The 14 th World Conference on Earthquake Engineering October 12-17, 2008, Beijing, China EXPERIMENTAL BEHAVIOR OF SINGLE AND DOUBLE MASONRY PANELS T. Albanesi 1 , A. V. Bergami 2 and C. Nuti 3 1 Assistant Professor, Dept. of Structural Engineering, University of Roma Tre, Rome. Italy 2 Fellow researcher, Dept. of Structural Engineering, University of Roma Tre, Rome. Italy 3 Full Professor, Dept. of Structural Engineering, University of Roma Tre, Rome. Italy Email: t.albanesi@uniroma3.it, abergami@uniroma3.it, c.nuti@uniroma3.it ABSTRACT: In this paper, the results of the experimental tests, carried out at the Laboratory on Materials and Structures of the University of Roma Tre to characterize masonry panels behavior are shown and discussed. 36 single and 12 double panels have been considered: 12 single panels are made of 80×160×330 mm 3 bricks with horizontal holes, 24 of 120×250×120 mm 3 half-full bricks with vertical holes and two different mortars and 12 double panels coupling the two previous types of simple panels. The panels have been built with a level of accuracy similar to the one adopted in buildings therefore they are well done but not lacking some defects that unavoidably would be found in real constructive practice. Compression tests in horizontal, vertical and diagonal directions were performed to evaluate their “constitutive relationships” in term of force-displacement diagrams and in particular their strength and elastic modulus. Experimental tests also included the characterization of the bricks and of the mortar used to realize the panels. KEYWORDS: masonry panels, infill 1. INTRODUCTION Mechanical properties of masonry panels are very relevant for r.c. infilled frame structural analysis both in terms of frame strength and stiffness and in terms of failure mechanisms. This paper focuses on some results of experimental tests performed on single and double infill panels at the Laboratory on Materials and Structures of the University of Roma Tre. The experimental study includes characterization of both brick and mortar components and infill specimens. First, two different kinds of mortar (in the following type 1 and type 2 mortar) and two of bricks (in the following hollow and half-full bricks) have been chosen after a careful selection among available basic materials and their mechanical characteristics identified by experimental tests. Then, a total of 48 walls (36 single and 12 double panels) have been built with these bricks and mortars: 12 single panels using hollow bricks and type 1 mortar, 12 single panels using half-full bricks and type 1 mortar, 12 single panels using half-full bricks and type 2 mortar, 12 double panel walls combining the previous types of brickwork both realized with type 1 mortar. A more detailed discussion of the experimental activity performed are given in A. V. Bergami (2008). 2. BASIC COMPONENTS 2.1. Characteristics of the Basic Components Two kinds of bricks are considered (Figure 2.1): 80×160×330 mm 3 bricks with an apparent weight density of 7.57 kNm -3 and horizontal holes and a hollow percentage ϕ > 55% (named hollow bricks) and 120×250×120 mm 3 bricks with an apparent weight density of 9.21 kNm -3 and vertical holes and a hollow percentage ϕ = 49% (named half-full bricks). Two kinds of mortars are selected: one to be realized on site with a specific mix (named type 1 mortar) and the other pre-mixed (named type 2 mortar). The composition of type 1 mortar is: 1 part of Portland cement (CEM II/B-M(L-S-V)32.5), ¼ of 32.5 cement, ¼ of 12.5 cement, 4 parts of sand (granulometry between 1-4 mm), 0.5 water-cement ratio. Type 2 mortar is a pre-mix consisting of hydrated lime,