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Limit States Testing of a Buried Deep-Corrugated Large-Span Box CulvertLougheed, ANDREA 15 January 2009 (has links)
Results are reported from full-scale testing of a buried, deep-corrugated, large-span box culvert with a 2.4 m rise and 10.0 m span under controlled laboratory conditions. A total of twenty-one experiments were conducted on the structure, measuring its response without backfill, during backfilling, under a loaded tandem axle dump truck, and under simulated vehicle loading with force applied by an actuator. Surface strain measurements were used to calculate bending moments and thrusts, while deflections were monitored using an electronic theodolite.
Tests conducted to a maximum force of truck loading specified by the Canadian Highway Bridge Design Code multiplied by a dynamic load allowance factor were performed at three cover depths. The maximum moment increased from 6 to 41 kNm/m as the cover was reduced from 1.5 to 0.45 m. This was attributed to less load distribution and decreased soil-structure system stiffness at shallower cover. The maximum bending moments were consistently observed directly beneath the applied force.
Tests were also conducted at forces larger than the design values to identify the ultimate limit state(s) of the structure. An ultimate limit state was encountered at approximately 800 kN where the geotechnical resistance beneath the loading pads was exceeded. A subsequent test with the loading pad force spread over larger areas permitted larger forces to be applied. An ultimate limit state of the structure involving the formation of three plastic hinges occurred at 1100 kN. The plastic hinge initially formed at the crown, followed by hinges located at each shoulder. Post-test observations showed evidence of local buckling of the conduit wall, gaps between the plates at the seams, the tilting of bolts along the longitudinal seams, and surface cracks in the soil. Applying the material resistance factor of 0.9 to the ultimate load limit of 1100 kN measured for the structure yields a reserve capacity of 1.7 when compared to the fully factored load including dynamic load allowance and live load factors. / Thesis (Master, Civil Engineering) -- Queen's University, 2008-12-23 11:56:12.314
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Stability Analysis of Non-overflow Section of Concrete Gravity Dams : A Longtan Dam case studyJohansson, Lukas, Valtersson, Dan January 2018 (has links)
No description available.
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Screw-Fastened Cold-Formed Steel-to-Steel Shear Connection Behavior and ModelsCorner, Sebastien Marc William 19 January 2015 (has links)
This research introduces a proposed model for predicting tilting angle and limit states of single-fastened cold-formed steel-to-steel shear connections. Predictions are validated through an experimental study considering ply configuration and a single Hex #10 -washer head fastener, centered in a 102 mm by 102 mm three boundary window. The fastener tilting angle is captured using an automated, optical non-contact measurement procedure. The results are used to identify cold-formed steel shear connection deformation as load progresses, including tilting, bearing, and combined tilting bearing at the plies and thread tension, shear and bearing fastener failure. Results shows that fastener tilting plays a kinematic affect for the connection. Fastener tilting is predicted in function of ply thickness and fastener pitch. Local ply bending deformation is reported to be the main deformation of the connection during fastener tilting. While fastener bending and shear failure occurred if the fastener does not tilt. / Master of Science
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Spojitý komorový most / Continuous box girder bridgeHajnoš, Mário January 2022 (has links)
The topic of this thesis is detailed design of supporting structure of continous box girder bridge across a deep valley called Lazný creek. The bridge have to pass the second class road with category S 9,5. The design is processed by two options. The chosen option is designed as a girder with five spans 44,8 m + 55 m + 55 m + 55 m +44,8 m. Total length of bridge is 268,57 m, the main girder is gradually cast into the formwork suspended on a special ceiling scaffolding. The axis of the bridge is in a plan straight with the constant transversal slope 2,5 %. The thesis contains six models in software SCIA ENGINEER. Part of the work is situated on time depended analysis with construction phases. Assesment of ultimate limit states and serviceability limit states were done by hand according to the valid standards and regulations. Structural analysis, drawing documentation and vizualization are parts of this work.
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Análise da segurança no projeto de estruturas: método dos estados limites / Safety in the structural design: limit states designCastro, Leila Aparecida de 18 June 1997 (has links)
Este trabalho aborda a introdução da segurança baseada em métodos probabilísticos, aplicados nos cálculos em estados limites, apresentando informações com o objetivo de esclarecer o meio técnico em geral a respeito dos fundamentos teóricos e das vantagens que tal método apresenta frente ao tradicional método das tensões admissíveis. Apresenta-se ainda alguns exemplos de cálculo, mostrando a determinação do índice de confiabilidade e dos coeficientes adotados no método dos estados limites, os quais são calibrados em relação aos tradicionais coeficientes de segurança do método das tensões admissíveis. / This work is about structural safety based in the probabilistic methods, applied in the structural design at limit states. Informations about theoretical background and advantages that this method shows related to traditional allowable stress design method are presented. In addition, some examples are presented, showing the determination of the reliability index and limit states factors, which are adjusted to original safety factors of the allowable stress design method.
