SammanfattningSvensk järnväg har aldrig varit mer belastad och trafikerad än idag, och värre kommer det att bli. Det har inte pågått några större investeringar i svensk järnväg sen 1990-talet, effekterna av den strategin börjar bli alltmer uppenbar. Sveriges järnvägssystem i jämförelse med många europeiska länder och även utanför Europa är teknologiskt och innovativt undermålig. Höghastighetståg som överstiger 250 km/h är ännu bara ett koncept i Sverige medan i länder som Frankrike, Tyskland, Kina och Japan är detta sen flera år tillbaka en verklighet. Det finns framträdande fördelar med etableringen av höghastighetsjärnväg som överstiger hastigheter på 250km/h. Utbyggnaden av höghastighetsjärnväg medför ett avsteg från konventionella järnvägsmetoder så som banvallar, i stället används prefabricerade broelement som möjliggör fast gjutning av spåret och utan användningen av ballast. Denna metod banar väg för högre tåghastigheter, mindre underhållsåtgärder, längre livslängd, passager under bron av befintlig transportinfrastruktur och besparing av natur och djurliv. Ovannämnda länder har kunnat omdirigera trafikbelastning på övriga transportsystem så som vägar och inrikes flygresor. En mindre belastning på exempelvis vägnätverket, leder till bättre trafikförhållanden, mindre slitage på vägbana och därmed sänkta kostnader för underhåll. Ur ett miljö- och hållbarhetsperspektiv minskar även utsläppet av farliga gaser och partiklar så som koldioxid, samt dämpar konsumtionen av fossila bränslen till fossildrivna fordon. Syftet med examensarbetet är att lyfta fördelarna med utbyggnaden av höghastighetsjärnväg i Sverige. Där fokus ligger i att göra detta genom att frångå den konventionella metoden av banvallar och i stället implementera brobanor med dess många framträdande fördelar. Arbetet genomsyras av utländska perspektiv gällande utbyggnad och underhåll, där höghastighetsjärnväg förlagd på bro används i större omfattning. Detta medför att arbetet kan erbjuda relevanta perspektiv från länder som exempelvis Kina som är världsledande inom området. Förhoppningen är att arbetet ska kunna användas som underlag för framtida järnvägsprojekt i Sverige. Resultatet för rapporten innehåller tre delar, kostnad, underhållsåtgärder samt miljö- och hållbarhetsperspektiv. Arbetet har redogjort för en grov kostnadsindikation på vad det kan kosta att bygga 1 km broförlagt ballastfritt dubbelspår, slutkostnaden hamnade på 929 miljoner kr med en standardavvikelse på ± 30 %. Underhåll av höghastighetsjärnväg på brobanor påvisas av många länder vara minimal. Det som möjliggör detta är innovativ detekteringsteknologi som regelbundet återger skick och funktionsduglighet av såväl banan som bron. Brobanor konstrueras för långa livslängder, det slitage som uppstår är generellt kopplat till rälsslipning och så kallade kritiska punkter vid sammanfogning av prefabricerade broelementen där det finns större risk för sprickbildning med mera. / Swedish railways have never been more congested than today, and it will get worse. There has been no major investment in Swedish railways since the 1990s, and the effects of that strategy are becoming increasingly apparent. Sweden's railway system, compared to many European countries and even countries outside Europe, is technologically and innovatively inferior. High-speed trains exceeding 250 km/h are still only a concept in Sweden, whereas in countries such as France, Germany, China, and Japan this has been a reality for several years. There are prominent advantages to the establishment of high-speed rail exceeding speeds of 250km/h. The development of high-speed rail involves a departure from conventional railway methods such as embankments, instead using prefabricated bridge elements that allow for the fixed casting of the track and without the use of ballast. This method paves the way for higher train speeds, less maintenance, longer service life, passage under the bridge of existing transport infrastructure, and conservation of nature and wildlife. The above-mentioned countries have been able to redirect traffic loads from other transport systems such as roads and domestic air