Parametric design has proven to be a powerful tool for structural engineers to find innovativesolutions to complex problems more effectively compared to conventional methods. Theflexibility off parametric design is immense since all types of structures depend on a range ofparameters that can be isolated, controlled and altered.In this thesis a parametric model was built with the software Grasshopper to manage thedesign process of a common type of foundation improvement. The technique has beensuccessfully used by Tyréns AB on several 19th century buildings in Stockholm in the pastdecade. The buildings were settling due to decay of the original wooden piles. To stop furthersettlements steel piles are drilled from under the building down to the bedrock. In thebasement of the buildings new and thick reinforced concrete slabs are cast which are connectedto the ground walls with concrete corbels.The available area for the installation of these corbels, the minimum distances between thecorbels and the dimensions of each corbel are all contributing factors that limit the number ofpossible design configurations. The dimensions of the concrete corbels affect the maximumload capacity which will determine their quantity and position. The corbels have to carry thevarying line loads and point loads acting on the ground walls from the structure above.With the plug-in finite element software Karamba, reaction forces in each pile were calculatedwhich also affected the possible designs.A well-functioning and adaptable parametric model presented logical results where decreasingheight of the concrete slab was affecting the capacity of each corbel which in turn generated alarger number of corbels. The model offered both manual control and automatic optimizationwhere real time variations of loads and reactions were shown depending on the changingdesign.In the optimization process which was based on genetic algorithm a cost function to deal withthe numerous contributing parameters was designed.Verification of important results increased the confidence in the model in most cases but thelack of trust in the calculated moments of each shell element created limitations. The thesisdoes not include a complete finite element analysis of the structures generated by theparametric model. However, it presents a simple export process to the third party softwareFEM-Design for verification.The role of the model was therefore not to work as a complete solution but as a powerful andeasy-to-use design tool for the structural designer to get instant feedback of chosen corbelplacements. The model offered a simplified way of achieving more slender and economicstructures both financially as well as environmentally.Parametric design was shown to be successful for solving structural problems if the model wasbased on appropriate engineering judgements.

Yes / The current design codes, such as ACI 318-14, EC2 and CSA23.3-04, in addition to previous research investigations suggested different expressions for concrete effectiveness factor for use in limit state design of concrete structures. All these equations are based on different design parameters and proposed for normal concrete deep beams. This research evaluates the use of different effectiveness factor equations in the upper and lower bond analyses of continuously-supported self-compacting concrete (SCC) deep beams. Moreover, a new effectiveness factor expression is suggested to be used for upper and lower bound solutions with the aim of improving predictions of the load capacity of continuously-supported SCC deep beams. For the range of deep beams considered, the strut-and-tie method with the proposed effectiveness factor formula achieved accurate predictions, with a mean of 1.01, a standard deviation of 6.7% and a coefficient of variation of 6.8%. For the upper-bound analysis, the predictions of the proposed effectiveness factor equation were more accurate than those of the formulas suggested by previous investigations. Overall, although the proposed effectiveness factor achieved very accurate predictions, further validation for the proposed formula is needed since the only data available on continuous SCC deep beams are those collected form the current study.

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Despite being the world’s second most important low-carbon source of electricity, the development of nuclear capacities is limited and does not comply with the International Energy Agency’s Sustainable Development Scenario. One of the main reasons for this lack of development is high and increasing costs of new nuclear capacities. In fact, capital costs can account for more than 80% of the Levelized Cost of Energy of a new nuclear power plant. Design accounts for about 10% and construction accounts for about 20% of the total capital cost.The importance of design and construction in nuclear power plants’ costs is partly due to limitations of traditional construction methods regarding both technical possibilities and realization schedules. Modular construction methods are proposed to reduce new nuclear power plants’ construction costs, and in particular steel-plate composite structures modular construction. Steel-plate composite structures consist of a structural interaction between thin steel plates and precast concrete. The aim of this thesis was to evaluate the capacity of modular construction, using steel-plate composite panels, to fulfil nuclear safety and functional requirements; as well as to identify potential related gains and opportunities. Advantages and constraints of steel-plate composite modules were identified in scientific literature and intergovernmental opportunity studies, and were related to the specificities of nuclear structures’ design and construction.Steel-plate composite structures modular construction is based on the manufacturing of steel concrete composite modules outside of the civil works site. The higher productivity of workshops and the possible task parallelization may lead to significant construction schedules shortening and capital costs reduction. In addition, steel-plate composite modules offer new technical possibilities which may help solving some constructability issues. However, steel-plate composite structures modular construction requires a reconsideration of the traditional design and construction methods, as they imply new challenges and constraints. In particular, the modularization issue should be addressed as soon as possible in the design, and the module manufacturing capacities should be quickly identified or created in order to deliver properly manufactured modules on-time.Considering the advantages and constraints of steel-plate composite structures modular construction, it appears that steel-plate composite modules may fit advantageously most of the nuclear design requirements. However, due to the lack of feedback, it is proposed that the usage of steel-plate composite modules be limited to critical concrete structures of the containment building. In particular, it appears that the containment dome and the reactor pit construction may benefit from steel-plate composite structures construction methods.

