Post-Earthquake Fire Resistance of Ductile Concrete Filled Double-Skin Tube Columns PDF Download
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Author: Reza Imani
Publisher:
ISBN:
Category :
Languages : en
Pages : 277
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Book Description
Fire following an earthquake has been a major cause of damage in a number of historic seismic events. Considering the amount of damage and statistics showing a high probability for the occurrence of post-earthquake ignitions, there is a need to study the effects of seismic damage on the fire resistance of structures. Concrete Filled Double-Skin Tube (CFDST) columns, a special composite structure which has been shown to have satisfactory performance under separate seismic loading and fire conditions, were studied in this research when subjected to post-earthquake fire scenarios. Experimental studies were conducted to examine the behavior of concrete filled double-skin tube (CFDST) columns exposed to fire after being subjected to simulated seismic loads. The experiments were conducted in two separate phases, consisting of the quasi-static cyclic tests followed by fire tests. Three nominally identical column specimens were constructed for these studies. One of the specimens was directly tested under fire to quantify its resistance in an undamaged condition. The other two specimens were first subjected to quasi-static cyclic lateral loads, imposing varying degrees of lateral drift to simulate two different seismic events with moderate and high damage levels before being exposed to fire. Both of the specimens were pushed to the maximum drift of 6-6. 5% with different residual drifts of 1. 4% and 3. 9% for moderate and high damage levels, respectively. The undamaged and damaged columns were then subjected to the same fire tests following the standard ASTM E119 (ASTM 2012) temperature-time curve while sustaining an axial load until the column failed due to global buckling. Local buckling of the tubes was also observed in the specimens due to the thermal expansion and separation from the concrete. Overall, the results showed marginal differences in the fire resistance of the three specimens, providing evidence for the resilient performance of these columns under post-earthquake fire scenarios. An additional quasi-static cyclic loading test was conducted on the specimen that had been exposed to fire without any prior damage, to investigate the behavior of the column subjected to seismic loads after the fire test. Again, differences in behavior were modest, except for a 5. 7% drop in strength attributed to permanent degradation in material properties due to the fire test. In addition to the experimental studies, detailed finite element analyses were conducted using ABAQUS and LS-DYNA to simulate the behavior of CFDST columns subjected to post-earthquake fires. The models were shown to be capable of replicating the experimental results with sufficient accuracy. A simplified step by step analytical procedure was proposed for calculation of the axial load capacity of CFDST columns subjected to fire. The procedure was defined based on an analytical solution to the heat transfer problem and calculation of axial load capacity using the fire-modified material properties. A number of design recommendations, based on the knowledge gained from the experimental and analytical studies, were proposed for CFDST columns subjected to fire.
Author: Reza Imani
Publisher:
ISBN:
Category :
Languages : en
Pages : 277
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Book Description
Fire following an earthquake has been a major cause of damage in a number of historic seismic events. Considering the amount of damage and statistics showing a high probability for the occurrence of post-earthquake ignitions, there is a need to study the effects of seismic damage on the fire resistance of structures. Concrete Filled Double-Skin Tube (CFDST) columns, a special composite structure which has been shown to have satisfactory performance under separate seismic loading and fire conditions, were studied in this research when subjected to post-earthquake fire scenarios. Experimental studies were conducted to examine the behavior of concrete filled double-skin tube (CFDST) columns exposed to fire after being subjected to simulated seismic loads. The experiments were conducted in two separate phases, consisting of the quasi-static cyclic tests followed by fire tests. Three nominally identical column specimens were constructed for these studies. One of the specimens was directly tested under fire to quantify its resistance in an undamaged condition. The other two specimens were first subjected to quasi-static cyclic lateral loads, imposing varying degrees of lateral drift to simulate two different seismic events with moderate and high damage levels before being exposed to fire. Both of the specimens were pushed to the maximum drift of 6-6. 5% with different residual drifts of 1. 4% and 3. 9% for moderate and high damage levels, respectively. The undamaged and damaged columns were then subjected to the same fire tests following the standard ASTM E119 (ASTM 2012) temperature-time curve while sustaining an axial load until the column failed due to global buckling. Local buckling of the tubes was also observed in the specimens due to the thermal expansion and separation from the concrete. Overall, the results showed marginal differences in the fire resistance of the three specimens, providing evidence for the resilient performance of these columns under post-earthquake fire scenarios. An additional quasi-static cyclic loading test was conducted on the specimen that had been exposed to fire without any prior damage, to investigate the behavior of the column subjected to seismic loads after the fire test. Again, differences in behavior were modest, except for a 5. 7% drop in strength attributed to permanent degradation in material properties due to the fire test. In addition to the experimental studies, detailed finite element analyses were conducted using ABAQUS and LS-DYNA to simulate the behavior of CFDST columns subjected to post-earthquake fires. The models were shown to be capable of replicating the experimental results with sufficient accuracy. A simplified step by step analytical procedure was proposed for calculation of the axial load capacity of CFDST columns subjected to fire. The procedure was defined based on an analytical solution to the heat transfer problem and calculation of axial load capacity using the fire-modified material properties. A number of design recommendations, based on the knowledge gained from the experimental and analytical studies, were proposed for CFDST columns subjected to fire.
