Assessment of the expected seismic damage in the aggregated masonry buildings of the late XIX century of Barcelona, Spain

This paper aims at the evaluation of expected seismic damage of aggregated masonry buildings system, formed by a line of buildings along of the street; real buildings were studied of whom structural drawings were available. Each structure was individually built without any gaps between them, producing interaction among the buildings under lateral loads. Numerical model consists of 7 buildings: 5 in-row with rectangular shape and 2 corners (in the intersection of two streets) with a pentagonal shape. Damage probability matrices were obtained from pushover analysis using the capacity and fragility curves. Seismic hazard is considered for the acceleration of Barcelona. Four damage states were considered: slight, moderate, extensive and complete (collapse). The results showed that aggregated system analysed presents slight damage in a hard soil while very extensive damage occur in soft soil, furthermore, the expected seismic damage is high considering the low seismic action of Barcelona.Peer ReviewedPostprint (published version

Seismic behavior of medium and high strength concrete buildings

Current concrete technology has made higher concrete grades more affordable to mid and high-rise buildings; hence its use has been increasing in the late years as it allows for smaller cross-sections, reduction of the structure’s weight, improve durability, among other benefits. However, it is known that brittleness of plain concrete increases with the strength; therefore, some national codes have limited the concrete’s strength in high seismic zones. In this paper, the seismic behavior of a 10 storey dual frame-wall building, designed with concrete grades C30, C60 and C90 is studied in order to assess the advantages and disadvantages of this material and investigate the effects of high concrete strength on the seismic behavior of buildings. In total, three models were studied. Furthermore, a comparison between Force-Based-Design (FBD) and Displacement-Based-Design (DBD) methodologies is made. DBD showed advantages in determining the adequate design ductility and the distribution of forces between frame and wall. The structures are designed according to Eurocode 8 for seismic design high ductility structures. To assess the seismic performance of the building, pushover analyses were made according to the Eurocode 8 (N2 method) in order to determine the performance point. It is observed that adequate design could accommodate concrete’s reduction of ductility. Needed confinement levels can objectively be defined for different concrete strength. Some benefits of the overall increase of strength are highlighted in the paper. The C90 building showed adequate response, although changes on the failure mode were observedPostprint (published version

Curvas de fragilidad para evaluar el daño sísmico en edificios de concreto armado con losas reticulares

Las estructuras con un comportamiento sísmico inadecuado son la causa principal de las pérdidas humanas y económicas durante la ocurrencia de temblores intensos. Para mejorar el diseño de las estructuras hay que comenzar por realizar estudios de riesgo sísmico en zonas urbanas, los cuales permiten evaluar la vulnerabilidad sísmica en dichas zonas y estimar el daño probable que se puede sufrir a causa de un evento sísmico. Actualmente, muchos de los edificios de Barcelona, España, son edificios de concreto armado con losas reticulares. Dentro de la ciudad, es la segunda tipología constructiva más representativa, y va en aumento, ya que es el sistema más utilizado en la actualidad. Este trabajo es una contribución al análisis del comportamiento sísmico de estos edificios y hace frente al análisis del riesgo sísmico en un área urbana situada en una zona de baja sismicidad. Para llevar a cabo un análisis adecuado se debe disponer de una amplia información, que muchas veces no se tiene y, además, existe una gran cantidad de incertidumbres involucradas, por lo tanto, el tratamiento adecuado del problema es el probabilista. En este trabajo se evalúa la vulnerabilidad y el riesgo sísmico de edificios de concreto armado con losas reticulares mediante una metodología basada en el método del espectro de capacidad. Los modelos estructurales que se utilizan en el análisis corresponden a edificios de 8, 5, 3 y 2 pisos. Para cada uno de estos edificios se determina su capacidad y se evalúa su fragilidad. Para la demanda sísmica esperable en Barcelona, se consideran dos escenarios sísmicos específicos. A partir de aquí, se obtienen las matrices de probabilidad de daño para cada modelo, para cada escenario sísmico y para cada tipo de suelo. // Structures with an inadequate seismic performance are the main source of the human death and economic losses when a major earthquake strikes an urban area. To improve buildings design one have to begin by carrying out seismic risk analysis in urban areas, which permit to assess the seismic vulnerability in these zones and to estimate the probable damage can be suffer by a seismic event. Currently, many of the housings in Barcelona, Spain, are multi-storey waffle slabs reinforced concrete buildings. In fact, this typology is the second most representative in the city and the number of this type of buildings is increasing because, at present, this is the most extended construction system. This work is a contribution to the analysis of the seismic behaviour of this type of buildings and it faces the seismic risk analysis in an urban area situated in a low seismic hazard region. In order to carry out a suitable analysis it is necessary to have enormous information, that often it is not available and, in addition, there exists a great amount of involved uncertainties; therefore, the adequate treatment of the problem is the probabilistic. In this work, the vulnerability and the seismic risk of waffle slabs reinforced concrete buildings are evaluated by means of a methodology based in the capacity spectrum method. The structural models used in the analysis correspond to buildings of 8, 5, 3 and 2 storeys. For each one of these buildings capacity and fragility curves are obtained. For a likely seismic demand in Barcelona, two specific seismic scenarios were considered. Taking into account all these results, the probability damage matrixes are also obtained.Peer ReviewedPostprint (published version

