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This paper describes a new seismic protection system for timber platform frame buildings, either for new construction or retrofit. The system consists in connecting the timber frame to a steel structure that includes hysteretic energy dissipators designed to absorb most of the seismic input energy thus protecting the timber frame and the other steel members; alternatively, the system might use other types of dissipative devices. The steel structure consists of four steel stacks (located at each of the four façades) and steel collectors embracing each slab; the stacks and the collectors are connected, at each floor level, through the energy dissipators. The steel structure is self-supporting, that is, the timber frame is not affected by horizontal actions and can be designed without accounting for any seismic provision; in turn, the steel members do not participate in the main load-carrying system. The timber-steel interface is designed to avoid any stress concentration in the transfer of horizontal forces and to guarantee that the yielding of the dissipators occurs prior to any timber failure. The energy dissipation capacity of the suggested system is discussed, and an application example on a six-story timber building is presented; this case corresponds to highly demanding conditions because of the relatively large building height and weight, the high local seismicity, and the soft soil condition. This research belongs to a wider project aiming to promote the structural use of timber by improving the seismic capacity of wooden buildings; this research includes experiments and advanced numerical simulation. Copyright © 2014 John Wiley & Sons, Ltd.

A parametric model for capacity curves and capacity spectra is proposed. The capacity curve is considered to be composed of a linear part and a nonlinear part. The normalized nonlinear part is modelled bymeans of a cumulative lognormal function. Instead, the cumulative Beta function can be used. Moreover, this new conceptualization of the capacity curves allows defining stiffness and energy functions relative to the total energy loss and stiffness degradation at the ultimate capacity point. Based on these functions, a new damage index is proposed and it is shown that this index, obtained from nonlinear static analysis, is compatible with the Park and Ang index obtained from dynamic analysis. This capacity based damage index allows setting up a fragility model. Specific reinforced concrete buildings are used to illustrate the adequacy of the capacity, damage and fragility models. The usefulness of the models here proposed is highlighted showing how the parametric model is representative for a family of capacity curves having the same normalized nonlinear part and how important variables can be tabulated as empirical functions of the two main parameters defining the capacity model. The availability of this new mathematical model may be a powerful tool for current earthquake engineering research, especially in seismic risk assessments at regional scale and in probabilistic approaches where massive computations are needed.

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This paper deals with a new seismic protection system for timber platform frame buildings, either for retrofit or for new construction. The system consists in connecting the timber frame to a steel framed structure that includes hysteretic energy dissipators designed to absorb most of the seismic input energy thus protecting the timber frame and the other steel members; alternatively, the system might contain other dissipative devices. The steel structure comprises horizontal beam-like elements, vertical column-like elements and chevron-like bracing members; the beam-like elements are steel belts embracing each slab of the building and the bracing members hold the energy dissipators. The steel structure is self-supporting, i.e. the timber frame is not affected by horizontal actions and can be designed without accounting for any seismic provision; in turn, the steel members do not participate in the main carrying-loads system. The timber-steel contact is even, smoothed and spread; it guarantees that the yielding of the dissipators is prior to any timber failure. This research belongs to a wider project aiming to promote the structural and constructional use of timber by improving the seismic capacity of wooden buildings; this research includes experiments and advanced numerical simulation aiming to derive accurate design criteria.

