PSI - Issue 81

Volodymyr Romaniuk et al. / Procedia Structural Integrity 81 (2026) 234–239

236

(a)

(b)

1 – perforated chords; 2 – tie rod; 3 – strut; 4 – prestressing mechanism; 5 – suspension

Fig. 1. Steel prestressed perforated arch: (a) – general view; (b) – half-arch with characteristic cross-sections.

4) the strut is attached to the chord on the right by welding it to the nodal fitting, and the strut is attached to the chord element on the left using a special device that ensures its pre-tensioning; 5) the arch is installed in the design position and attached to the left support with mounting bolts, which ensure the creation of a hinged-fixed support in the structural scheme, and the design of the support on the right provides for free support also using mounting bolts, but at the same time it is hinged-movable; 6) on the chord element on the left, using a special device, the strut is pre-tensioned until the required design force is generated in it, after which its position is fixed by welding to the nodal fitting; 7) the position of the right support is fixed with mounting bolts only after the roof is installed. Experimental studies of a steel perforated arch with a tie rod and a strut were conducted in the research laboratory of the Department of Industrial, Civil Construction and Engineering Structures of the National University of Water and Environmental Engineering. The span L = 9m, the rise f = 2.25m (Fig. 1a) with a rigid flanged ridge node A , support hinge nodes B and C , and strut mounting nodes D as described in Romaniuk et al. (2024b), Tsavdaridis and D’Mello (2011 a). The calculated symmetrical uniformly distributed load on the arch was 8.35 kN/m. During experimental studies, it was replaced by concentrated equivalent nodal loads of 8.4 kN, applied with a step of 0.9 m (Fig. 1b). The sum of concentrated forces F =8.4 kN is equivalent to the value of the design uniformly distributed load q = 8.35 kN/m applied to the upper chord along the entire length of the arch. The experimental structure consisted of two half-arches, which were fabricated from the original I-beam No. 12 according to DSTU 8768:2018*. As a result of perforation, the height of the chord cross-section increased by 22% (Fig. 3). A tie made of two rods with a diameter of 16 mm, and a strut designed fr om two angles ∟63×6 according to DSTU 2251 -93, assembled in a T-shape. The gusset plates, flanges, and support joints of the arch were fabricated from steel sheet with a thickness of 10 mm according to DSTU 4747:2007. The actual values of mechanical characteristics of steel for all profiles were determined by testing standard specimens in the "UMM-50" testing machine. For this purpose, three specimens were cut from each element. The test results are presented in Table 1. The rigidity of nodal connections was ensured by bolts, and the hinged joints by the presence of gusset plates. The analysis of the stress state of the perforated compression-flexural arch chord was carried out by comparing theoretical and experimental stresses in 14 of its cross-sections (7 for each half-arch) near the support nodes, strut attachment nodes, ridge node, and points of application of concentrated forces (see Fig.1b). Theoretical stresses were calculated using the design standards method by DBN V.2.6-198 (2014) and EN 1993-1-8 (2005), which uses bending theory and assumes that stresses are determined

Fig. 2. The assembly for fastening the strut to the chord with its prestressing mechanism.

Fig. 3. Geometric dimensions of the perforated I-beam