The aim of this thesis was to suggest two alternatives of a prestressed concrete bridge structure over the river Jihlava in Ivančice and to design the chosen one. The structure was designed as a one-span frame bridge with the span range of 46,0 m. Both design and relevant drawing documentation of the slab, abutment and strip foundation was made.

The effect of different vertical support stiffness of a frame railway bridge is investigated in this study. Due to the dynamic loads of the high speed trains that run over the railway bridges, the response of these structures is far from the static effects. The frame bridge chosen for this study is the Rössjö bridge, located on the Bothnia Line, the first high speed railway built in Sweden. Using a theoretical model of this bridge, the eigenfrequencies of the structure and the vertical accelerations of the deck are evaluated. Not only different vertical support stiffness, but also different trains and train speeds are studied. Finally, some real in-situ measurements are compared with the results from the theoretical model.

FE-modeling is a rapidly spreading method to analyze structures nowadays. With this theunderstanding of the outcome is of very high importance and potential inaccuracies areimportant to find so that faulty and over dimensioning of the structure does not occur whichleads to unnecessary costs. One of these inaccuracies is the unrealistic sectional forces that occurdue to thermal effects in the transversal direction for concrete frame bridges which leads to anexcessive amount much reinforcement in the structure than actually needed. This has beenstudied with several cases by using two approaches on how to apply the temperature in the framebridge, only in the superstructure and in the whole structure, but also by analyzing severalboundary conditions. By examining the results for the sectional forces and stresses one of thetemperature approaches could be disregarded because of the extreme values in the transitionbetween superstructure and support. But the other approach was much more useful because ofits better compliance with reality. With these results and by calculating the reinforcement neededfor the worst case, one model has been found to be the most favorable and can be used whenmodeling concrete frame bridges with acceptable outcome. The study resulted in a model whereone applies a varying temperature on the whole structure, with spring boundary conditions over asurface that represents the bottom slab.

With the development of high-speed railroads the dynamic behaviour of railroad bridges is increasingly important to explore. Deeper knowledge about the influence of different factors and what should be included in a model is essential if the designer shall be able to make reliable estimates of responses in existing and new structures. One factor is the soil-structure interaction (SSI), describing how the foundation of the bridge and the soil properties affect the behavior of the bridge under dynamic loading. In this thesis, the influence of including SSI in a model of a portal frame railway bridge is studied, and an analysis procedure in the frequency domain for models with frequency-dependent boundary conditions is described. A 3D finite element model of an e isting bridge has been built up, based on the theory of linear elasticity. The model has been given three different types of boundary conditions: clamped, static stiffness and frequency-dependent stiffness from SSI. Results from simulated train passages, with a train set consisting of two wagons, were compared for the different boundary conditions. The models have also been compared with measurement data from the bridge, which has given indications about which model describes reality in the best way. The results show that the model in which SSI is included by frequency dependent boundary conditions is in slightly better agreement with measurement data than the clamped model and the model with static stiffness. The model gives a slightly better damping of the free vibrations and the natural frequencies correspond better with experimental data. The difference in maximum acceleration from a train passage is very small between the different models, even if it is found that the clamped model generally has lower accelerations and hence is non-conservative. It appears that the train speed affects the maximum acceleration, the size of the free vibrations and the natural frequencies that are present in the free vibrations in the models. Further studies are suggested where it is emphasized that an analysis with longer trains, which give resonance phenomena, should be made to see how the different eigenfrequencies in the models affect the accelerations at different speeds. It is also noted that more measurements would be needed in order to draw more general conclusions about the degree of correspondence between the measurements and the models, and to calibrate the parameters of the model against measurement data.

FEM program, program som använder finita element metoden, har en långhistoria av användning inom ingenjörsyrken. I modern tid har FEM programblivit en nödvändighet för beräkningar inte bara i byggbranchen, men ocksåinom andra ingenjörsverksamheter där stora mängder beräkningar krävs.Programmen har hjälpt ingenjörer att göra allt mer komplicerade beräkningarför projekt som inte bara tilltalar de av oss som är sakkunniga, utan också gerresultat som tilltalar de daglig användarna av projekt för vilka beräkningarnasom behövde göras för utformningen av projektet är mindre intressanta änarkitekturen och slutresultaten.Syftet med denna studie är att undersöka och jämföra modelleringen i två FEMprogram för att granska svagheterna och styrkorna som respektive program harsamt för att ge en grund för val av program i kvalitativa alternativt kvantitativastudier.I studien har analysobjektet, en plattramsbro som är en del av Umeåprojektetsom sammanlänkar motorvägen E12 norr om Ume älv med E4 motorvägensöder om Umeå, valts som objekt att analyseras i en komparativ studie med tvåFEM program, SOFiSTiK och Brigade/Standard. För att genomföra denna jämförelsemodelleras analysobjektet i båda programmen för att sedan genom attutföra laskombinationer erhålla de mest ogynsamma lasterna som kan tänkaskomma på bron i from av momentkrafter och tvärkrafter, och som bron behöverdimensionernas mot.Studien vissade att det finns ett samband mellan frihet och komplexitet i FEMprogram. Genom modelleringens gång kom det fram tydligt att automatiseringi form av moduler skapar ett resultat snabbare, men i utbyte begränsasanvändarens modelleringsfrihet när det kommer till att bygga upp egenskaperoch villkor från grunden.Studien kan grovt delas in bakgrund, lastförklaringar, modellering, analys ochslutsats. / FEM programs, programs that use the finite element method, have a longhistory of use within the engineering discipline. In modern times, FEMprograms have become a necessity for calculations not only in the constructionindustry, but also in other engineering branches where large amountsof calculations are required. The programs have helped engineers makeincreasingly complex calculations for projects that not only appeal to those whoare versed in the subject, but also provide results that appeal to the everydayusers of projects for whom the calculations that need to be made to shape theseprojects are less interesting than the architecture and the end results.The purpose of this study is to investigate and compare the modelling process intwo FEM programs in order to gauge the weaknesses and strengths that respectiveprogram brings, and to build a basis for election of FEM program in qualitativeand quantitative studies respectively.In the study, the analysis object, a slab frame bridge that is part of the Umeåproject that links the E12 highway north of the Ume River with the E4 motorwaysouth of Umeå, has been chosen as an object to be analyzed in a comparativestudy with two FEM programs, SOFiSTiK and Brigade/Standard. To do thiscomparative study the bridge will be modelled in both programs and then besubject to load combinations to find the most unfavorable load combinationsthat can occure on the bridge in the form of torque forces and transverse forcesare obtained. These loads will become the forces that the bridge will have toresist.The study showed that there is a connection between freedom and complexity inFEM programs. Through the modeling process, it became clear that automationin the form of modules creates a faster result, but in return the user’s freedomof modeling is limited when it comes to building properties and conditions fromthe ground up.The study can be roughly divided into background, explanations of load,modeling, analysis and conclusions.