Desde que el hombre apareciÃó en la tierra-cazador y recolector-hasta nuestros tiempos, ha estado en busca de un refugio y de la naturaleza se lo ha proporcionado, pero a la vez y de forma aleatoria, se lo ha arrebatado. AsÃí, en cada generación de su evolución ha aprendido a construirlos. De ese aprendizaje, que aún no acaba, surge la creación que lo lleva a edificar modernos refugios proyectado hacia el sol. La vivienda es una necesidad básica del hombre. Sudamárica (y en especial Colombia), presenta un alto déficit habitacional en la mayor parte de su territorio. Además no abundan los estudios e investigaciones para buscar soluciones idóneas, con materiales autóctonos, con tecnologías apropiadas y buen desempeño estructural. Colombia está localizada a lo largo del borde de la placa tectónica Sur América, que está siendo subcionada por la placa Nazca. Estos movimientos tectónicos generan una importante actividad volcánica y una variada actividad sÃísmica que hace que el paí­s tenga zonas de amenaza sísmica alta, intermedia y baja. El ferrocemento fue patentado por Joseph Louis Lambot, en 1852. Desde entonces, se ha utilizado de forma empÃírica en muchos pai­ses del tercer mundo, especialmente en Asia. Sólo en la segunda mitad del siglo XX, a partir de la década de los 60, se desarrolla interés en la comunidad científica por estudiar su comportamiento. En la actualidad se considera un material alternativo en muchas sociedades . El comité ACI-549 está dedicado a su estudio. Es un material de bajo costo, que requiere mano de obra intensiva, pero no calificada, lo que lo hace un material ideal para un medio ávido de vivienda y empleo.

Se presenta la obtención de la vulnerabilidad sísmica para una catedral Gótica de grandes dimensiones mediante la aplicación del Método del Espectro de Capacidad, y la obtención de las probabilidades de daño asociadas.

The non-destructive study of historical buildings, archaeological sites and other Cultural Heritage structures requires high resolution methodologies and a good knowledge of the potential of the different methods. Laboratory measurements provide valuable information about the ability to detect different targets and to determine structural problems, but these data must be compared to the results obtained in real and complex structures. In this work, we present experimental GPR measurements made in order to determine the spatial resolution under laboratory conditions. These results were compared to the data obtained in different GPR surveys applied to Cultural Heritage. The information obtained in drillings, in visual inspections and in old documentation about the historical buildings and archaeological sites is used to determine the resolution in each case.

The preservation of old downtowns has become a necessity of growing interest. New urban policies have been approved in different countries in order to revive the old city centers and make them economically sustainable. In this global trend, the municipality of Manresa (Barcelona) developed an important urban planning operation in the old district that included the demolition of a group of existing buildings and the construction of a new modern one in close proximity to a group of old residential buildings which are cultural heritage of the city. As a consequence, specific areas of risk were generated which lead to the adoption of precautionary measures to ensure safety. This paper presents the preliminary analysis, diagnostics and monitoring carried out on this group of heterogeneous old buildings, as well as the results and precautionary measures taken to ensure their safety. The paper also provides a translatable methodology that combines qualitative and quantitative aspects.

The simplified nonlinear static procedures (conventional pushover) have become a useful tool to assess the seismic performance of buildings. Beyond their inherent static character, such methods include two major inaccuracies: poor consideration of the higher-mode effects and lack of consideration of the changes in the modal characteristics of the structure (mainly, the modal shapes) as the damage progresses; both issues are particularly relevant for tall buildings. To cope with these two subjects, the modal and adaptive pushover strategies have been proposed, respectively. The objective of this paper is to evaluate the suitability of these procedures for high-rise buildings. The research approach consists in selecting two representative prototype buildings with 30 and 45 stories and carrying out a number of nonlinear static and dynamic analyses and comparing their results. Preliminary results show that current pushover methods cannot predict with enough accuracy the response of high-rise buildings under dynamic seismic action.

A probabilistic method called LM1_P, which is based on the LM1 method of the RISK-UE project is used to estimate the seismic risk of buildings in Barcelona. The LM1_P method allows taking into account numerous uncertainties that are present in any seismic risk estimation. In this method the quantity and quality of the data are considered to estimate seismic vulnerability, seismic hazard and seismic risk. One of the main differences of the LM1_P method with respect to similar methods is the way in that the seismic vulnerability is considered. The seismic hazard that is estimated for Barcelona is mainly expressed in terms of exceedance rate of the intensity. Curves that represent the seismic vulnerability of 54,375 buildings are estimated. The seismic risk estimated for each building is represented through seismic risk curves. According to the results, the studied buildings will suffer moderate damage in average one time every 2860 years.

