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1
Hertanto, Eric. "Seismic Assessment of Pre-1970s Reinforced Concrete Structure". Thesis, University of Canterbury. Civil Engineering, 2005. http://hdl.handle.net/10092/1120.
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Reinforced concrete structures designed in pre-1970s are vulnerable under earthquakes due to lack of seismic detailing to provide adequate ductility. Typical deficiencies of pre-1970s reinforced concrete structures are (a) use of plain bars as longitudinal reinforcement, (b) inadequate anchorage of beam longitudinal reinforcement in the column (particularly exterior column), (c) lack of joint transverse reinforcement if any, (d) lapped splices located just above joint, and (e) low concrete strength. Furthermore, the use of infill walls is a controversial issue because it can help to provide additional stiffness to the structure on the positive side and on the negative side it can increase the possibility of soft-storey mechanisms if it is distributed irregularly. Experimental research to investigate the possible seismic behaviour of pre-1970s reinforced concrete structures have been carried out in the past. However, there is still an absence of experimental tests on the 3-D response of existing beam-column joints under bi-directional cyclic loading, such as corner joints. As part of the research work herein presented, a series of experimental tests on beam-column subassemblies with typical detailing of pre-1970s buildings has been carried out to investigate the behaviour of existing reinforced concrete structures. Six two-third scale plane frame exterior beam-column joint subassemblies were constructed and tested under quasi-static cyclic loading in the Structural Laboratory of the University of Canterbury. The reinforcement detailing and beam dimension were varied to investigate their effect on the seismic behaviour. Four specimens were conventional deep beam-column joint, with two of them using deformed longitudinal bars and beam bars bent in to the joint and the two others using plain round longitudinal bars and beam bars with end hooks. The other two specimens were shallow beam-column joint, one with deformed longitudinal bars and beam bars bent in to the joint, the other with plain round longitudinal bars and beam bars with end hooks. All units had one transverse reinforcement in the joint. The results of the experimental tests indicated that conventional exterior beam-column joint with typical detailing of pre-1970s building would experience serious diagonal tension cracking in the joint panel under earthquake. The use of plain round bars with end hooks for beam longitudinal reinforcement results in more severe damage in the joint core when compared to the use of deformed bars for beam longitudinal reinforcement bent in to the joint, due to the combination of bar slips and concrete crushing. One interesting outcome is that the use of shallow beam in the exterior beam-column joint could avoid the joint cracking due to the beam size although the strength provided lower when compared with the use of deep beam with equal moment capacity. Therefore, taking into account the low strength and stiffness, shallow beam can be reintroduced as an alternative solution in design process. In addition, the presence of single transverse reinforcement in the joint core can provide additional confinement after the first crack occurred, thus delaying the strength degradation of the structure. Three two-third scale space frame corner beam-column joint subassemblies were also constructed to investigate the biaxial loading effect. Two specimens were deep-deep beam-corner column joint specimens and the other one was deep-shallow beam-corner column joint specimen. One deep-deep beam-corner column joint specimen was not using any transverse reinforcement in the joint core while the two other specimens were using one transverse reinforcement in the joint core. Plain round longitudinal bars were used for all units with hook anchorage for the beam bars. Results from the tests confirmed the evidences from earthquake damage observations with the exterior 3-D (corner) beam-column joint subjected to biaxial loading would have less strength and suffer higher damage in the joint area under earthquake. Furthermore, the joint shear relation in the two directions is calibrated from the results to provide better analysis. An analytical model was used to simulate the seismic behaviour of the joints with the help of Ruaumoko software. Alternative strength degradation curves corresponding to different reinforcement detailing of beam-column joint unit were proposed based on the test results.
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Starczewski, Jerzy Andrzej. "Felix Candela : the structure and form of reinforced concrete shells". Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/22954.
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Harry, Ofonime Akpan. "Behaviour of reinforced concrete frame structure against progressive collapse". Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/29623.
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A structure subjected to extreme load due to explosion or human error may lead to progressive collapse. One of the direct methods specified by design guidelines for assessing progressive collapse is the Alternate Load Path method which involves removal of a structural member and analysing the structure to assess its potential of bridging over the removed member without collapse. The use of this method in assessing progressive collapse therefore requires that the vertical load resistance function of the bridging beam assembly, which for a typical laterally restrained reinforced concrete (RC) beams include flexural, compressive arching action and catenary action, be accurately predicted. In this thesis, a comprehensive study on a reliable prediction of the resistance function for the bridging RC beam assemblies is conducted, with a particular focus on a) the arching effect, and b) the catenary effect considering strength degradations. A critical analysis of the effect of axial restraint, flexural reinforcement ratio and span-depth ratio on compressive arching action are evaluated in quantitative terms. A more detailed theoretical model for the prediction of load-displacement behaviour of RC beam assemblies within the compressive arching response regime is presented. The proposed model takes into account the compounding effect of bending and arching from both the deformation and force points of view. Comparisons with experimental results show good agreement. Following the compressive arching action, catenary action can develop at a much larger displacement regime, and this action could help address collapse. A complete resistance function should adequately account for the catenary action as well as the arching effect. To this end, a generic catenary model which takes into consideration the strength degradation due to local failure events (e.g. rupture of bottom rebar or fracture of a steel weld) and the eventual failure limit is proposed. The application of the model in predicting the resistance function in beam assemblies with strength degradations is discussed. The validity of the proposed model is checked against predictions from finite element model and experimental tests. The result indicate that strength degradation can be accurately captured by the model. Finally, the above developed model framework is employed in investigative studies to demonstrate the application of the resistance functions in a dynamic analysis procedure, as well as the significance of the compressive arching effect and the catenary action in the progressive collapse resistance in different designs. The importance of an accurate prediction of the arching effect and the limiting displacement for the catenary action is highlighted.
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GINO, DIEGO. "ADVANCES IN RELIABILITY METHODS FOR REINFORCED CONCRETE STRUCTURES". Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2754713.
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Zhao, Li. "SPATIAL RELIABILITY ANALYSIS FOR CORRODED REINFORCED CONCRETE STRUCTURES". University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1479123930240399.
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De, Rose David. "The rehabilitation of a concrete structure using fibre reinforced plastics". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ29388.pdf.
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Ouyang, Yi y 欧阳禕. "Theoretical study of hybrid masonry : RC structure behaviour under lateral earthquake loading". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hdl.handle.net/10722/196090.
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A confined masonry (CM) wall consists of a masonry wall panel surrounded by reinforced concrete (RC) members on its perimeters. Low-rise CM structures are widely used in earthquake-risked (EQ-risked) rural or suburban areas all over the world. Most of these structures fail in shear pattern under lateral EQ loads, and some of them collapse under a severe or even a moderate EQ due to inappropriate design. On the other hand, buildings constructed of RC frames have much better performance in resisting EQs, since their RC members have larger dimensions and heavier reinforcing ratios than those in CM structures. Nonetheless, RC-frame buildings are normally too expensive for most inhabitants in less developed regions.
In this study, as an improvement to the conventional CM buildings for EQ resistance and for the sake of post-EQ restoration, a hybrid masonry – RC (HMR) structure, whose working mechanism is different from that of a conventional CM structure, is proposed. The RC members (i.e. “tie beams” and “tie columns”), which function only as confinement in a CM building, will resist most of gravity load and part of lateral EQ load in an HMR structure, while the wall panels will take most of lateral EQ load and part of gravity load. This is achievable by slightly increasing the sizes and reinforcing ratios of RC members in HMR structures. Such buildings will not collapse in the absence of masonry wall panels because the gravity load bearing system is still intact. On the other hand, as the wall panels in the proposed HMR structure will absorb most of the energy induced by lateral EQ load, severe damages will be controlled within the wall panel region, so that only the wall panels need to be replaced instead of rebuilding the whole structure after the EQ event.
