1,720,966 research outputs found
Experimental study of confined masonry walls under blast loading
No full textTerrorist organizations around the world have used explosives on many occasions to carry out attacks in urban centers. The victims and injuries in these attacks are often due to structural collapses and the impact of debris. This threat leads researchers to study the performance of ordinary building systems exposed to extreme impulsive loads. Confined masonry buildings are a widely used construction system in seismic zones in many parts of the world and have been widely studied under seismic loads. On the other hand, studies of the response to out-of-plane impulsive loads, such as those caused by intentional or accidental explosions, are scarce. In this paper, results of three experimental explosions at different scaled distances are presented. The explosives on and 1 m above the ground were used. Confined masonry walls with and without openings were tested. The complex interaction between air blast and ground shock was analyzed. Levels of damage obtained with different scaled distances are presented. The results are compared with iso-damage curves.Fil: Codina, Ramon Humberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería; ArgentinaFil: Ambrosini, Ricardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería; Argentin
Muros de mamposteria sometidos a explosiones
Full text linkLas organizaciones terroristas de todo el mundo han utilizado explosivos en muchas ocasiones para llevar a cabo atentados en centros urbanos. Algunas de las víctimas y los heridos en estos tentados suelen deberse a colapsos estructurales y al impacto de escombros. Esta amenaza obliga a los nvestigadores a estudiar el comportamiento de los sistemas de construcción ordinarios expuestos a cargas impulsivas extremas. La mampostería encadenada es un sistema de construcción muy utilizadon en zonas sísmicas de muchas partes del mundo, ampliamente estudiados bajo cargas sísmicas. En cambio, son escasos los estudios sobre su respuesta a cargas impulsivas fuera del plano, como las causadas por explosiones intencionadas o accidentales. En este trabajo se estudian 2 explosiones con diferentes distancias escaladas. Se utilizaron explosivos apoyados el suelo cerca de muros de mampostería encadenada con una abertura. Se analizó la compleja interacción entre las ondas de presión y la estructura. Se modela usando codigos comerciales las sobrepresiones, impulsos y la respuesta estructural.Fil: Codina, Ramon Humberto. Universidad Nacional de Cuyo. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Ambrosini, Ricardo Daniel. Universidad Nacional de Cuyo. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaXXVII Congreso Argentino de Mecánica ComputacionalResistenciaArgentinaUniversidad Nacional del Nordeste. Facultad de IngenieríaAsociación Argentima de Mecánica Computaciona
Numerical and analytical study of overpressures and impulses inside a masonry box subjected to external blast loading
No full textBlast loads have attracted considerable attention in recent years due to accidental or intentional events involving important structures, which have occurred around the world. The activities related to terrorist attacks have increased and, unfortunately, the current trend suggests that they will continue to rise in the future. In relation to the design of structures subjected to blast loadings, there are still many uncertainties in the specialized technical literature. Particularly, the overpressures and impulses inside constructions are difficult to estimate due to many reflections of the shock wave. The main objective of this work is to study the propagation of the blast wave inside constructions subjected to external loadings. An experimental study was performed using a masonry box with reinforced concrete beams and columns and a typical window. The results were previously presented. In this article, numerical models are developed in order to compare results and to obtain design guidelines. Explosive charges of equivalent 1?5 kg of TNT and elevated 1m above the ground were detonated at different distances from the window, and overpressures and impulses were obtained at five points inside and outside the room. However, empirical?analytical results using a well-known technical manual are also obtained and compared. The obtained results are useful to evaluate numerical codes and empirical formulas.Fil: Codina, Ramon Humberto. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Ambrosini, Ricardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico; Argentin
Full-scale testing of leakage of blast waves inside a partially vented room exposed to external air blast loading
No full textFor the last few decades, the effects of blast loading on structures have been studied by many researchers around the world. Explosions can be caused by events such as industrial accidents, military conflicts or terrorist attacks. Urban centers have been prone to various threats including car bombs, suicide attacks, and improvised explosive devices. Partially vented constructions subjected to external blast loading represent an important topic in protective engineering. The assessment of blast survivability inside structures and the development of design provisions with respect to internal elements require the study of the propagation and leakage of blast waves inside buildings. In this paper, full-scale tests are performed to study the effects of the leakage of blast waves inside a partially vented room which is subjected to different external blast loadings. The results obtained may be useful for proving the validity of different methods of calculation, both empirical and numerical. Moreover, the experimental results are compared with those computed using the empirical curves of the US Defense report/manual UFC 3-340. Finally, results of the dynamic response of the front masonry wall are presented in terms of accelerations and an iso-damage diagram.Fil: Codina, Ramon Humberto. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Ambrosini, Ricardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico. Maestría en Ingeniería Estructural; Argentin
Alternatives to prevent progressive collapse protecting reinforced concrete columns subjected to near field blast loading
Full text linkExtensive research activities in the field of blast loads have taken place in the last few decades. Explosive blast research is important not only for the understanding of damage caused by explosions but also for predicting vulnerability of structures and human to blast and for the development of blast-resistant materials and protective elements. In this sense, the façade columns in buildings are key elements to protect in order to avoid progressive collapse. In this paper, a numerical-experimental study of the dynamic response of reinforced concrete (RC) columns with different sacrificial layers of protection is presented. Different alternatives of protection of RC columns are designed and studied, from classical steel jacketing to crushable materials. The mitigation of shock and absorption of energy under blast loading conditions is studied by numerical and experimental methods. For comparison purposes, a RC column without protection is also tested and studied. The obtained results are useful to explore new alternatives of protection of RC columns as well as to calibrate numerical codes.Fil: Codina, Ramon Humberto. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Ambrosini, Ricardo Daniel. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: de Borbon, Fernanda Maria. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentin
New sacrificial cladding system for the reduction of blast damage in reinforced concrete structures
