e seguiu os mesmos princípios de racionalização empregada nos principais prédios da Universidade. Localizados no extremo norte do Campus, conforme zoneamento previsto no plano urbanístico de Lucio Costa, as residências para professores foram propostas para serem construídas em etapas, em virtude de alguns aprimoramentos de ordem técnica, construtiva e espacial incorporados ao projeto. O objetivo era garantir a desejada flexibilização dos espaços internos atendendo às mais variadas composições familiares dos futuros moradores. Partindo dessa premissa, além dos fechamentos em placas de concreto pré-moldadas, optou-se pelo uso de divisórias removíveis que se adaptassem facilmente às necessidades das famílias dos professores da universidade, tentando com isso uma maior flexibilização da planta.

Este trabalho tem como objetivo realizar um estudo comparativo entre os dois projetos, identificando elementos de coordenação modular, organização espacial e aspectos construtivos. A racionalização do projeto – que, num primeiro momento, procurava apenas reduzir custos e prazos – também se manifestou em termos da configuração espacial das unidades de habitação e das relações formais dos blocos. Neste sentido, o artigo procura traçar paralelos e convergências entre as duas propostas que, mesmo concebidas quase que concomitantemente, apresentam diferenças significativas tanto espaciais quanto construtivas. A pré-fabricação – ou, no caso específico a pré-moldagem – estava no início de sua história no Brasil e por isso ainda se apresentava em nível investigativo, tanto nas estratégias de projeto quanto na solução estrutural.

Mitra Solusi Konstruksi adalah perusahaan yang bergerak di bidang jasa supply bahan-bahan bangunan, diantaranya beton precast, beton ready mix, baja ringan, dan produk lainnya. Jasa lainnya yaitu penywaan jenis alat-alat yaitu jasa sewa concrete pump dan jasa sewa scaffolding

Geopolymer results from the reaction of a source material that is rich in silica and alumina with alkaline liquid. It is essentially cement free concrete. This material is being studied extensively and shows promise as a greener substitute for ordinary Portland cement concrete in some applications. Research is shifting from the chemistry domain to engineering applications and commercial production of geopolymer concrete. It has been found that geopolymer concrete has good engineering properties with a reduced global warming potential resulting from the total replacement of ordinary Portland cement. The research undertaken at Curtin University of Technology has included studies on geopolymer concrete mix design, structural behavior and durability. This paper presents the results from studies on mix design development to enhance workability and strength of geopolymer concrete. The influence of factors such as, curing temperature and régime, aggregate shape, strengths, moisture content, preparation and grading, on workability and strength are presented. The paper also includes brief details of some recent applications of geopolymer concrete.

No Brasil, tem-se observado o crescente uso de elementos pré-fabricados de concreto, nesse contexto, encontram-se os painéis de parede dupla pré-moldados que são um sistema construtivo formado por duas placas de concreto de pequena espessura mantidas unidas através de armadura treliçada. A armação estrutural necessária para todo o painel é construída dentro do componente pré-fabricado e após a instalação dos painéis, o espaço entre as placas pode ou não ser preenchido com concreto misturado e despejado no local da obra; neste sentido, o painel de parede dupla é um componente semi pré-fabricado. Esses painéis de fato combinam as maiores vantagens da pré-fabricação com as de uma parede fabricada em moldes concretados na obra. O presente trabalho apresenta uma investigação exploratória realizada através de revisão bibliográfica na qual será descrito e verificado as indicações de desempenho dos painéis de parede dupla pré-moldado conforme a recém lançada norma ABNT NBR 16475:2017, analisando criticamente os aspectos abordados e as lacunas deixadas pela a mesma; tendo com isto, o intuito de contribuir com a sistematização e difusão do tema na comunidade da construção civil brasileira.

Tiang pancang yaitu tiang yang merupakan bagian dari konstruksi pondasi bangunan yang digunakan untuk membantu mengurangi tekanan dari bangunan beserta seluruh isinya, terutama jika tinggi bangunan lebih dari 3 lantai sementara struktur tanah di bawah bangunan terlalu lembek atau lunak dimana Tanah tersebut keras berada jauh di bawah bangunan. Banyak orang yang menyebut tiang pancang adalah paku bumi. Perusahaan kami melayani pengiriman produk tiang pancang ini ke seluruh wilayah Indonesia, terutama di wilayah Jabodetabek.