Author: Kok Keong Choong
Publisher: Springer Nature
ISBN: 9811627150
Category : Technology & Engineering
Languages : en
Pages : 81
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Book Description
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.
Author: Mahendrakumar Madhavan
Publisher: Springer Nature
ISBN: 9811993947
Category : Technology & Engineering
Languages : en
Pages : 576
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Book Description
This book comprises the select peer-reviewed proceedings of the Indian Structural Steel Conference (ISSC 2020). The topics cover state-of-the-art and state-of-the-practice in structural engineering, and latest research in structural modeling and design. Novel analytical, computational and experimental techniques, proposal of new structural systems, innovative methods for maintenance, rehabilitation, and monitoring of existing structures, and investigation of the properties of engineering materials as related to structural behavior are presented in the book. This book will be very useful for structural engineers, researchers, and consultants interested in sustainable materials and steel construction.
Author: K. V. L. Subramaniam
Publisher: Springer Nature
ISBN: 9811540799
Category : Technology & Engineering
Languages : en
Pages : 244
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Book Description
This book contains selected papers in the area of structural engineering from the proceedings of the conference, Futuristic Approaches in Civil Engineering (FACE) 2019. In the area of construction materials, the book covers high quality research papers on raw materials and manufacture of cement, mixing, rheology and hydration, admixtures, characterization techniques and modeling, fiber-reinforced concrete, repair and retrofitting of concrete structures, novel testing techniques such as digital image correlation (DIC). Research on sustainable building materials like Geopolymer concrete and recycled aggregates are covered. In the area of earthquake engineering, papers related to the seismic response of load-bearing unreinforced masonry walls, reinforced concrete frame and buildings with dampers are covered. Additionally, there are chapters on structures subjected to vehicular impact and fire. The contents of this book will be useful for graduate students, researchers and practitioners working in the areas of concrete, earthquake and structural engineering.
Author: Hui Lu
Publisher:
ISBN:
Category :
Languages : en
Pages : 476
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Book Description
The concrete-filled double skin tubular column (CFDST) is an innovative type of steel-concrete element which has potential for use as piers in bridges and columns in buildings. The use of self-compacting concrete (SCC) in CFDST is seen as a solution to resolve the challenge of concrete compaction in the columns. The behaviour of CFDST under static and cyclic loading at ambient temperature has been extensively studied. The fire performance of CFDST is crucial due to the direct fire exposure of the outer steel tube. Nevertheless, there is at present little information about the fire performance of CFDST. This thesis reports on research into the fire performance of SCC-filled CFDST columns. The research aims to understand the fundamental behaviour of SCC-filled CFDST columns under standard fire exposure by means of standard fire tests and finite element modelling and to develop guidance for fire resistance design of the columns.Given the complexity in the responses of SCC-filled CFDST in fires, SCC-filled steel tubular stub columns (CFST), a specific type of CFDST without an inner steel tube, were selected for study in the first phase of the research program because of their simple configuration. Six SCC-filled CFST stub columns were prepared for standard fire tests and a finite element model to simulate the thermal and structural responses was developed. The main purpose of this phase of research was to develop a methodology for the further study of fire behaviour of CDFST columns by investigating how SCC affects the fire behaviour of composite columns and how steel tube affords confinement of the SCC to alter its behaviour at elevated temperature.A series of standard fire tests for CFDST columns was conducted in the second phase of the research. Six CFDST columns and sixteen CFDST stub columns were prepared for standard fire tests. A further two CFDST stub columns were prepared as reference specimens to test the axial capacity at ambient temperature. The columns and stub columns in the tests represent slender and stub columns in authentic engineering practice in which the failure modes are buckling and compression failure respectively. Data obtained from the fire tests, i.e. temperatures, axial deformation, failure modes and fire resistance, were used to investigate the fire behaviour of the columns. Interaction among the three components in the columns during fire exposure was clearly shown in the tests. Such interaction is beneficial to the fire performance of CFDST columns. Confinement of the tubes on the SCC prevents its spalling. Components which help each other through a load transfer mechanism are typical of the composite interaction in CFDST columns. Methods to enhance the fire resistance performance of CFDST, i.e. fire protection and steel fibre reinforced concrete, were also validated in the tests. In addition, the fire tests accumulated data to verify the numerical model in the subsequent research.A finite element model was developed and used to study in detail the fire behaviour of CFDST columns and for the parametric study in the third phase of the research. An advanced finite element model which accounts for material and geometric non-linearity and the interaction of tubes and concrete was proposed to simulate the thermal and structural responses of CFDST columns under standard fire exposure. A concrete material model for confined concrete in CFDST at elevated temperature was developed accordingly. The model was then used to analyse the fire behaviour of the columns in terms of stress, strain and load share in components which cannot be obtained directly from fire tests. Yield of the inner steel tube was found to be a major cause of the final failure of the columns. The influence of a number of parameters on the fire resistance performance of the columns was investigated. The parameters which have significant influence on the fire resistance performance of the columns were identified. Finally, guidelines for the fire resistance design of CFDST columns are proposed. These guidelines deal with how to appropriately select parameters for CFDST columns to ensure the columns achieve the anticipated fire resistance. Several practical design tables are also presented to illustrate how to use the guidelines to design CFDST columns to achieve a certain level of fire resistance.