The Swedish government is planning to increase the maximum vehicle gross load regulations on parts of the national roads from the present 60 t, for the load carrying capacity class BK1, to 74 t, for the proposed new load carrying capacity class BK4. The initial implementation of the new load carrying capacity class for 74 t vehicles will only regard major highways and important roads, however, at a later stage the plan is to implement the new BK4 class on the full current BK1 road network. The biggest obstacle which arises when implementing these increased traffic loads is insufficient load carrying capacity for the bridges on the road network.   Thus, the objective of this thesis is to examine and analyze the effects of the increased traffic loads on Swedish road bridges. In order to identify the structural effects of the load increase, and draw general conclusions regarding the effects on the bridge network as a whole, a case study with load carrying capacity calculations is carried out on a two-span concrete slab fram bridge at a highway interchange in Värö in western Sweden. The bridge is classified as critical by Trafikverket. The load carrying capacity calculation is carried out using the Swedish standards, in which maximum load values for the axle load, A, and the bogie load, B, is calculated.   The load effects acting on the bridge are calculated using the finite element software BRIGADE/Standard, with input traffic A and B loads amounting to 12 t and 21 t respectively for the new BK4 class and to 12 t and 18 t respectively for class BK1. In addition to the load carrying capacity calculations with BK4 traffic loads, a comparison is carried out between the results obtained when using the axle- and bogie loads from the BK1 versus the BK4 load carrying capacity class in the load carrying capacity calculations.   The load carrying capacity calculations performed on the studied bridge shows that the capacity of the bridge, both in regards to moment and shear force, is insufficient to meet the new, increased, BK4 A/B – requirements. The critical A/B – values for the whole bridge are 17 t and 18 t respectively, to be compared with the required 12- and 21 t limit for the new BK4 load carrying capacity class, thus, making the load carrying capacity of the bridge inadequate. The critical A/B – values appear for the longitudinal shear force load case at the point where the shear force reinforcement over the column support ends. Moreover, the difference between the results obtained when using the BK1 versus the BK4 traffic loads in the calculations were found to be negligible.   Due to the differing properties and characteristics of each individual bridge on the Swedish road network it is difficult to make general statements regarding the effects of the increased traffic loads on the bridge network as a whole. Specific load carrying capacity calculations will need to be performed on each individual bridge in order to evaluate its capability to withstand the new increased BK4 traffic load. However, capacity calculations regarding the BK1 load carrying capacity class can, with sufficient accuracy, be used to evaluate the capability of a bridge to withstand the increased traffic loads in the BK4 load carrying capacity class, thus, making it easier to evaluate the strengthening needs for the bridge network as a whole. / Sveriges regering planerar en utökning av den maximalt tillåtna bruttovikten för fordon på delar av det allmänna vägnätet från den nuvarande begränsningen på 60 t, för bärighetsklass BK1, till 74 t, för den nya föreslagna bärighetsklassen BK4. I det första skedet kommer den nya bärighetsklassen, för fordon med bruttovikt upp till 74 t, bara att implementeras på stora motorvägar och andra ur transportsynpunkt viktiga vägar, men, i ett senare skede finns också planer på att implementera den nya bärighetsklassen, BK4, på hela det nuvarande BK1 vägnätet. Det största problemet som förväntas uppkomma under införandet av de nya, ökade, trafiklasterna är otillräcklig bärighet på vägnätets broar.   Således är målet med denna uppsats att undersöka och analysera effekterna av dessa ökade trafiklaster för broar på det Svenska vägnätet. För att identifiera effekterna, och dra generella slutsatser, gällande denna ökade trafiklast för broarna på det Svenska vägnätet i sin helhet kommer en fallstudie med bärighetsberäkningar utföras på en plattrambro vid trafikplats Värö - en bro som Trafikverket bedömer som kritisk. Bärighetsberäkningen utförs enligt svenska standarder, där maximala tillåtna värden på axellasten, A, och bogielasten, B, beräknas.   Lasteffekterna som verkar på bron beräknas med hjälp finita element programvaran BRIGADE/Standard med trafiklaster, A och B, som uppgår till 12  respektive 21 t för den nya BK4 bärighetsklassen och 12 respektive 18 t för bärighetsklass BK1. Som tillägg till bärighetsberäkningarna med BK4 laster utförs också en jämförelse av resultaten som uppkommer när axel- och bogielasterna från BK1 respektive BK4 används i beräkningarna.    Bärighetsberäkningarna på den studerade bron visar att brons kapacitet, både gällande moment och tvärkraft, är otillräcklig när den belastas med de ökade BK4 trafiklasterna. De kritiska A- och B- värdena för bron är 17 respektive 18 t, värden som skall jämföras med kraven på 12 respektive 21 t för den nya bärighetsklassen BK4 – därmed är brons bärighet otillräcklig. De kritiska A- och B-värdena för bron uppkommer för lastfallet med longitudinell tvärkraft vid punkten där tvärkraftsarmeringen över mittstödet slutar verka. Jämförelsen mellan beräkningsresultaten som uppkom med trafiklaster enligt BK1 respektive BK4 visade att skillnaden mellan beräkningsresultaten var försumbar.   På grund av de varierande egenskaperna hos varje enskild bro på det Svenska vägnätet är det svårt att dra generella slutsatser gällande effekterna av lastökningen för vägnätet som helhet. Specifika bärighetsberäkningar måste utföras på varje individuell bro för att kunna utvärdera dess kapacitet att klara av de nya, ökade, BK4 trafiklasterna. Emellertid kan bärighetsberäkningar som beträffar bärighetsklassen BK1, med tillräcklig tillförlitlighet, användas för att bedöma en bros möjlighet att motstå de ökade trafiklasterna i den nya bärighetsklassen BK4, vilket förenklar utvärderingen av vilka broar som kräver förstärkning.

This thesis deals with a design of a two-track railway frame bridge over a valley. Out of three proposed variants was chosen the variant number 1 - prestressed frame construction with variable beam section. According to actual EN standards the construction was designed and assessed to the serviceability limit state and the ultimate limit state.

No description available.