travel. Less strain on the road network, leads to better traffic conditions, less wear and tear on the road surface and thus reduced maintenance costs. From an environmental and sustainability perspective, it also reduces emissions of hazardous gases and particulates such as carbon dioxide and curbs the consumption of fossil fuels by fossil fuel powered vehicles.The aim of the thesis is to highlight the benefits of the expansion of high-speed rail in Sweden. The focus is to do this by abandoning the conventional approach of embankments and instead implementing bridge lanes with its many prominent advantages. The work is permeated by foreign perspectives regarding development and maintenance, where high-speed rail on bridges is more widely used. This means that the work can offer relevant perspectives from countries such as China, which is world leading in this field. It is hoped that the work can be used as a basis for future railway projects in Sweden. The result of the report contains three parts, cost, maintenance measures and environmental and sustainability perspectives. The work has given a rough cost indication of what it might cost to build 1 km of bridge-laid ballastless double track, the final cost ended up at 929 million SEK with a standard deviation of ± 30%. Maintenance of high-speed rail on bridge tracks is shown by many countries to be minimal. This is made possible by innovative detection technology that regularly reproduces the condition and operability of both the track and the bridge. Bridge decks are designed for long lifetimes, the wear and tear that occurs is generally related to rail grinding and so-called critical points in the joining of prefabricated bridge elements where there is a higher risk of cracking etc.

The inverted T-beam bridge system provides an accelerated bridge construction alternative for short-to-medium-span bridges. The system consists of adjacent precast inverted T-beams finished with a cast-in-place concrete topping. The system offers enhanced performance against reflective cracking, and reduces the likelihood of cracking due to time dependent effects. The effects of transverse bending due to concentrated wheel loads are investigated with respect to reflective cracking. Transverse bending moment are quantified and compared to transverse moment capacities provided by a combination of various cross-sectional shapes and transverse connections. A design methodology for transverse bending is suggested. Tensile stresses created due to time dependent and temperature effects are quantified at the cross-sectional and structure level and strategies for how to alleviate these tensile stresses are proposed. Because differential shrinkage is believed to be one of the causes of deck cracking in composite bridges, a study on shrinkage and creep properties of seven deck mixes is presented with the goal of identifying a mix whose long terms properties reduce the likelihood of deck cracking. The effects of differential shrinkage at a cross-sectional level are numerically demonstrated for a variety of composite bridge systems and the resistance of the inverted T-beam system against time dependent effects is highlighted. End stresses in the end zones of such a uniquely shaped precast element are investigated analytically in the vertical and horizontal planes. Existing design methods are evaluated and strut-and-tie models, calibrated to match the results of 3-D finite element analyses, are proposed as alternatives to existing methods to aid designers in sizing reinforcing in the end zones. Composite action between the precast beam and the cast-in-place topping is examined via a full scale test and the necessity of extended stirrups is explored. It is concluded that because of the large contact surface between the precast and cast-in-place elements, cohesion alone appears to provide the necessary horizontal shear strength to ensure full composite action. Live load distribution factors are quantified analytically and by performing four live loads tests. It is concluded that AASHTO's method for cast-in-place slab span bridges can be conservatively used in design. / Ph. D.