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NUMERICAL STUDY AND LOAD AND RESISTANCE FACTOR DESIGN (LRFD) CALIBRATION FOR REINFORCED SOIL RETAINING WALLSHUANG, BING 29 January 2010 (has links)
Load and resistance factor design (LRFD) (often called limit states design (LSD)) has been mandated in the AASHTO Bridge Design Specifications and will be adopted in future editions of Canadian Highway Bridge Design Code for all transportation-related structures including reinforced soil retaining walls. The ultimate objective of this thesis work was to carry out reliability-based analysis for load and resistance factor design calibration for rupture and pullout limit states for steel and geosynthetic reinforced soil walls under self-weight and permanent surcharge loading conditions. In order to meet this objective it was necessary to generate large databases of measured load and resistance data from many sources and in some cases to propose new design models that improve the accuracy of underlying deterministic load and resistance models. Numerical models were also developed to model reinforced soil wall performance. These models were used to investigate load prediction accuracy of current analytical reinforcement load models. An important feature of the calibration method adopted in this study is the use of bias statistics to account for prediction accuracy of the underlying deterministic models for load and resistance calculations, random variability in input parameter values, spatial variation and quality of data. In this thesis, bias is defined as the ratio of measured to predicted value. The most important end product of the work described in this thesis is tabulated resistance factors for rupture and pullout limit states for the internal stability of steel and geosynthetic reinforced soil walls. These factors are developed for geosynthetic reinforced soil wall design using the current AASHTO Simplified Method, a new modified Simplified Method, and the recently proposed K-Stiffness Method. Useful quantitative comparisons are made between these three methods by introducing the concept of computed operational factors of safety. This allows designers to quantify the actual margin of safety using different design approaches.
The thesis format is paper-based. Ten of the chapters are comprised of journal papers that have been published (2), are in press (2), in review (3) and the remaining (3) to be submitted once the earlier background papers are accepted. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2010-01-28 18:07:22.284
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Semi-Quantitative Assessment Framework for Corrosion Damaged Slab-on-Girder Bridge Columns Using Simplified Nonlinear Finite Element AnalysisMohammed, Amina 06 May 2014 (has links)
Most of existing North American bridge infrastructure is reported to be deficient. Present infrastructure management mainly relies on qualitative evaluation, where bridge safety and serviceability are judged through routine visual inspection. With the successive increase in the number of severely deficient bridges and the limited available resources, it is crucial to develop a performance-based quantitative assessment evaluation approach that enables an accurate estimation of aging bridges ultimate and seismic capacities and ensures their serviceability. Reinforcement corrosion is the main cause of most of North American concrete infrastructure deterioration. Experimental investigations prove that reinforcement corrosion results in reduction of the steel reinforcement cross sectional area, localized (or global in very extreme cases) loss of bond action, concrete spalling, loss of core concrete confinement, and structural collapse. Field observations show that damage due to reinforcement corrosion in reinforced concrete (RC) bridge columns is localized in highly affected zones by splash of deicing water.
In this thesis, an innovative performance-based semi-quantitative assessment framework is developed using newly developed simplified nonlinear static and dynamic finite element analysis approaches. The framework integrates the bridge’s available design and after-construction information with enhanced inspection and additional material testing as sources for accurate input data. In order to evaluate the structural performance and the capacity of the corrosion-damaged bridge columns, four nonlinear static and dynamic analysis approaches have been developed: (i) simplified nonlinear sectional analysis (NLSA) approach that presents the basis of the analysis approaches to estimate the ultimate and seismic capacities, and serviceability of bridge columns; (ii) simplified nonlinear finite element analysis (NLFEA) approach, which enables estimating the ultimate structural capacity of corrosion-damaged RC columns; (iii) simplified hybrid linear/nonlinear dynamic finite element analysis (SHDFEA) approach to evaluate the serviceability of the bridge; and, (iv) simplified non-linear seismic analysis (SNLSA) approach to evaluate the seismic capacity of the bridge columns. The four analysis approaches are verified by comprehensive comparisons with available test experimental and analytical results. The proposed semi-quantitative assessment framework suggests three thresholds for each performance measure of the evaluation limit states to be decided by the bridge management system team. Case studies are presented to show the integrity and the consistency of using the proposed assessment framework. The proposed assessment framework together with the analysis approaches provide bridge owners, practicing engineers, and management teams with simplified and accurate evaluation tools, which lead to reduce the maintenance/rehabilitation cost and provide better safety, and reduce the variation in the data collected using only traditional inspection methods.
