Download or read book Dynamic Analysis of Steel Confined Concrete Tubular Columns Against Blast Loads written by Fangrui Zhang and published by . This book was released on 2017 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of composite construction has drawn more and more attention in recent decades. This thesis contains a number of journal articles which aim to enrich the knowledge of the performance of concrete filled tubular columns when subjected to blast loading. Experimental investigations are used in conjunction with numerical analysis to provide a thorough assessment of the blast-resistance of concrete filled tubular columns. The first chapter mainly focuses on the experimental study on concrete filled tubular columns under blast loading. A large-scale blast experimental program is carried out on concrete filled double-skin steel tube (CFDST) columns. The blast experiment aims to examine the blast-resistance of ten CFDST specimens, including five with square cross-section and the other five with circular cross-section. The parameters that are investigated during the blast experiment include: cross-sectional geometry, explosive charge weight and magnitude of axial load. After the experiment, several damaged test specimens are then transported back to the laboratory for residual axial load-carrying capacity tests. The proposed CFDST columns are able to retain more than 60% of its axial load-carrying capacity even after being subjected to close-range explosion. As blast experiments are often costly and associated with potential safety concerns, numerical tools have been adopted by more and more researchers. In the second chapter of the thesis, numerical approaches in modelling the dynamic behaviour of concrete filled steel tube (CFST) columns and CFDST columns under blast loading are presented. The numerical models are validated against the results of the blast experiment as described in the first chapter and good agreement is achieved. Parametric studies on the effect of column dimensions and material properties are also discussed through intensive numerical simulations. In the last chapter, a numerical method to generate pressure-impulse diagrams for CFDST columns is proposed which uses a damage criterion involving the residual axial load-carrying capacity. Based on the numerical method, pressure-impulse diagrams for different column configurations are derived and analytical expressions of deriving pressure-impulse diagrams for CFDST columns are also developed through regression analysis.

Download or read book Technical Report written by and published by . This book was released on 2008 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nonlinear Analysis of Concrete Columns Under Non Uniform and Anisotropic Confinement written by Yi Ouyang and published by . This book was released on 2017-01-26 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Nonlinear Analysis of Concrete Columns Under Non-uniform and Anisotropic Confinement" by Yi, Ouyang, 歐陽禕, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: For the past twenty years, more and more attention has been drawn to the "performance-based design" of structures due to the concerns of earthquakes, dynamic impact, wind loads and so on. As a result, the ductility of a building has become an important aspect on par with its strength. As far as construction material is concerned, concrete structures have been the most prevalent in these years. As a matter of fact, the ductility of concrete structures is inferior to that of steel structures. However, recent studies have proved that the confinement effect will improve the strength and the ductility of concrete. In traditional concrete construction, confinement is provided by transverse steel hoops placed inside the concrete members with certain spacings, i.e. discontinuously. New forms of concrete structures, such as concrete columns confined by fibre-reinforced polymer (FRP) and concrete-filled steel tubular (CFST) columns, are therefore proposed to enhance the efficiency of confinement, since the concrete in these structures is confined continuously. The mechanisms of uniform and isotropic confinement effect in FRP-confined concrete columns and CFST columns have been well studied, and the existing theoretical models can be applied to those typical load cases, such as FRP-confined circular concrete columns and circular CFST columns under axial compression. But the research on the mechanisms of non-uniform and anisotropic confinement effect is still evolving, in order to predict the behaviour of confined concrete columns with sections of various shapes under combined axial loads and bending moments. Usually finite element (FE) method is used to analyse such complicated problems. However, in a lot of current studies using FE method, the dilation angle of plastic flow of concrete is often treated as a constant, which does not reflect the observed behaviour of concrete regarding the variation of volumetric strain under triaxial compression. In reality, the volume of concrete will eventually expand due to the propagation of splitting cracks, and the true dilatancy of concrete should be non-linear. In this study, a new FE model is developed through Fortran 90 to account for the nonlinearity of the dilatancy of concrete, and verified against several load cases with non-uniform and anisotropic confinement effect, i.e. eccentrically loaded FRP-confined circular concrete columns, axially loaded FRP-confined rectangular concrete columns and eccentrically loaded CFST columns. Moreover, a simplified method is also proposed to provide quick estimations on the behaviour of circular CFST columns under eccentric compression. Subjects: Columns, Concrete - Testing