Full text linkOver the past few decades, explosive devices have become the weapon of choice for many terrorist attacks. In some of these attacks, large amounts of explosives are detonated within a short distance of building structures. It has been shown that current design methods are inadequate for the prevention of progressive collapse. The protection of key elements, such as columns, is necessary to prevent this catastrophic response sufficiently. This article discusses the performance of a new sacrificial cladding that protects reinforced concrete members under blast loading. It consists of reinforced resin panels with an insulation layer. For comparison purposes, two reinforced concrete members were previously experimentally studied, a reinforced concrete column without protection and reinforced concrete column with classical steel jacketing. It can be observed from the experimental results that the new sacrificial cladding achieves an important reduction in damage and displacements.Fil: Codina, Ramon Humberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico. Maestría en Ingeniería Estructural; ArgentinaFil: Ambrosini, Ricardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico. Maestría en Ingeniería Estructural; ArgentinaFil: de Borbon, Fernanda Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico. Maestría en Ingeniería Estructural; Argentin
Alternatives to prevent the failure of RC members under close-in blast loadings
Full text linkIn this paper, an experimental study of the dynamic response of reinforced concrete (RC) members protected in different ways is presented. Two alternatives for the protection of RC members are designed and studied; classical steel jacketing and a new reinforced polyurethane sacrificial layer. The mitigation of shock and absorption of energy from the blast is studied with experimental methods. For comparison purposes, a RC member without protection is also tested and studied. As expected, the steel jacketing provided excellent protection reducing the maximum final deflection as well as reducing damage to the member. On the other hand, the proposed reinforced polyurethane protection performed reasonably well. The obtained results are useful for exploring new alternatives for the protection of RC columns as well as for the calibration of numerical codes.Fil: Codina, Ramon Humberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico. Maestría en Ingeniería Estructural; ArgentinaFil: Ambrosini, Ricardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico. Maestría en Ingeniería Estructural; ArgentinaFil: de Borbon, Fernanda Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico. Maestría en Ingeniería Estructural; Argentin
Numerical Study of Confined Explosions in Urban Environments
Full text linkIn recent years, events such as the attack on the World Trade Center as well as many other attacks around the world have shown that terrorism related activity is dramatically increasing. Such a situation makes necessary to study the effects of blast loading on complex urban environments. In this paper, the phenomenon of channelling in congested urban environments is studied. Channelling is a phenomenon that can significantly increase the destructive potential of a shock wave of an explosion. Hence, channelling must be taken into account in the design of structures subjected to extreme loads in congested urban environments. This paper presents a novel approach to understanding channelling effects using maps of overpressure amplification and impulse amplification. These maps are developed for different street widths and amounts and locations of explosive loads and could be used as a first approximation for design purposes. The characteristic channelling zones are defined and characterised for the first time in the open technical literature. Finally, quantitative conclusions about the influence of the different parameters are highlighted.Fil: Codina, Ramon Humberto. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico. Maestría en Ingeniería Estructural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza; ArgentinaFil: Ambrosini, Ricardo Daniel. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico. Maestría en Ingeniería Estructural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza; ArgentinaFil: de Borbon, Fernanda Maria. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico. Maestría en Ingeniería Estructural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza; Argentin
Experimental and numerical study of a RC member under a close-in blast loading
Full text linkIn recent years, many attacks all over the world have shown that terrorism related activity is dramatically increasing. In this context, columns are the most critical structural components and their failure is the primary cause for progressive collapse in framed structures. The effects of near-field explosions on structural elements, especially columns, have not been widely investigated in the literature. Therefore, the main objectives of this paper are: to evaluate the effectiveness of a numerical model to replicate the experimental damages of reinforced concrete (RC) columns subjected to close-in blast loading; to obtain modelling guidelines for this phenomenon and to provide quality experimental data that could be used as a reference to check the accuracy of a variety of calculation methods. For these purposes, RC members were subjected to a near field explosion in full scale. Experimental tests and numerical simulations are carried out in order to calibrate the numerical model. In this context, a new set of parameters for the constitutive equations of the concrete is proposed and verified.Fil: Codina, Ramon Humberto. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico. Maestría en Ingeniería Estructural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Ambrosini, Ricardo Daniel. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico. Maestría en Ingeniería Estructural; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: de Borbon, Fernanda Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico. Maestría en Ingeniería Estructural; Argentin
Structural analysis of the CAREM-25 nuclear power plant subjected to the design basis accident and seismic loads
Full text linkIn this paper, a numerical study about the structural response of the Argentine nuclear power plant CAREM-25 subjected to the design basis accident (DBA) and seismic loads is presented. Taking into account the hardware capabilities available, a full 3D finite element model was adopted. A significant part of the building was modeled using more than 2 M solid elements. In order to take into account the foundation flexibility, linear springs were used. The springs and the model were calibrated against a greater model used to study the soil-structure interaction. The structure was subjected to the DBA and seismic loads as combinations defined by ASME international code. First, a transient thermal analysis was performed with the conditions defined by DBA and evaluating the time history of the temperature of the model, each 1 h until 36 h. The final results of this stage were considered as initial conditions of a static structural analysis including the pressure defined by DBA. Finally, an equivalent static analysis was performed to analyze the seismic response considering the design basis spectra for the site. The different loads were combined and the abnormal/extreme environmental combination was the most unfavorable for the structure, defining the design.Fil: Ambrosini, Ricardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería; ArgentinaFil: Codina, Ramon Humberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería; ArgentinaFil: Curadelli, Raul Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería; ArgentinaFil: Martínez, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería; Argentin
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