PSI - Issue 37

Dmitrijs Serdjuks et al. / Procedia Structural Integrity 37 (2022) 555–562 Dmitrijs Serdjuks et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 3. (a) steel beams stand, consisting of the main and additional beams; (b) semi-rigid joint with variable stiffness of the joint between the main and additional beams; I, II and III are positions, where stresses and vertical displacements were determined.

4. Results and discussion 4.1. Results of static loading

Static test of the steel beam stand was carried out to specify the static diagram of the stand and beams’ joint stiffness. Experimentally and analytically obtained values of the maximum vertical displacements and stresses at all loading stages are shown in the diagrams for position III (middle of the span of the girder) in Fig 3a. The values of the maximum vertical displacements and normal stresses when the structure was loaded by the total vertical load of 10 kN are shown in Tables 1 and 2 for positions I, II and III. The values are obtained for the case, when the joint of the steel beams have it maximum stiffness and considered as a rigid one.

Table 1. Comparison of experimental and design values of the maximum vertical displacements . Position Experimental maximum vertical displacements, 10 -2 mm Design maximum vertical displacements, 10 -2 mm Difference Δ , 10 -2 mm

Difference Δ , %

I

15.25 31.00 39.50

14.10 29.90 37.80

1.15 1.10 1.70

7.54 3.55 4.30

II

III

Table 2. Comparison of experimental and design values of normal stresses . Position Experimental normal stresses , MPa Design normal stresses , MPa

Difference Δ , MPa Difference Δ , %

I

8.14 6.83

7.60 6.38

0.54 0.45 0.21

6.61 6.52 2.08

II

III

10.24

10.45

Comparison of experimentally and analytically obtained results enabled to conclude that considered joint could be considered as the rigid one when the total value of the vertical load did not exceed 10 kN. The difference between the experimentally and analytically obtained results was 6.61% for stresses and 7.54% for the maximum vertical displacements. Results obtained for the pinned joint also showed high correspondence between the experimentally and theoretically obtained values. The difference between the experimentally and analytically obtained results was 9.06% for stresses and 6.21% for the maximum vertical displacements. It enabled to conclude that considered variant of the beams joint was the rigid one at the applied level of loading (Topcijs (2021)).