Issue 39

V. Salajka et alii, Frattura ed Integrità Strutturale, 39 (2017) 88-99; DOI: 10.3221/IGF-ESIS.39.10 93 model reflects the real behaviour of the compressive device in a better way. The real version of the compressive device is in the Fig. 6. Figure 8 : Contact finite elements (on left) and the beams and the concrete blocks (on right) of “S” type model. Brick body and mortar properties are derived from the measurement [3]. The material model of the steel girders and concrete beams is considered as isotropic and linearly elastic. On the contrary, the material model of the brick body and mortar is considered as nonlinear with different tensile and compression strength. A summary of the properties of the individual parts of the model have been used in calculations as it is mentioned in Tab. 1. Brick body Mortar Concrete Steel Modulus of Elasticity E [GPa] 14.0 7.9 30 210.0 Lateral Contraction Coefficient ν [-] 0.1 0.2 0.2 0.3 Specific Weight ρ [kg.m -3 ] 1390 1400 2300 7850 Compression Strength f c [MPa] 19.2 17.3 - - Tensile Strength f t [MPa] 3.7 4.6 - - Table 1 : Material properties. The total computational model for alternative solutions with the “L” type wall consists of 113,337 finite elements localized by 134,550 nodes and has 399,477 degrees of freedom. The total computational model for alternative solutions with the “S” type wall consists of 68,799 finite elements localized by 83,177 nodes and has 246,013 degrees of freedom. The imposed functions are modified functions taken from response at the experiments. The major adjustment consists of the correction of the excitation point location. The response functions are monitored at the height of 2,824 mm (“L” type) above the wall bed joint, while the excitation point by the forced motion of the girder is at the different place, at higher level from the centre of the bottom of the wall during the experiment. The displacement correction corresponds to approximately 5 to 6 percent. That means that the imposed lateral displacement function used as the excitation were increased by 6 percent. Calculation Four calculations were carried out on models L1, L2, S1 and S2. The calculations are nonlinear, time-consuming and required large disc space. The solution is considered as quasi-static due to the slow loading process. The time step is considered as variable with the largest step of 15 s. In each time step an iterative state of equilibrium is searched. In case that the time step cannot be already decreased and the calculation does not converge, the calculation process is terminated.