TESTS FOR EVALUATION OF SLENDERNESS CORRECTION FACTOR FOR MASONRY PRISMS Angel San Bartolomé 1 and Daniel Quiun 1 Abstract A series of experimental compression tests were performed to evaluate the slenderness correction factors for masonry prisms, with typical masonry units used in Peru. The Masonry Design Code, called “Norma E.070” (SENCICO 2006), considers a nominal slenderness ratio of five, and provides correction factors for other slenderness ratios. However, these factors are different than the ones used in other Codes, as well as the ASTM C 1314, 2003 standard, in which the nominal slenderness ratio of two is used. The experimental results showed that slenderness ratios less than 3 give erratic results; therefore, the nominal slenderness of two is not adequate. The tendency curve showed better results with the Peru code factors than with other codes and standards. Introduction The masonry compressive strength, f´ m , is widely used in masonry design. ASTM C1314 (2003) is usually the standard used to evaluate f´ m . In developing countries, ASTM standards are very important, mainly because experimental data are nonexistent or unavailable, and local researchers rely on the experience of a prestigious institution to copy the standard. Therefore, the evaluation of a design parameter such as f´ m should be precise taking into account local materials and workmanship. The masonry compressive strength, f´ m , is calculated by testing masonry prisms, composed of two or more units, placed one over the other with mortar. To facilitate the construction, handling, storage, and transportation from the construction site to the laboratory for the tests, total prisms height should not be too tall. 1 Professor of Civil Engineering, Pontificia Universidad Católica del Perú, Departamento de Ingeniería, Apartado Postal 1761, Lima , PERU.