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A new method of constructing open spandrel arch bridge has been developed for span ranges from 12m to 27m using precast concrete techniques. The buildability of this new system has been proven in a pilot project featuring simple precasting method, handling process, installation sequence with manageable units, and practical jointing means with “self-propping” construction techniques. This revolutionary arch bridge construction with simplified processes has resulted in substantial labour and material costs saving.  It has also been proven to be an economically viable alternative to conventional bridge solution. Nonetheless, stocks of steel moulds catering for the full spectrum of span ranges have remained a costly logistic issue with many operational difficulties. The problem may become more acute especially for bridge market of relatively lower volume but with many geometrical variations. This paper presents a systematic approach to standardise the design and development process with great emphasis on the practical aspects of precasting and moulding requirements. Three sets of moulds for two types of geometrical framing, called M-Series and K-Series Open Spandrel Arch Bridge have been developed to cater for the targeted span segment with due considerations on the functionality and applicability.

aus: LVR-Amt für Denkmalpflege (Hg.): Neues Bauen! Moderne Architektur der Weimarer Republik im Rheinland (= Mitteilungen aus dem LVR-Amt für Denkmalpflege im Rheinland), Köln 2019 6. Großwohnsiedlung Neue Vahr in Bremen, 1957-62, nach einer Gesamtplanung von Max Säume und Günther Hafemann von Ernst May, Hans Bernhard Reichow, Alvar Aalto und anderen. Blick vom Aalto-Hochhaus, 1962. Foto: Franz Scheper. Hamburgisches Architekturarchiv. 7. Großwohnsiedlungen der Nachkriegszeit in Ost-und Westdeutschland.

This research investigates the use of glass fiber reinforced polymer (GFRP) bars in bridge decks and ultra-high performance fibre-reinforced concrete (UHPFRC) as filling materials in (i) panel-to-panel closure strips between transverse precast full-depth deck panels (FDDPs) supported over girders and (ii) the shear pockets for the panel-to-girder connection. The experimental research program included three phases. Phase I examined pullout strength of straight-end and headed-end GFRP bars embedded into UHPFRC to determine the required closure strip width to develop bar full strength. Phase II included the development and study of closure strip details incorporating UHPFRC as joint-filling materials and GFRP bars projecting into the joint. Three joints of width 200 mm between precast FDDPs were developed, namely: angle-shape joint (A-joint), C-shape joint (C-shape), and zigzag-shape joint (Z-joint), with 175-mm projecting length of GFRP bars into the joint. Two series of 2500x600x200 mm one-way slabs were cast to investigate the flexural strength of the jointed precast slabs compared to cast-in-place slabs. Two types of concrete were used to fabricate the precast FDDPs, namely: normal concrete (NSC) and high-performance concrete (HPC). Correlation between experimental results and available design equations for moment and shear capacities, as well as CHBDC and AASHTO-LRFD applied factored design moments, was performed. All specimens failed in either flexural or flexural-shear mode outside the UHPFRC-filled joint. Phase III included testing three pairs of 3700x2500x200 mm laterally-restrained precast FDDPs incorporating the three developed joint details in the transverse direction of the girders. Each pair of specimens was tested under 600x250 mm wheel loading located beside the closure strip, considering (i) constant amplitude fatigue (CAF) loading up to 4 million cycles followed by increasing static loading to-collapse, and (ii) incremental variable amplitude fatigue (VAF) loading to-collapse. The failure mode of the tested slabs was punching shear, with the transverse UHPFRC joint diverting the extension of the punching shear plane to the adjacent precast FDDP segment. Results of fatigue load tests on the three-jointed pairs of slabs showed high fatigue performance. A new prediction model for fatigue life of the GFRP-reinforced, UHPFRC-filled jointed deck slabs was developed.

