Bond-slip in reinforced concrete elements

A model for fiber reinforced composites that takes into account the fiber slipping is presented in this paper and applied to the analysis of reinforced concrete elements. The model is formulated within the framework of the plasticity theory and the mixtures theory, considering two phases corresponding to the matrix (concrete) and the fibers (reinforcing bars) and modifying the behavior of the last to take into account the relative displacement between the two phases. An elasto-plastic interface model developed by other writers is used to describe the bond-slip mechanism. The resulting model is attractive for the analysis of reinforced concrete problems at the macro-structural level since the explicit discretization of reinforcing bars and interface is not required, with the consequent computational cost reduction. The paper concludes with application examples and comparisons with experimental results of reinforced concrete elements that show the capacity of the model developed. © ASCE.Fil: Luccioni, Bibiana Maria. Universidad Nacional de Tucuman. Facultad de Cs.exactas y Tecnología. Laboratorio de Estructuras; ArgentinaFil: López, Daniel Ernesto. Universidad Nacional de Cuyo; ArgentinaFil: Danesi, Rodolfo Francisco. Universidad Nacional de Tucuman. Facultad de Cs.exactas y Tecnología. Laboratorio de Estructuras; Argentin

Colapso estructural bajo cargas explosivas

Las estructuras civiles no son generalmente diseñadas para resistir cargas dinámicas de muy corta duración y gran amplitud como las generadas por explosiones e impacto. Hasta hace muy poco tiempo, la consideración de cargas explosivas debidas a un ataque terrorista se limitaba principalmente a estructuras tales como estructuras militares, centrales nucleares, embajadas, etc. En este trabajo se presenta la simulación del proceso de destrucción de estructuras de hormigón producido por la detonación de cargas explosivas. Dicho estudio se realiza mediante un hidrocódigo que considera la interacción fluido (aire)- estructura. Se describen en el trabajo los modelos materiales utilizados para el hormigón y mampostería.Dichos modelos incluyen la simulación del fenómeno de desintegración o fractura del material que permite eliminar al mismo del cálculo para simular erosión o discontinuidades producidas en el material por la carga explosiva. Se presentan, además, las distintas estrategias de calculo utilizadas en la simulación del proceso completo, desde la detonación del explosivo, hasta la caída del edificio.Fil: Luccioni, Bibiana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Estructuras "Ing. Arturo M. Guzmán"; ArgentinaFil: Ambrosini, Ricardo Daniel. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico; ArgentinaFil: Danesi, Rodolfo Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucuman. Facultad de Cs.exactas y Tecnología. Laboratorio de Estructuras; Argentin

Prestressed Concrete Box Girders of Deformable Cross - Section.

Imperial Users onl

Blast load assessment using hydrocodes

The evaluation of pressures and impulses produced by blast loads with the aid of hydrocodes is studied in this paper. Numerical results are compared with those obtained with existing analytical expressions for different scaled distances and boundary conditions. In particular, the capacity of both methods to capture multiple reflections of the blast load is analyzed. The effects of mesh size on pressure and impulse distribution are also studied. Some interesting conclusions regarding the determination of the best mesh size for calculation of actual events are obtained. Finally, the analysis of blast load in the case of the AMIA (Israel–Argentina Mutual Association) building attack which occurred in Buenos Aires, Argentina in July 1994 is presented. A computational dynamic analysis was carried out over the congested urban environment that corresponds to the opposite rows of buildings of a block, in the same street. The results obtained for different positions of the explosive charge are presented and compared.Fil: Luccioni, Bibiana Maria. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Estructuras "Ing. Arturo M. Guzmán"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Ambrosini, Ricardo Daniel. 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 - San Juan; ArgentinaFil: Danesi, Rodolfo Francisco. Universidad Nacional de Tucuman. Facultad de Cs.exactas y Tecnología. Laboratorio de Estructuras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentin

Analysing explosive damage in an urban environment

This paper describes the determination of the mass of explosive and the location of the source of the explosion in a terrorist attack in a congested urban environment. A computational dynamic analysis was carried out for a real congested urban environment that corresponds to opposite rows of blocks of buildings in the same street. Many combinations corresponding to different locations and explosive masses were simulated, and the corresponding distributions of pressure and impulse on the building façades were obtained. Additionally, conclusions about the applicability of empirical expressions for evaluating incident and reflected pressure and associated impulses in a congested urban environment arise from a comparison with the numerical results, and are discussed in the paper. The structural damage produced by an explosion can be assessed with the use of isodamage curves, which approximately relate pressures and impulses to the damage produced in different types of building and parts of them. In general, isodamage curves have been obtained from a vast compilation of damage produced in masonry houses and other buildings and structural members, in both experimental and actual explosions. Damage contours were defined and used in order to compare the real damage with that obtained by the numerical simulation over a wide zone around the origin of the explosion. Additionally, conclusions that lead to the ability to discard many combinations of mass of explosive and location of the source of the explosion arise from the comparison of real and simulated damages, and are discussed in the paper.Fil: Luccioni, Bibiana Maria. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Estructuras "Ing. Arturo M. Guzmán"; ArgentinaFil: Ambrosini, Ricardo Daniel. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Estructuras "Ing. Arturo M. Guzmán"; ArgentinaFil: Danesi, Rodolfo Francisco. Universidad Nacional de Tucuman. Facultad de Cs.exactas y Tecnología. Laboratorio de Estructuras; Argentin

Analysis of building collapse under blast loads

The analysis of the structural failure of a reinforced concrete building caused by a blast load is presented in this paper. All the process from the detonation of the explosive charge to the complete demolition, including the propagation of the blast wave and its interaction with the structure is reproduced. The analysis was carried out with a hydrocode.The problem analysed corresponds to an actual building that has suffered a terrorist attack. The paper includes comparisons with photographs of the real damage produced by the explosive charge that validates all the simulation procedure. © 2003 Elsevier Ltd. All rights reserved.Fil: Luccioni, Bibiana Maria. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Estructuras "Ing. Arturo M. Guzmán"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Ambrosini, Ricardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Danesi, Rodolfo Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucuman. Facultad de Cs.exactas y Tecnología. Laboratorio de Estructuras; Argentina. Universidad Nacional de Tucumán; Argentin

Experimental and computational analysis of plates under air blast loading

The main objective of this paper is the comparison between testing and numerical responses of metallic plates subjected to explosive loads, in order to obtain guides to the numerical modeling and analysis of this phenomenon. Moreover, the secondary objective was to provide data that could be used for checking the accuracy of a variety of calculation methods. A set of four tests at natural scale is presented on two nonstiffened metallic steel plates with different boundary conditions (one clamped in the soil and another clamped in the four edges), subjected to the action of pressure waves originated by the detonation of explosive loads. The time history of the acceleration in different points of both plates and the pressure waves in selected points, are recorded. On the other hand, a linear dynamic analysis of the plate models with the code ABAQUS was carried out. The influence of the number of natural modes that are considered for the analysis and the refinement of the mesh are analyzed. Moreover, a nonl inear geometric analysis was carried out in order to verify this possible behavior in the first plate. Suggestions to computational modeling of structures under impulsive loads arise from the comparison of numerical and experimental results. © 2001 Elsevier Science Ltd. All rights reserved.Fil: Jacinto, Abel Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Ambrosini, Ricardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán; ArgentinaFil: Danesi, Rodolfo Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán; Argentin

Thermo-mechanic model for concrete exposed to elevated temperatures

A thermo-mechanical model for concrete subjected to high temperatures is presented in this paper. The model is based on a coupled plastic-damage model that has been extended to consider damage induced by high temperatures. The model is calibrated with experimental results of residual strength tests in concrete specimens. The paper is completed with application examples and comparisons with experimental results that validate the model presented. The model is also used to the damage assessment of a concrete structure that has been subjected to fire.Fil: Luccioni, Bibiana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Estructuras "Ing. Arturo M. Guzmán"; ArgentinaFil: Figueroa, Maria Ines. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Estructuras "Ing. Arturo M. Guzmán"; ArgentinaFil: Danesi, Rodolfo Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucuman. Facultad de Cs.exactas y Tecnología. Laboratorio de Estructuras; Argentin

Size of craters produced by explosive charges on or above the ground surface

The results of a series of tests performed with different amounts of explosive at short distances above and below ground level, as well as on the soil surface are briefly described. After an introductory description of both the main features of the blast wave and the mechanics of crater formation, a brief review of empirical methods for crater size prediction is presented. Next, the experimental design and the results obtained are described. The crater dimensions for underground explosions coincide with those found in the literature. For explosions at ground level the results are qualitatively described by empirical equations. For explosive charges situated above ground level, the dimensions of the craters are smaller than those observed in underground and near the surface explosions. Two new single prediction equations for this case are presented.Fil: Ambrosini, Ricardo Daniel. Universidad Nacional de Cuyo. Facultad de Ingeniería. Instituto de Mecánica Estructural y Riesgo Sísmico; ArgentinaFil: Luccioni, Bibiana Maria. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Instituto de Estructuras "Ing. Arturo M. Guzmán"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Danesi, Rodolfo Francisco. Universidad Nacional de Tucuman. Facultad de Cs.exactas y Tecnología. Laboratorio de Estructuras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Riera, Jorge D.. Universidade Federal do Rio Grande do Sul; BrasilFil: Rocha, Marcelo. Universidade Federal do Rio Grande do Sul; Brasi