The subject of this thesis is to create a project documentation of the design of new construction of fire station in Šumperk. The fire station is designed according to ČSN 73 5710 as a C type station that will be used by professional fire brigade of Olomouc district. The object is structurally divided into two parts - a masonry building, and a reinforced concrete frame. The administrative part of the building together with the base of the fire brigade, technical room, and a fire tower are designed as a masonry building made of Ytong cellular concrete units. One of the parts is designed as a two-level object, while the technical room and the fire tower are designed as a sigle-level object. The circumferential masonry is insulated by contact thermal insulation system. The floor construction is made of Spiroll prestressed floor slabs. The roof is designed as a warm flat roof. The garage is a single-level building with built-in structure of storerooms in part of the garage. The precast reinforced concrete frame is set on foundation pads and foundation sills. The horizontal and vertical supporting structure consists of reinforced concrete parts – columns, Spiroll floor slabs, floor girders, sway frames, purlins and small purlins. The whole object is covered by a warm flat roof. The external cladding consists of PUR isolating sanwich panels.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This thesis is a study in the use of precast modular construction as an alternative to current methods of school construction in South Africa. Precast Modular Construction is a concept which utilises the principles of prefabrication and precast concrete. Concrete components, be they beams, columns, slabs or full volumetric modules, are manufactured either off-site in factories or in on-site facilities. These components are then assembled on-site to form the structural envelope of a building. This approach contains many inherent advantages: Time is saved due to on-site and off-site work happening concurrently and hence earlier building occupancy results which directly translates to cost reparation; quality is improved due to most of the work being carried out in a controlled factory environment; and health and safety is heightened. However, when viewed from a South African perspective, the fact that less work is done on-site indirectly implicates job loss, a serious issue in the country. Furthermore, implementing a prefabricated approach in the construction of South African schools requires a complete restructuring of the Department of Public Works’ current procurement approach. Prefabrication requires maximum integration between all parties to a project so that design and constructability issues can be addressed at an early stage. The design-build contract strategy is found to be the most integrated approach and allows for optimal collaboration between all project members. However, to only change the procurement route would not suffice as a complete solution. A broader approach is required which addresses issues prevalent in South Africa. These issues include job creation and the establishment of a sustainable and knowledgeable industry. Concepts such as standardisation and strategic partnering, in response, satisfy the need of the manufacturer - for economies of scale, and the employee - for creation of secure working environments. Verification is obtained from all of the aforementioned to propose that the optimal solution to successfully implement Precast Modular Construction for schools in South Africa would be to implement a design-build procurement approach, whereby a single design-build contractor is awarded by the Department of Public Works a contract, via competitive tendering, for the construction of a predetermined number of schools, preferably exceeding 3, over a given contract period using a standardised design and utilising customisable standardised prefabricated precast construction systems, i.e. Precast Modular Construction. This proposal will theoretically result, amongst other things, in the following: - Precast manufacturers will have a confirmed number of orders for products, and can hence be assured of a constant flow of income. This translates directly to an increase in both employment and job security at the manufacturing plant. - The economies of scale principle is satisfied and prefabricated components can therefore be manufactured or ‘mass customised’ in the most