Variation of peak positive incident pressure with scale distance in free field spherical burst and surface burst scenarios, proposed by different researchers, is presented and compared. Some attributes of ductile design for blast design are as follows. Structural design of buildings to resist blast and. To protect structures against explosion loads, corrugated blast walls are. Types of loads on structures buildings and other structures. The structural behavior in response to these loads is inelastic as well. The paper describes the process of determining the blast load on structures and provides a numerical example of a fictive structure exposed to. In commonly used broad terms, security engineering involves detecting the possibility of intrusive behavior, deterring.
The optimal device arrangements are found to be those that reduce the. These issues are this seminar will teach you how to design steel and concrete structures to withstand bomb blasts and accidental chemical explosions. However,asce 702 and aci 318 imply a desired alternate load path in the event one or more beams. This paper discusses factors pertinent to the design of blast resistant glazing. To achieve targeted integrity during blast, the redundancy of the gravity load carrying structural system takes center stage in tackling the issue of progressive collapse. Dynamic response of composite structures subjected to. Syngellakis, wessex institute of technology, uk price. Using extreme loading for structures els software, structural engineers can design and analyze a structure subjected to blast loads with full 3d nonlinear dynamic analysis. Explosions and blasts can produce, in a very short time, an overload much greater than the design load of a building.
The authors offer a relatively simple approach to facilitate blast resistant glazing design in terms of traditional window glass design methodologies for laminated glass and insulating glass fabricated with laminated glass. Terrorist attacks and other destructive incidents caused by explosives have, in recent years, prompted considerable research and development into the protection of structures against blast loads. Building design guidance 3 building design guidance 31 this chapter addresses explosive blast and cbr concerns from terrorist attacks, highlighting mitigation measures that may be applied to building elements, including architectural, structural, and building envelope systems. Blastresistant design of structures practice periodical. A subsequent group of articles is concerned with the accurate definition of blast pressure, which is an essential prerequisite to the reliable assessment of the consequences of an explosion.
Proceedings of the 2014 ground vehicle systems engineering and technology symposium gvsets reducing structural weight and increasing protection in simple structures subjected to blast loads, jiang et al unclassified. Structural design for bomb blast loads and accidental. It describes the different structural response regimes to dynamic loads caused by blast action and then focuses on the use of single degree of freedom sdof methods of analysis. One of the most critical parameters for blast loading computations is the distance of the detonation point from the structure of interest. As a result of repeated terrorist incidents around the world causing huge loss of property and human lives. Because of the uniqueness of each buildings mission, functional requirements, and physical security design objectives, there are limited codes and standards that apply to blast mitigation design. Explosions external to a building tend to result in a single predominate reflected. Load definition and structural response wit transactions on stateoftheart in science and engineer by s. However, it is noticed that this method can significantly underestimate structural response and damage if brittle shear damage occurs in the structure during the blast. Therefore, the thematic group tg on the resistance of structures to explosion effects was formed in order to bring the required expertise together, make it commonly available and to find and define harmonised methods and solutions which can be provided to the decisionmakers responsible for critical infrastructure protection. The present study is concerned with analysis of blast load considering two variations of charge weights and standoff distance. While the threat of a conventional explosion charge is defined by two equally important elements, the charge quantity weight, the standoff. The various blast load analyses presented in this paper are discussed in. In the past few years, a structure subjected to blast load gained importance due to accidental events or natural events.
In addition material about two rather more specialised topics blast wave propagation in a complex urban setting and the way that walls can be used to protect buildings was prepared. Many industrial sites now carry out processes that require building within the vicinity to be blast resistant. Unlike earthquake design, blast resistant design is a new concept which has gained huge importance in order to make structures safe again blast effect. Response of buildings exposed to blast load method evaluation. In this study both regular and irregular buildings are analyzed. The duration of the action of the overpressuret d is about the same as the duration of shock wave. Predictions of structural response to dynamic loads of different. The inertia, as measured by the mass of the structure or structural member, is an important factor in the response to a dynamicimpulse lateral load such as a shock wave.