The seismic sequence which hit the Northern Italian territory in 2012 produced extensive damage to reinforced concrete (RC) precast buildings typically adopted as industrial facilities. The considered
damaged buildings are constituted by one-storey precast structures with RC columns connected to the ground by means of isolated socket foundations. The roof structural layout is composed of pre-stressed RC beams supporting pre-stressed RC floor elements, both designed as simply supported beams. The observed
damage pattern, already highlighted in previous earthquakes, is mainly related to insufficient connection strength and ductility or to the absence of mechanical devices, being the connections designed neglecting seismic loads or neglecting displacement and rotation compatibility between adjacent elements.
Following the vulnerabilities emerged in past seismic events, the paper investigates the seismic performance of industrial facilities typical of the Italian territory. The European building code seismic assessment methodologies are presented and discussed, as well as the retrofit interventions required to achieve an appropriate level of seismic capacity. The assessment procedure and retrofit solutions are applied to a selected case study.

O presente trabalho realizou um estudo sobre o comportamento de estruturas aporticadas em concreto pré-moldado preenchidas com painéis de alvenaria, para fim de contraventamento de edificações, considerando a contribuição dessa alvenaria de preenchimento no pórtico pré- moldado para análise de ações horizontais. O estudo traz uma revisão da literatura sobre o tema. Um ensaio experimental de um pórtico de concreto armado preenchido ou não com alvenaria é usado para calibrar um modelo de elementos finitos usando o pacote Simulia Abaqus 2017. O modelo utiliza o dano plástico do concreto (CDP) para considerar o comportamento do concreto e alvenaria. Elementos embutidos são usados para considerar armaduras dentro do concreto. Os elementos de alvenaria são considerados homogêneos com as superfícies de contato ao longo da interface concreto-alvenaria. Depois que as propriedades foram calibradas, os modelos numéricos apresentaram excelente precisão quando comparados aos testes experimentais. Os quadros de concreto pré-fabricados, cujas dimensões e propriedades eram de um caso real, foram então modelados com e sem o preenchimento de alvenaria participante. A conexão pilar- viga foi modelada com elementos sólidos com superfície de contato na interface permitindo representar seu comportamento. Os modelos considerados foram um quadro com um, cinco e dez andares, duas resistências de alvenaria e o uso ou não de uma camada de argamassa para fixar alvenaria sob a viga de concreto. A conclusão das análises do modelo de elementos finitos indica a influência de cada parâmetro no comportamento do sistema. Os resultados de MEF foram utilizados para calibrar a largura de uma diagonal equivalente para ser usado em modelos simples de elementos de barras. Finalmente, um modelo de pórticos em 3D foi usado para avaliar um prédio de concreto pré-moldado de 10 andares, considerando ou não a alvenaria participante. Apenas duas paredes de alvenaria, perto do núcleo central do edifício e sem aberturas foram consideradas, os resultados indicam grande influência ao considerar o preenchimento participante, levando a um projeto de construção eficiente. O trabalho futuro é proposto para avaliar experimentalmente as conclusões das análises numéricas aqui relatadas.

This study presents an evaluation of the performance of eight cone penetration test (CPT) methods in predicting the ultimate load carrying capacity of square precast prestressed concrete (PPC) piles driven into Louisiana soils. A search in the DOTD files was conducted to identify pile load test reports with cone penetration soundings adjacent to test piles. Sixty piles were identified, collected, and analyzed. The measured ultimate load carrying capacity for each pile was interpreted from the pile load test using Butler-Hoy method, which is the primary method used by DOTD. The following methods were used to predict the load carrying capacity of the collected piles using the CPT data: Schmertmann, Bustamante and Gianeselli (LCPC/LCP), de Ruiter and Beringen, Tumay and Fakhroo, Price and Wardle, Philipponnat, Aoki and De Alencar, and the penpile method. The ultimate load carrying capacity for each pile was also predicted using the static "-method, which is used by DOTD for pile design and analysis.

Spring 2013 | PCI Journal 64 P recast, prestressed concrete girders are extensively used in the construction of multiple-span, simplespan, and continuous bridges. In the 1960s the concept of making continuous precast, prestressed concrete bridges for live loads was introduced through the use of solid cast-in-place concrete diaphragms 1,2 . The main advantage is that they reduce maintenance costs by eliminating deck joints 3 that are problematic, especially in bridges subjected to heavy truck loading.