To investigate the mechanical behaviours of masonry assemblages to be used in HMR structures, a series of experimental tests were conducted. Having established the relevant material properties for HMR structures, finite element (FE) simulation was performed to verify its work mechanism.
Prior to applying the FE simulation to HMR structures, the FE technique was first applied to simulate the behaviours of two concrete-brick masonry panels under diagonal compression loading and a CM wall under cyclic lateral loading. The results show a good correlation between the experimental results and the simulated ones. This has validated the feasibility of using the FE software to study the proposed HMR structure.
The theoretical simulation results show that in a properly designed HMR wall, depending on the masonry reinforcing details and the boundary conditions of simulated load cases, about 70% of the gravity load imposed on the RC beam will be transferred to the RC columns and more than 80% of the seismic energy (in terms of strain energy) will be absorbed by the masonry panel. Therefore, it is obvious that the proposed HMR structure is very feasible to replace the conventional CM structure in resisting EQ attacks with no risk of collapse.published_or_final_version
Civil Engineering
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Master of Philosophy
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Al, Mamun Abdullah. "Seismic Damage Assessment of Reinforced Concrete Frame Buildings in Canada". Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36188.
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The emphasis on seismic design and assessment of reinforced concrete (RC) frame structure has shifted from force-based to performance-based design and assessment to accommodate strength and ductility for required performance of building. RC frame structure may suffer different levels of damage under seismic-induced ground motions, with potentials for formation of hinges in structural elements, depending on the level of stringency in design. Thus it is required to monitor the seismic behaviour and performance of buildings, which depend on the structural system, year of construction and the level of irregularities in the structural system. It is the objective of the current research project to assess seismic performance of RC frame buildings in Canada, while developing fragility curves as analytical tools for such assessment. This was done through dynamic inelastic analysis by modelling selected building structures and using PERFORM-3D as analysis software, while employing incremental dynamic analysis to generate performance data under incrementally increasing seismic intensity of selected earthquake records. The results lead to probabilistic tools to assess the performance of buildings designed following the National Building Code of Canada in different years of construction with and without irregularities. The research consists of three phases; i) regular buildings designed after 1975, ii) regular buildings designed prior to 1975, and iii) irregular buildings designed prior to 1975. The latter two phases address older buildings prior to the development of modern seismic building codes. All three phases were carried out by selecting and designing buildings in Ottawa, representing the seismic region in eastern Canada, as well as buildings in Vancouver, representing the seismic region in western Canada. Buildings had three heights (2; 5; and 10-stories) to cover a wide range of building periods encountered in practice. The resulting fragility curves indicated that the older buildings showed higher probabilities of exceeding life safety and/or collapse prevention performance levels. Newer buildings showed higher probabilities of exceeding target performance levels in western Canada than those located in the east.
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Albostan, Utku. "Implementation Of Coupled Thermal And Structural Analysis Methods For Reinforced Concrete Structures". Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615393/index.pdf.
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Temperature gradient causes volume change (elongation/shortening) in concrete structures. If the movement of the structure is restrained, significant stresses may occur on the structure. These stresses may be so significant that they can cause considerable cracking at structural components of large concrete structures. Thus, during the design of a concrete structure, the actual temperature gradient in the structure should be obtained in order to compute the stress distribution on the structure due to thermal effects. This study focuses on the implementation of a solution procedure for coupled thermal and structural analysis with finite element method for such structures. For this purpose, first transient heat transfer analysis algorithm is implemented to compute the thermal gradient occurring inside the concrete structures. Then, the output of the thermal analysis is combined with the linear static solution algorithm to compute stresses due to temperature gradient. Several, 2D and 3D, finite elements having both structural and thermal analysis capabilities are developed. The performances of each finite element are investigated. As a case study, the top floor of two L-shaped reinforced concrete parking structure and office building are analyzed. Both structures are subjected to heat convection at top face of the slabs as ambient condition. The bottom face of the slab of the parking structure has the same thermal conditions as the top face whereas in the office building the temperature inside the building is fixed to 20 degrees. The differences in the stress distribution of the slabs and the internal forces of the vertical structural members are discussed.
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Bai, Jong-Wha. "Seismic fragility and retrofitting for a reinforced concrete flat-slab structure". Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/521.
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The effectiveness of seismic retrofitting applied to enhance seismic performance was assessed for a five-story reinforced concrete (RC) flat-slab building structure in the central United States. In addition to this, an assessment of seismic fragility that relates the probability of exceeding a performance level to the earthquake intensity was conducted. The response of the structure was predicted using nonlinear static and dynamic analyses with synthetic ground motion records for the central U.S. region. In addition, two analytical approaches for nonlinear response analysis were compared. FEMA 356 (ASCE 2000) criteria were used to evaluate the seismic performance of the case study building. Two approaches of FEMA 356 were used for seismic evaluation: global-level and member-level using three performance levels (Immediate Occupancy, Life Safety and Collapse Prevention). In addition to these limit states, punching shear drift limits were also considered to establish an upper bound drift capacity limit for collapse prevention. Based on the seismic evaluation results, three possible retrofit techniques were applied to improve the seismic performance of the structure, including addition of shear walls, addition of RC column jackets, and confinement of the column plastic hinge zones using externally bonded steel plates. Finally, fragility relationships were developed for the existing and retrofitted structure using several performance levels. Fragility curves for the retrofitted structure were compared with those for the unretrofitted structure. For various performance levels to assess the fragility curves, FEMA global drift limits were compared with the drift limits based on the FEMA member-level criteria. In addition to this, performance levels which were based on additional quantitative limits were also considered and compared with FEMA drift limits.
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Irving, Jonathan. "Soil structure interaction of fibre reinforced concrete floor slabs on grade". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0016/MQ54627.pdf.
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OLIVA, VALERIO. "Methodological approaches to the condition assessment of reinforced concrete architectural heritage". Doctoral thesis, Politecnico di Torino, 2022. https://hdl.handle.net/11583/2972790.
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Kuzmanovic, Sasha. "An investigation of the shear design of a reinforced concrete box structure". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq40923.pdf.
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Parsa, Arash. "Finite element modelling of stress concentrations in a reinforced concrete offshore structure". Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292406.
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Magnanini, Nicola. "Seismic retrofit of a reinforced concrete building placed in L'Aquila". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/4778/.
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XUAN, GANG. "PERFORMANCE-BASED DESIGN OF A 15-STORY REINFORCED CONCRETE COUPLED CORE WALL STRUCTURE". University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1133636553.
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Xuan, Gang. "Performance Based Design of a 15 Story Reinforced Concrete Coupled Core Wall Structure". Cincinnati, Ohio : University of Cincinnati, 2005. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1133636553.
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Chuang, Tsai-Fu. "Numerical modelling of reinforced concrete structure under monotonic and earthquake-like dynamic loading". Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368434.
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Stokic, Marko. "Numerical modelling of tunnelling-induced damage on reinforced concrete buildings". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
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The goal of this study is to gain insight into mechanisms of soil-structure interaction for buildings affected by tunnel excavation and to discuss reliable methods to evaluate the potential damage. Assessing the structural response to excavation-induced deformations involve a combination of both geotechnical and structural aspects, such as soil behaviour, building behavior, soil-structure interaction and modelling techniques.