The objective of this study is to determine the seismic response and torsional effects of an existing Reinforced Concrete building with irregular plant and five levels projected according to an older version of Venezuelan seismic design code. Two structures were analysed: the original building and a redesigned version. Nonlinear static analysis and nonlinear 3D dynamic analysis were applied, based on registers of three synthetic accelerograms compatible with the elastic design spectrum for the used code. In 3D analysis, four structures were simulated, with and without rigid diaphragms so as to compare the seismic behaviour of the buildings. Through this nonlinear analysis parameters were determined that define the behaviour of the structure, torsional moments and rotations in columns reached for simulated buildings. Also, to obtain damage fragility curves for five states damage were generated. Results show that the original structure has an inadequate resistant behaviour and a high probability of exceeding the moderate damage state, while the redesigned structure presents good performance under seismic events according to the existing code. It was also observed that maximum torsional effects occur in the entrant corners of the irregular plant, which are reduced in mid-rise buildings by using a rigid diaphragm.

The multifractal detrended fluctuation algorithm is applied to a series of distances and elapsed times between consecutive earthquakes recorded along the years 2000–2018 in the Canterbury region (New Zealand). The time evolution of several multifractal parameters (Hurst exponent, Hölder central and maximum exponents, spectral amplitude, asymmetry, and complexity index) is analyzed. Peaks of multifractal parameters, with statistical significance exceeding 95%, are associated with three earthquakes of notable magnitude (equaling or exceeding Mw = 5.7). Additionally, some other peaks are also associated with the swarm of earthquakes of moderate magnitude. Possible shortcomings created by this assignment to mainshocks or swarms can be removed by comparing the results corresponding to elapsed times and interevent distances between consecutive events. Additionally, the Buishand test, which is used to verify the statistical significance of the detected peaks, also discriminates between mainshocks of notable seismic magnitude and swarms of earthquakes with moderate magnitude. The obtained results, based on the multifractal structure of the seismic activity, could also represent some advances in predicting, with sufficient time, forthcoming mainshocks of high magnitude and mitigate their destructive effects. The research leading to these results has received funding from the European Union’s Horizon 2020 research and innovation program, under Grant Agreement No. 823844, the ChEESE CoE Project.

Soil site studies are crucial in the analysis of seismic hazard in populated areas. This study focusses on the use of the Ground Penetrating Radar as a non-destructive geophysical method to analysis the water content of a sedimentary basin of a local urban area in Cervantes Parks in Barcelona city. Main objective of this work is to understand further the local seismic soil site, and analysis the background clutter amplitude and frequency of the GPR signal applied on the seasonal changes of the underground water content. Changes produces in the GPR signal could be associated to the changes of the ground material due to the existence of water content and water flow, which influence the grain size distribution of the soil characterisation. Previously, several methodologies have been applied to determine the changes of the ground material due to the existence of water content and most importantly effect of the seasonal changes on the soil characterisation. GPR has been applied as a new technology and non-invasive to further analysis water content in shallow geology. Methodology applied on this study compromised in four different phases; Two seasonal data collection using 100 MHz centre frequency shielded antenna in both dry and wet season, radar images are proceeded with common post-processing approaches, following more innovative processing approach based on the Fast Fourier Transform (FFT) method in order to analysis background clutter amplitude and frequency spectrum to achieve an accurate interpretation of underground water content activities, in conclusion a comparative study of the results driven from radar images are elaborated considering historical knowledge. Results show that GPR is an efficient technique to analysis water content invasively considering low frequency antennas to achieve deeper penetration depth in sedimentary deposits, and predict shifting and increasing of the underground streams due to changes in weather conditions. Results could contribute to the enhancing local seismic site behaviour in populated areas considering continuous monitoring of underground water activities in sedimentary basin sites.