Seismic analysis of earthen churches: the triumphal arch at andahuaylillas, Peru

The Saint Peter Apostle Church of Andahuaylillas, also known as the Sistine Chapel of Latin America for its magnificent paintings, is an important religious monument dating from the late 16th or early 17th century. This church is representative of a large number of adobe colonial churches in the Andes. Saint Peter Apostle of Andahuaylillas, considered a masterpiece for its historical, architectural and artistic features, was declared part of the Cultural Heritage of Peru in 2010. This paper presents a summary of the preliminary experimental work and numerical analysis that is being conducted for assessing the seismic vulnerability of the monument. The first part briefly discusses the structural pathologies found in the building and the results of the operational modal analysis tests performed to date. As a result of the current damaged state of the triumphal arch of the church, the second part of the study focuses on the assessment of the structural behaviour of the triumphal arch under in plane horizontal accelerations simulating earthquake conditions. Nonlinear finite element models of the triumphal arch, developed using ABAQUS/CAE Explicit and DIANA, are used to identify the critical accelerations leading to collapse and the related damage patterns, as well as to explore the effect of possible geometrical modifications intended to increase the structural capacity of the arch. In the ABAQUS/CAE Explicit models the identification of the collapse parameters is achieved by simulating quasi-static conditions up to complete structural collapse of the arch.