Download or read book Concrete Filled Double Skin Steel Tubular Columns written by Mostafa Fahmi Hassanein and published by Elsevier. This book was released on 2023-02-16 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concrete-Filled Double-Skin Steel Tubular Columns: Behavior and Design provides a thorough review of the recent advances on the behaviour and design of concrete-filled double-skin steel tubular (CFDST) columns. Drawing on their extensive knowledge and research, the authors cover topics such as different CFDST columns under axial compression, innovative techniques including the use of rubberised concrete, columns with different cross-sections, and steel material envelops and failure modes. This book is an overview of research carried out by this highly experienced and leading research group with specialist knowledge in the topic. It is an invaluable resource for researchers, graduates and post-graduate civil engineers and civil engineering designers. Provides a comprehensive overview of advances on the behaviour and design of concrete-filled double-skin steel tubular (CFDST) columns over the past decade Gives deep-dive explanation of important concepts such as the void ratio which makes these girders different from conventional concrete-filled steel tubular (CFST) columns Explains the failure modes of short and slender columns under compression, with detailed illustrations and photos from both real-life and virtual tests performed by the authors Presents in-depth analysis of the ultimate strengths of CFDST columns with different steel envelops and concrete infills Makes a detailed comparison with available international codes, such as Eurocode 3, and provides recommendations for future studies Discusses new innovative confining stress-based design for different types of CFDST short columns

Download or read book Concrete Filled Stainless Steel Tubular Columns written by Vipulkumar Patel and published by CRC Press. This book was released on 2018-12-07 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concrete-filled stainless steel tubular (CFSST) columns are increasingly used in modern composite construction due to their high strength, high ductility, high corrosion resistance, high durability and aesthetics and ease of maintenance. Thin-walled CFSST columns are characterized by the different strain-hardening behavior of stainless steel in tension and in compression, local buckling of stainless steel tubes and concrete confinement. Design codes and numerical models often overestimate or underestimate the ultimate strengths of CFSST columns. This book presents accurate and efficient computational models for the nonlinear inelastic analysis and design of CFSST short and slender columns under axial load and biaxial bending. The effects of different strain-hardening characteristics of stainless steel in tension and in compression, progressive local and post-local buckling of stainless steel tubes and concrete confinement are taken into account in the computational models. The numerical models simulate the axial load-strain behavior, moment-curvature curves, axial load-deflection responses and axial load-moment strength interaction diagrams of CFSST columns. The book describes the mathematical formulations, computational procedures and model verifications for circular and rectangular CFSST short and slender columns. The behavior of CFSST columns under various loading conditions is demonstrated by numerous numerical examples. This book is written for practising structural and civil engineers, academic researchers and graduate students in civil engineering who are interested in the latest computational techniques and design methods for CFSST columns.

Download or read book Experimental and Analytical Investigation of Blast Performance of Seismically Resistant Bridge Piers written by Shūichi Fujikura and published by . This book was released on 2008 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nonlinear Inelastic Analysis of Concrete filled Steel Tubular Slender Beam columns written by Vipulkumar Ishvarbhai Patel and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: High strength thin-walled concrete-filled steel tubular (CFST) slender beam-columns may undergo local and global buckling when subjected to biaxial loads, preloads or cyclic loading. The local buckling effects of steel tube walls under stress gradients have not been considered in existing numerical models for CFST slender beam-columns. This thesis presents a systematic development of new numerical models for the nonlinear inelastic analysis of thin-walled rectangular and circular CFST slender beam-columns incorporating the effects of local buckling, concrete confinement, geometric imperfections, preloads, high strength materials, second order and cyclic behavior. In the proposed numerical models, the inelastic behavior of column cross-sections is simulated using the accurate fiber element method. Accurate constitutive laws for confined concrete are implemented in the models. The effects of progressive local buckling are taken into account in the models by using effective width formulas. Axial load-moment-curvature relationships computed from the fiber analysis of sections are used in the column stability analysis to determine equilibrium states. Deflections caused by preloads on the steel tubes arising from the construction of upper floors are included in the analysis of CFST slender columns. Efficient computational algorithms based on the Müller's method are developed to obtain nonlinear solutions. Analysis procedures are proposed for predicting load-deflection and axial load-moment interaction curves for CFST slender columns under axial load and uniaxial bending, biaxial loads, preloads or axial load and cyclic lateral loading. The numerical models developed are verified by comparisons of computer solutions with existing experimental results and then utilized to undertake extensive parametric studies on the fundamental behavior of CFST slender columns covering a wide range of parameters. The numerical models are shown to be efficient computer simulation tools for designing safe and economical thin-walled CFST slender beam-columns with any steel and concrete strength grades. The thesis presents benchmark numerical results on the behavior of high strength thin-walled CFST slender beam-columns accounting for progressive local buckling effects. These results provide a better understanding of the fundamental behavior of CFST columns and are valuable to structural designers and composite code writers.

