Historic earthen structures are a significant portion of the built heritage worldwide and are associated with intangible building techniques, wide material availability and low-cost construction. Nonetheless, dueto their low mechanical properties and, often poor connections, historic earthen structures are susceptible to early structural damage, and even collapse in areas of high seismic hazard. Inaddition, the lack of maintenance can further reduce structural performance and durability. The Getty Conservation Institute (GCI)’s Seismic Retrofitting Project (SRP) aims to research, designand test low-tech retrofitting techniques, as well as to implement maintenance programs, enhancing the performance of historicearthen buildings in seismic areas where the most advanced equipment, structural skills and materials are not easily available. Results: Accounting for recommendations from national building codes, conservation principles and local practices, the complete design, assessment and implementation of strengthening for twoprototype buildings in Peru, involved in the SRP, are discussed; the Church of Kuño Tambo and Ica Cathedral. Conclusions: Theretrofitted structures, complied with performance criteria and seismic local demands, with sufficient safety and acceptable levels of repairable damage.

Introduction

The Seismic Retrofitting Project (SRP) is an ongoing project of the Getty Conservation Institute (GCI), part of the Earthen Architecture Initiative (EAI), which involves the collaboration of several partners and organizations, including the Ministerio de Cultura del Perú, the Escuela de Ciencias e Ingeniería of the Pontificia Universidad Católica del Perú (PUCP) and the University of Minho (UMINHO). The main SRP objective is to develop guidelines in countries, where advanced equipment, materials, and technical skills are not readily available, by providing efficient lowtech seismic retrofitting techniques and easy-to-implement maintenance programs for historical earthen buildings, in order to improve their seismic performance, while preserving their historical fabric. The SRP selected Peru as the ideal location for the work due to its diverse and rich earthen architectural heritage, the current and historical knowledge and professional interest in the subject, the ongoing revision of the NTE-80.1 Moreover, these rich architectural heritage (both monumental and vernacular) are at high risk of being irrevocably lost due to their seismic vulnerability and Peruvian seismic hazard, as learnt from the 2007 Pisco earthquake (Cancino 2011). All the SRP planned activities can be divided in four phases, covering (1) feasibility and research; (2) analysis, testing, and design; (3) dissemination; and (4) implementation. Each phase outcomes get evaluated systematically by the partners as well as by external peer reviewers, as shown in Figure 1. In phase 1, the SRP team identified and structurally assessed four (4) building typologies that are priorities for application of seismic retrofit techniques based on level of significance, where solutions are most needed, and which modes of failure and their reinforcement techniques will have the most widespread application in Peru and other countries in Latin America (Cancino et al. 2012). These were: the Temple of Santiago Apostol of Kuño Tambo, Ica Cathedral, Casa Arones, and Hotel el Comercio. In phase 2, PUCP conducted an extensive laboratory testing campaign to characterize material properties and the behavior of the main structural systems (Vicente and Torrealva 2014). Finally, in-situ inspection and non-destructive tests (namely, sonic and dynamic identification tests) were performed by the University of Minho to evaluate the structural damage, the level of interaction between structural parts and the elastic properties of masonry (Lourenço, Karanikoloudis, and Greco 2016).