As a result, the structure is susceptible to damage from blast load. Some design strategies are also recommended aiming to ensure increased robustness in building structures that are to endure localized failure. Evaluation of blast loads on buildings in urban environment a. The objective of this research was to test and compare its results to the deflections from blast loads using fem of analysis and to compare them to equivalent loading response. Blast assessment of load bearing reinforced concrete shear walls. It enhances toughness, ductility, strength and dynamic characteristics of individual structural elements for resistance to air blast induced loading. The phase 1 fema 439a report demonstrated that, with such seismic design features in place, the structural system would have been better able to dissipate and manage the blast load effects, reducing or avoiding catastrophic chainreaction impacts on portions. Load computation, structural response analysis and structural design for these types of buildings also need to be measured. Although small weights of explosives are not likely to produce significant blast loads on the roof, lowrise buildings may be vulnerable to blast loadings resulting from large weights of explosives at large stand. Evaluation of the structure response the magnitudes of the internal forces in the structure are. Numerical, theoretical and experimental studies on the effect of blast on components, structures and its occupants combine physics of detonation chemistry, shock physics, solid mechanics, structural dynamics, nonlinear material behaviour, human physiology and injury mechanics. The results allow users to visualize in 3d how the building or different structural components inside the building will behave under the. Numerical investigation of structural response of corrugated blast. Overpressure resulting from a small device 20kg tnt equivalent detonated in a builtup urban area.
Blast can be defined as a rapid phase of a created pressure by a sudden release of energy. Effect of blast loading on reinforced concrete structures. A design blast pressure may be defined in terms of just the peak pressure only if there is an understanding that the blastload duration is long compared with the response time of the buildings structural components. Response of building structures to blast effects humanitarian library. The designer has the difficult task of predicting what type of explosive load a. In addition, design of the overall structure and its primary load. Blast load demand relates to the amount ofenergy a blast imparts to a structure, while blast load resistance is the physical strength ofa structure to withstand a blast load. The design of the protection of critical infrastructure in particular where glass elements are of concern against terrorist attacks is usually done along the following lines. Federal standards and criteria are widely recognized as the primary source of guidelines for the design of buildings to resist explosive threats. Generally, load combination is composed of individual loads, i. Master of applied science philip miller 2004 department of civil engineering university of toronto this research examines the physics behind blast waves and their interaction with structures. However, no guidelines are provided in en 199117 for the calculation of external blast induced loads.
Dynamic response of composite structures subjected to blast loading waruna seneviratne and john tomblin wichita state university. To design against explosions, a procedure has been developed to devise a uniform dynamic load on a roof that matches the response from blast loads. Blast load classification, design of blast resistant building, effect of blast load, structural response. The use of explosives by terrorist groups around the world that target civilian buildings and other structures is becoming a growing problem in modern societies. Main substation building located at esfahan refinery plant in iran. Pdf structural blast design has become a necessary part of the design with. Blast loads are in fact dynamic loads that need to be carefully calculated just like earthquake and wind loads. Pdf blast loading and blast effects on structures an overview. Load definition and structural response wit transactions on stateoftheart in science and engineer s. Abstract design and structural evaluation of the building systems subjected to blast load form the important task of the present generation.
The main objective of this study was to verify the structural performance levels under the impact of. Generally conventional structures are not designed for blast load due to the reason that the magnitude of load caused by blast is huge and, the cost of design and construction is very high. Simplified design procedure for blast resistant glazing. Because steel is the most dense construction material, heavy and robust steel members are especially effective in resisting blast loads.
This article is devoted to blast resistant design, though there is overlap with progressive collapseresistant design. Reflection of the blast wavefront is shown, resulting in successive cycles of overpressure. Weggel a comparison of hydrodynamic and analytic predicted blast pressure profiles g. Calculation of blast loads for application to structural. Load definition and structural response wit transactions on stateoftheart in science and engineer. Designing buildings to resist explosive threats wbdg. This paper presents a comprehensive overview of the effects of explosion on structures. Api rp 2f, recommended practice for the design of offshore facilities against fire and blast loading, recommends that a drag coefficient, cd 1. What is the structural design considerations of blast. Prediction of airblast loads in complex environments using artificial neural networks. This paper presents a comprehensive overview of the effects of the explosion on structures. This is not explicitly addressed in mainstream building codes. Further in limit state method the factor for design load is reduced to 1.
Blast loads are typically combined with gravity loads and load factors are set equal to 1. Challenges in a multidisciplinary approach for explosion. The horizontal forces exerted by the components of winds is to be kept in mind while designing is the building. The intensity of blast loading on a given structure depends upon several key factors, such as the type of energetic material, distance between load origin and the structure, position of the load origin relative to the ground, the relative orientation of the structure, etc. Blast design associated with intentional load sources is one aspect of the broader subject of security engineering. Blast loads are dynamic, impulsive and nonsimultaneous over the length of a roof. The document includes as section 18, fire, blast and accidental loading that provides, for the first time in api, a recommended practice for design of fixed steel offshore structures against fire and blast events. This is a joint decision of the owner or stakeholder and the designer. This is the case for some industrial explosions and for nuclear explosions.