This study focuses on the behavior of reinforced concrete buildings founded on coarse-grained soils. In particular, reference was made to the case study of new Milan (Italy) metro-line 5, excavated in sandy soils by an earth pressure balance (EPB) machine. Observed volume loss was averagely equal to 0.5%, which did not produce any damage on surrounding buildings due to efficient excavation procedure. The goal of this work is to simulate different scenarios of volume losses and structural configurations through numerical FE simulation. Therefore, a maximum volume loss of 3%, index of inappropriate execution of excavation work was considered. Moreover, the influence of structural stiffness is investigated by taking into account different building configurations including the presence of infills and openings due to doors and windows. A 5-storey RC building founded on a strip footing and interacting with tunnel excavation is modelled in detail. The numerical analyses are performed with the commercial software Abaqus. Damage assessment is carried out both by direct analysis of the stress-strain response of the structure in the numerical analyses and by empirical and analytical methods typically used in the engineering design. Recent researches illustrate that infill masonry walls should be taken into consideration as far as they are most sensitive elements to damage when affected by excavation. This thesis illustrates the beneficial effect, in reducing the deflection ratio and damage to building when modeling it with presence of infills.
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Kassem, Fidaa. "Reliability of reinforced concrete structures : Case of slabs subjected to impact". Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0096/document.
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Dans le domaine du génie civil, le dimensionnement des structures en béton armé est essentiellement basé sur des démarches déterministes. Cependant, les informations fournies par des analyses déterministes sont insuffisantes pour étudier la variabilité de la réponse de la dalle. Le manque de connaissance des charges appliquées ainsi que les incertitudes liées à la géométrie de la dalle et les caractéristiques des matériaux nécessitent donc l’utilisation d’une approche fiabiliste qui permet la propagation de ces incertitudes dans les analyses déterministes. L'approche fiabiliste est basée sur le principe de couplage mécano-fiabiliste qui consiste à coupler un modèle stochastique et un modèle déterministe. Cependant un couplage mécano-fiabiliste peut être très exigeant en temps de calcul. Dans le cadre de cette thèse, la méthodologie propre aux problématiques des ouvrages du génie civil est développée et validée tout d'abord sur un cas simple de structures en béton armé. Le cas d'une poutre encastrée en béton armée est proposé. Le système est modélisé sous CASTEM par une approche aux éléments finis de type multifibre. Puis la fiabilité d'une dalle en béton armé impactée par une masse rigide à faible vitesse est étudiée en couplant OpenTURNS à Abaqus. Enfin, une enceinte de confinement en béton précontrainte modélisée sous ASTER est étudiée d'un point de vue probabiliste. Seul le problème physique des dalles en béton armé soumises à une chute de colis dans les centrales nucléaires est examiné en détail. Deux modèles déterministes sont utilisés et évalués afin d’étudier les phénomènes dynamiques appliqués aux dalles en béton armé sous impact : un modèle par éléments finis en 3D modélisé sous Abaqus et un modèle simplifié de type masse-ressort amorti à deux degrés de liberté. Afin d’étudier la fiabilité des dalles en béton armé, nous avons couplé les méthodes Monte Carlo et simulation d’importance avec le modèle de type masse-ressort. FORM est utilisée avec le modèle par éléments finis. L’objectif de cette étude est de proposer des solutions pour diminuer le temps de calcul d'une analyse fiabiliste en utilisant deux stratégies dans le cas des dalles impactées. La première stratégie consiste à utiliser des modèles analytiques qui permettent de prédire avec précision la réponse mécanique de la dalle et qui sont moins coûteux en temps de calcul. La deuxième consiste à réduire le nombre d’appels au modèle déterministe, surtout dans le cas des modèles par éléments finis, en utilisant des méthodes probabilistes d'approximation. Ces deux stratégies sont comparées afin de vérifier l’efficacité de chacune pour calculer la probabilité de défaillance. Enfin, une étude paramétrique est réalisée afin d’étudier l’effet des paramètres d’entrées des modèles déterministes sur le calcul de la probabilité de défaillanceReinforced concrete structures (RC) are subjected to several sources of uncertainties that highly affect their response. These uncertainties are related to the structure geometry, material properties and the loads applied. The lack of knowledge on the potential load, as well as the uncertainties related to the features of the structure shows that the design of RC structures could be made in a reliability framework. This latter allows propagating uncertainties in the deterministic analysis. However, in order to compute failure probability according to one or several failure criteria, mechanical and stochastic models have to be coupled which can be very time consuming and in some cases impossible. The platform OpenTURNS is used to perform the reliability analysis of three different structures . OpenTURNS is coupled to CASTEM to study the reliability of a RC multifiber cantilever beam subjected to a concentrated load at the free end, to Abaqus to study the reliability of RC slabs which are subjected to accidental dropped object impact during handling operations within nuclear plant buildings, and to ASTER to study the reliability of a prestressed concrete containment building. Only the physical problem of reinforced concrete impacted by a free flying object is investigated in detail. Two deterministic models are used and evaluated: a 3D finite element model simulated with the commercial code “Abaqus/Explicit” and an analytical mass-spring model. The aim of this study is to address this issue of reliability computational effort. Two strategies are proposed for the application of impacted RC slabs. The first one consists in using deterministic analytical models which predict accurately the response of the slab. In the opposite case, when finite element models are needed, the second strategy consists in reducing the number of simulations needed to assess the failure probability. In order to examine the reliability of RC slabs, Monte Carlo and importance sampling methods are coupled with the mass-spring model, while FORM is used with the finite element model. These two stategies are compared in order to verify their efficiency to calculate the probability of failure. Finally, a parametric study is performed to identify the influence of deterministic model parameters on the calculation of failure probability (dimensions of slabs, impact velocity and mass, boundary conditions, impact point, reinforcement
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Prakash, Shruthi. "Nonlinear Finite Element Analysis of Shrinking Reinforced Concrete Slabs-on-ground". Thesis, KTH, Betongbyggnad, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-231361.
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Concrete slabs-on-ground are commonly used in many types of industrial floors, warehouses, highways, parking lots and buildings. Cracks and deflection of slabs are undesired events caused by differential shrinkage, which limits the service life of the slabs. Non-linear behavior of cracks and deflections, interaction of concrete and reinforcement increase the complexity in predicting the occurrence and positioning of cracks. The Eurocode 2 provides a reference for theoretical approximation for design of concrete structures. This thesis intent to investigate the crack behavior of slabs-on-ground subjected to gradient shrinkage using nonlinear finite element analysis, as implemented in the software package Atena 2D. The first part of the thesis is focused on suitable modeling techniques for predicting cracks in concrete slabs-on-ground due to gradient shrinkage. The second part is directed towards parametric studies, performed to explore the significance of varying thickness, length, concrete strength class, bond types, reinforcement content and friction coefficient. The results obtained with the Atena 2D was validated using the design software WIN-statik for calculating the maximum crack width in the context of obtaining realistic results. Finally, the WSP guide recommended parameters were tested as inputs to the model. A slab-on-ground was modeled in Atena 2D considering these as statically indeterminate structures, where both slab and grade were included and the convergence analysis performed under plane stress conditions enabling prediction of the maximum crack widths for increasing applied shrinkage loads. Parametric studies demonstrate the dependency of the slab length, showing that a smaller length reduces the crack width, since such a slab is less constrained by the sub-base. To avoid cracks in the slabs their relative thickness should not be increased above a certain thickness, instead the reinforcement content should be increased. The numerical simulation shows that different concrete strength classes give similar cracks widths. Sand as sub-base provides less crack widths for interface materials EPS, sand and gravel. Although, dry sand as interface material gives similar crack widths as EPS, it is the best to use EPS that is also used to retard the moisture diffusion from the sub-base. The numerical model developed was validated for the recommended values given by the WSP guide, which gives less crack widths and deflections. The numerical model gives less crack widths compared to the Eurocode 2, which considers only the statistically determinant problems overestimating the crack widths. The presented examples demonstrate that the developed model can accurately predict crack formation, crack behavior and vertical deflection in concrete slabs-on-ground subjected to gradient shrinkage loads.
