PSI - Issue 59

Volodymyr Romanіuk et al. / Procedia Structural Integrity 59 (2024) 471 – 478 Volodymyr Romanіuk et al. / Structural Integrity Procedia 00 (2019) 000 – 000

474

4

Fig. 4. Support section without stiffener and with welded holes (type 3).

Fig. 5. Support section with stiffener and with welded holes (type 4).

the point of intersection of the bending moment curve M with the neutral line to the axis of the intermediate support. Using known formulas for calculating transverse forces and bending moments at characteristic points and cross sections along the length of a two-span continuous beam subjected to a uniformly distributed load, it is possible to determine the critical load magnitude leading to the ultimate limit state in the beam. This limit state involves the loss of load-bearing capacity, specifically reaching the limit values of normal stresses in the cross-section of the beam. Consequently, based on these calculations, the critical uniformly distributed loads for the specified beam heights are as follows: q = 16.45; 45.22; 85.24; 142.1; 229.0 kN/m. 3. Research results In result of the calculation, a very large array of information was obtained, which cannot be presented in a single article. Therefore, the following results are specific to the supporting parts of a perforated beam with a height of h = 300 mm. These findings give a comprehensive understanding of the behavior of various types of intermediate support for beams with other height values. The analysis of the obtained results of the calculation values of maximum deflections and stresses in the span of a continuous perforated beam (Table 1) shows that the design of the intermediate support has minimal impact on these values. The only exception is observed in a beam with a support part of type 1, where the maximum stresses are approximately 10% higher compared to beams with other support types. The differences in deflection magnitudes are no more than 4%. Obviously, this is because the stiffness of the type 1 support itself is significantly lower since there is no stiffening rib along the axis of the support, and the perforation holes are left unwelded. Violation from the linear relationship between deflections and stresses on the one hand and the value of the applied load on the other hand is observed only when subjected to a load of q = 49.4 kN/m (Figs. 6, 7). This can be explained by the concentration of deformations and stresses at certain locations along the beam's length, particularly with a significant increase in stresses at the corners of the holes. The indicated violation from linearity is most

Table 1. Maximum values of deflections and stresses in the span of a perforated I-beam.

Limit design uniformly distributed load, kN/m

Maximum in span

Support type

No.

for the original I-beam with a height of 200 mm

for perforated I-beam with a height of 300 mm

Deflections, mm

Stress, MPa

1 2 3 4

1 2 3 4

-6.440 -6.410 -6.230 -6.200

-181.00 -165.0 -166.0 -166.0

16.45

64.5