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Author: Abdullah Al-Bayti Publisher: ISBN: Category : Languages : en Pages :
Book Description
Reinforced concrete columns are essential elements that are responsible for overall strength and stability of structures. Loss of a column within a frame can cause progressive collapse. While some research has been conducted on blast performance of reinforced columns, primarily under far-field explosions, very limited work exists on the effects of close-in explosions. Dynamic response of concrete columns, in multi storey building, was investigated under close-in blast loads numerically, using FEM software LS-DYNA. A six-storey reinforced concrete building was selected for this purpose. Different standoff distance/charge mass combinations were used to investigate the failure modes of external building columns. Three different charge masses were used; i) backpack bomb having 22.67 kg (50 lbs) of TNT, ii) compact sedan car bomb with 227 kg (500 lbs) of TNT and iii) sedan car bomb with 454 kg (1000 lbs) of TNT. The explosives were placed at different distances relatively close to the structure, triggering different failure modes. Effects of transverse reinforcement and column location (edge versus corner column) were studied under different combinations of charge weight and standoff distance. Column response under dynamic blast load was identified as either local or global. The results show that the failure mode with backpack bombs located at small standoff distance is either local breaching or concrete scabbing. Direct shear failure occurred at column supports when higher charge masses were detonated at close distances. As the standoff distance increased the response changed from breaching or direct shear to diagonal tension and flexure. The column transverse reinforcement played a major role in controlling diagonal shear cracks and promoting flexural response. Hence, the amount and spacing of transverse reinforcement were observed to be important design parameters.
Author: Abdullah Al-Bayti Publisher: ISBN: Category : Languages : en Pages :
Book Description
Reinforced concrete columns are essential elements that are responsible for overall strength and stability of structures. Loss of a column within a frame can cause progressive collapse. While some research has been conducted on blast performance of reinforced columns, primarily under far-field explosions, very limited work exists on the effects of close-in explosions. Dynamic response of concrete columns, in multi storey building, was investigated under close-in blast loads numerically, using FEM software LS-DYNA. A six-storey reinforced concrete building was selected for this purpose. Different standoff distance/charge mass combinations were used to investigate the failure modes of external building columns. Three different charge masses were used; i) backpack bomb having 22.67 kg (50 lbs) of TNT, ii) compact sedan car bomb with 227 kg (500 lbs) of TNT and iii) sedan car bomb with 454 kg (1000 lbs) of TNT. The explosives were placed at different distances relatively close to the structure, triggering different failure modes. Effects of transverse reinforcement and column location (edge versus corner column) were studied under different combinations of charge weight and standoff distance. Column response under dynamic blast load was identified as either local or global. The results show that the failure mode with backpack bombs located at small standoff distance is either local breaching or concrete scabbing. Direct shear failure occurred at column supports when higher charge masses were detonated at close distances. As the standoff distance increased the response changed from breaching or direct shear to diagonal tension and flexure. The column transverse reinforcement played a major role in controlling diagonal shear cracks and promoting flexural response. Hence, the amount and spacing of transverse reinforcement were observed to be important design parameters.
Author: Sarah De Carufel Publisher: ISBN: Category : Languages : en Pages :
Book Description
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.
Author: W.E. Baker Publisher: Elsevier ISBN: 0444599886 Category : Political Science Languages : en Pages : 840
Book Description
Explosion Hazards and Evaluation presents the principles and applications of explosion hazards evaluation. The text is organized into nine chapters. Chapters 1 and 2 discuss the energy release processes which generate accidental explosions, and the resulting development of pressure and shock waves in a surrounding atmosphere. The manner in which the "free-field" waves are modified in interacting with structures or other objects in their paths is discussed in Chapter 3. Structural response to blast loading and non-penetrating impact is covered in two chapters, with Chapter 4 including simplified analysis methods and Chapter 5 including numerical methods. Chapter 6 includes a rather comprehensive treatment of generation of fragments and missiles in explosions, and the flight and effects of impact of these objects. Chapter 7 considers thermal radiation of large chemical explosions. Explosions may or may not cause damage or casualty, and various damage criteria have been developed for structures, vehicles, and people. These criteria are presented in Chapter 8. General procedures for both the postmortem evaluation of accidental explosions and for design for blast and impact resistance are reviewed in Chapter 9. Engineers, scientists, and plant safety personnel will find the book very useful.
