Strengthening of historical earthen constructions with steel plates: Full-scale test of a two-story wall subjected to in-plane lateral load

Abstract

The Spanish conquerors that came to Latin America built earthen dwellings (one- and two- stories). In this way, construction with earthen materials was introduced in the history and the cultural heritage of the Northern South American territory. Unfortunately, past earthquakes have shown that historic earthen buildings are highly vulnerable. Research on this subject has focused on the evaluation of seismic retrofitting alternatives, especially in one-story earthen walls without openings, or studying reduced-scale earthen models. According to the scientific literature consulted, few pseudo-static tests have been conducted on full-scale earthen walls with openings. For this reason, in this research, a full-scale two-story earthen wall specimen with dimensions of 5.95 m long, 6.20 m high, and 0.65 m thick (both floors with openings) was subjected to cyclic lateral loads (in-plane shear load). Based on the authors’ knowledge, this is the largest full-scale two-story earthen wall tested to date in a structures laboratory. After inducing repairable damage to the unreinforced wall, a rehabilitation strategy based on steel plates (conforming to a grid) was installed on both sides of the wall. The steel plates were connected (welded) with pass-through steel rods. Subsequently, the repaired and reinforced wall was retested and the experimental results showed that the in-plane stiffness was improved or at least restored. In addition, the lateral load capacity increased by 208 % on average compared to the unreinforced wall test results. Lastly, the unreinforced wall had a drift capacity of 0.5 % while the reinforced wall reached a maximum drift of 1.8 %. Therefore, it was found that the proposed reinforcement with steel plates significantly improves the seismic performance of two-story historic earthen walls.