*4.2. Global Analysis with Only Mechanical Loads*

The displacements and the stresses occurring in the truss roof system were calculated by using the finite element analysis software. Figure 11 shows the vertical displacement (in meters) under the considered loads. The largest displacements of about 4.7 cm occurred in blocks A, C, and E, where the gap between the columns was the largest (28 m), as was expected. It should be noted here that due to the positive direction of the axis, which is upwards, blue colours are around zero and red is the largest in terms of absolute values. The region of the larger resultant displacements is not where the real damage happened. The deformations of the column structures are so small that they do not suggest any safety issues. The analyses demonstrate clearly that the system is safe and that the results are consistent with the results obtained by the engineering bureau.

**Figure 11.** Vertical displacement of the steel-reinforced concrete column system.

Considering the stress analysis, the equivalent stresses using the von Mises criteria were calculated for all the structures. Figure 12 gives the von Mises stresses in the roof structure (in Pa). It can be seen that all stresses of the roof structure together with the columns are within the safety limits. The collapsed regions are also within the safety limits. As well as the displacements, the stresses occurring in the column structures are well below the safety limits. Although exaggerated loads are applied on the roof structure, the stresses and displacements in the beams and rods show that the structure would not fail under these combinations of excessive loads.

**Figure 12.** Equivalent von Mises stress distribution of the steel-reinforced concrete columns.

The greatest stresses occur at these "U" shaped connections shown in Figure 13; however, the displacements are not excessive. It is important to note that this connection structure does not exist in the real application. These connections are used in the CAD/FE model in order not

to distort the dimensions of the truss structure. In reality, there are walls with certain thicknesses whereas the FE model used beam elements. To connect the trusses with the supports, such a "dummy" structure was used. Therefore, the stress values that were read at these connections were disregarded.

**Figure 13.** Connections with the supports and steel truss at the block interfaces.