Influencia de los cerramientos de fábrica en el comportamiento sísmico de edificios de hormigón armado

En España, la mayoría de los edificios de hormigón armado son de forjados reticulares y los cerramientos en estos edificios se suelen materializar con paredes de fábrica que rellenan los marcos entre pilares y forjados. Estas paredes no son portantes y, generalmente, no se considera su contribución resistente ante cargas gravita- torias. No obstante, ante acciones laterales (sismo o viento) la existencia o no de estas paredes puede influir en la respuesta de la estructura. El objetivo de este trabajo es conocer la influencia de la tabiquería en la respuesta sísmica. A partir de planos estructurales reales se define un edificio tipo de 8 plantas, se evalúa su capacidad y respuesta sísmica con y sin tabiquería mediante un análisis estático no lineal. Los resultados muestran la influencia de las paredes en el comportamiento de la estructura frente a cargas laterales, tanto en su rigidez como en su capacidad resistente. The seismic behaviour of a very common building typology in Spain, reinforced concrete (RC) frame buildings, is inves- tigated. Usually, divisions in these buildings are made by means of non-bearing masonry infill walls. It is the traditional practice not to consider the contribution of these in the resisting mechanism, especially for gravitational loads. However, under lateral loading, such as wind or earthquake, the existence or not of these infill walls may significantly influence the structural response. The objective of this paper is to know the influence of masonry infill walls in the seismic response of RC buildings. Based on structural details of a series of real drawings, an 8 stories reference building was defined and by means of non-linear static analysis, structural response and capacity with and without infill walls are evaluated. The results shown that infill walls are determinant in the structural behaviour against lateral loads, both in terms of stiffness and resistance.Postprint (published version

Herramientas necesarias para la evaluación sísmica de edificios

En esta monografía de presenta de forma resumida, los conceptos fundamentales relacionados con la acción sísmica, la respuesta estructural de los edificios, la evaluación de la vulnerabilidad, el riesgo y el daño sí­smico. Se presentan también algunos índices de daño propuestos por diferentes investigadores para evaluar el nivel de degradación que sufren los edificios cuando soportan acciones sísmicas. También se describen las formas para definir la acción sísmica que son adecuadas al cálculo estructural.Postprint (published version

Curvas de fragilidad para evaluar el daño sísmico en edificios de concreto armado con losas reticulares

