In most of the structural design codes, the foundation sites are classified through the mean stiffness of the soil profile, obtained on the basis of the mean shear wave velocity of the upper 30 m Vs30. Because it is an averaged index, the site classification does not directly take into account the properties of shallower soil layers, neither the fact that sites with different soil stiffness distribution are classified as the same site class. Moreover, the way in how this situation can affect the response of the structures is not clearly specified. In this work, the effect of the site stiffness distribution on the seismic performance and level of damage of structures is explored by means of numerical models. Under a direct approach, two-dimensional numerical models are developed on OpenSees, where the structure has a nonlinear elastoplastic constitutive law. The soil is represented by nonlinear elements sensitive to confinement pressure. The soil-foundation interface is modeled with contact elements allowing the sliding and rocking of the foundation. Different structures (with periods between 0.3 to 1.2 s) are subjected to dynamic analyses using seismic records of different frequency content and amplitudes. The results show significant differences on the structural response among sites of the same class, but with different stiffness distribution, particularly when the structure remains on the elastic range, suggesting that the classification of foundation sites through an average index can underestimate the effects of the dynamic coupling of the soil, the foundation and the structure.

La mayoría de normas de diseño estructural clasifican los sitios de fundación a través de la rigidez media que presenta el suelo, obtenida a partir de la velocidad promedio de ondas de corte en los primeros treinta metros Vs30. Al tratarse de un promedio, la clasificación no considera directamente las características de los estratos cercanos a la fundación, ni que sitios con distinta configuración de rigideces son clasificados como un mismo tipo. Por otra parte, tampoco hay indicaciones claras respecto de la forma en que esto podría afectar la respuesta estructural. Este trabajo busca establecer si la distribución de la rigidez del suelo de fundación afecta el desempeño sísmico de las estructuras mediante modelos numéricos en OpenSees. Bajo un enfoque de análisis directo bidimensional, la estructura es modelada con una constitutiva elastoplástica. El suelo se representa por elementos no lineales sensibles a la presión de confinamiento. La interfaz suelo-fundación se modela con elementos de contacto que permiten el deslizamiento y balanceo de la fundación. Se someten distintas estructuras (con períodos entre 0.3 a 1.2 s), a análisis dinámicos con registros sísmicos de diferentes contenidos de frecuencia y amplitudes. Los resultados muestran que existen diferencias significativas en la respuesta estructural entre sitios clasificados como un mismo tipo, pero con distinta configuración de rigideces, especialmente cuando la estructura se mantiene en el rango lineal, lo que sugiere que la clasificación sísmica de sitios de fundación en base a un indicador medio podría subestimar los efectos de acoplamiento dinámico del sistema suelo-fundación-estructura.

Abstract: Natural disasters affect the construction industry in many ways other than the direct damages. This paper presents a model that evaluates the performance impacts caused by an earthquake to the construction industry by using the 2010 Chilean earthquake as case study. The main variables affected by a seismic event in construction companies and their relationships were modeled by means of the use of Partial Least Square (PLS). The modeling framework was developed by interviewing CEOs of construction companies located in areas affected by the earthquake. Then, a model of interrelationships, which would explain how variables are affected by an earthquake was developed. The main findings showed that when a severe telluric event occurs, the two most affected factors were Relationship with the Owner/Clients and Image, while the most affected indexes were Owner/Client Satisfaction and Financial Situation. Thus, this research emphasizes the importance of these four variables (factors and indexes), when the construction industry faces a large earthquake.

Resumen: Los desastres naturales afectan a la industria de la construcción de muchas maneras distintas más allá de los daños directos. Este artículo presenta un modelo que evalúa los impactos en el desempeño, causados por un terremoto a la industria de la construcción, utilizando el terremoto ocurrido en Chile el año 2010 como caso de estudio. Se modelaron las principales variables afectadas por un evento sísmico en las empresas constructoras y sus relaciones, por medio del uso de Mínimos Cuadrados Parciales. El marco bajo el cual se desarrolló la modelización, fue mediante entrevistas a directores generales de empresas constructoras, ubicadas en zonas afectadas por el terremoto. Luego, se desarrolló un modelo de interrelaciones que explicaría cómo las variables se ven afectadas por un terremoto. Los principales hallazgos muestran que cuando se produce un evento telúrico severo, los dos factores más afectados son Relación con el Mandante/Cliente e Imagen, mientras que los índices más afectados fueron Satisfacción del Mandante/Cliente y Situación Financiera. Por lo tanto, esta investigación destaca la importancia de estas cuatro variables (factores e índices), cuando la industria de la construcción se ve enfrentada a un terremoto de gran magnitud.

The Human Development Index HDI is a summarized quantification of human development of nations, based on three dimensions: income, education and health, classifying countries differently to the Gross National Income GNI index classification. However, for the construction industry, the authors found no plausible evidence of exhaustive studies in this sector, from the standpoint of the HDI. Thus, the present study seeks to provide a methodology to calculate the HDI for workers in the construction industry by using Chile as a case study. In this study, it was found that the HDI in construction varies geographically with the variation in the income dimension, but not with respect to education or health dimensions. These results for the construction sector were then compared with the conventional HDI, finding differences. This would confirm that workers in construction differ from workers in other sectors.

El Indice de Desarrollo Humano IDH es una cuantificación resumida del desarrollo humano de las naciones, basado en tres dimensiones: ingreso, educación y salud, que clasifica a los países de forma distinta a la entregada por el Producto Interno Bruto PIB. Sin embargo, para la industria de la construcción, los autores no encontraron evidencia plausible de estudios exhaustivos en este sector, desde el punto de vista del IDH. Así, el presente estudio busca proveer una metodología para calcular el IDH para trabajadores en la industria de la construcción, usando a Chile como caso de estudio. En este estudio, se encontró que el IDH en la construcción varía geográficamente con la variación de la dimensión ingreso, pero no en relación a las dimensiones educación o salud. Estos resultados para el sector de la construcción fueron luego comparados con el IDH convencional, encontrando diferencias. Esto confirmaría que los trabajadores en la construcción se diferencian de los trabajadores de otros sectores.

The last Chilean earthquake, occurred on February 27, 2010, allowed establishing important patterns of structural failures in reinforced concrete residential buildings; however, limited progress has been made in the study of basic standards of serviceability, such as obstruction of doors. Thus, this study focused on measuring the influence of design specifications and construction criteria of lintels and columns, in terms of obstruction of doors, considering capacity thresholds for certain levels of displacement. The study consisted of the design and construction of a full-scale prototype of a reinforced concrete frame, designed in accordance with all the ACI-318-08 requirements, taking into account typical aspects of geometry and materiality widely used by the real estate industry, for location and size of doors. In order to quantify the structural capacity of the prototype and to study the serviceability of the door, a quasi-static cyclic test was conducted, according to load and displacement protocols specified in FEMA 356 and FEMA 461, which was adjusted by using virtual models based on a static nonlinear analysis called "Pushover". This research verified that, for displacement levels even five times higher than those established by codes considered, the cracking degree was minimal and fully recoverable. It was also found the door evidenced malfunction when the displacements were greater than those specified by design only, validating a high degree of accomplishment of current codes, in terms of capacity and serviceability, when dealing with obstruction of residential doors.