feasible way possible. - The design-build contractor will be guaranteed employment for a given period, once again providing job security for its employees, of which the number can also potentially increase. - The design-build contractor carries with it experience and lessons learned from each successfully completed project on to the next, and so becomes more proficient, resulting in better, higher quality schools delivered in shorter periods and with increased efficiency. It is recognised that the proposal is untested in practise but in a socio-economic situation such as South Africa, where large numbers of schools are required quickly, the above proposal makes sense. To additionally develop this hypothesis, further research is required in the fields of design-build procurement and strategic partnering. / AFRIKAANSE OPSOMMING: Hierdie tesis is 'n studie in die gebruik van modulêre voorafvervaardigte beton konstruksie as 'n alternatief vir die huidige metodes van skool konstruksie in Suid-Afrika. Modulêre voorafvervaardigte beton konstruksie bevat baie inherente voordele. Tyd word bespaar as gevolg van werk wat gelyktydig op en van die terrein af gebeur. Dus word die gebou vroeër betrek wat direk lei tot kostebesparings. Kwaliteit verbeter as gevolg van meeste van die werk wat in 'n beheerde fabriek omgewing uitgevoer word en as sulks lei tot beter gesondheid en veiligheid van werkers. Egter, vanuit 'n Suid-Afrikaanse perspektief impliseer die feit dat daar minder werk op die terrein gedoen word indirek werksverlies, 'n ernstige probleem in die land. Die implementering van 'n voorafvervaardigde benadering tot die bou van skole in Suid-Afrika vereis verder 'n volledige herstrukturering van die huidige verskaffing model. Voorafvervaardiging vereis maksimum integrasie tussen alle partye sodat projek ontwerp en boubaarheid op 'n vroeë stadium aangespreek kan word. Die ontwerp-bou kontrak strategie is die mees geïntegreerde benadering en laat toe vir optimale samewerking tussen alle projek lede. Om egter net die verskaffing roete te verander, sou nie voldoen as 'n enkele oplossing nie. 'n Breër benadering word vereis wat kwessies algemeen in Suid-Afrika aanspreek. Hierdie kwessies sluit in werkskepping en die vestiging van 'n volhoubare en kundige industrie. Konsepte soos standaardisering en strategiese vennootskap, as oplossings, voldoen aan die behoeftes van die vervaardiger - vir 'n ekonomieë van skaal, en die werknemer - vir die skepping van 'n versekerde werksomgewing. Die voorafgaande bevestig dat die optimale oplossing vir suksesvolle implementering van Beton Modulêre Konstruksie vir skole in Suid-Afrika sou wees om 'n ontwerp-bou verskaffingsprosedure te volg. Hierdeur kan 'n kontrak aan 'n enkele ontwerp-bou kontrakteur deur die Departement van Openbare Werke toegeken word, deur middel van ‘n mededingende tender proses. Daar word voorgestel dat die projek, vir die konstruksie van 'n voorafbepaalde aantal skole behoort te wees, verkieslik meer as 3, oor 'n bepaalde kontrak tydperk met behulp van 'n gestandaardiseerde ontwerp. Voorts word daar voorgestel om gebruik te maak van aanpasbare gestandaardiseerde voorafvervaardigde beton konstruksie stelsels, dws Beton Modulêre Konstruksie. Hierdie voorstel sal teoreties, onder andere, die volgende gevolge hê: - Beton vervaardigers sal 'n bevestigde aantal bestellings vir produkte hê, en kan dus verseker wees van 'n konstante vloei van inkomste. Dit lei direk tot 'n toename in indiensneming en werksekerheid by die fabriek. - Die ekonomieë van skaal beginsel is bevredig en voorafvervaardigde komponente kan dus vervaardig word in die mees haalbare manier moontlik. - Die ontwerp-bou kontrakteur is gewaarborg van indiensneming vir 'n gegewe tydperk, as sulks ook die verskaffing van werksekerheid vir sy werknemers, waarvan die aantal moontlik ook kan vermeerder. - Die ontwerp-bou kontrakteur neem ondervinding en lesse wat geleer is uit elke suksesvolle voltooide projek saam na die volgende een, en raak dus meer bedrewe, wat lei tot beter, hoër gehalte skole gelewer in korter tydperke en met toenemende doeltreffendheid. Die voorstel is egter ongetoets in die praktyk, maar in 'n sosio-ekonomiese situasie soos die van Suid-Afrika, waar 'n groot aantal skole vinnig benodig word, maak die bogenoemde voorstel sin. Om hierdie hipotese te ontwikkel, is verdere navorsing nodig in die gebied van ontwerp-bou verskaffing en strategiese vennootskappe.

Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Construction of structural concrete frames may take place by using either cast in-situ or precast methods. With the cast in-situ method, these elements are constructed on the construction site as needed. Precast construction on the other hand is more resembles a line. The elements are constructed in a precast yard in a systematic fashion and once completed, they are taken to the construction site where they are to be erected. This study identifies the aspects and attributes which influence the quality of concrete during the construction phase of these two construction methods. The study is independent from the conceptual or design phase. Information regarding these aspects and attributes were obtained from literature and from contractors in industry through interviews and site visits. The literature review also focuses on quality management techniques and factors that influence quality in the construction environment. The information obtained from the site visits and literature was used to design a survey which was sent out to a number of respondents. A comparison between in-situ and precast construction was made based on the results of the survey. The synthesis of the research findings can be used by project teams to help them decide on the choice between in-situ and precast construction. It was found that precast construction is better for durability, and fitness for purpose is less complex for the in-situ solution. Recommendations for future studies are provided at the end of the document. / AFRIKAANSE OPSOMMING: Konstruksie van beton struktuurrame kan plaasvind deur die gebruik van in-situ of voorafvervaardigde metodes. Met die in-situ metode, word hierdie elemente op die terrein gebou soos benodig. Tydens voorafvervaardigde konstruksie aan die ander kant is die konstruksie soortgelyk aan 'n produksielyn. Die elemente word gegiet in 'n voorafvervaardingsterrein in 'n sistematiese wyse, en sodra dit voltooi is, word dit na die konstruksie terrein geneem waar dit opgerig word. Hierdie studie identifiseer die aspekte en eienskappe wat 'n invloed op die kwaliteit van beton het tydens die konstruksiefase van hierdie twee konstruksie metodes. Die studie is onafhanklike van die konseptuele of ontwerp fases. Inligting rakende hierdie aspekte en eienskappe is verkry uit die literatuur en van kontrakteurs in die bedryf deur middel van onderhoude en besoeke. Die literatuur fokus ook op die gehalte, bestuurs-tegnieke en faktore van gehalte in die bou-omgewing. Die inligting is verkry deur ‘n vraelys wat aan 'n aantal respondente gestuur is. 'n Vergelyking tussen in-situ en voorafvervaardigde konstruksie is vervolgens gemaak op grond van die resultate van die opname. Die sintese van die bevindinge kan gebruik word deur projek spanne om hulle te help besluit oor die keuse tussen in-situ en voorafvervaardigde konstruksie. Die resultate dui daarop dat voorafvervaardigde konstruksie beter is vir duursaamheid, maar passing op terrein is minder kompleks vir die in-situ oplossing. Aanbevelings vir toekomstige ondersoeke word aan die einde van die studie gemaak.

Šiame darbe nagrinėjama standžių sujungimo mazgų įrengimo įtaka iš anksto įtemptų surenkamų gelžbetoninių sijų laikomajai galiai ir įlinkiams. Laikomosios galios analizės metu nagrinėjama sijų ribinės apkrovos ir tempiamos zonos armatūros kiekio priklausomybė nuo standžiai jungčiai įrengti naudojamos jungiamosios armatūros skerspjūvio ploto ir betono klasės. Sijų įlinkių analizės metu nagrinėjama, kiek galima sumažinti sijų įlinkius, skerspjūvio aukštį ar padidinti tarpatramio ilgį įrengus standžias jungtis. Taip pat atliekama standaus mazgo apspaudimo įtakos sijų įlinkiams analizė. Remiantis moksliniais straipsniais ir mokomosiomis knygomis nagrinėjami įvairūs standaus mazgo įrengimo konstrukciniai sprendiniai bei kontinualių sijų įrąžų ir įlinkių skaičiavimo metodai. Standžios jungties įtempių ir deformacijų būvis tiriamas baigtinių elementų metodu naudojant kompiuterinę statybinių konstrukcijų skaičiavimo programą LUSAS Analyst. Atlikus iš anksto įtemptų surenkamųjų gelžbetoninių sijų, sujungtų tarpusavyje standžiu mazgu, darbo analizę pateikiamos baigiamojo magistro darbo išvados ir pasiūlymai. Darbą sudaro 8 dalys: įvadas, standžių mazgų įrengimo ypatumai ir konstrukcinai sprendiniai, kontinualių sijų įrąžų ir įlinkių skaičiavimo metodai, standžių mazgų įrengimo įtakos sijų laikomajai galiai analizė, standžių mazgų įrengimo įtakos sijų įlinkiams analizė, standaus mazgo analizė baigtinių elementų metodu, išvados ir pasiūlymai, literatūros sąrašas. Darbo apimtis –... [toliau žr. visą tekstą] / The paper investigates precast prestressed beams and increase of their carrying capacity and decrease of deflections by providing rigid connections between adjascent spans. The analysis of carrying capacity includes relations between load capacity (herewith the sectional area of tensile reinforcement) and material properties of rigid connection, such as sectional area of continuity reinforcement and concrete grade. The analaysis of deflections investigates the reduction of beam height and increase of span length by providing moment continuity between adjascent spans. The effects of prestressing rigid connection is also discussed. Various moment continuity provision methods are reviewed. The stress-strain state of rigid connection is analysed by using finite element method. The conclutions and suggestions are made at the end of the thesis. The master thesis includes these parts: introduction, analysis of moment continuity provision methods, review of moment redistribution and deflection calculation methods, analysis of increased load carrying capacity after provision of moment continuity, analysis of decreased deflections after provision of moment continuity, rigid connection analysis using finite element method, conclusions and suggestions, references. Master thesis consists of – 77 p. text without appendixes, 24 pictures, 16 tables, 15 bibliographical entries.