Author: Paolo Gardoni
Publisher: Routledge
ISBN: 1351392778
Category : Business & Economics
Languages : en
Pages : 951
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Book Description
To best serve current and future generations, infrastructure needs to be resilient to the changing world while using limited resources in a sustainable manner. Research on and funding towards sustainability and resilience are growing rapidly, and significant research is being carried out at a number of institutions and centers worldwide. This handbook brings together current research on sustainable and resilient infrastructure and, in particular, stresses the fundamental nexus between sustainability and resilience. It aims to coalesce work from a large and diverse group of contributors across a wide range of disciplines including engineering, technology and informatics, urban planning, public policy, economics, and finance. Not only does it present a theoretical formulation of sustainability and resilience but it also demonstrates how these ideals can be realized in practice. This work will provide a reference text to students and scholars of a number of disciplines.
Author: Mostafa Fahmi Hassanein
Publisher: Elsevier
ISBN: 0443152292
Category : Technology & Engineering
Languages : en
Pages : 360
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Book Description
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
Author: Venkatesh Kumar R. Kodur
Publisher:
ISBN:
Category :
Languages : en
Pages : 4
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Book Description
Author: A. Aulick
Publisher: Canada Institute for Scientific and Technical Information
ISBN:
Category :
Languages : en
Pages : 19
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Book Description
Author: Sherif Ahmed Elkarim Ibrahim Soliman Elsawaf
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Joint behaviour in fire is currently one of the most important topics of research in structural fire resistance. The collapse of World Trade Center buildings and the results of the Cardington full-scale eight storey steel framed building fire tests in the UK have demonstrated that steel joints are particularly vulnerable during the heating and cooling phases of fire. The main purpose of this research is to develop robust joints to CFT columns that are capable of providing very high rotational and tying resistances to make it possible for the connected beam to fully develop catenary action during the heating phase of fire attack and to retain integrity during the cooling phase of fire attack. This research employed the general finite element software ABAQUS to numerically model the behaviour of restrained structural subassemblies of steel beam to concrete filled tubular (CFT) columns and their joints in fire. For validation, this research compared the simulation and test results for 10 fire tests previously conducted at the University of Manchester. It was envisaged that catenary action in the connected beams at very large deflections would play an important role in ensuring robustness of steel framed structures in fire. Therefore, it was vital that the numerical simulations could accurately predict the structural behaviour at very large deflections. In particular, the transitional behaviour of the beam from compression to catenary action presented tremendous difficulties in numerical simulations due to the extremely high rate of deflection increase. This thesis will explain the methodology of a suitable simulation method, by introducing a pseudo damping factor. The comparison between the FE and the experimental results demonstrates that the 3-D finite element model is able to successfully simulate the fire tests. The validated ABAQUS model was then applied to conduct a thorough set of numerical studies to investigate methods of improving the survival temperatures under heating in fire of steel beams to concrete filled tubular (CFT) columns using reverse channel connection. This study investigated five different joint types of reverse channel connection: extended endplate, flush endplate, flexible endplate, hybrid flush/flexible endplate and hybrid extended/flexible endplate. The connection details investigated include reverse channel web thickness, bolt diameter and grade, using fire-resistant (FR) steel for different joint components (reverse channel, end plate and bolts) and joint temperature control. The effects of changing the applied beam and column loads were also considered. It is concluded that by adopting some of the joint details to improve the joint tensile strength and deformation capacity, it is possible for the beams to develop substantial catenary action to survive very high temperatures. This thesis also explains the implications on fire resistant design of the connected columns in order to resist the additional catenary force in the beam. The validated numerical model was also used to perform extensive parametric studies on steel framed structures using concrete filled tubular (CFT) columns with flexible reverse channel connection and fin plate connection to find means of reducing the risk of structural failure during cooling. The results lead to the suggestion that in order to avoid connection fracture during cooling, the most effective and simplest method would be to reduce the limiting temperature of the connected beam by less than 50°C from the limiting temperature calculated without considering any axial force in the beam.
