Seismic Vulnerability Assessment of a 17th Century Colonial Adobe Church in the Central Valley of Chile

This paper focuses on the seismic vulnerability assessment of the San Judas Tadeo´s church in Malloa (Chile), an iconic example of Colonial Chilean architecture. This small adobe structure is a single-nave building consisting of the main nave, a bell-tower located in the façade, two external wooden galleries and additional units such as the sacristy, chapel, and two services areas. The Church has survived several strong earthquakes larger than Mw>8. Besides, after the February 27th, 2010 Maule event it showed remarkable resilience due to the implementation of traditional timber retrofits inserted in the earthen walls. The use of traditional wooden devices such as bond beams, corner keys, and wooden gables, proved to be effective solutions against strong earthquakes. Therefore, this church appears as a relevant case of the use of seismic resistant constructive techniques of the17th century colonial architecture and the study of its seismic behaviour holds great interest and relevance. Aimed to assess the seismic performance of the monument, a complete preliminary study of the church was carried out using a multi-level approach comprising historical research, in situ surveys, crack pattern analysis, physical and mechanical characterization of materials, and structural analyses. In particular as part of an ongoing research, linear and incremental kinematic approaches of limit analyses have been employed with the aim of interpreting the local mechanisms activated during the 2010 Maule earthquake. In these models, the effect of friction on masonry-to-masonry and timber-to-masonry interfaces was considered with promising outcomes. This study results prove the general validity in the field of timber seismic retrofitting of unreinforced adobe buildings

A New Method for Assessing Compatibility of Consolidation Procedures with Conservation Principles: Intervention Quality Index (IQI)

In current times, built heritage is being lost at an alarming rate due to natural and human hazards. Policies for its protection and rehabilitation involve, among other things, challenges related to the refinement of suitable structural strengthening approaches. The arduous balance between gaining acceptable safety levels for occupants without deploying intrusive devices, inconsistent with conservation principles such as those of the ICOMOS charters, is not a simple task. The interest and efforts of the scientific community in this regard have been increasing for decades, but still, it is the structural professional 's responsibility and experience which must define this arduous balance on a case-to-case basis. This study addresses the question: How can the quality of structural rehabilitation interventions be assessed in light of conservation principles such as those given by ICOMOS? Here, a preliminary method - called “Intervention Quality Index” (IQI) method is proposed. It assesses the restoration intervention quality in relation to: (i) the level of compliance given by the conservation ́s principle score (conservation ́s factor, CF); and (ii) the current state of conservation of the monument (safety factor of building considering the seismic intensity, Δs). The IQI method considers the compliance level of the designed reinforcement with conservation principle, formalized through the fulfillment of a category, i.e. respected, partially respected, and not respected. Then, these judgments are translated into scores and statistically evaluated. Scores are attributed in relation to the relevance of the fulfillment of a certain conservation principle (authenticity, minimal intervention and intrusiveness, compatibility, recognizability and reversibility) for the seismic structural safety point of view. Preliminary results show that an effective employment of traditional earthquake-resistant practices together with a wise use of modern retrofit strategies allow for the preservation and reinforcement of built heritage without harming its identity

Fire risk assessment of historic urban aggregates: An application to the Yungay neighborhood in Santiago, Chile

Concern for the preservation of historic urban centers has become an issue of international relevance, not only because of their irreplaceable cultural value, but also because of their potential positive role for the sustainable development of countries. Several disasters have shown that historic centers are particularly vulnerable to natural and anthropogenic hazards. The constructive characteristics of buildings and the urban morphology in which they are inserted increase the fragility of their historic fabric and vulnerability in case of disasters. In this context, a comprehensive understanding of vulnerabilities of historic centers is an essential step for the definition and adoption of more effective risk reduction strategies.This paper presents a fire risk assessment at the urban scale, using the Fire Risk Index (FRI) method. The selected case study corresponds to the historic center of Yungay, located in Santiago de Chile. The case study is particularly relevant because of the high presence of historic heritage buildings and because between 2016 and 2021 it has been the scene of 21 structural fires, causing irreparable human and heritage losses.Through the adaptation of the methodology to Chilean fire regulations and urban code, 443 unreinforced masonry buildings were evaluated. Finally, fire risk factors for the ignition, propagation, evacuation and combat phases were identified and mapped through the GIS tool. The results represent a valuable step towards the identification of large-scale risks in Chilean and Latin American historic urban centers, as well as providing the basis for the definition of risk mitigation strategies by decision-makers