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 Performance of Reinforced Concrete Columns Under Shock Tube Induced Shock Wave Loading written by Alan Lloyd and published by . This book was released on 2010 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Performance of Ultra High Performance Fiber Reinforced Concrete Columns Under Blast Loading written by Frederic Dagenais 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 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 Effect of High Performance Steel Materials on the Blast Behaviour of Ultra High Performance Concrete Columns written by Sarah De Carufel and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Previous events have demonstrated the vulnerability of reinforced concrete infrastructure to blast loading. In buildings, ground-story columns are key structural components, and their failure can lead to extensive damages which can cause progressive collapse. To prevent such disasters, the steel reinforcement in such columns must be properly detailed to ensure sufficient strength and ductility. The use of modern concrete materials such ultra-high performance concrete (UHPC) is one potential solution to improve the blast performance of columns. UHPC shows high compressive strength, high tensile resistance and superior toughness, properties which make it ideal for use in the blast-resistant design of columns. The combined use of UHPC and high-performance steels can potentially be used to further enhance the blast resistance of columns. This thesis presents an experimental and analytical study which investigated the use of high-performance materials to increase the blast capacity and ductility of reinforced concrete columns. As part of the experimental study, a total of seventeen columns were tested under simulated blast loading using the University of Ottawa Shock-Tube. Parameters investigated included the effect of concrete type (NSC and UHPC), steel reinforcement type (normal-strength, high-strength or highly ductile), longitudinal reinforcement ratio, seismic detailing and fiber properties. The test program included two control specimens built with normal-strength concrete, five specimens built with UHPC in combination with high-strength steel, and ten columns built with highly ductile stainless steel reinforcement. Each column was subjected to a series of increasing blast pressures until failure. The performance of the columns is investigated by comparing the displacements, impulse capacity and secondary fragmentation resistance of the columns. The results show that using high-performance steels increases the blast performance of UHPC columns. The use of sufficient amounts of high-strength steel in combination with UHPC led to important increases in column blast capacity. The use of ductile stainless steel reinforcement allowed for important enhancements in column ductility, with an ability to prevent rupture of tension steel reinforcement. The study also shows that increasing the longitudinal reinforcement ratio is an effective means of increasing the blast resistance of UHPC columns The thesis also presents an extensive analytical study which aimed at predicting the response of the test columns using dynamic inelastic, single-degree-of-freedom (SDOF) analysis. A sensitivity analysis was also performed to examine the effect of various modelling parameters on the analytical predictions. Overall, it was shown that SDOF analysis could be used to predict the blast response of UHPC columns with reasonable accuracy. To further corroborate the results from the experimental study, the thesis also presents an analytical parametric study examining the blast performance of larger-scale columns. The results further demonstrate the benefits of using UHPC and high-performance steel reinforcement in columns subjected to blast loading.

Download or read book Behaviour of High Performance Fibre Reinforced Concrete Columns Under Axial Loading written by Milad Mohammadi Hosinieh and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: When compared to traditional concrete, steel fibre reinforced concrete (SFRC) shows several enhancements in performance, including improved tensile resistance, toughness and ductility. One potential application for SFRC is in columns where the provision of steel fibres can improve performance under axial and lateral loads. The use of SFRC can also allow for partial replacement of transverse reinforcement required by modern seismic codes. To improve workability, self-consolidating concrete (SCC) can be combined with steel fibres, leading to highly workable SFRC suitable for structural applications. Recent advances in material science have also led to the development of ultra-high performance fibre reinforced concretes (UHPFRC), a material which exhibits very high compressive strength, enhanced post-cracking resistance and high damage tolerance. In heavily loaded ground-story columns, the use of UHPFRC can allow for reduced column sections. This thesis presents the results from a comprehensive research program conducted to study the axial behaviour of columns constructed with highly workable SFRC and UHPFRC. As part of the experimental program, twenty-three full-scale columns were tested under pure axial compressive loading. In the case of the SFRC columns, columns having rectangular section and constructed with SCC and steel fibres were tested, with variables including fibre content and spacing of transverse reinforcement. The results confirm that use of fibres results in improved column behaviour due to enhancements in core confinement and cover behaviour. Furthermore, the results demonstrate that the provision of steel fibres in columns can allow for partial replacement of transverse reinforcement required by modern codes. The analytical investigation indicates that confinement models proposed by other researchers for traditional RC and SFRC can predict the response of columns constructed with SCC and highly workable SFRC. In the case of the UHPFRC columns, variables included configuration and spacing of transverse reinforcement. The results demonstrate that the use of appropriate detailing in UHPFRC columns can result in suitable ductility. Furthermore, the results demonstrate the improved damage tolerance of UHPFRC when compared to traditional high-strength concrete. The analytical investigation demonstrates the need for development of confinement models specific for UHPFRC.