A mechanism analysis is developed to predict the shear capacity of reinforced concrete corbels. Based on shear failure observed in experimental tests, kinematically admissible failure mechanisms are idealised as an assemblage of two rigid blocks separated by a failure plane of displacement discontinuity. Shear capacity predictions obtained from the developed mechanism analysis are in better agreement with corbel test results of a comprehensive database compiled from the available literature than other existing models for corbels. The developed mechanism model shows that the shear capacity of corbels generally decreases with the increase of shear span-to-depth ratio, increases with the increase of main longitudinal reinforcement up to a certain limit beyond which it remains constant, and decreases with the increase of horizontal applied loads. It also demonstrates that the smaller the shear span-to-overall depth ratio of corbels, the more effective the horizontal shear reinforcement.

yes / Ten reinforced-concrete continuous deep beams with openings were tested to failure. The main variables investigated were the shear span-to-overall depth ratio, and the size and location of openings. Two failure modes influenced by the size and location of web openings regardless of the shear span-to-overall depth ratio were observed. The normalised load capacity of beams having a web opening area ratio of 0·025 within exterior shear spans was approximately similar to that of their companion solid beams. Continuous deep beams having web openings within interior shear spans exhibited a higher load capacity reduction with the increase of the opening size, similar to simply supported deep beams with web openings. Formulae based on the upper bound analysis of the plasticity theory were proposed to predict the load capacity of continuous deep beams with web openings. Comparisons between the measured and predicted load capacities showed a good agreement.

yes / This paper reports the testing of five reinforced concrete continuous beams strengthened in flexure with externally bonded carbon-fibre-reinforced polymer (CFRP) laminates. All beams had the same geometrical dimensions and internal steel reinforcement. The main parameters studied were the position and form of the CFRP laminates. Three of the beams were strengthened using different arrangements of CFRP plate reinforcement, and one was strengthened using CFRP sheets. The performance of the CFRP-strengthened beams was compared with that of an unstrengthened control beam. Peeling failure was the dominant mode of failure for all the strengthened beams tested. The beam strengthened with both top and bottom CFRP plates produced the highest load capacity. It was found that the longitudinal elastic shear stresses at the adhesive/concrete interface calculated at beam failure were close to the limiting value recommended in Concrete Society Technical Report 55.

