Issue 39

V. Salajka et alii, Frattura ed Integrità Strutturale, 39 (2017) 88-99; DOI: 10.3221/IGF-ESIS.39.10 89 in TZÚS brunch office in Brno. The clay block masonry walls were tested for a load capacity under the short-term and long-term static load on small masonry walls [3, 4], possibly on walls and pillars of an actual size [5, 6]. Seismic resistance testing was carried out according to the instructions of Klouda, J. K. and with his attendance in a testing department of the National Building and Civil Engineering Institute (ZAG) Ljubljana, Slovenia. Shear tests for the cyclic loading of four (2+2) constantly vertically preloaded walls were conducted. The walls were 2750 mm high and 440 mm thick. They differed in the length. Two of the walls were 2500 mm long and the other two 1500 mm, the wall width and height ratio was then ca. 1 : 1 and 1 : 2. The vertical preload was designed at two levels, at a nominal amount of approximately 1/3 or 2/3 of the value of the wall vertical design load capacity. At the same time, numerical simulations of the experiments for obtaining additional information on the clay block masonry wall behaviour were carried out – the same as by eccentric loaded pillars [7]. The mathematical analyses were carried out using the finite element method on the detailed wall models. Block material properties (modulus of elasticity, tensile strength, compression strength, tensile strength in bending, etc.) were determined experimentally before performing the calculations. The models were considered as geometrically and materially nonlinear, including unilateral bonds. The calculation results are further compared with the results of the conducted tests. T HE CLAY BLOCK MASONRY WALLS UNDER THE STATIC LOAD he load-bearing capacity of brick walls fabricated from ceramic blocks (Fig. 1) under static loading was first tested on small specimens consisting of three rows in the single block format, then on medium-height pillars consisting of seven rows of blocks and finally on high wall pillars consisting of eleven rows of blocks. The test specimens were loaded centrically and eccentrically. Figure 1 : Masonry block used in experimental walls and FEM model of masonry block. Details regarding the executed tests are shown in [5] and [6]. Detailed models were created using the Finite Element Method for use in the numerical simulation of static tests. The brick blocks were modelled along with the mortar in the bed joints, the steel plates under and above the pillars, and the steel apparatus for imposing load. Planar elements under the bottom plate simulate the possible flexibility of the placement of the steel plate. Contact pairs (elements) for the modelling of interaction between the blocks, mortar and steel plates are inserted between the blocks and the areas adjacent to them. These contact elements transfer only compressive and shear forces. Please see Fig. 2 a) for an example computational model of a wall pillar. Fig. 1 and 2 b) illustrates the division of a block into volumetric finite elements. The loading carried out in accordance with the test was considered to be forced displacement load. Details about the calculations can be found in [7]. Fig. 3 shows the dependence of relative transformation in the vertical direction on load. The dashed lines show the measured results and the full (FLX – flexible support) and dotted (SLD – solid support) curves show the results of the calculations. Calculated values of deformation are identical in various levels. It is apparent that the support of the wall needs to be modelled carefully as the seemingly stiffness of support the test specimen can influence the results of the measurements significantly. T