Download or read book Concrete Structures Subjected to Impact and Blast Loadings and Their Combinations written by Chunwei Zhang and published by CRC Press. This book was released on 2022-05-08 with total page 335 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although much research focuses on investigating the responses of reinforced concrete (RC) structures under sole impact or blast loads, the responses of RC structures under a combination of impact and blast loads currently represent a gap in our knowledge. The combined actions of impact and blast loadings may be applied to RC structures during accidental or intentional collision of vessels, vehicles, etc., carrying explosive materials. A comprehensive study on the vulnerability of various structural members is carried out using finite element (FE) simulations under combination of impact and blast loads with the variations of various loading- and structural-related parameters and key parameters. This book introduces various structural analysis approaches for concrete structures when subjected to extreme loads such as impact and blast loadings. The theory of the combinations of impact and blast loads is proposed that can provide primary insights to the specific readers to develop new ideas in impact and blast engineering, including combined actions of extreme loads arising from real-world intentional or accidental events. This book will be of value to students (undergraduate or postgraduate), engineers, and researchers in structural and civil engineering, and specifically, those who are studying and investigating the performances of concrete structures under extreme loads.

Download or read book ICSCEA 2019 written by J. N. Reddy and published by Springer Nature. This book was released on 2020-07-27 with total page 1219 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents papers from the International Conference on Sustainable Civil Engineering and Architecture 2019, which was held in Ho Chi Minh City, Vietnam, from 24–26 October 2019. The conference brought together international experts from both academia and industry to share their knowledge and experiences, and to facilitate collaboration and improve cooperation in the field. The book highlights the latest advances in sustainable architecture and civil engineering, covering topics such as offshore structures, structural engineering, construction materials, and architecture.

Download or read book Performance of FRP strengthened Reinforced Concrete Columns Under Impact Loading written by Alaa Omar Moftah Swesi and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Seismic Performance of Circular Reinforced Concrete Columns Under Varying Axial Load written by Gianmario Benzoni and published by . This book was released on 1996 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: The behavior of four circular reinforced concrete bridge columns, with different axial load regimes, is investigated. The first unit was tested under constant compressive axial load corresponding to an axial load ratio of 0.35. The second specimen was subjected to a constant tensile axial force equivalent to 0.087 axial load ratio. Two specimens were tested under varying regime of axial load, ranging between the two previous load limits, in order to simulate realistic seismic conditions of outer columns of multi-column bents. Extended comparison between experimental and predicted shear response, from different current equations, is provided.

