Use of superficial reinforcement for reducing the seismic vulnerability of unreinforced masonry houses in Peru

Masonry is the main construction system for individual houses in Peru, the use of simple manual tools, the economy of the materials and the flexibility of construction that allows the users to build their houses by parts make the system the most appropriate for self-managing construction. At the same time, the construction of these houses is made in the majority of the cases without technical intervention which make them vulnerable to strong earthquakes. It is estimated that more than 70% of the masonry houses in Peru are built without technical or professional intervention and only in Lima it is estimated than one million houses are highly vulnerable to strong earthquakes In 2014, the government of Peru through the Ministry of Housing launched a pilot program for reducing the seismic vulnerability of masonry houses built informally without technical support. The program focused on seismically vulnerable masonry houses that belong to families without economic resources to reinforce their houses. From the technical point of view, the program aimed to reinforce one part of the house that was to be used as a safe area in case of earthquakes. The amount allocated for each intervention was Twelve Thousand Soles, approximately Four Thousand US Dollars. This paper describes the design of the technical solution for a massive intervention using polymer grid as superficial reinforcement for brick masonry walls, the reinforcement was placed continuously on the wall, mechanically anchored to the wall surface and then plaster with a cement/lime/sand mortar. This technique has proved to be appropriate from the technical, social and economic aspects.