O presente trabalho trata do estudo do comportamento de chumbadores grauteados inseridos em concreto com fibras de aço em ligações viga-pilar de estruturas de concreto pré-moldado. Este estudo é importante para se entender e poder quantificar a influência da rigidez deste componente no comportamento de ligações semirrígidas de estruturas de concreto pré-moldado. O objetivo do trabalho é estudar o mecanismo do chumbador no concreto com fibras de aço em ensaios específicos e avaliar também o comportamento de uma ligação viga-pilar de concreto pré-moldado utilizando estas fibras no consolo e no dente da viga. Nesta pesquisa foi realizado um programa experimental no Laboratório de Estruturas da EESC, uma análise numérica com o emprego do software DIANA® e uma comparação com formulações analíticas existentes para o cálculo da força última destes componentes. Foram ensaiados nove modelos experimentais para avaliar especificamente o mecanismo resistente do chumbador, variando-se os diâmetros das barras, sua inclinação e a porcentagem de fibras de aço no concreto. Além destes modelos, foi realizado ensaio de uma ligação viga-pilar de concreto pré-moldado para avaliar a rigidez da ligação com chumbador inserido em concreto com fibras de aço. Nos ensaios experimentais dos chumbadores observou-se que modelos com concreto com fibras de aço apresentam rigidez até 25% maior se comparado ao modelo com concreto convencional. Verificou-se que o graute utilizado para solidarizar os chumbadores exerce significativa influência na capacidade última do modelo, podendo diminuir em cerca de 30% a capacidade de carga. A ligação viga-pilar de concreto pré-moldado utilizando concreto com fibras de aço no consolo e no dente da viga se comportou de maneira satisfatória, não apresentando fissuração na interface dos diferentes concretos. Na comparação dos modelos ensaiados com as formulações teóricas extraídas de trabalhos de referência verificou-se que, para os modelos específicos de chumbador, a formulação existente é representativa. Para a ligação viga-pilar, alguns ajustes na formulação analítica se fizeram necessários para considerações de efeitos de grupo e de borda observados e decorrentes da utilização de dois chumbadores na ligação proposta neste trabalho. / This research deals with the study of the behavior of grouted dowels embedded in concrete with steel fibers. This study is important to understand and quantify the stiffness transmitted by this component in a semi-rigid connection of precast concrete structures. The objective is to study the mechanism of the dowel in the concrete with steel fibers and evaluate the mechanical behavior of a precast beam-column connection using this type of concrete on the corbels and in the dapped-end beam. In this research, an experimental program in the EESC Structures Laboratory was carried out, as well as a numerical analysis with the use of DIANA® software and a comparison with existing formulations to calculate these components. Nine models were experimentally tested to specifically evaluate the dowel resistant mechanism by varying the diameters of the bars, the declination and the percentage of steel fibers in concrete. Furthermore, an experimental test was performed in order to evaluate the behavior of the connector. The results indicate that for the dowels with concrete and steel fibers, the ultimate capacity of the connection occurs by failure of the connector (excessive deformation of the bars), while in conventional concrete this capability is associated with the rupture of the concrete and that the concrete with steel fibers decreases by 25% the deformability of the models. The grout has a significant impact on the ultimate capacity of the model, which may increase in less than 30%. In the analysis of the beam-column connection, it is possible to observe that the proposed connection exceeds by more than 20% the ultimate capacity compared to traditional beam-column connections. In comparing the theoretical models tested with the formulations shown by previous studies, it was found that for specific models dowels, the existing formulation is representative. For the beam-column connection, adjustment was performed in the previous formulation considerations group and edge effects that occur due to the use of two dowels on the tested connection.

As galerias enterradas são amplamente utilizadas em obras de arte corrente (OAC) na infraestrutura de rodovias e ferrovias. Visando disponibilizar mais alternativas na produção de galerias de concreto pré-moldado, a pesquisa apresenta uma análise comparativa de custos para seções transversais não usuais, direcionado a grandes profundidades de instalação. A primeira seção proposta é denominada modificada e é composta por uma base retangular com uma cobertura em arco e a segunda seção proposta é definida por três arcos com uma base plana. Essas seções além de possuir formato de geometria favorável à distribuição dos esforços solicitantes, mantêm o benefício de possibilitar uma compactação adequada do solo na lateral da galeria, como acontece em galerias retangulares convencionais, e isso garante o confinamento do solo e a redistribuição de pressões, graças à mobilização do efeito de arqueamento. Para considerar a interação solo-estrutura foram realizadas análises via elementos finitos com o pacote computacional GeoStudio® próprio para análises geotécnicas. Os resultados comprovaram a interferência do formato das geometrias no comportamento da interação solo-galeria e também evidenciaram que a redução da espessura das paredes da galeria mobiliza em maior intensidade a capacidade resistente do solo e isso reduz os esforços na estrutura. Quanto à análise dos dimensionamentos, com base na comparação dos custos evidenciou-se que, para as galerias modificadas a redução das taxas de armadura está relacionada com flecha do arco da cobertura, sendo que a economia verificada no custo total de materiais das seções estudadas variou de 4 a 29% comparado à galeria retangular. Para a galeria definida por três arcos, confirmou-se que quanto mais alongado for o seu formato, melhor é o comportamento à grandes profundidades de instalação, sendo que a economia verificada no custo total da galeria mais elíptica (DTA I-b) chegou a 50% em relação à galeria retangular e demais geometrias estudadas tiveram economia entre 17 e 42%. / Box culverts are often used in current drainage in the infrastructure of highways and railways. In order to provide more production\'s alternatives of precast concrete culvert, the research presents the comparative cost analysis for unusual cross sections, directed to large depths of installation. The first proposed cross section called modified culvert is composed of a rectangular base with an arc roof. The second is defined by three arcs with a flat base. These cross sections have geometric shapes favorable to the distribution of bending moment and shear forces. It maintains the benefit of adequate compaction of the backfill at the side of the culvert, as well as in conventional box culvert, which ensures ground confinement and pressure redistribution due to the mobilization of the arching effect. In order to consider the soil-structure interaction, finite element analyzes were performed using GeoStudio® software, which is a computational package specific for geotechnical analysis. The results showed that the geometries have influence on the behavior of the soil-culvert interaction, and that the reduction of the thickness of the culvert walls mobilizes the soil resistant capacity, reducing the stresses in the structure. Regarding the structural design, considering the comparison of costs, it was evidenced a reduction of steel reinforcements for the modified culvert, which is related to the arrow of the arc of the cover. The materials saving verified in the total cost of the studied sections ranged from 4% to 29% compared to the box culvert. For the culvert defined by three arches, it was evidenced that the more elongated its geometry, better the behavior for the great depths of installation. The highest materials saving was verified in the total cost of the most elliptical culvert (DTA I-b), which reached a value of 50%. Compared to the box culvert, the others geometries studied had savings between 17-42%.

