Characterization of the building stock heritage oriented to studies of seismic vulnerability at urban scale: case study historic centre of Cuenca, Ecuador

Abstract

Cuenca is a city located in southern Ecuador (the third in importance), whose Spanish foundation dates back to 1557. Declared, in 1999, a World Cultural Heritage city by UNESCO, largely due to the valuation of its Historic Centre. The city is categorized as high seismic threat, with PGA: 0.25g, according to the Ecuadorian Construction Standard (NEC, acronym in Spanish). The Austro Seismic Network, a research center attached to the University of Cuenca, carried out, in the late 2000s, the first (and only) seismic vulnerability study of the city. The damage scenarios obtained showed that the Historic Centre of Cuenca (CHC, acronym in Spanish), where the oldest non-reinforced masonry (MNR, acronym in Spanish) buildings in the city are concentrated, is the most vulnerable area. This study was based on a simulation of seismic behavior at territorial scale with simple 1D models. With this background, within the framework of a seismic vulnerability project for the CHC whose objective is the establishment of more reliable damage scenarios, this work considered the characterization of its building stock, in typological and geometric terms. The characterization was oriented towards the estimation of the damage by means of static non-linear pushover analysis on 3D models, assuming as a strategy the condensation of the typicality of the existing buildings in a family of buildings-prototypes (EPs, acronym in Spanish). Focused on two of the three existing sub-typologies: adobe and brick MNR buildings, the characterization strategy was developed in three sections: 1) chronological study of construction practices and technologies of construction materials, 2) identification of predominant uses, 3) study of geometric and architectural features. As a synthesis of such studies, a catalog of six buildings-prototypes was obtained, three for each sub-typology.