PSI - Issue 81

Bohdan Karavan et al. / Procedia Structural Integrity 81 (2026) 396–400

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3.2. Arch A2

At a load of F = 130 kN, the deflection of the arch belt was f = 12.5 mm, which is less than the maximum permissible value fu = 1/150 l = 13.3 mm (Fig. 5). The increase in deflections at load steps: in the range F = 5...85 kN was on average Δ f = 0.4 mm, in the range F = 90...130 kN was on average Δ f = 0.67 mm per 5 kN of load. The dependence of the arch belt deflection on loads up to F = 85 kN is linear. At load levels of F = 90...130 kN, the increase in deflections increases, which is associated with an increase in plastic deformations in concrete and excessive crack opening (Fig. 5). The horizontal displacement of the hinged support of the arch at a load of F = 130 kN was Δ = 12 mm, which corresponds to the values of the deflection of the arch at the load stages (Fig. 5). The increase in the values of support displacements at the load stages: in the range F = 8...85 kN was on average Δ = 0.4 mm, in the range F = 90...130 kN was on average Δ = 0.66 mm per 5 kN of load. The increase in the increase in support displacement values at load stages at F = 90...130 kN is generally explained by a decrease in the stiffness of the arch belt. As with deflections, the dependence of arch support displacement on loads up to F = 85 kN is linear. a b

100 110 120 130

100 110 120 130

F, kN

F, kN

0 10 20 30 40 50 60 70 80 90

0 10 20 30 40 50 60 70 80 90

f,mm

Δ ,mm

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Fig. 5. Dependencies: a) deflection of the belt under load in arch A2; b) movement of supports from load in arch A2.

Arch A2 collapsed under a load of Fu = 120 kN along a through-going normal crack under a concentrated force (Fig. 6).

Fig. 6. Cracks in the belt of the experimental arch A2.

4. Conclusions For the first time, experimental data on the performance of double-hinged reinforced concrete arches made of high-strength fast-setting concrete were obtained, which made it possible to identify the features of the stress-strain state of normal cross-sections and the nature of the development of deflections and cracks under single short-term static loads. The belt of a double-hinged reinforced concrete arch under load is a compressed-bent element. In the lower zone in the support cross-sections (at a distance of 35 cm from the supports) of arches with tightening, at the stages of their loading, the stresses in the concrete can change their sign (compression – tension – compression). The concrete of the upper zone of the belt in the sections at a distance of 35 cm, 68 cm, and in the arch lock was subjected to compressive stresses during all stages of loading. The compressive forces and, accordingly, the stresses in the materials in the arch belt without tensioning A1 were greater than the corresponding forces and stresses at the loading stages of the test arch with tensioning A2. With a single short-term static load up to F = 90 kN, the dependence of “load - thrust force”, “load - deflection”, “load - support displacement” of the test arches is linear.