Countries world-over have thousands of critical structures and bridges which have been built decades back when strength-based designs were the order of the day. Over the years, magnitude and frequency of loadings on these have increased. Also, these structures have been exposed to environmental degradation during their service life. Hence, structural health monitoring (SHM) has attracted the attention of researchers, world over. Structural health monitoring is recommended both for vulnerable old bridges and structures as well as for new important structures. Structural health monitoring as a principle is derived from condition monitoring of machinery, where the day-to-day recordings of sound and vibration from machinery is compared and sudden changes in their features is reported for inspection and trouble-shooting. With the availability of funds for repair and retrofitting being limited, it has become imperative to rank buildings and bridges that require rehabilitation for prioritization. Visual inspection and expert judgment continues to rule the roost. Non-destructive testing techniques though have come of age and are providing excellent inputs for judgment cannot be carried out indiscriminately. They are best suited for evaluating local damage when restricted areas are investigated in detail. A few modern bridges, particularly long-span bridges have been provided with sophisticated instrumentation for health monitoring. It is necessary to identify local damages existing in normal bridges. The methodology adopted for such identification should be simple, both in terms of investigations involved and the instrumentation. Researchers have proposed various methodologies including damage identification from mode shapes, wavelet-based formulations and optimization-based damage identification and instrumentation schemes and so on. These are technically involved but may be difficult to be applied for all critical bridges, where the sheer volume of number of bridges to be investigated is enormous. Ideally, structural health monitoring has to be carried out in two stages: (a) Stage-1: Remote monitoring of global damage indicators and inference of the health of the structure. Instrumentation for this stage should be less, simple, but at critical locations to capture the global damage in a reasonable sense. (b) Stage -2: If global indicators show deviation beyond a specified threshold, then a detailed and localized instrumentation and monitoring, with controlled application of static and dynamic loads is to be carried out to infer the health of the structure and take a decision on the repair and retrofit strategies. The thesis proposes the first stage structural health monitoring methodology using natural frequencies and static deflections as damage indicators. The idea is that the stage-1 monitoring has to be done for a large number of bridges and vulnerable structures in a remote and wire-less way and a centralized control and processing unit should be able to number-crunch the in-coming data automatically and the features extracted from the data should help in determining whether any particular bridge warrants second stage detailed investigation. Hence, simple and robust strategies are required for estimating the health of the structure using some of the globally available response data. Identification methodology developed in this thesis is applicable to distributed smeared damage, which is typical of reinforced concrete structures. Simplified expressions and methodologies are proposed in the thesis and numerically and experimentally validated towards damage estimation of typical structures and elements from measured natural frequencies and static deflections. The first-order perturbation equation for a dynamical system is used to derive the relevant expressions for damage identification. The sensitivity of Eigen-value-cumvector pair to damage, modeled as reduction in flexural rigidity (EI for beams, AE for axial rods and Et 12(1 2 )3− μ for plates) is derived. The forward equation relating the changes in EI to changes in frequencies is derived for typical structural elements like simply-supported beams, plates and axial rods (along with position and extent of damage as the other controlling parameters). A distributed damage is uniquely defined with its position, extent and magnitude of EI reduction. A methodology is proposed for the inverse problem, making use of the linear relationship between the reductions in EI (in a smeared sense) to Eigen-values, such that multiple damages could be estimated using changes in natural frequencies. The methodology is applied to beams, plates and axial rods. The performance of this inverse methodology under influence of measurement errors is investigated for typical error profiles. For a discrete three dimensional structure, computationally derived sensitivity matrix is used to solve the damages in each floor levels, simulating the post-earthquake damage scenario. An artificial neural network (ANN) based Radial basis function network (RBFN) is also used to solve the multivariate interpolation problem, with appropriate training sets involving a number of pairs of damage and Eigen-value-change vectors. The acclaimed Cawley-Adams criteria (1979) states that, “the ratio of changes in natural frequencies between two modes is independent of the damage magnitude” and is governed only by the position (or location) and extent of damage. This criterion is applied to a multiple damage problem and contours with equal frequency change ratios, termed as Iso_Eigen_value_change contours are developed. Intersection of these contours for different pairs of frequencies shows the position and extent of damage. Experimental and analytical verification of damage identification methodology using Cawley-Adams criteria is successfully demonstrated. Sensitivity expressions relating the damages to changes in static deflections are derived and numerically and experimentally proved. It is seen that this process of damage identification from static deflections is prone to more errors if not cautiously exercised. Engineering and physics based intuition is adopted in setting the guidelines for efficient damage detection using static deflections. In lines of Cawley-Adams criteria for frequencies, an invariant factor based on static deflections measured at pairs of symmetrical points on a simply supported beam is developed and established. The power of the factor is such that it is governed only by the position of damage and invariant with reference to extent and magnitude of damage. Such a revelation is one step ahead of Caddemi and Morassi’s (2007) recent paper, dealing with static deflection based damage identification for concentrated damage. The invariant factor makes it an ideal candidate for base-line-free measurement, if the quality and resolution of instrumentation is good. A moving damage problem is innovatively introduced in the experiment. An attempt is made to examine wave-propagation techniques for damage identification and a guideline for modeling wave propagation as a transient dynamic problem is done. The reflected-wave response velocity (peak particle velocity) as a ratio of incident wave response is proposed as a damage indicator for an axial rod (representing an end-supported pile foundation). Suitable modifications are incorporated in the classical expressions to correct for damping and partial-enveloping of advancing wave in the damage zone. The experimental results on axial dynamic response of free-free beams suggest that vibration frequency based damage identification is a viable complementary tool to wave propagation. Wavelet-multi-resolution analysis as a feature extraction tool for damage identification is also investigated and structural slope (rotation) and curvatures are found to be the better indicators of damage coupled with wavelet analysis. An adaptive excitation scheme for maximizing the curvature at any arbitrary point of interest is also proposed. However more work is to be done to establish the efficiency of wavelets on experimentally derived parameters, where large noise-ingression may affect the analysis. The application of time-period based damage identification methodology for post-seismic damage estimation is investigated. Seismic damage is postulated by an index based on its plastic displacement excursion and the cumulative energy dissipated. Damage index is a convenient tool for decision making on immediate-occupancy, life-safety after repair and demolition of the structure. Damage sensitive soft storey structure and a weak story structure are used in the non-linear dynamic analysis and the DiPasquale-Cakmak (1987) damage index is calibrated with Park-Ang (1985) damage index. The exponent of the time-period ratio of DiPasquale-Cakmak model is modified to have consistency of damage index with Park-Ang (1985) model.