Este trabalho apresenta uma análise da ligação pilar-fundação por meio de cálice em estruturas de concreto pré-moldado, focando os esforços nas paredes transversais do colarinho. No programa experimental foram ensaiados dois protótipos submetidos à flexão com grande excentricidade: um com interface pilar-colarinho lisa e o outro com interface rugosa por meio de chaves de cisalhamento. Foi adotado um detalhamento diferenciado para as armaduras verticais principais concentrando as mesmas próximas aos cantos, bem como foi adotada, para o colarinho, uma espessura inferior à recomendada pela literatura técnica. Com os resultados experimentais foi possível analisar a resistência dos protótipos, as deformações das armaduras e os deslocamentos das paredes. Foi realizada uma análise dos resultados experimentais com um modelo de cálculo da literatura técnica, no que diz respeito às forças resultantes nas armaduras verticais principais e nas armaduras horizontais principais situadas nas paredes transversais do colarinho, considerando duas situações distintas de comportamento para as paredes transversais: flexo-tração e tração. Em função dos resultados foi verificado que as armaduras verticais situadas próximo aos cantos contribuíram efetivamente para a resistência do protótipo com interface lisa. Comprovou-se que as paredes transversais foram submetidas a uma flexo-tração e que o modelo teórico aplicado considerando 15% de flexão e 85% de tração apresenta os melhores resultados, se comparados com os valores obtidos experimentalmente. / This research presents an analysis of socket base connections of precast concrete structures, with emphasis on the e orts of transverse walls. In the experimental program were tested two prototypes subjected to bending with great eccentricity: one with smooth interface, and other with rough interface through shear keys. It adopted a different detail for main vertical reiforcement, concentrating them around the corner, and was adopted for the socket, a thickness less than that recommended by the technical literature. Based on experimental results were performed the analysis of the strenght of prototypes, the deformations of the reinforcement, and the deflection of the walls. It was performed an analysis of experimental results with a design model of the technical literature regarding to the forces resulting in main vertical and horizontal reinforcement located on the transverse walls of socket, considering two different situations of behavior to transverse walls: bending-tension and tension. Analyzing the results, it was verified that the vertical reinforcement located near the corners effectively contributed to the strength of the prototype with smooth interface. It has been proved that the walls were subjected to a bending tension and that the theoretical model applied with 15% of bending and 85% of tension gives the best results, when compared with the values obtained experimentally.

Este trabalho aborda um dos tipos construtivos mais empregados em lajes de edificações no Brasil, que são as lajes com nervuras pré-moldadas com armação treliçada. O objetivo principal do trabalho é contribuir na avaliação da continuidade estrutural relativa aos momentos fletores negativos nos apoios destas lajes. Para a realização deste trabalho, as lajes em concreto pré-moldado formadas por vigota com armação treliçada foram analisadas segundo modelos teóricos e experimentais. Na análise teórica, a consideração da não-linearidade física do concreto é realizada a partir do uso da relação momento x curvatura proposta pelo código modelo CEB-90 em conjunto com a técnica do carregamento incremental. Os resultados do modelo teórico são confrontados com os resultados obtidos em ensaios experimentais de faixas de lajes contínuas dimensionadas com diferentes graus de redistribuição dos momentos fletores negativos. Nas análises realizadas observa-se que: a) o modelo teórico apresenta bons resultados comparados aos resultados experimentais, b) as lajes apresentam boa capacidade de rotação plástica, c) com alta taxa de armadura negativa não ocorre redistribuição de esforços, d) as flechas praticamente independem da taxa de armadura negativa e e) a força última é praticamente independente do grau de redistribuição adotado no dimensionamento. / This work deal with an usual type of slab in Brazil: slabs made by precast joist with lattice reinforcement. The goal of this work is the structural analysis of bending moments in the supports of slabs made by this kind of precast element. Theoretical and experimental models analyze this type of slab. In the theoretical analysis, the non-linear concrete behavior is done by moment x curvature relationship of Model Code CEB-90 add incremental load technique. The theoretical model is compared with experimental results of continuous strip slabs designed with different degrees of bending moment redistribution. In these analysis had been noted: a) the theoretical model presents good results compared with the experimental results, b) the slabs present good plastic rotation capacity, c) with high negative reinforcement ratio in the support does not happen moment redistribution, d) the displacement is practically independent of negative reinforcement ratio and e) the ultimate load is practically independent of redistribution degree idealized in the design.