PSI - Issue 59

Bykiv N. et al. / Procedia Structural Integrity 59 (2024) 793–798

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N.Bykiv et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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Stress, MPa

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Fig. 3. Stress-strain dependencies of polymers: 1 – PLA+; 2 – T-PLA; 3 – Elastan D100

The connected rods were put under uniaxial tension on a servo-hydraulic machine STM-100, with a loading speed of 3.3 mm/s. As a result, the static friction F sf was measured at 0.45 kN, without the need for additional compression or the use of composite resins by Ivanytskyi et al., (2005); by Kohut & Humeniuk, (2014). This method eliminates the disadvantages of coupling connections, such as requiring special tools and machinery, and extra care needed in the entire process from cutting of threads to installation. This connection was tested for its intended purpose. A reinforced concrete beam was made with dimensions: 1250x140x80 mm. Concrete strength class C20/25 in accordance to DBN B.2.6-98:2009. Reinforcement is made by two rods of smooth reinforcement. Yield strength σ y = 612 MPa according to the certificate. The reinforcing bars were divided into three parts and connected by a polymer tube. As a result, the beam collapsed under a load of 3.25 kN and a deflection of 0.96 mm (Fig. 4). The reinforcement and polymer couplings remained undamaged. The beam failure occurred gradually with ductile behaviour. A total of two cracks were detected in the middle of the RC beam span (Fig. 5). This was followed by brittle concrete failure behaviour due to the 5% reinforcement of the beam.

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Load, kN

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Displacement, mm

Fig. 4. Load-displacement dependencies of RC beam with couplings