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Análise da segurança no projeto de estruturas: método dos estados limites / Safety in the structural design: limit states designLeila Aparecida de Castro 18 June 1997 (has links)
Este trabalho aborda a introdução da segurança baseada em métodos probabilísticos, aplicados nos cálculos em estados limites, apresentando informações com o objetivo de esclarecer o meio técnico em geral a respeito dos fundamentos teóricos e das vantagens que tal método apresenta frente ao tradicional método das tensões admissíveis. Apresenta-se ainda alguns exemplos de cálculo, mostrando a determinação do índice de confiabilidade e dos coeficientes adotados no método dos estados limites, os quais são calibrados em relação aos tradicionais coeficientes de segurança do método das tensões admissíveis. / This work is about structural safety based in the probabilistic methods, applied in the structural design at limit states. Informations about theoretical background and advantages that this method shows related to traditional allowable stress design method are presented. In addition, some examples are presented, showing the determination of the reliability index and limit states factors, which are adjusted to original safety factors of the allowable stress design method.
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Semi-Quantitative Assessment Framework for Corrosion Damaged Slab-on-Girder Bridge Columns Using Simplified Nonlinear Finite Element AnalysisMohammed, Amina January 2014 (has links)
Most of existing North American bridge infrastructure is reported to be deficient. Present infrastructure management mainly relies on qualitative evaluation, where bridge safety and serviceability are judged through routine visual inspection. With the successive increase in the number of severely deficient bridges and the limited available resources, it is crucial to develop a performance-based quantitative assessment evaluation approach that enables an accurate estimation of aging bridges ultimate and seismic capacities and ensures their serviceability. Reinforcement corrosion is the main cause of most of North American concrete infrastructure deterioration. Experimental investigations prove that reinforcement corrosion results in reduction of the steel reinforcement cross sectional area, localized (or global in very extreme cases) loss of bond action, concrete spalling, loss of core concrete confinement, and structural collapse. Field observations show that damage due to reinforcement corrosion in reinforced concrete (RC) bridge columns is localized in highly affected zones by splash of deicing water.
In this thesis, an innovative performance-based semi-quantitative assessment framework is developed using newly developed simplified nonlinear static and dynamic finite element analysis approaches. The framework integrates the bridge’s available design and after-construction information with enhanced inspection and additional material testing as sources for accurate input data. In order to evaluate the structural performance and the capacity of the corrosion-damaged bridge columns, four nonlinear static and dynamic analysis approaches have been developed: (i) simplified nonlinear sectional analysis (NLSA) approach that presents the basis of the analysis approaches to estimate the ultimate and seismic capacities, and serviceability of bridge columns; (ii) simplified nonlinear finite element analysis (NLFEA) approach, which enables estimating the ultimate structural capacity of corrosion-damaged RC columns; (iii) simplified hybrid linear/nonlinear dynamic finite element analysis (SHDFEA) approach to evaluate the serviceability of the bridge; and, (iv) simplified non-linear seismic analysis (SNLSA) approach to evaluate the seismic capacity of the bridge columns. The four analysis approaches are verified by comprehensive comparisons with available test experimental and analytical results. The proposed semi-quantitative assessment framework suggests three thresholds for each performance measure of the evaluation limit states to be decided by the bridge management system team. Case studies are presented to show the integrity and the consistency of using the proposed assessment framework. The proposed assessment framework together with the analysis approaches provide bridge owners, practicing engineers, and management teams with simplified and accurate evaluation tools, which lead to reduce the maintenance/rehabilitation cost and provide better safety, and reduce the variation in the data collected using only traditional inspection methods.
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Železniční obloukový most / Railway arch concrete bridgeŠkrabal, Jan January 2022 (has links)
The subject of this diploma thesis is the structural design of a railway bridge over river Dyje based on materials given by my supervisor. The tied arch bridge with prestressed concrete girder is chosen for the structural check. The structural assesment is focused on prestressed concrete girder and basic calculations are made to check steel arch and hangers as well. Eigenvalue analysis provides dynamic properties of this structure. Appendices contain Structural design report, drawings including Construction stages scheme and visualization. For structural analysis Midas Civil software was used. Other used softwares for visualization, and outputs etc are: Lumion12, IdeaStatica, Microsoft excel and Autocad
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