I Sverige finns 21 000 broar som Trafikverket förvaltar (Trafikverket, 2018a). Två brotyper som finns är rambro och balkbro. Rambron är en av de vanligaste brotyperna och är uppbyggd som en fast inspänd konstruktion. Brosystemet kallas plattrambro eller balkrambro beroende på om balkarna eller plattan är det bärande elementet. Om bron istället är fritt upplagd på stödkonstruktionen, kallas brosystemet för plattbro eller balkbro (Vägverket, 1996). ZIP-balksbron är uppbyggd som en balkbro med en modell liknande omvända T-balkar som läggs fläns mot fläns. Brosystemet kommer ursprungligen från Spanbeton i Holland och gjorde under år 2019 premiär på den svenska marknaden med ett projekt i Härnösand. Bron har en spännvidd på 20,55 meter bestående av nio ZIP-balkar. Balkarna prefabriceras på Strängbetongs fabrik i Långviksmon utanför Härnösand. Projektet blev klart under hösten 2019. Syfte och mål med examensarbetet var att undersöka skillnader mellan ZIP-balksbron och en traditionell exemplifierad plattrambro. Aspekterna som undersöktes var underhållet hos de två brotyperna, materialåtgång av betong och armering, last av trafik samt att det gjordes en utvärdering av projektet. Resultatet visar att ZIP-balksbron kräver mer underhåll än en plattrambro eftersom balkbroar har övergångskonstruktion och brolager. Den tar även mer tid att inspektera då den innehåller manhål. ZIP-balksbron använder sig av 29,38 % mindre betong på en meter. Armeringsdifferensen mellan broarna är försumbart. Momentet av den vertikala respektive horisontella lasten av trafik är 44,5 % respektive 19,2 % större hos ZIP-balksbron jämfört med plattrambron. Resultatet visar även på ett bra utfört brobygge som kan hänvisas i brolösningen, samt nöjda parter från flera håll. Slutsatsen är att plattrambron är mer fördelaktig att använda ur ett underhållsperspektiv, en balkbro kräver betydligt större underhåll än de driftåtgärder som årligen sker på broar. Men, genom arbetets bevisning använder ZIP-balksbron mindre betong än hos en traditionell plattrambro och har en enkel byggprocess, vilket ökar förtroendet för brolösningen och framförallt för prefabricering inom brobranschen. Trots att brotypen kräver ett större underhåll samt en ökad och mer komplex momentfördelning än hos en plattrambro, kan säkerheten under byggtiden vara en avgörande aspekt vid val av brobyggen i framtiden. / The ZIP-beam bridge is constructed as a beam bridge with inverted T-beams placed with flanges next to each other. The bridge system is originally from Spanbeton in Holland and it is having its premiere on the Swedish market during year 2019 with an ongoing project in Härnösand. The bridge span is 20,55 meters consisted with nine ZIP-beams. The project was finished in august 2019.  The purpose and goal were to examine differences between the ZIP-beam bridge and a traditional slab frame bridge. The aspects to examine was maintence, use of concrete and reinforcement and traffic loads.  The results show that the ZIP-beam bridge requires more maintenance than the slab frame bridge. The ZIP-beam bridge uses 29,38 % less concrete per metre. The use of reinforcement is negligible. The moment force of the horisontal and vertical traffic loads is 44,5 % respective 19,2 % larger at the ZIP-beam bridge. The conclusion of this paper shows that even though the ZIP-beam bridge requires more maintenance and a more complex moment force than a slab frame bridge, the safety during the building time as well as the less amount of concrete used can be a conclusive factor when building bridges in Sweden in the future.

This research encompasses the automated design and structural optimization of reinforced concrete slab frame bridges, considering investment costs and environmental impacts. The most important feature of this work is that it focusses on realistic and complete models of slab frame bridges rather than on optimization of only individual members or sections of a bridge. The thesis consists of an extended summary of publications and three appended papers. In the first paper, using simple assumptions, the possibility of applying cost-optimization to the structural design of slab frame bridges was investigated. The results of the optimization of an existing constructed bridge showed the potential to reduce the investment cost of slab frame bridges. The procedure was further developed in the second paper. In this paper, automated design was integrated to a more refined cost-optimization methodology based on more detailed assumptions and including extra constructability factors. This procedure was then applied to a bridge under design, before its construction. From the point of view of sustainability, bridge design should not only consider criteria such as cost but also environmental performance. The third paper thus integrated life cycle assessment (LCA) with the design optimization procedure to perform environmental impact optimization of the same case study bridge as in the second paper. The results of investment cost and environmental impact optimization were then compared. The obtained results presented in the appended papers highlight the successful application of optimization techniques to the structural design of reinforced concrete slab frame bridges. Moreover, the results indicate that a multi-objective optimization that simultaneously considers both environmental impacts and investment cost is necessary in order to generate more sustainable designs. The presented methodology has been applied to the design process for a time-effective, sustainable, and optimal design of concrete slab frame bridges. / <p>QC 20170316</p>