A disposição das armaduras nos elementos estruturais não influencia somente o comportamento do elemento estrutural, mas também a facilidade e viabilidade da sua execução na obra. O detalhamento do arranjo de armadura está diretamente ligado com a segurança da construção. Os textos que existem sobre técnica de armar se encontram dispersos, dificultando o acesso dos profissionais e estudantes de engenharia de estruturas. Este trabalho analisa os vários arranjos de armaduras propostos para lajes maciças e nervuradas, vigas e pilares procurando indicar o mais adequado de acordo com os critérios de economia, facilidade de execução e comportamento do elemento estrutural, quando possível. Para melhor ilustrar os arranjos de armaduras, é apresentado o dimensionamento de um edifício residencial de pequena altura, onde, podem ser observadas as rotinas de projeto adotadas, bem como os processos para o detalhamento das armaduras. Usaram-se o programa computacional elaborado por TQS Informática Ltda e também processo não computacional. Este programa para análise estrutural de edifícios apresenta boa interface com o usuário, proporcionando-lhe grande interesse e relativa facilidade de utilização. / The disposition of the reinforcement in the structural elements does not affect only the structural element behaviour, but also the facility and the viability of the building execution. The detailing of the reinforcement arrange is directly connected to the building safety. The existing texts about the technícs of reinforcing are spread in the literature of the structural engineering, making the access of the students and professionals to them difficult. The present work analyses the many different proposed arrangements of reinforcement for the slabs, joist floors, beams and columns, trying to indicate the most adequate one, according to the economic criteria, facility of execution, and the structural element behaviour, when possible. The design of a building of a short height is presented, as a way of better visualizing the reinforcement arrangements. In that example the adopted project routines could be observed, as well as the process of detailing the reinforcements. To reach this purpose, a software designed by TQS Informática Ltda was used, as well as a non-computer process. This software for the structural analysis of building presents a good interface with the users, providing them with great interest and relative facility of use.

Este trabalho trata de detalhes de modelagem de estruturas de contraventamento de edifícios de concreto armado. Inicialmente são discutidos esquemas de modelagem para núcleos de rigidez. São comparados resultados obtidos através de três procedimentos distintos, com diferentes graus de simplicidade e eficiência. É também avaliada a contribuição de vigas secundárias, vigas que não estão conectadas diretamente em pilares, na estrutura de contraventamento. Para tanto são apresentados alguns arranjos onde a consideração das referidas vigas muda significativamente os resultados obtidos e a modelagem de uma estrutura completa de edifício com e sem as referidas vigas secundárias. Por fim, são apresentados um gerador de estruturas de contraventamento e um pós-processador gráfico para visualização da estrutura gerada e dos resultados obtidos, sejam esforços ou deslocamentos. / This work deals with some modelling details of bracing structures for reinforced concrete buildings. lnitially, modelling schemes of structural cores are discussed. Results obtained by three different procedures, with distinct levels of simplicity and efficacy, are compared. The work also shows the contribution of secondary beams, ones that are not directly connected to columns, to the stiffness of bracing structures. Some schemes, in which the consideration of those beams changes expressively the obtained results, and the complete modelling of a building structure, with and without secondary beams, are presented. Finally, the work also introduces a generator of bracing structures and a pos-processor, that permit the visualisation of the obtained results: internal efforts and displacements.