The variation is found significant in the region of. Young a study of the jwl equation of state parameters of dynamite for use in airblast models b. Structural design of buildings to resist blast and progressive collapse case study. Once the ductility ratio is equal to one, it means that the structural response is. Blast response mitigation strategies can be incorporated in the structural design at concept stage, leading to a welldesigned and constructed structure that can exhibit improved blast resistance and at the same time maintain its architecturally appealing appearance. Due to different accidental and intentional acts, the response of the structures for these high impulse, impact loads forms a necessary subject in the recent times. Structural blast design has become a necessary part of the design with increasing terrorist attacks. Differences between blast and seismic loading are presented in figure 1. This paper investigates, through numerical simulations, the effects of blast. Blast load bl, the effects of blast load is considered by removing failed columns and proceeding alternate path analysis. The studies have shown the terrorist attacks against civil transport aircraft is a significant threat, i. Blast safety of the building envelope whole building design. Comparative study of response of structures subjected to.
The problem of structural resistance under explosive loads has been under investigation for many years and has been well advanced in the military community. A computer program, vector blast, is developed based on the blast wave characteristics of tnt. Other papers are concerned with alternative methods for the determination of blast pressure, based on experimental measurements or neural networks. Although these kinds of attacks are exceptional cases, manmade disasters. Architectural and structural design for blast resistant buildings2008 the objective of this study is the. An explanation of the nature of explosions and the mechanism of blast waves in free air is given. The structural designer, in order to design a new structure or retrofit an existing structure for explosion resistance, generally requires certain information as summarized below.
Terrorist attacks are not the one to make the structures important against blast loading where other explosions such as high gas explosions also take an important place in structural safety. Review of blast loading models, masonry response, and. For complex structures requiring refined estimates of blast load. Foundation design for blast loads archie264 structural 19 dec 15. The analysis and design of structures subjected to blast loads require a detailed understanding of blast phenomena and the dynamic response of various structural elements. Feb 07, 2017 explosions and blasts can produce, in a very short time, an overload much greater than the design load of a building. The peak pressure value and velocity of the blast wave, which were described earlier, decrease rapidly by increasing the distance between the blast source and the target surface, as shown in figure 2. Blast loading and blast effects on structures an overview. The list of specific targets to be designed against blast the performance criteria to satisfy during an explosion event the corresponding effectiveappliedexplosion load designexplosion load. The effect of blast load on both corroded and uncorroded reinforced concrete buildings was examined. The analysis and design of structures subjected to blast loads require a detailed understanding of blast phenomena and the dynamic response of various. In october 2001, api sc2 formed a fire and blast task group under the chairmanship of bps patrick o connor. Different models for prediction of blast loading, response of masonry structure against blast load, and various mitigation strategies are discussed.
Volume 4, issue 2, august 2014 response of building. Volume 4, issue 2, august 2014 167 abstract as a result of repeated terrorist incidents around the world that target important and military structures, blast loads have received great interest in recent years. The pressures that load the roof, sides, and rear of the building are termed incident pressures, while the pressures that load the building envelope directly opposite the explosion are termed reflected pressures. These patterns of blast load intensity are complicated as the waves engulf the entire building.
The book starts with an overview of key physicsbased algorithms for blast and fragment environment characterisation, structural response analyses and structural assessments with reference to a terrorist attack in an urban environment and the management of its inherent uncertainties. Recent past blast incidents in the country trigger the minds of developers. Foundation design for blast loads structural engineering. Structural aspect of blast resistant building design the front face of a building experiences peak overpressures due to reflection of a. While blast loads are dynamic, in some circumstances it makes sense to use equivalent static blast loads for design. All the information in the preceding is provided by the safety engineer to the disciplines in charge of the explosion response by. Introduction the blast loading is a very rapid release of stored energy, imposes extreme loadin g on window glazing which produces high velocity airborne sharp glass fragments that causes large percent of all nonfatal injuries. Prediction of airblast loads in complex environments using. Unlike seismic and wind loads, blast loads have a short duration that is measured in milliseconds. Design of blastresistant buildings in petrochemical. Nonductile concrete design such is used in nonseismic design can perform badly, as is witnessed by the collapse of the alfred p.
881 457 557 10 901 229 1412 619 1233 808 1232 484 1403 1185 1259 318 1052 373 1412 252 1232 777 1004 531 1150 574 851 111 374 1284