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Nash, T. "The experimental behaviour of double skinned composite and reinforced concrete shells subjected to external hydrostatic pressure". Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383249.
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Campiz, Ryan. "Coupling Radio Frequency Energy Via the Embedded Rebar Cage in a Reinforced Concrete Structure for the Purpose of Concrete Degradation Sensing". UNF Digital Commons, 2018. https://digitalcommons.unf.edu/etd/836.
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This study focuses on utilizing an energy harvesting system in which a dedicated Radio Frequency (RF) power source transmits RF power via rebar in a reinforced concrete column. The RF power is received and decoupled by a receiver, and is then rectified, boosted, and stored as electrical energy in a supercapacitor, later to be used to make measurements, process data, and communicate to the source via rebar. Two design attempts are presented in this study: (a) one uses single line conduction at 2.4 GHz for RF power transfer; (b) the other uses a more conventional two-line conduction at 8.0 kHz for RF power transfer. Both designs were unsuccessful: (a) the 2.4 GHz attempt demonstrated that no detectable RF power propagated through the concrete medium; (b) the 8.0 kHz attempt demonstrated that too much of the RF power was attenuated through the concrete medium for the energy harvesting circuitry work properly. A potential third design approach is posited in the conclusion of this study. In addition to investigating power transfer designs, a study on the energy harvesting circuitry was performed. A Two-Stage Dickson Multiplier was utilized in conjunction with a Texas Instruments BQ25504 Ultra-Low Power Energy Harvesting Circuit. For these two components to function best, it was shown that the BQ25504’s input filtering capacitor needed to be on the same order of magnitude as the charging capacitors of the Two-Stage Dickson Multiplier, otherwise, if the filtering capacitor was comparatively too large, it would short the output of the Two-Stage Dickson Multiplier. With that said, the lowest power input observed was at 7.83 dBm, but with lower input powers expected to be achievable. Nevertheless, since the second design attempt showed power losses were too significant, it was deemed that at present, unless the power transfer design were improved, then contemporary commercial off the shelf energy harvesting approaches are insufficient.
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Miller, Tri Huu. "NONDESTRUCTIVE INSPECTION OF CORROSION AND DELAMINATION AT THE CONCRETE-STEEL REINFORCEMENT INTERFACE". Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/194077.
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The proposed study explores the feasibility of detecting and quantifying corrosion and delamination (physical separation) at the interface between reinforcing steel bars and concrete using ultrasonic guided waves. The problem of corrosion of the reinforcing steel in structures has increased significantly in recent years. The emergence of this type of concrete deterioration, which was first observed in marine structures and chemical manufacturing plants, coincided with the increased applications of deicing salts (sodium and calcium chlorides) to roads and bridges during winter months in those states where ice and snow are of major concern. Concrete is strengthened by the inclusion of the reinforcement steel such as deformed or corrugated steel bars. Bonding between the two materials plays a vital role in maximizing performance capacity of the structural members. Durability of the structure is of concern when it is exposed to aggressive environments. Corrosion of reinforcing steel has led to premature deterioration of many concrete members before their design life is attained. It is therefore, important to be able to detect and measure the level of corrosion in reinforcing steel or delamination at the interface. The development and implementation of damage detection strategies, and the continuous health assessment of concrete structures then become a matter of utmost importance. The ultimate goal of this research is to develop a nondestructive testing technique to quantify the amount of corrosion in the reinforcing steel. The guided mechanical wave approach has been explored towards the development of such methodology. The use of an embedded ultrasonic network for monitoring corrosion in real structures is feasible due to its simplicity. The ultrasonic waves, specifically cylindrical guided waves can propagate a long distance along the reinforcing steel bars and are found to be sensitive to the interface conditions between steel bars and concrete. Ultrasonic transducers are used to launch and detect cylindrical guided waves along the steel bar.In this dissertation, in-situ corrosion monitoring technique for reinforced concrete is developed based on two methods - 1) variation of signal strength and 2) the time-of-flight (TOF) variations as the corroded member is loaded transversely. This is the first attempt ever to monitor corrosion inside concrete by measuring the change in the time of flight of guided waves along reinforcing bars as the concrete beam is subjected to bending. Advantages of corrosion monitoring by TOF change are discussed in the dissertation.
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Ceccon, Jorge Luiz. "Análise dos efeitos de segunda ordem em pilares solicitados a flexão oblíqua composta". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-07112008-105053/.
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Na verificação do estado limite último das estruturas reticuladas em concreto armado se tem sempre os pilares solicitados à flexão oblíqua composta, seja devido a momentos fletores transmitidos pelas vigas ou lajes ou devido a imperfeições construtivas ou por ações normais ao eixo da peça comprimida, atuantes entre seus pontos de vinculação. Neste trabalho se está comparando os resultados que se obtém por dois processos de cálculo, quais sejam, a) Integração numérica com desacoplamentos das flexões nas duas direções principais de inércia com o uso da rigidez secante obtida de diagrama momento-curvatura, ou seja, os esforços de segunda ordem são calculados em cada direção como se não houvesse a solicitação de flexão na direção ortogonal e ao final se verifica a segurança da peça no Estado Limite Último considerando a flexão oblíqua composta; b) integração numérica considerando a flexão oblíqua composta com a curvatura obtida de diagrama momento-curvatura ponto a ponto já no cálculo dos efeitos de segunda ordem. Foram processados 215.740 pilares cuja análise conduz à conclusão de que se pode usar o procedimento citado no item (a) acima, com segurança e sem prejuízo da economia.At check reticulated reinforced concrete structures in the ultimate limit state one always have the columns requested by a compression with biaxial bending , be due bending moments transmitted bay beams or slabs or due constructions imperfections or actions normal to the axis of the compressed piece acting between its points of attachment. This work is to compare the results that are obtained by two methods of calculation, which are: a) Numerical integration in each main direction of inertia with the use of secant stiffness obtained from bending-curvature diagram, it is, the second order efforts are calculated in each direction as if there was not request bending in the orthogonal direction and the end check the safety at ultimate limit state of the column by considering the biaxial bending; b) Numerical integration in each main direction of inertia with curvatures obtained point to point of moment-curvature diagrams, that consider the biaxial bending, to calculate the second order effects. Were processed 215.740 columns whose analysis leads to the conclusion that we can use the procedure mentioned in tem a) above, safely and without prejudice to the economy.
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Ospina, Larrea Pedro Manuel. "Analysis of an innovative slim floor composite beam conformed by a custom GFRP pultruded profile and reinforced concrete". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/6392/.
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GFRP pultruded profiles have shown to be structural profiles with great stiffness, strenght and very low specific weight, making it a great candidate for the rehabilitation of damaged strucutres. To further enhance the strucutral mechanism of these type of beams, the Slimflor composite structural system has lead as basis for this analysis; by replacing the steel beam with a GFRP pultruded profile. To further increase its composite action, a continuous shear connector has been set as part of the beam cross section as well as its needed reinforcement and fire protection.
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Richardson, Sarah. "In-Situ Testing of a Carbon/Epoxy IsoTruss Reinforced Concrete Foundation Pile". Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1280.pdf.
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Rajman, Martin. "Železobetonová skeletová konstrukce nákupního centra". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225356.