Download or read book Blast Retrofit of Reinforced Concrete Columns written by Alan Eric Walker Lloyd and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Concrete filled Tubular Members and Connections written by Xiao-Ling Zhao and published by CRC Press. This book was released on 2010-07-27 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using steel and concrete together utilizes the beneficial material properties of both elements. Concrete filled steel tubes represent a good example of a concrete - steel composite structure, and are particularly useful as columns in high rise buildings and bridge piers. They can be used in a range of fields, from civil and industrial construction

Download or read book Concrete Filled Double Skin Steel Tubular Column with Hybrid Fibre Reinforced Polymer written by Kok Keong Choong and published by Springer Nature. This book was released on 2021-07-06 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights the residual strength of the CFDST column, that can be used to determine the most suitable repair method in order to retrofit the column. The book elaborates on the behavior of CFDST column after being exposed to fire. This book also discusses the effectiveness of repair method using single and Hybrid Fibre Reinforced Polymer (FRP) of fire-damaged CFDST columns. It concludes by taking a look at different parameters such as thickness of outer steel tube and fire exposure time as factors affecting thermal properties/stability.

Download or read book UHPCC Under Impact and Blast written by Qin Fang and published by Springer Nature. This book was released on 2021-02-22 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is about the Ultra-high Performance Cementitious Composites (UHPCC), which is a relativity new type of cementitious materials. UHPCC has very low water-to-binder ratio, high amount of high-range water reducer, fine aggregates and high-strength steel or organic fibers. With the prominent mechanical properties, e.g., high compressive and tensile strength, high ductility, and high fracture energy, UHPCC has been becoming the most prospective construction cement-based material for both civil and military structures to resist high-speed projectile penetration, low-velocity impact and blast loadings. In this book, the related work conducted by authors on the static and dynamic mechanical properties, as well as the impact and blast resistance of UHPCC are presented. This book is written for the researchers, engineers and graduate students in the fields of protective structures and terminal ballistics.

Download or read book Performance of High Strength Reinforced Concrete Columns Under Shock Tube Induced Blast Loading written by Amer Hammoud and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Accounting for blast hazards has become one of the major concerns for civil engineers when analysing and designing structures. Recent terrorist attacks and accidental explosions have demonstrated the importance of mitigating blast effects on buildings to ensure safety, preserve life and ensure structural integrity. Innovative materials such as high-strength concrete, steel fibers, and high-strength steel offer a potential solution to increase resistance against extreme dynamic loading and improve the blast resilience of buildings. This thesis presents the results of an experimental and analytical study examining the effect of high-strength concrete, high-strength reinforcement and steel fibers on the blast behaviour of reinforced concrete columns. As part of the study, a total of seventeen reinforced concrete columns with different design combinations of concrete, steel fibers, and steel reinforcement were designed, constructed, and tested under gradually increasing blast loads using the University of Ottawa shock-tube facility. Criteria used to assess the blast performance of the columns and the effect of the test variables included overall blast capacity, mid-span displacements, cracking patterns, secondary fragmentation, and failure modes. The effect of concrete strength was found to only have a moderate effect on the blast performance of the columns. However, the results showed that benefits are associated with the combined use of high-strength concrete with steel fibers and high-strength reinforcement in columns tested under blast loads. In addition to the experimental program, a dynamic inelastic single-degree-of-freedom analysis was performed to predict the displacement response of the test columns. A sensitivity analysis was also conducted to examine the effect of various modelling parameters such as materials models, DIFs, and accumulated damage on the analytical predictions.

Download or read book Blast Performance of Reinforced Concrete Columns Protected by FRP Laminates written by Bessam Kadhom and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Concrete Composite Columns written by Chong Rong and published by Elsevier. This book was released on 2022-11-25 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concrete Composite Columns: Behavior and Design focuses on confined concrete and establishes analytical methods for each composite column. The volume moves beyond existing resources to study the relationship between existing composite structures and design methods for the sectional form of a concrete composite structure. Chapters cover the failure criteria of concrete, confined concrete types, models, including axial stress prediction, analysis and design-oriented constitutive models, the design and analysis of section form, axial and seismic behaviors of concrete composite columns, the seismic design of concrete composite columns, and the engineering application. This book offers a practical solution to students, researchers, and engineers working with both steel and FRP-confined concrete composite columns. Focuses on confined concrete and provides analytical methods for composite columns Discusses different types of composite columns, including FRP and steel-concrete composites Considers the construction method and confining forces in composite concrete columns Details confined concrete from basic theoretical analysis to seismic behaviors and design methods Provides a solution to students, researchers, and engineers working with confined composite columns