Las estructuras con un comportamiento sísmico inadecuado son la causa principal de las pérdidas humanas y económicas durante la ocurrencia de temblores intensos. Para mejorar el diseño de las estructuras hay que comenzar por realizar estudios de riesgo sísmico en zonas urbanas, los cuales permiten evaluar la vulnerabilidad sísmica en dichas zonas y estimar el daño probable que se puede sufrir a causa de un evento sísmico. Actualmente, muchos de los edificios de Barcelona, España, son edificios de concreto armado con losas reticulares. Dentro de la ciudad, es la segunda tipología constructiva más representativa, y va en aumento, ya que es el sistema más utilizado en la actualidad. Este trabajo es una contribución al análisis del comportamiento sísmico de estos edificios y hace frente al análisis del riesgo sísmico en un área urbana situada en una zona de baja sismicidad. Para llevar a cabo un análisis adecuado se debe disponer de una amplia información, que muchas veces no se tiene y, además, existe una gran cantidad de incertidumbres involucradas, por lo tanto, el tratamiento adecuado del problema es el probabilista. En este trabajo se evalúa la vulnerabilidad y el riesgo sísmico de edificios de concreto armado con losas reticulares mediante una metodología basada en el método del espectro de capacidad. Los modelos estructurales que se utilizan en el análisis corresponden a edificios de 8, 5, 3 y 2 pisos. Para cada uno de estos edificios se determina su capacidad y se evalúa su fragilidad. Para la demanda sísmica esperable en Barcelona, se consideran dos escenarios sísmicos específicos. A partir de aquí, se obtienen las matrices de probabilidad de daño para cada modelo, para cada escenario sísmico y para cada tipo de suelo. // Structures with an inadequate seismic performance are the main source of the human death and economic losses when a major earthquake strikes an urban area. To improve buildings design one have to begin by carrying out seismic risk analysis in urban areas, which permit to assess the seismic vulnerability in these zones and to estimate the probable damage can be suffer by a seismic event. Currently, many of the housings in Barcelona, Spain, are multi-storey waffle slabs reinforced concrete buildings. In fact, this typology is the second most representative in the city and the number of this type of buildings is increasing because, at present, this is the most extended construction system. This work is a contribution to the analysis of the seismic behaviour of this type of buildings and it faces the seismic risk analysis in an urban area situated in a low seismic hazard region. In order to carry out a suitable analysis it is necessary to have enormous information, that often it is not available and, in addition, there exists a great amount of involved uncertainties; therefore, the adequate treatment of the problem is the probabilistic. In this work, the vulnerability and the seismic risk of waffle slabs reinforced concrete buildings are evaluated by means of a methodology based in the capacity spectrum method. The structural models used in the analysis correspond to buildings of 8, 5, 3 and 2 storeys. For each one of these buildings capacity and fragility curves are obtained. For a likely seismic demand in Barcelona, two specific seismic scenarios were considered. Taking into account all these results, the probability damage matrixes are also obtained.Peer Reviewe

CURVAS DE FRAGILIDAD PARA EVALUAR EL DAÑO SÍSMICO EN EDIFICIOS DE CONCRETO ARMADO CON LOSAS RETICULARES / Fragility Curves to Assess the Seismic Risk in Reinforced Concrete Buildings with Waffled Slabs