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The point of my diploma thesis was design elements of reinforced concrete frame structures mounted single – storey mall.I choose the most exposed to the specified longitudinal frame structure, where I assumed the most highly stressed elements, which I subsequently designed. All documents and calculations are illustrated in part B2 of my diploma thesis.
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Elshesheny, Ahmed. "Dynamic soil-structure interaction of reinforced concrete buried structures under the effect of dynamic loads using soil reinforcement new technologies. Soil-structure interaction of buried rigid and flexible pipes under geogrid-reinforced soil subjected to cyclic loads". Thesis, University of Bradford, 2019. http://hdl.handle.net/10454/18312.
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Recent developments in constructions have heightened the need for protecting existing buried infrastructure. New roads and buildings may be constructed over already existing buried infrastructures e.g. buried utility pipes, leading to excessive loads threatening their stability and longevity. Additionally applied loads over water mains led to catastrophic damage, which result in severe damage to the infrastructure surrounding these mains. Therefore, providing protection to these existing buried infrastructure against increased loads due to new constructions is important and necessary.
In this research, a solution was proposed and assessed, where the protection concept would be achieved through the inclusion process of geogrid-reinforcing layers in the soil cover above the buried infrastructure. The controlling parameters for the inclusion of geogrid-reinforcing layers was assessed experimentally and numerically. Twenty-three laboratory tests were conducted on buried flexible and rigid pipes under unreinforced and geogrid-reinforced sand beds. All the investigated systems were subjected to incrementally increasing cyclic loading, where the contribution of varying the burial depth of the pipe and the number of the geogrid-reinforcing layers on the overall behaviour of the systems was investigated. To further investigate the contribution of the controlling parameters in the pipe-soil systems performance, thirty-five numerical models were performed using Abaqus software. The contribution of increasing the amplitude of the applied cyclic loading, the number of the geogrid-reinforcing layers, the burial depth of the pipe and the unit-weight of the backfill soil was investigated numerically.
The inclusion of the geogrid-reinforcing layers in the investigated pipe-soil systems had a significant influence on decreasing the transferred pressure to the crown of the pipe, generated strains along its crown, invert and spring-line, and its deformation, where reinforcing-layers sustained tensile strains. Concerning rigid pipes, the inclusion of the reinforcing-layers controlled the rebound that occurred in their invert deformation. With respect to the numerical investigation, increasing the number of the reinforcing-layers, the burial depth of the pipe and the unit-weight of the backfill soil had positive effect in decreasing the generated deformations, stresses and strains in the system, until reaching an optimum value for each parameter. Increasing the amplitude of the applied loading profile resulted in remarkable increase in the deformations, stresses and strains generated in the system. Moreover, the location of the maximum tensile strain generated in the soil was varied, as well as the reinforcing-layer, which suffered the maximum tensile strain.Government of Egypt
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Eliášová, Kristýna. "Železobetonová nosná konstrukce". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227461.
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My diploma thesis presents structural design of an apartment block in Praha Smíchov. It is a reinforced concrete column structure with six floors. Plane dimensions of the building are 19x36 m. The project includes design of main structural system elements - columns, ceiling plate, foundation and staircase structure.
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Vitálišová, Barbora. "Návrh a posouzení vybraných částí ŽB nosné konstrukce". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392081.
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The diploma thesis deals with the design of selected parts of reinforced concrete elements of the exhibition room. Simultaneously, the optimization of selected elements according to valid standards and Eurocodes was carried out and the impact of these changes on the economy of construction was developed.
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Konečný, Michal. "Alternativní řešení montovaného železobetonového skeletu výrobní haly". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-391882.
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The aim of the thesis is to design a load-bearing precast concrete structure of production facility. Part of the diploma thesis is to design alternative roofing construction including economic comparison. Internal forces analysis was processed by Dlubal RFEM 5.16 software. In order to find out the expected results, were created simple bar models and the spatial model of the structure was processed later. Structural design report was created for selected elements of the concrete structure including drawings.
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Rendon, Adam Russell. "DETERMINATION OF THE MODAL PARAMETERS OF A FIVE STORY REINFORCED CONCRETE STRUCTURE USING ULTRA-LOW LEVEL EXCITATION AND COMPUTATIONAL ANALYSIS". DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/687.
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The determination of a building’s modal parameters (natural periods and mode shapes) using ultra-low level forced vibration testing and analytical modeling were critically compared. The structure utilized for this experiment is the Robert E. Kennedy Library on the campus of California Polytechnic State University San Luis Obispo, a five-story reinforced concrete shear wall structure. The specific testing procedure used has been verified to produce accurate results in smaller buildings, but the Kennedy Library represents the most massive subject structure. Other characteristics of this structure that make it unique include a large atrium at the center of the building and modes that are closely spaced in the frequency domain. Comparing the results from the computational models and the experimental analysis showed that the computational models underestimated the building periods by approximately 6-12%. This discrepancy in the results was attributed to an underestimation of the building mass, possible soil-structure interaction, and likely cracking of the concrete slab and shear walls. Modeling of the shear walls as both line elements and area elements was also explored and the consequences of each were determined.
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Švehla, Ľuboš. "Vysokoškolský internát". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226334.
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New university dormitory in Trnava with five stories is based on the flat land. The first floor is the technical part of the building, space for a temporary accommodation and a separate sales area. Part of the second floor consists of offices for administration, the second part of the floor, as well as the other three stories are designed as a unit system for student accommodation. Total bed capacity is designed for 134 students. The bearing structure of the building is reinforced concrete monolithic skeleton with infill perimeter walls of ceramic bricks. The flat roof of the building is not walkable.
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Cach, Ladislav. "Truhlárna Slaný". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265447.
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The thesis theme is a carpentry production facility with the adjacent office building at Slané. The thesis deals about the proposal of the object with building and construction solutions of the building. The thesis includes a detialed solution of the exhaustion ventilation the technology part of the carpentry. In the office building there is a reception in the 1st floor and the exhibition spaces. The vertical communication in the building is solved by two-arm straight starcases, one in office building and the second in the annexe hall for the employes. The construction system of the hall is reinforced concrete prefabricated system with advanced prestressed girders. Office building is designed like a reinforced concrete monolithic frame. Buildings are divided by dilatation. The object is based on the footings which are connected to base thresholds. The rooftops of the objects are flat.
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Júnior, Osvaldo Gomes de Holanda. "Interação solo-estrutura para edifícios de concreto armado sobre fundações diretas". Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-21122017-114906/.
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Interação solo-estrutura é o objeto de estudo deste trabalho. O principal objetivo é verificar a verdadeira importância desse fenômeno na análise estrutural de edifícios usuais em concreto armado sobre fundações diretas. Inicialmente apresenta-se um estudo sobre o comportamento do solo. Logo após são descritos os processos de dimensionamento de fundações superficiais, com base na NBR 6122 (1996). Descrevem-se em seguida os elementos barra e sapata rígida, utilizados na modelagem do sistema superestrutura-subestrutura-maciço de solos. Discute-se a modificação do elemento sapata rígida, que representa fundação e solo, para a consideração de uma camada indeslocável no interior do solo. De acordo com a teoria apresentada, dois exemplos são submetidos a duas análises, com ou sem a consideração da interação sol-estrutura, para que os resultados sejam comparados. Aplicam-se separadamente as ações verticais e horizontais. A influência duma camada indeslocável no interior do solo e os efeitos da seqüência construtiva dos edifícios também são analisados.Soil-structure interaction is the subject of this work. The foremost aim is to verify the real importance of that phenomenon on the structural analysis of usual reinforced concrete buildings on shallow foundations. At first, it is presented a study of soil behaviour. Design procedures of shallow foundations based on NBR 6122 (1996) are described afterwards. Then, the beam and rigid footing elements, used for modelling the superstructure-infrastructure-foundation soil system, are described. It is discussed the modification of the rigid footing element, which represents foundation and soil, to consider a rigid layer within soil. According to the theory above presented, two examples are subjected to two analysis, with or without the consideration of soil-structure interaction, in order to compare the results. Vertical and horizontal loads are separately applied. The influence of a rigid layer within soil and the effects of the sequence of buildings construction are also analysed.
