marco barrientos

Unreinforced masonry (URM) historic churches are highly seismic vulnerable buildings due to its structural and material features. This condition partially explains the irreversible cultural heritage loss in Chile. After earthquakes, many URM churches have been strengthened with reinforced concrete (RC) elements as a seismic proof strategy. In this context, this paper aims to examine the Recoleta Dominica basilica, as a prominent building with architectural, historical, and constructive attributes with efficient seismic performance along years as well, as reported after the 1985 and 2010 megathrust earthquakes. Its seismic performance can be explained by the RC strengthening elements added after the 1927 earthquake, and later 1981-1982 and 2000 structural interventions, avoiding local collapses as serving its conservation. The paper concludes by highlighting the 1927 RC project impact, its early technique reflected on its structural design criteria and following the original building nature. Some other studies in this research line may contribute to a better understanding of the inherited scopes involved in any structural RC project, its impact on the architectural features, the seismic-resistant improvements, and its cultural preservation.

In this paper, a modified empirical large-territorial-scale procedure to assess the seismic vulnerability of aggregate buildings in urban areas located within a highly seismic context is proposed. The methodology is applied to a group of unreinforced masonry (URM) aggregates located in the Yungay’s historic center in downtown Santiago, Chile. This assessment was carried out by modifying and integrating a vulnerability-index-based procedure, a specific existing approach called first level macro-seismic method used to predict seismic damage and loss scenarios through fragility curves of structural components. The procedure was calibrated using the observed damage after the 2010 Chile earthquake in 292 URM structural units. The results of this new damage index for URM aggregate buildings are used to derive Probability Mass Functions (PMFs) of the different damage states and preliminary Empirical Fragility Functions (EFFs). To the best of the authors’ knowledge, these EFFs are the first publicly available for aggregate Chilean URM buildings. This research and its results are the starting point for a more comprehensive study for assessing damage scenarios and vulnerabilities of aggregate URM buildings in historic centers of older Chilean cities. These functions may be used in risk assessment, and are useful to prioritize possible future damage mitigation strategies and other processes involving this historical heritage. We foresee that these results could be at least partially applied to other historical urban areas in Chile, and perhaps other old Latin American cities located along the subduction convergence region between the Pacific and Continental plates, which were founded similarly.

El trabajo establece una aproximación al concepto de Edificio Chileno a partir del reconocimiento de sus alcances en el campo teórico y práctico de la ingeniería y cálculo estructural en Chile, su relación con la disciplina y práctica de la arquitectura y el fenómeno sísmico. Se plantea como hipótesis, que el Ministerio de Hacienda -ubicado en Santiago y construido entre 1929 y 1933 constituye la primera la obra de arquitectura moderna en altura en el país que de manera temprana anticipó parte importantes de los preceptos del Edificio Chileno, conjugando demandas arquitectónicas, estructurales y de resistencia sísmica. La obra examina la estrategia de diseño arquitectónico de sus plantas libres desplegadas en todos los niveles de la obra, en función de los principios de estructuración basados en resistencia sísmica por rigidez, monolitismo y prevalencia de muros de corte.

The paper aims to analyze the Chilean Building as a concept and practice in the structural engineering field in Chile, its relationship with the architectural discipline and its practice, and the seismic phenomena. The hypothesis suggests that the Ministry of Treasure building, located
in Santiago de Chile and built between 1929 and 1933, represents an earlier and advanced exponent of the Chilean Building as it crystallized some of its main issues with architectural, structural and seismic resistant requirements. The opened-plan architectural design criterion is examined under the structural seismic-resistant principles based on rigidity, monolithic and shear walls’ huge presence on each story.

El trabajo indaga la noción de edificio chileno, en tanto convención estructural basada en el empleo de muros de hormigón armado como recurso sísmicamente eficiente. Se contrasta la idea y la práctica de esta convención con la norma chilena de diseño sísmico a través de tres obras de arquitectura construidas entre la década de los sesenta y 2009. Finalmente se debaten los alcances respecto a la convención y se propone una ampliación conceptual del edificio chileno desde una perspectiva arquitectónica.