Download or read book Performance of Steel Fibre Reinforced Concrete Columns Under Shock Tube Induced Shock Wave Loading written by Russell P. Burrell and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It is important to ensure that vulnerable structures (federal and provincial offices, military structures, embassies, etc) are blast resistant to safeguard life and critical infrastructure. In the wake of recent malicious attacks and accidental explosions, it is becoming increasingly important to ensure that columns in structures are properly detailed to provide the ductility and continuity necessary to prevent progressive collapse. Research has shown that steel fibre reinforced concrete (SFRC) can enhance many of the properties of concrete, including improved post-cracking tensile capacity, enhanced shear resistance, and increased ductility. The enhanced properties of SFRC make it an ideal candidate for use in the blast resistant design of structures. There is limited research on the behaviour of SFRC under high strain rates, including impact and blast loading, and some of this data is conflicting, with some researchers showing that the additional ductility normally evident in SFRC is absent or reduced at high strain loading. On the other hand, other data indicates that SFRC can improve toughness and energy-absorption capacity under extreme loading conditions. This thesis presents the results of experimental research involving tests of scaled reinforced concrete columns exposed to shock wave induced impulsive loads using the University of Ottawa Shock Tube. A total of 13 half-scale steel fibre reinforced concrete columns, 8 with normal strength steel fibre reinforced concrete (SFRC) and 5 with an ultra high performance fibre reinforced concrete (UHPFRC), were constructed and tested under simulated blast pressures. The columns were designed according to CSA A23.3 standards for both seismic and non-seismic regions, using various fibre amounts and types. Each column was exposed to similar shock wave loads in order to provide direct comparisons between seismic and non-seismically detailed columns, amount of steel fibres, type of steel fibres, and type of concrete. The dynamic response of the columns tested in the experimental program is predicted by generating dynamic load-deformation resistance functions for SFRC and UHPFRC columns and using single degree of freedom dynamic analysis software, RCBlast. The analytical results are compared to experimental data, and shown to accurately predict the maximum mid-span displacements of the fibre reinforced concrete columns under shock wave loading.

Download or read book Behavior of Expansive Concrete filled Steel Tubular EcfSt Columns Under Axial Loadings written by Abdulaziz Lazkani and published by . This book was released on 2016 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concrete-filled steel tubes (CFST) have been introduced in high-rise buildings in order to expedite construction and increase the confinement of concrete by the steel tube, and hence increase the capacity of the column cross-section. More recently, expansive additives (EAs) that counteract the shrinkage of concrete have been used in CFST to improve the bond between the concrete and steel tube. Although changing the confinement level exerted by the steel tube on concrete will have an impact on the behavior of CFSTs, little information is available regarding the influence of EAs on the mechanical characteristics of expansive concrete-filled steel tubular (ECFST) columns. The objective of this study is thus twofold: (i) to experimentally assess the behavior of concentrically loaded ECFSTs with different parameters, and (ii) to investigate the correlation between the test results and those obtained from different analytical modeling techniques and previous prediction approaches. The experimental program of this study consists of testing 16 CFST/ECFST columns. Fourteen concrete mixes are prepared with four different concrete strength values (16, 40, 50 and 90 MPa), four EA dosages (0%, 6%, 12% and 24%), and two concrete mixing approaches. Steel tubes in two different diameters (89.6 and 153.6 mm), thicknesses (2 and 3 mm), and lengths (370 and 1500 mm) are fabricated. In order to arrive at an effective prestressing action during the hardening process of concrete, two end plates are tied to each ECFST specimen immediately after casting. Each of the tested specimens is effectively instrumented using four LVDTs and several strain gauges. The behavior of the tested column specimens and those collected from previous studies is also assessed using two numerical modeling techniques, namely the fiber-based modeling (FBM) and finite element method (FEM), as well as using several prediction approaches. The results indicate that increasing the concrete strength significantly improves the axial load capacity of CFST columns by up to 76%. Using EA with a concrete strength of 40 MPa results in the most pronounced improvements in the axial load capacity of columns, whilst the most promising EA dosage for the ECFST short columns is 6%.Good agreement is observed between the experimental results and those obtained fromboth FBM and FEM in terms of ultimate load capacity, and hence the adopted modeling techniques can be used in further parametric studies on CFSTs/ECFSTs. It is also recommended to employ specific confined concrete models with the predictive approaches of Euro code 4 and AISC to arrive at the best correlation with CFST test results. This study provides insights into the behavior of pre-stressing CFST columns and presents test results with diverse parameters that contribute to filling gaps in the existing research, verify computational models and provide support for the development of prediction approaches for ECFSTs.

Download or read book Analysis of Steel reinforced Concrete filled Steel Tube Columns CFT Under Axial Compression and Moment written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This study presents an investigation into the behavior of steel-reinforced concrete filled steel tubular columns (CFT) using the finite element software ABAQUS. The steel tube provides lateral confinement to the concrete core which results in an increased concrete compressive strength and deformation capacity. The concrete infill, in return, prevents the inward local buckling within steel tubes. The axial load bearing capacity of CFT is thus higher than the summation of axial load-bearing capacities of the concrete core and the hollow steel tube. The axial force P and moment M interaction diagram is generated.