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Takata, Leandro Teixeira. "Aspectos executivos e a qualidade de estruturas em concreto armado : estudo de caso". Universidade Federal de São Carlos, 2009. https://repositorio.ufscar.br/handle/ufscar/4655.
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Previous issue date: 2009-09-29Financiadora de Estudos e Projetos
The execution of reinforced concrete structures is a construction stage that has significant importance in the overall context of a work and involves materials, suppliers, work fronts in the workplace and a large number of professionals. In this stage many problems may occur: inadequate use of materials, misinterpretation of the project, incorrect use of equipments, action of weather and other inconveniences. Carelessness at this stage can lead to major schedule delays and extra costs, as this will require new tasks, materials and equipment not predicted (a new set of forms can be used, but the material and labor for the service may not be available). Surveillance and attention are needed for a good final product which, however, is not always achieved. That is where the pathology of structures acts, aiming to correct and prevent failures in all constructive stages. Otherwise, problems may appear in the global chain of the work, leading to the need to restructure the process of execution of the building. Therefore, several authors propose standard, and even alternative, construction methods, companies provide manuals of performance and quality control of materials and the codes propose minimum requirements for safety, durability and quality of buildings. To study and improve the execution phase means, therefore, avoiding delays and additional costs, as well as ensuring that the building will have quality and durability. This paper analyzes the execution phase of a given multiple floor building, pointing out mistakes and their possible influences on the quality of the building during its service life.
A execução de estruturas em concreto armado é uma etapa da construção que tem importância significativa no contexto global de uma obra e envolve materiais, fornecedores, frentes de trabalho no canteiro e vários profissionais. Nessa etapa podem ocorrer muitos problemas: uso inadequado de materiais, má interpretação de projetos, uso incorreto de equipamentos, ação de intempéries e outros inconvenientes. Descuidos nessa fase podem gerar atrasos importantes no cronograma e custos adicionais, por acarretar novas tarefas e exigir materiais e equipamentos não previstos (um novo jogo de fôrmas pode ser utilizado, mas o material e mão-de-obra para o serviço podem não estar disponíveis). Fiscalização e cuidados são necessários para um bom produto final o que, porém, nem sempre é atingido. É aí que entra a patologia das estruturas, que visa à prevenção e correção de falhas em todas as etapas construtivas. Caso contrário podem aparecer problemas na cadeia global da obra, com a necessidade de reestruturar o processo de execução da edificação. Por isso, diversos autores propõem métodos construtivos padrões e até alternativos, empresas disponibilizam manuais da boa execução e controle de qualidade dos materiais e as normas propõem requisitos mínimos para a segurança, durabilidade e qualidade das edificações. Estudar e melhorar a etapa de execução significa, portanto, evitar atrasos e custos adicionais, assim como garantir que a edificação tenha qualidade e durabilidade. Este trabalho analisa a etapa de execução de um edifício de múltiplos pavimentos, apontando erros e suas possíveis influências na qualidade do edifício durante sua vida útil.
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Arnaud, Ivana Raquel Lima. "Patologia prematura de blocos de fundação de edificação residencial de múltiplos pavimentos em ambiente urbano". Universidade Federal da Paraíba, 2010. http://tede.biblioteca.ufpb.br:8080/handle/tede/5562.
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Previous issue date: 2010-03-30Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The amount of pathologies in young reinforced concrete structures inserted in the urban surroundings have been of some relevance because they are reducing the structures‟ life, causing great troubles and financial losses for users and builders. Concrete pathologies may have different origins and its diagnosis may be quite complex, with the possibility of a simultaneous occurrence, leading difficult the adequate therapy in each case. This research presents a study of a case in which the pathologies have appeared in a building‟s foundation blocks, despite the criteria of ABNT- NBR 6118/2004 being followed in relation to durability. The blocks have shown generalized cracking whose aspect is similar to the alkali-aggregate reaction (RAA) phenomenon. This phenomenon is considered to be a deterioration mechanism caused by chemical actions. Taking this into consideration, the main goal of the present research is to verify if the alkali-aggregate reaction was occurring in the concrete foundation blocks of an building in the city of João Pessoa, presenting, analyzing and discussing the pathological problem. For this, concrete micro-structural tests were carried out through the use of some material characterization analytical techniques such as mineralogical analysis by x-ray diffractions (DRX), microscopic analysis by optical microscopy and by sweeping electronic microscopy (MEV) and thermal analysis by thermogravimetry. Despite the similarity with the RAA, the results of the micro-structural analysis indicated that there was not the presence of the alkali-aggregate reaction nor the one of delayed ettringite as there was no formation of material of a different composition (contrast of gray) inside any cracks nor in the contour of the aggregate, which is typical of a chemical reaction. The outcomes suggest that the cracks in these blocks do not seem to have been generated by expansive mechanisms of a chemical origin. This is due to the fact that no mineral responsible for expansive pathologies such as alkali-silica, ettringite or gypsium has been found (Calcium Sulfate). The cracks that propagate through the cement matrix and contour the aggregate are possibly induced by tensions of a thermal origin.
O crescimento dos casos de patologias precoces em estruturas de concreto armado, inseridas no ambiente urbano, tem gerado grande interesse porque estão reduzindo a vida útil das estruturas, causando muitos transtornos e prejuízos financeiros para os seus usuários e construtores. As patologias do concreto armado podem ter diversas origens e o seu diagnóstico ser bastante complexo, inclusive podendo ocorrer simultaneamente, dificultando a aplicação da terapia adequada a cada caso. Neste trabalho apresenta-se um estudo de caso em que patologias estão se manifestando em blocos de fundação de um prédio, malgrado tenham sido obedecidos os critérios da ABNT- NBR 6118/2004, quanto à questão da durabilidade. Os blocos apresentam fissuração generalizada, cujo aspecto é semelhante ao do fenômeno da reação álcali-agregado. Este fenômeno é considerado um mecanismo de deterioração cuja causa é originada por ações químicas. Face ao exposto, objetivo deste trabalho é verificar se estava ocorrendo ou não a reação álcali-agregado no concreto dos blocos de fundação de um edifício residencial em construção na cidade de João Pessoa, apresentando, analisando, e discutindo o problema patológico neles ocorrido. Para isto, foram realizadas análises microestruturais do concreto, através da utilização de algumas técnicas analíticas de caracterização dos materiais, como análise mineralógica por difração de raios x (DRX), análise microscópica por microscopia óptica e por microscopia eletrônica de varredura (MEV) e análise térmica por termogravimetria. Apesar da semelhança com a RAA, os resultados da análise microestrutural do concreto estudados, indicou que não houve a presença da reação álcali-agregado, nem de formação de etringita retardada, pois não houve formação de material de diferente composição (contraste de cinza) dentro de nenhuma fissura, nem no contorno dos agregados, típica de reação química. Os resultados sugerem que as fissuras nestes blocos não aparentam terem sido geradas por mecanismos expansivos de origem química. Isto porque não foi detectada a presença de nenhum mineral responsável por patologias expansivas tais como gel de álcali-sílica, etringita, nem gypsum (sulfato de cálcio). As fissuras se propagam através da matriz de cimento e contornam o agregado, são possivelmente induzidas por tensões de origem térmica.