A mi amada esposa Diana A mí amado Paquito A mis queridos hermanos mayores: Crisóforo, Rodrigo, Héctor, Eusebio por ser sumamente entusiastas y emprendedores y demostrarme que si uno está dispuesto a pagar el precio todo es posible A mis padres Eusebio e Isabel, que siempre han sido un excelente ejemplo de perseverancia y bondad A mis maestros: Amador Terán, Miguel Torres, Mario Rodríguez…por mencionar solo algunos. Pilares del conocimiento adquirido en esta etapa de estudios.

É indiscutível que, entre todas as obras realizadas por Oscar Niemeyer em Brasília, os palácios da nova capital constituem marcos reconhecidos como patrimônio cultural e arquitetônico do país. O Palácio da Alvorada e os palácios da Praça dos Três Poderes são realizações de primeira ordem, sendo sucesso de público e de crítica, figurando em qualquer lista das principais obras realizadas por Niemeyer. Ao se estabelecer uma relação com a indústria da música, esses palácios estariam no topo da parada de sucessos, sendo os mais tocados e os mais reconhecidos pelo público. Essa consagração é confirmada até mesmo pelo próprio autor, que sempre procurou dar destaque para essas composições do que para outras, consideradas de menor importância. Por outro lado, as obras da Universidade de Brasília, que foram criadas dois anos depois do “lançamento” da nova capital, acabaram entrando para um universo mais underground, raramente citadas nos textos de seu criador, nas suas entrevistas ou palestras. Seriam, dentro da relação do mercado fonográfico, composições “lado B”. Esses edifícios, construídos em concreto pré-moldado e sem a estética palaciana de seus grandes hits em concreto armado, tem uma “pegada” absolutamente distinta, conferida justamente pela utilização industrial dos “instrumentos”, agora mais cadenciados e intencionalmente mais repetitivos, mas em nenhum momento deixar de levar em consideração a harmonia e o ritmo já característicos de seu repertório. Busca-se identificar, a partir de obras menos cultuadas de Brasília, semelhanças e diferenças de um sistema estrutural à brasileira, que privilegia grandes vãos, um menor número de apoios verticais e que tem como alvo uma maior qualidade e versatilidade dos espaços.

This dissertation investigates the work and industrial thinking of João Filgueiras Lima – or simply Lelé (Rio de Janeiro, 1932 – Salvador, 2014) – within the context of the seven state-owned factories for precast building elements that he founded in Brazil over the course of 30 years of intense manufacturing activity (1979-2009). It aims to explore three interrelated levels of his architecture – factories, systems and components – as they constitute the fundamentals of his constructive approach, in terms of both conception and production. From the perspective of the architect acting beyond the scope of the designer, manufacturer and builder, this study seeks to portray how Lelé broadened the discipline throughout his practice. In view of an inconstant notion of industrialization – which would affect the way his precast plants were organized – it is argued that Lelé incorporated a strong manual dimension in his modus operandi. Thus, his compromises and convictions were paradoxically centered upon the combination of crafted and industrial ways of producing the technical object; ways that might prove less expensive and more efficient, given the community-oriented use of the structures concerned. The reason for conducting this study on Lelé is to re-evaluate his contribution through the prism of the operationalization of prefabricated architecture in a wider context; this will bring into question political, economic and social issues as determinants in his manufactured work.
Supervisor: Laurent Stalder (ETH Zurich)
Co-supervisors: Sylvia Ficher (UnB) and Max Risselada (TU Delft)

Full text available at ETH Research Collection:
https://www.research-collection.ethz.ch/handle/20.500.11850/301849

A key economic value for multi-story office buildings, hotels, and similar structures is to have a shallow floor system that reduces the total building height and, consequently, reduces overall building cost. Additionally, minimizing the need for shear walls results in additional economy and flexibility in re-modelling. This paper presents the development of a new precast prestressed concrete framing system that achieves both goals for buildings up to six-story tall built in areas of low seismicity. The proposed system consists of precast hollow core slabs, shallow inverted tee beams, multi-story columns, and cast-in-place topping, which are the common components in conventional precast construction. The proposed system eliminates the need for permanent concrete column corbels, and achieves continuity in the inverted tee beam through column block-outs to improve the system's resistance to lateral and gravity loads. Hollowcore slabs are also made continuous to minimize the need for shear walls in the hollow core direction. An experimental investigation was carried out to verify the theoretical capacities of the system components and to ensure that demand was met for the conditions being considered. Testing was performed using a full-scale specimen representing the area around an interior column. Test results indicated that the system is simple to construct and connection capacities can be adequately predicted using strain compatibility and shear friction theories. The design and construction of an office building in Lincoln, NE was presented as a successful implementation of the new system.