Las estructuras con un comportamiento sísmico inadecuado son la causa principal de las pérdidas humanas y económicasdurante la ocurrencia de temblores intensos. Para mejorar el diseño de las estructuras hay que comenzar por realizar estudiosde riesgo sísmico en zonas urbanas, los cuales permiten evaluar la vulnerabilidad sísmica en dichas zonas y estimarel daño probable que se puede sufrir a causa de un evento sísmico. Actualmente, muchos de los edificios de Barcelona,España, son edificios de concreto armado con losas reticulares. Dentro de la ciudad, es la segunda tipología constructivamás representativa, y va en aumento, ya que es el sistema más utilizado en la actualidad. Este trabajo es una contribución alanálisis del comportamiento sísmico de estos edificios y hace frente al análisis del riesgo sísmico en un área urbana situadaen una zona de baja sismicidad. Para llevar a cabo un análisis adecuado se debe disponer de una amplia información, quemuchas veces no se tiene y, además, existe una gran cantidad de incertidumbres involucradas, por lo tanto, el tratamientoadecuado del problema es el probabilista. En este trabajo se evalúa la vulnerabilidad y el riesgo sísmico de edificios deconcreto armado con losas reticulares mediante una metodología basada en el método del espectro de capacidad. Losmodelos estructurales que se utilizan en el análisis corresponden a edificios de 8, 5, 3 y 2 pisos. Para cada uno de estos edificiosse determina su capacidad y se evalúa su fragilidad. Para la demanda sísmica esperable en Barcelona, se considerandos escenarios sísmicos específicos. A partir de aquí, se obtienen las matrices de probabilidad de daño para cada modelo,para cada escenario sísmico y para cada tipo de suelo.ABSTRACTStructures with an inadequate seismic performance are the main source of the human death and economic losses when amajor earthquake strikes an urban area. To improve buildings design one have to begin by carrying out seismic risk analysisin urban areas, which permit to assess the seismic vulnerability in these zones and to estimate the probable damage canbe suffer by a seismic event. Currently, many of the housings in Barcelona, Spain, are multi-storey waffle slabs reinforcedconcrete buildings. In fact, this typology is the second most representative in the city and the number of this type of buildingsis increasing because, at present, this is the most extended construction system. This work is a contribution to theanalysis of the seismic behaviour of this type of buildings and it faces the seismic risk analysis in an urban area situated in alow seismic hazard region. In order to carry out a suitable analysis it is necessary to have enormous information, that oftenit is not available and, in addition, there exists a great amount of involved uncertainties; therefore, the adequate treatmentof the problem is the probabilistic. In this work, the vulnerability and the seismic risk of waffle slabs reinforced concretebuildings are evaluated by means of a methodology based in the capacity spectrum method. The structural models used inthe analysis correspond to buildings of 8, 5, 3 and 2 storeys. For each one of these buildings capacity and fragility curvesare obtained. For a likely seismic demand in Barcelona, two specific seismic scenarios were considered. Taking into accountall these results, the probability damage matrixes are also obtained.Keywords: Fragility curves, Capacity spectra, Vulnerability, Seismic risk, Damage probability matrices, Waffled slab

Assessment of the expected seismic damage in the aggregated masonry buildings of the late XIX century of Barcelona, Spain

This paper aims at the evaluation of expected seismic damage of aggregated masonry buildings system, formed by a line of buildings along of the street; real buildings were studied of whom structural drawings were available. Each structure was individually built without any gaps between them, producing interaction among the buildings under lateral loads. Numerical model consists of 7 buildings: 5 in-row with rectangular shape and 2 corners (in the intersection of two streets) with a pentagonal shape. Damage probability matrices were obtained from pushover analysis using the capacity and fragility curves. Seismic hazard is considered for the acceleration of Barcelona. Four damage states were considered: slight, moderate, extensive and complete (collapse). The results showed that aggregated system analysed presents slight damage in a hard soil while very extensive damage occur in soft soil, furthermore, the expected seismic damage is high considering the low seismic action of Barcelona.Peer Reviewe

Seismic damage assessment of waffled slabs RC buildings of Barcelona

The seismic damage of waffled-slabs reinforced concrete buildings in the city of Barcelona (Spain) is evaluated using Risk-UE methodology, which enables obtaining fragility curves of the structure in a simplified manner through capacity curves. The seismic hazard is described by means of the reduced 5%-damped elastic response spectrum specific to Barcelona. Capacity curves are obtained using a non-linear static analysis and are used to obtain the performance point and probability damage matrices corresponding to the specified seismic hazard. Four different buildings, representing most typical structure configuration used in the city, are studied based on detailed data from real structures. Despite low-to-moderate seismic hazard in the region, the results show that these buildings present a considerable seismic vulnerability and a relevant expected seismic damage due to its poor expected performance.Peer Reviewe