Author: Publisher: ISBN: Category : Languages : en Pages : 18
Book Description
Analyses were conducted to demonstrate the effectiveness of composite wrapped columns for improving the survivability of existing reinforced concrete multistory buildings to attacks by explosives. Different standoff distances and charge sizes were considered. Two building designs were analyzed: one in which the building members were designed primarily for gravity loads (UBC seismic zone 1) and one in which the members were designed to resist seismic loads (UBC seismic zone 4). Structural response predictions were performed with the three-dimensional Lagrangian finite element code DYNA3D, using a concrete material model especially designed to predict nonlinear concrete responses to explosive loads. The results indicate that under some circumstances composite wrap can be an effective means to retrofit an existing facility to lessen its vulnerability to blast loads.
Author: John Perdikaris Publisher: CRC Press ISBN: 1482211947 Category : Social Science Languages : en Pages : 348
Book Description
Manage a Hazard or Threat Effectively and Prevent It from Becoming a Disaster When disaster strikes, it can present challenges to those caught off guard, leaving them to cope with the fallout. Adopting a risk management approach to addressing threats, vulnerability, and risk assessments is critical to those on the frontline. Developed with first responders at the municipal, state, provincial, and federal level in mind, Physical Security and Environmental Protection guides readers through the various phases of disaster management, including prevention, mitigation, preparedness, response, and recovery. It contains the steps and principles essential to effectively managing a hazard or threat, preventing it from becoming a disaster. From the Initial Threat Assessment to Response and Recovery Operations Considering both natural and manmade disasters, this text includes sections on hazard analysis, emergency planning, effective communication, and leadership. It covers threat assessment, examines critical infrastructure protection, and addresses violent behavior. The text also outlines protection strategies; discussing strategy management, identifying suspicious behavior, and detailing how to avoid a potential attack. The text includes an overview on developing force protection plans, security plans, and business continuity plans. The book also addresses response and recovery operations, explores post-incident stress management, and poses the following questions: What hazards exist in or near the community? How frequently do these hazards occur? How much damage can they cause? Which hazards pose the greatest threat? This text includes the tools and information necessary to help readers develop business continuity, force protection, and emergency preparedness plans for their own group or organization.
Author: National Research Council Publisher: National Academies Press ISBN: 0309070481 Category : Technology & Engineering Languages : en Pages : 85
Book Description
The Blast Mitigation for Structures Program (BMSP) is a research and development activity conducted by the Defense Threat Reduction Agency (DTRA) to improve the performance of buildings that are targets of terrorist attack. The primary goal of the BMSP is to reduce loss of life and injuries to the occupants of these buildings through the development of innovative techniques for new structures and retrofitting existing facilities. The committee's findings and recommendations are contained in this initial assessment report.
Author: Chengqing Wu Publisher: Woodhead Publishing ISBN: 0081024967 Category : Technology & Engineering Languages : en Pages : 424
Book Description
Development of Ultra-High Performance Concrete against Blasts: From Materials to Structures presents a detailed overview of UHPC development and its related applications in an era of rising terrorism around the world. Chapters present case studies on the novel development of the new generation of UHPC with nano additives. Field blast test results on reinforced concrete columns made with UHPC and UHPC filled double-skin tubes columns are also presented and compiled, as is the residual load-carrying capacities of blast-damaged structural members and the exceptional performance of novel UHPC materials that illustrate its potential in protective structural design. As a notable representative, ultra-high performance concrete (UHPC) has now been widely investigated by government agencies and universities. UHPC inherits many positive aspects of ultra-high strength concrete (UHSC) and is equipped with improved ductility as a result of fiber addition. These features make it an ideal construction material for bridge decks, storage halls, thin-wall shell structures, and other infrastructure because of its protective properties against seismic, impact and blast loads. Focuses on the principles behind UHPC production, properties, design and detailing aspects Presents a series of case studies and filed blast tests on columns and slabs Focuses on applications and future developments
Author: Abdullah Al-Bayti
Author: Abdullah Al-Bayti
Author: Omer Salem Ahmed Yagob
Author: Sarah De Carufel
Author: W.E. Baker
Author: 
Author: Bessam Kadhom
Author: John Perdikaris
Author: Frederic Dagenais
Author: National Research Council
Author: Chengqing Wu