Download or read book Numerical Investigations of High Strength Steel Fiber Reinforced Concrete Columns Under Axial and Cyclic Loading written by 阮德俊 and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Performance of Reinforced Concrete Columns Strengthened with Fiber Reinforced Polymers Under Various Loading Conditions written by Mohamed Gamal Mohamed El Sayed and published by . This book was released on 2010 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Response of Reinforced Concrete Columns Under Temperature Induced Transient Creep Strain written by Saleh Mohammad Alogla and published by . This book was released on 2019 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural members experience significant creep deformations in later stages of fire exposure and are susceptible to failure due to temperature induced creep strains. Fire in a concrete structure can burn for several hours, and temperatures in concrete and reinforcing steel can exceed 500 °C. At such temperatures, high levels of creep strains can develop in concrete and steel, especially in reinforced concrete columns. However, temperature induced creep strains are not fully accounted for in evaluating fire resistance of concrete members even through advanced analysis, and there is a lack of data on high-temperature creep strains for specific types of concrete. To overcome current limitations, comprehensive experiments on evolution of transient creep strain are undertaken under various heating and loading regimes. Transient creep tests are conducted in the temperature range of 20 °C to 750 °C on four types of concrete; normal strength concrete, steel fiber reinforced concrete, high strength concrete, and high strength concrete with polypropylene fibers. The test variables include temperature, load level, rate of heating, strength of concrete and presence of fibers. Data from these tests indicate that transient creep strain constitutes a significant portion of the total strain developed during high-temperature exposure. Data also affirm that temperature range and stress level have significant influence on transient creep strain. However, rate of heating and presence of fibers have only a moderate influence on the extent of transient creep in concrete. Presence of steel fibers in normal strength concrete slightly reduce transient creep strain, while the presence of polypropylene fibers in high strength concrete leads to higher transient creep strain. Generated data from experiments is then utilized to propose temperature and stress dependent creep strain relations for concrete. These transient creep strain relations can be implemented in fire resistance evaluation of concrete members. To account for transient creep in undertaking fire resistance analysis of reinforced concrete (RC) columns, a three-dimensional finite element based numerical model is developed in ABAQUS. Temperature-induced creep strains in concrete and reinforcing steel are explicitly accounted for in this advanced analysis. The model also accounts for temperature induced degradation in concrete and reinforcing steel, and material and geometrical nonlinearities. The validity of the model is established by comparing fire response predictions generated from the model with measured response parameters in fire tests on RC columns. Results from the analysis clearly indicate that transient creep strain significantly influences the extent of deformations when the temperatures in concrete exceed 500 °C for stress level of 40% or more, and this in turn influences fire resistance of RC columns. The validated model is applied to assess the influence of transient creep on fire response of RC columns under different conditions, including different fire scenarios, load level, and number of exposed sides in a column. Results from the numerical studies clearly indicate that severe fire exposure induces higher creep strains in RC columns in much shorter duration than exposure to a standard building fire. Moreover, asymmetric thermal gradients resulting from two or three side fire exposure on a column, can increase transient creep effects and, thus, affect fire resistance. The extent of the developed transient creep in concrete columns under various scenarios of fire exposure is highly dependent on the type of concrete. Overall, results from the analysis infer that neglecting transient creep can lead to a lower prediction of deformations and, thus, overestimation of fire resistance in RC columns, particularly when subjected to severe fire exposure scenarios, with higher thermal gradients.

Download or read book Performance of Confined Concrete Columns Under Simulated Life Cycles written by Steven D. Hart and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past 30 years, FRP composites (carbon, glass, or aramid fibers) have arisen as a method of retrofitting existing reinforced concrete structures to bring them up to current code standards of confinement and ductility. The development of stress-strain models for FRP confined concrete began with the adaptation of steel confinement models then progressed to models specifically developed based on test results from FRP confined specimens. State of the art stress-strain models for FRP confined concrete models may now be validated against a wide variety of published experimental results. Recent publications show researchers branching out and looking at other aspects of FRP confined concrete behavior, including the impact of sustained service loads on long term and ultimate behavior. An experimental program which examines the effects of sustained service loading on the ultimate axial performance of FRP confined concrete is presented. The program's purpose is to determine whether or not a material model developed without the presence of a sustained load accurately predicts the ultimate stress-strain response of FRP confined concrete previously subjected to a sustained service load. Equipment and procedures were developed to model the critical events in a building life cycle: construction, sustained service loading, minor critical events, rehabilitation, and ultimate performance. Varying the order of these events produces a simulated life cycle allowing analysis of the impact of strain history on ultimate performance. The results of the experimental program indicate that the presence of a sustained service load changes the expected failure mode from FRP rupture to FRP de-lamination and the stress-strain response of a specimen is approximately 10% below published models when sustained service loads are included in the life cycle. A comprehensive modeling process is proposed for modeling significant events in a structure's life cycle. Impacts on earthquake engineering and reliability studies are addressed and future research suggested. This research shows that life cycle modeling can improve the design and rehabilitation of structures so that they meet safety requirements in future seismic events.

Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: