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The present paper investigates the effect of the harmfulness of a potential earthquake on structural and seismic risks. It takes into account the magnitude, epicentral distance, and pseudo depth at the hypocenter as well as the soil classification in order to generate synthetic seismic motions to be considered as signal inputs for a structural seismic analysis. The most typical typology of dwellings and buildings that are widely existing in Algeria, i.e., a reinforced concrete frame structure, is considered for the case study. The results show that the theoretical models developed in this study are able to predict the performance point (spectral displacement) according to the cumulative absolute velocity. They also show that(CAV-Sd) (Sd being the spectral displacement of the performance point defined by a pushover analysis) is slightly influenced by the value of the ultimate displacements of the structures and the soil parameters (shear velocity Vs).

The thesis work focused on the development of a formal model to quantify the disturbances intrinsically produced by a construction project on the performance of uses of a building. In order to characterize the interaction between these two systems, explanatory parameters have been identified in order to influence the probability of achieving a given level of performance and thus maximize the probability of satisfaction of stakeholders with their preferences. The model positions itself as a decision aid when choosing constructive options and improving the effective performances of use of buildings is the main industrial application expected, Les travaux de thèse ont porté sur la confection d'un modèle formel permettant de quantifier les perturbations intrinsèquement produites par un projet de construction sur les performances d'usages d'un bâtiment. Afin de caractériser l'interaction entre ces deux systèmes, des paramètres explicatifs ont été identifiés afin d'influencer la probabilité d'atteindre un niveau de performance donné et ainsi maximiser la probabilité de satisfaction des parties prenantes vis-à-vis de leurs préférences. Le modèle se positionne comme une aide à la décision lors de choix d'options constructives et l'amélioration des performances d'usages effectives des bâtiments est la principale application industrielle attendue.

This article presents an original identification method for the assessment of flexure and shear stiffness of cantilever structures or shear wall buildings. Required data include an initial (theoretical) model, an estimation of lumped mass values (by floor) and an experimental evaluation of two eigenvalues (modal frequencies and their modal shapes). The method estimates coefficients whenever flexural (EI) or shear (GA) values are relevant or irrelevant. An initial formula includes both shear and flexural components. Furthermore, particular developments are carried out for particular cases of irrelevant shear or flexural deformations. A numerical simulation of a real chimney is performed to study the effectiveness of the methodology in identifying damage under noise conditions. A dynamic-test experiment is carried out on a steel cantilever which suffers damage in two sections. The result obtained from the application of the proposed methodology is satisfactory in both numerical and experimental cases, identifying precisely the stiffness changes in the system.

This study deals with industrial accidents and domino effects that may occur in an industrial plant, the initial accident being supposed to take place in any of the tanks either under or at atmospheric pressure. This initial sequence might generate sets of structural fragments, fire balls, blast waves as well as critical losses of containment (liquid and gas) that threaten the surrounding facilities and may cause serious damages. The structural fragments, the blast wave and the fire ball can be described following database and feedback collected from past accidents. The vulnerability of the potential targeted tanks is investigated in order to assess the risk of propagation of the first sequence of industrial hazard. Cascading sequences of accidents, explosions and fires can take place, giving rise to the domino effect. This risk of domino effect occurrence is investigated herein. The interaction and the behavior of the targets affected or impacted by the first explosion effects are described by adequate simplified mechanical models: perforation and penetration of metal fragments when they impact surrounding tanks, as well as global failure such as overturning, buckling, excessive bending or shear effects, etc. Sensitivity analysis is performed thanks to Monte Carlo simulations: the probability of impact and risk of failure of target tanks are reported. A comparison between risks due to blast wave and fragments impacts is performed., Este estudio trata de los accidentes industriales y los efectos dominó que pueden producirse en una planta industrial, suponiendo que el accidente inicial tiene lugar en cualquiera de los tanques, ya sea a presión atmosférica o bajo ella. Esta secuencia inicial puede generar conjuntos de fragmentos estructurales, bolas de fuego, ondas expansivas, así como pérdidas críticas de contención (líquido y gas) que amenazan las instalaciones circundantes y pueden causar graves daños. Los fragmentos estructurales, la onda expansiva y la bola de fuego pueden describirse siguiendo la base de datos y la información recogida de accidentes anteriores. Se investiga la vulnerabilidad de los posibles tanques objetivo para evaluar el riesgo de propagación de la primera secuencia de peligro industrial. Pueden producirse secuencias en cascada de accidentes, explosiones e incendios, dando lugar al efecto dominó. Aquí se investiga este riesgo de aparición del efecto dominó. La interacción y el comportamiento de los objetivos afectados o impactados por los primeros efectos de la explosión se describen mediante modelos mecánicos simplificados adecuados: perforación y penetración de fragmentos metálicos cuando impactan en los depósitos circundantes, así como fallos globales como el vuelco, el pandeo, los efectos de flexión o cizallamiento excesivos, etc. El análisis de sensibilidad se realiza gracias a las simulaciones de Monte Carlo: se informa de la probabilidad de impacto y del riesgo de fallo de los tanques objetivo. Se realiza una comparación entre los riesgos debidos a la onda expansiva y a los impactos de fragmentos. Traducción realizada con la versión gratuita del traductor www.DeepL.com/Translator, a Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME, UMR 8208 CNRS, 5 Bd Descartes, 77454 Marne-La-Vallée, France b INERIS, Institut National de l’Environnement Industriel et des Risques, Parc Technologique ALATA, BP 2 - 60550 Verneuil-en-Halatte, France

International audience

International audience; The paper develops a probabilistic approach in order to deal with domino effects that may occur in industrial facilities : an explosion or accident may generate various sets of projectiles that may impact other existing facilities (tanks under high-pressure, etc) and may generate other sets of projectiles and so on. Three main parts are considered : 1- Source term : for the first set of generated projectiles, probabilistic distributions are considered for the number, masses, velocities, departure angles, geometrical form, dimensions, and constitutive materials properties. The authors have collected existing models from the literature. 2- Target term : for the set of impacted targets, probabilistic distributions are considered for the number of impacting projectiles, velocities, incidence angles and energy at impact, constitutive materials properties, dimensions of the impacted targets, and projectiles penetration depths into the targets. In this paper, new models for the impact are proposed to calculate the penetration depth after impact : case of cylindrical rods impacting rectangular plates, both are metal made. The theoretical results are compared to the experimental data (4 data sets) collected from the literature with the following features : projectiles mass ranging from 0.1g up to 250 kg, projectiles velocity ranging from 10 m/s up to 2100 m/s, projectiles diameters ranging from 1.5 mm up to 90 mm, target strength ranging from 300 MPa up to 1400 MPa and incidence angles ranging from 0 degree up to 70 degrees. 3- Domino effect term : evaluation of the risks of second set of explosions that may take place in the impacted components. Monte Carlo simulations are used in order to calculate the different probabilities : probability of impact, distribution of the penetration depth and probability of domino effect.

Se presenta la identificación del daño introducido en un modelo aporticado a escalada reducida, usando dos metodologías de evaluación, las cuales requieren de un ensayo experimental dinámico previo y de un modelo teórico inicial. Estas metodologías aprovechan la configuración de los edificios aporticados en la ecuación que rige el sistema. La primera de las metodologías se ocupa de la estimación de la rigidez, para ello se parte del conocimiento previo de los valores de masa de la estructura. La segunda metodología considera que no se conoce la matriz de masa del sistema. A continuación se describe el modelo ensayado, luego se detalla el procedimiento de ensayo dinámico realizado y la identificación que conduce a la obtención de los parámetros dinámicos correspondientes. Finalmente, se estiman los cambios de rigidez en la estructura ensayada, producidos por el daño, mediante la aplicación de las metodologías inicialmente expuestas. Los resultados obtenidos son satisfactorios.

En este trabajo se presenta la aplicación de un método de estimación de la rigidez a estructuras de baja altura compuestas por muros de mampostería confinada. El método estima la rigidez a cortante (GA) y a flexión (EI), a partir del conocimiento de la matriz de masa y de una evaluación experimental previa, de la cual se hayan obtenido al menos dos frecuencias de vibración y sus respectivas formas modales. Una vez presentados los métodos de identificación de la rigidez y ajuste de la matriz de masa, se realizan simulaciones numéricas, que permiten establecer la sensibilidad de la estimación de la rigidez en función de diversas variables tales como el modelo de masa utilizado, la geometría de la estructura y la presencia de aberturas. Adicionalmente se propone una metodología para la cuantificación del cambio de rigidez ocurridos en una estructura compuesta por muros de mampostería confinada.

The paper deals with the effect of the depth to bedrock randomness on the seismic response of an Algiers site in time and frequency domains. Stochastic soil profile seismic analysis is carried out via Monte Carlo simulations coupled to the stiffness matrix method. The soil height is assumed to be a random variable with a log-normal distribution. The stochastic behavior of extreme ground acceleration and its response spectrum, transfer function, fundamental frequency, maximum amplitude, short- and mid-period amplification factors are derived from 1000 samples, as a parametric study is performed accounting for the influence of the coefficient of variation of the depth to bedrock. As the study herein considers a SH wave propagation pattern (SH stands for shear horizontal), the accelerations under study correspond to the E–W and N–S horizontal directions. The seismic acceleration corresponds to the Boumerdes earthquake (Algeria, May 21, 2003, Mw = 6.5). The probability density functions of the output parameters are derived using the maximum entropy principle, and compared to the log-normal distribution. The soil height heterogeneity causes an increase in the fundamental frequency of the soil profile, as well as a wider frequency content, in such a way that a larger number of structures are concerned by the resonance phenomenon.

A semi empiric method to evaluate the ultimate shear of confined masonry walls with the assumption of a failure surface by shear effect in the diagonal wall is presented. For its application, masonry and reinforced concrete properties are required. The model provides results that range within 73% up to 113 % of the experimental strength of 25 walls tested under lateral cyclic and monotonic loads in Mexico and Venezuela, with several ratios H/L by using concrete hollow blocks and solid bricks. The applied vertical stresses are the usual values for buildings up to 5 levels.