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Andreotti, Elena. "Study of an alternative structural solution for the new quay of Trattaroli Terminal in Ravenna". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
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The thesis developed, aims the entire design for the new quay structure of Trattaroli peninsula in the port of Ravenna. The topic has been developed during a stage, lasting five months, at Sapir Engineering S.r.l. that operates in the field of public and private civil engineering works.
The Port of Ravenna is the main port of Emilia-Romagna region. Docks are mainly on a channel that connects the town centre of Ravenna to the open sea, which is almost 10,00 km away. It hosts shipyards, multipurpose terminals, bulk cargo terminals and a containerized cargo terminal. The study at issue, regards the Candiano Channel, in particular the Trattaroli peninsula, located in the internal part of the Corsini Port that connects the centre of Ravenna with the open sea and is part of the commercial and industrial port.
Specifically, in the thesis, it has been modified the existing project with new technological solutions and using alternative materials for structural and lasting performance improvements. For this reason, some numerical models have been applied to elaborate the study in terms of hydraulic, geotechnical and structural design.
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Louw, Hendrik. "Modelling horizontally loaded piles in the geotechnical centrifuge". Diss., University of Pretoria, 2020. http://hdl.handle.net/2263/73182.
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Pile foundations are extensively used to support various structures that are constructed in soft/loose soils, where shallow foundations would be considered ineffective due to low bearing capacities and large settlements. The design of these structures to accommodate lateral applied loads in particular, usually imposed by winds, water and earth pressures, has gained popularity over the past few decades. The behaviour of horizontally loaded piled foundations is a complex soil-structure interaction problem and is usually concerned with the relative stiffness between the pile and the surrounding soil, where the relative stiffness is a function of both the stiffness and properties of the pile and the stiffness of the soil.
Many design assumptions and methods used for pile foundations are based on the principles observed from metal piles. This raises the question of the validity and accuracy of assumptions and methods for the use of analysing and designing reinforced concrete piles, that exhibits highly non-linear material behaviour and changing pile properties after cracking. Due to the elastic behaviour of metal sections, these methods typically only focus on the soil component of the soil-structure interaction problem, only allowing changes and non-linear behaviour of the soil surrounding the pile to take place upon load application, mostly disregarding the behaviour and response of the pile itself.
The main purpose and objective of the study was to determine whether aluminium sections in a centrifuge could be used to realistically and sufficiently accurately model the monotonic and cyclic response of reinforced concrete piles subjected to lateral loading. This was observed though a number of tests conducted in a geotechnical centrifuge on scaled aluminium and reinforced concrete piles, subjected to both monotonic and cyclic loading.
After conducting the tests on both the scaled aluminium and reinforced concrete piles in the centrifuge it was concluded that aluminium sections cannot be used to accurately model and predict the lateral behaviour of reinforced concrete piles. Both the scaled aluminium and reinforced concrete piles proved to model the concept of laterally loaded piles quite well regarding bending at low loads. However, even at low lateral loads, the observed response of the scaled reinforced concrete was significantly different than that observed from the scaled aluminium pile. Furthermore, as the magnitude of the applied load and bending increased, the scaled reinforced concrete pile cracked, resulting in non-linear behaviour of the section under loading, which was not the case for the scaled aluminium pile that remained uncracked. This contributed to the difference in behaviour between the piles studied, therefore, the true material behaviour and failure mechanisms involved with reinforced concrete piles were not replicated by using a scaled aluminium pile section. The non-linear behaviour of the scaled reinforced concrete pile after cracking affected both the behaviour of the pile, as well as the response of the soil surrounding the pile, in contrast with the behaviour observed from the scaled aluminium pile.Dissertation (MEng)--University of Pretoria, 2020.
The Concrete Institute
Concrete Society of Southern Africa
WindAfrica project
Civil Engineering
MEng (Structural Engineering)
Unrestricted
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Starý, Marek. "Rekonstrukce budovy pivovaru". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226422.
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Luliak, Ondřej. "Statická analýza konstrukce pro zpracování odpadu". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227574.
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Master thesis deals with static analysis of construction of hall type for waste treatment. Thesis includes design and structural assessment of main support elements of construction. This is two-aisled combined skeleton object. The roof system is composed of steel truss structure.
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Jiang, Yin-Xian y 江育賢. "A Study for Concrete Structure Reinforced". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/98604974423276051626.
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碩士國立臺灣科技大學
營建工程系
90
ABSTRACT The object of this study is to develop a new way to construct reinforced concrete structures. The main difference is the construction procedure is changed to build the steel reinforcement first. There are two kinds of steel frame were suggested. The first one uses steel sheets to build the steel frame. The second one uses traditional reinforcement plus steel sheets to build the steel frame. However, these steel frames are different from the steel sections used in the steel reinforced concrete structures. The beam unit, column unit, and connection unit were developed in this study. All these units were designed for easy construction and improved structural strength. Also, all the faults could be made in the traditional reinforcement construction can be avoided. Therefore the most important improvement could be obtained through this new suggestion is a better quality. The suggested steel frame should be treated as a three-dimension structure. This frame can resist forces come from any direction instead of the longitudinal strength only. Due to the strong connection between frame members, the ductility of the reinforced concrete member can be improved a lot also. An economic study was made to compare the cost of traditional reinforced concrete structures and the suggested new structure. It was found that the construction cost can be increased a little around 10%. However, the construction time can be reduced in a range of 30% to 50%. Many new technologies like high-strength concrete, composite plate, light-weight partition wall, etc. can be integrated to this new method to get a light weight but high-strength concrete structure, which is suitable for the high-rise buildings.
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TSAI, TE YUAN y 蔡德源. "Object-orirnted reinforced concrete structure design". Thesis, 1997. http://ndltd.ncl.edu.tw/handle/02091753290706872375.
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Lin, Wen-Long y 林文隆. "Seismic Vulnerability Analysis of Reinforced Concrete Structure". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/41551051767766485463.
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碩士國立中央大學
土木工程研究所
95
Sensible earthquakes hit Taiwan frequently. An earthquake has catastrophic characteristics of low frequency and devastating disaster. In this case, in the earthquake loss, structure damage assessment plays an important role. Also, this provides reasonable and reliable results of structure earthquake damage assessment to be as applications of earthquake catastrophe risk management. In the earthquake damage assessment, this article applies nonlinear dynamic analysis structure model to stimulate the structure possible damage condition. The main cause of forming earthquake damage is that dynamic response exceeds in structure itself damaging threshold. Therefore, story drift ratio is adopted to determine damage state of building. damage state could be identified with different drift ratio. This will help to assess buildings damage rapidly according to establish fragility curve of building. The seismic structure damage appraisal is to establish all kinds of structure fragility curve, this article aim to do researches on typical reinforced concrete via theoretical analysis method and determine typical structure vulnerability analysis parameters in Kaohsiung County areas. This will help to assess similar buildings under earthquake which causes different damage state and probability as well as to evaluate the economic benefit of building retrofitting or reference of earthquake risk management in the future.
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Lee, Bo-Yan y 李柏彥. "Limit Load Analysis of Steel Reinforced Concrete Structure". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/246scb.