In this study, constitutive relationships are developed/or normal-strength concrete (NSC) and high-strength concrete (HSC) subjected to fire to provide efficient modeling and specify the fire-performance criteria for concrete structures exposed to fire. They are developed for unconfined NSC and HSC specimens that include compressive and tensile strengths, compressive elastic modulus, and compressive and tensile stress-strain relationships at elevated temperatures. The proposed relationships at elevated temperatures are compared with the experimental results and previous existing relationships revealing several advantages and disadvantages of present stress-strain relationships. These results are used to establish more accurate and general compressive and tensile stress-strain relationships. Further experimental results for tension and the other main parameters at elevated temperatures are needed to establish well-founded models and improve the proposed constitutive relationships, wh...

Many researches have been carried out on production and properties of pre-cast concretes. Currently, most of them have focused on normal concrete, and are unable to completely represent the behavior of lightweight concrete (LWC). In this study, physical and mechanical properties of LWC produced with diatomite and pumice lightweight aggregates after autoclave curing were investigated. In the production of LWC, 0-4 mm maximum sizes of aggregates were used. Cement content and water/cement ratio were kept at 300 kg/m 3 and 0.20, respectively. The specimens were prepared in +50 Â 100 mm cylindrical shape, and after 24 h of demoulding exposed to autoclave curing for 2, 4, 6, 8 and 10 h. Besides, two different cures were applied on the specimens as in water and in air at 20 1C72, respectively. At the end of autoclaving and environmental cure, compressive strength in 7, 28 and 590 d, unit weight, specific porosity, thermal conductivity and water absorption were tested. Also, microstructures of LWC produced with diatomite and pumice aggregate were investigated. As a result, it is concluded that by autoclaving of specimens in 8-10 h, especially, compressive strength of specimens have increased 75% of strength of 28 aged specimens cured in water. r

In the present paper, a numerical and experimental study about creep and shrinkage behavior of a high strength self-compacting concrete is performed. Two new creep and shrinkage prediction models based on the comprehensive analysis on the available models of both conventional concrete and self-compacting concrete are proposed for high strength self-compacting concrete structures. In order to evaluate the predictability of the proposed models, an experimental program was carried out. A concrete which develops 60 MPa within 24 h was used to obtain experimental results. Several specimens were loaded: (i) at different ages and (ii) with different stress-to-strength ratios. Deformation in non-loaded specimens was also measured to assess shrinkage. All specimens were kept under constant stress during at least 600 days in a climatic chamber with temperature and relative humidity of 208C and 50%, respectively. Results showed that the new models were able to predict deformations with good ac...

Ceplan (Centro de Planejamento Arquitetônico e Urbanístico) era o órgão da Universidade de Brasília responsável pelos projetos da nova Universidade nos anos 1960. O artigo aborda as questões construtivas do Centro e os aspectos que envolvem os interiores e a criação de seu mobiliário.

Review Project Report PDF Jembatan tukad Yeh Otan Tabanan
Halaman : XIII + 300 halaman
Tahun Dibuat : 2020

Nama Proyek : Perencanaan Jembatan Tukad Yeh Otan
Jenis Struktur : PC I Girder
Jumlah Bentang : 7 Bentang
Panjang Total : 277,08 m
Lokasi : Tabanan, Bali

The present work focuses on comparing the performance of precast and monolithic beamcolumn joints subjected to cyclic loading. Experiments were conducted on 1/3 scale models of two types of precast beam-column connections and a monolithic connection. The precast connections considered are the beam-column connections in which beam is connected to column with corbel using (i) J-bolt and (ii) cleat angle. The specimens were subjected to reverse cyclic loading. The experimental results of the precast specimens were compared with those of the monolithic connection. Axial load was applied to the column using 400kN capacity actuator. The cyclic loading is applied in the beam using another two actuators, one for positive load cycle and the other for the negative load cycle. The hysteresis behaviour, load carrying capacity, energy dissipation capacity and ductility factor were measured and the performance for the precast and monolithic beam-column connections were compared.