El trabajo indaga la noción de edificio chileno, en tanto convención estructural basada en el empleo de muros de hormigón armado como recurso sísmicamente eficiente. Se contrasta la idea y la práctica de esta convención con la norma chilena de diseño sísmico a través de tres obras de arquitectura construidas entre la década de los sesenta y 2009. Finalmente se debaten los alcances respecto a la convención y se propone una ampliación conceptual del edificio chileno desde una perspectiva arquitectónica.

This article examines the process of morphologic development of Santiago’s Cathedral block, between 1874 and 1913. During this period the block experienced radical transformations and alterations that were linked to a phenomenon of urban expansion and contraction. This process reflected the gradual redefinition of the interior and exterior contours of the buildings, the transformations of building typologies and of urban densification. This phenomenon of expansion became evident with the hegemony reached by the church as owner of most of the
buildings on the block. The article proposes that the entirety of the block, as well as most of its emblematic buildings- Metropolitan Cathedral, Archbishop’s Palace and the Sagrario Parish - were permeable to social and political factors, to the changes that were affecting the church as an institution, the permanent transformations in the urban fabric and the modernization of Santiago from the last decades of the nineteenth century.

Contemporary high standards in seismic building behavior in Chile, evidence structural and architectural design efficiency reached during the past few decades. Limited damages and building destruction after great earthquakes show some of this condition. In contrast, some other aspects, referred to theoretical and empirical approaches in which earthquake proof building design is based on, are less evident. Such basis refer to a historic process developed from the beginning of the XXth century in the country, which explains how earthquake proof buildings have been progressively consolidating all around the country, and consequently, reducing earthquake destruction.
This paper examines the structural engineering historical sources that provided some essential concepts related with stability and earthquake resistance at the beginning of the XXth century. It suggests that part of the tendency toward erecting reinforced concrete buildings can be explained by some critical studies, projects and construction processes of concrete bridges developed during this period. The article contributes to a better understanding of local architectural historiography, through the transferences between scientific and technological historical advances that provided theoretical and empirical approaches to seismic resistance in Chile, and its impact on buildings, and structural criteria based on monolithic and rigidity principles.

The city of Santiago del Nuevo Extremo, capital of Chile was founded in
1541 and has preserved the same location then. The historical nucleus also
preserves its location centered by the Plaza Mayor. There have been some
archaeological investigations recorded since the decade of 1970 that has
yielded evidence from de Colonial Period, even though they have mainly
responded to urbanistic expansions of the city that have accidentally
exposed historical traits. So, the main objective of those activities was
to record the evidence but did not focus on responding neither specific
hypothesis nor search for explanations concerning the historical process.
In the present article we have integrated the archaeological information
collected to this day into the architectural and urbanistic project La manzana
de la catedral, la trama de la historia (FONDECYT Number 1090325, years
2009 and 2010) so that the general expansion process of the city is fully
understood. We also analyze the history of the urbanization of the block
where the cathedral and other particular residences were constructed.
The mentioned information gives us evidence of residential
constructions from the first years of the eighteenth century, an area that
was later acquired to build the cathedral. Part of the foundations, walls and
pavement has been preserved and are concordant with the techniques and
materials used and applied until the twentieth century. On the other hand,
it gives us partial evidence of the cathedral, or cathedrals, constructed
previous to 1746: foundations, columns, pavements and inhumation areas.
The archaeological facts were not always concordant with the written descriptions we have for that period, which led us to reformulate the
previous interpretations done. Based on the archaeological and written
record we propose a hypothetical plan view and layout with two versions
concerning the location of the old cathedral.
A new project has been presented in order to elucidate the doubts
concerning the particular characteristics and location of the religious
building. Excavations will be oriented to the definition of the layout plan
and specific location of the construction with a thorough review of the
historical and documental facts. The understanding of the formation
processes involved and further consolidation of the cathedral complex is
considered as well as its relation with the development of the city during the
Colonial Period. The information collected will help determine protection
areas for the places where Colonial architectural evidence is present.

In Chile, disasters were decisive, although not only the single factor, for the legitimization
of urbanism as a discipline and as a practice, for the realization of reconstruction plans and works and for the implementation of prevention policies in conjunction with the establishment of structured thinking about the city and its regulation, that took into consideration the security of the population. The disasters proposed at least three approaches directly oriented to urban planning: the gradual construction of the urban information base; the generation of a legal corpus oriented towards prevention; and the definition of institutional structures and instruments for the reconstruction and control of future urban development.