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碩士朝陽科技大學
營建工程系碩士班
94
First, this study refers the national code of the Republic of China, textbook and domestic experiment about steel structure reinforced concrete (SRC). The SRC component of experimentation was transformed to the equivalent steel component. The equivalent steel component was input to SAP2000 structure analyzing program. Then, this project confer the relationship of the initial stiffness and limit load of equivalent steel component analyzed by SAP2000 and tested by experiment. The transferred equivalent cross-section theory was applied to New Engineering Building at Chaoyang University of Technology. The pushover analyzing method of SAP2000 was used to study the failure mode and the earthquake bearing ability. In order to know the contribution of SRC structure, the original steel columns was replaced by SRC columns in the second floor and the third floor. Finally, this study compares the minimum earthquake force according to the code and the 921 earthquake force. Earthquake thrust in 921 earthquake and the base force analyzed by SAP2000 were used to realize that whether New Engineering Building can resist the similar earthquake attack or not.
47
Chen, Zhi-Hong y 陳志宏. "Research of Damage Index of Reinforced Concrete Structure". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/25734364164134865364.
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碩士國立臺灣大學
土木工程學研究所
98
This thesis is for the purpose of discussing the damage index of buildings under the earthquake over the years of definition by scholars, the so-called damage index,is refers to the structure to receive a succession of structure response parameter which under the earthquake function, and to establish a set of computation flow the damaged condition size. We may because of the damage index, to cognitive structure of extent of damage preliminary to judge this structure whether suits the housing or use again. We use the structure to suffer a strong earthquake to make the system enter the non-linearity, cause the natural frequency of structure to start to change and judges its damage. This thesis simulates behavior of the nonlinear system in use Least-Squares Method to get the equivalent linear damping and frequency, and confirms its accuracy by Newmark-β Method, after judges the extent of damage of structure by the Maximum softening damage index, and improves it by the frequency with stiffness relations to damage index to promote its sensitivity. Then uses Park and Ang damage index this index is formed by the structure displacement and the energy dissipation under the carrying capacity, and considered its structural material parameter, the Maximum softening damage index, stiffness destruction index and Park and the Ang destruction index will do reorganizes and compares its good and bad points. Finally, we can get the time history and material parameter of frames of one layer three cross frame collapse tests in National Center for Research on Earthquake Engineering to treat as measured value, carries on the example analysis. By way of identification as well as calculates result of each destruction index to make a comparison.
48
Menichini, Giovanni. "Seismic response of vertical concrete façade systems in reinforced concrete prefabricated buildings". Doctoral thesis, 2020. http://hdl.handle.net/2158/1220505.
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The design of “non-structural” elements, including the cladding panels for precast RC buildings,
plays a key role in the building seismic response. The large damages that occurred in precast RC
buildings, during the recent earthquakes in southern Europe were mainly caused by the collapse
of the cladding panels. Therefore, is required to revise, to revise the technological and design
philosophy the panel-to-structure connection devices in RC precast structures.
Starting from these considerations, the main topic of this thesis is the investigation of such
connection devices. Deeply understanding the working principle of these systems makes it
possible to open a way to solve the problem.
The influence of the panels to the global response of precast structure is studied for different
types of panel-to-structure connections (two types of hammer-head straps) and panels-to-foundation
connections (fixed and rocking panels). Numerical models for the in-plane response
of connection devices are developed using both existing experimental data from shaking table
test performed by University of Ljubljana and result of new tests carried out at the Structures
and Materials Testing Laboratory of University of Florence
A new connection device, which better uncouples the in-plane seismic response, is developed
and studied analytically and experimentally.
The study highlights that traditional devices fail due to their limited in-plane displacement
capacity while the new device has much better behaviour. The study showed that in-plane
direction was critical for connection compared to the out-of-plane one. It also showed that
fixed-base panels provide a better seismic performance of connection devices.
49
Tomeo, Romeo. "Soil-structure interaction effects on the seismic behaviour of reinforced concrete structures". Tesi di dottorato, 2017. http://www.fedoa.unina.it/11537/1/tomeo_romeo_29.pdf.
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In common seismic design practice, the design of a new building or the vulnerability assessment of an existing one is usually performed assuming that the structure is fixed at the base and assuming that the signal at the base is that evaluated in free field conditions.
This assumption, reasonable for structures founded on stiff soils, can be unrealistic in case of structures founded on soft soils.
Despite an intense scientific production on the topic, the diffusion of soil-structure interaction (SSI) analyses in the field of civil constructions is nowadays rather limited, mainly because of three reasons: (1) the lack, in many countries, of specific code prescriptions; (2) the belief that soil-structure interaction has a beneficial effect on the structural response and thus it is possible to have an increase of the safety level neglecting it; (3) the complexity in performing a rigorous analysis.
In the thesis these three issues were faced.
In order to validate the simplified formulations suggested by American Standards and Guidelines for the evaluation of SSI effects, a sensitivity analysis was performed, by means of linear modal analyses, for Reinforced Concrete (RC) structures (regular and not regular) of different heights and founded on stiff or soft soil.
Non-Linear Static Analyses (Push Over) were then performed for two RC Moment Resisting Frames (MRFs) designed without seismic provisions, in order to evaluate the influence of SSI effects on the ratios Capacity/Demand (C/D), which can strongly affect the design strategies of seismic retrofitting interventions.
In order to investigate more accurately the influence of SSI effects on the seismic performances of RC MRFs, more refined non-linear dynamic analyses were performed by means of the software OpenSees.
The analyses showed that, based on the modelling approach adopted, SSI can affect more or less the estimation of the seismic demand with respect to a fixed-base model.
The adoption of a complete FEM model, in which soil and structure are modelled together in one single step, can lead to significant reductions, with respect to a fixed base model, in the estimation of the seismic demand, especially in terms of maximum inter-storey drift ratio.
On the contrary, a simplified modelling approach with non-linear springs and dashpots, seems to not adequately capture SSI effects.
Moreover, it is emphasized that in case of stiffer structural systems, as dual systems with frames and shear walls, founded on a soft soil, SSI can imply a very high increase of the seismic demand with respect to the fixed base configuration. Thus, SSI effects should be properly taken into account in the design of retrofitting interventions that can involve a strong modification of the structural stiffness.
50
Deng, Fu-Sheng y 鄧福勝. "Numerical Simulations of Reinforced Concrete Structure Containing Brick Wall". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/81331179546250485600.
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碩士國立中央大學
土木工程研究所
89
The behaviors of reinforced concrete structures containing brick wall under earthquake loading are quite complicated. It is very difficult to analyze the problem analytically. Experiment and numerical simulation are two possible solutions to extract reference information for the development of design code. However, the experimental approach requires much effort and expense to built very limited number of specimens to explore the behaviors of RC structures. The main advantage of using numerical simulation code to study the structural problem is that any detail response of the system can be detected easily from the calculated data. In this thesis, a computation code is developed based on the finite element method (FEM) and the discontinuous deformation analysis (DDA) theory. Each brick is modeled as a DDA block patched with finite element mesh. After cracking of mortar, the multi-body dynamics and contact analysis among bricks and RC frame are dealt by the DDA theory. Truss element is used to model the behavior of reinforcement inside the concrete and is tied up with the concrete at the node of concrete element. Both the nonlinear behaviors of the reinforcement and concrete material are considered into the analysis. To model the behavior of the mortar between bricks, a special interface element is developed. This element can provide suitable bond force between two blocks due to mortar. This interaction force can be reduced according to the interfacial friction and contact laws if interfacial cracking is identified. Besides, smear damage model of cracked concrete material is also acquired to adjust its coefficients of elasticity at Gaussian points according to the direction of crack surface. The accuracy and effectiveness of this simulation code were verified by some benchmark problems and experiment results of large-scale structural tests.