Issue 62

Y. Boulmaali-Hacene Chaouche et alii, Frattura ed Integrità Strutturale, 61 (2022) 61-106; DOI: 10.3221/IGF-ESIS.62.07

Fig. 10 shows the lateral (LE11) and vertical (LE33) deformation state of T2 and T3 tubes successively filled with C1, C2 and C3 type concrete under elasto-plastic behavior with confined concrete proposed by Tao et al [12]. The lateral deformations (LE11) are due to the traction generated by the concrete confined by the steel tube; on the other hand, the vertical deformations (LE33) are compression deformations due to the axial compression. The curves follow a nonlinear elasto-plastic behavior with the highest value of lateral deformation corresponding to the T3C3 tube reaching 25 ×10 -3 , with a local buckling at its ends. The majority of the vertical deformations (of compression) present a plastic flow with large deformations reaching an average of 30 ×10 -3 ; we notice however that the tubes T3C1 and T3C2, gave lateral and vertical deformations of the same order.

LE11-T2C1 LE11-T3C2 LE33-T2C3

LE11-T2C2 LE11-T3C3 LE33-T3C1

LE11-T2C3 LE33-T2C1 LE33-T3C2

LE11-T3C1 LE33-T2C2 LE33-T3C3

0 100 200 300 400 500 600 700 800 900

Load (kN)

-40

-30

-20

-10

0

10

20

30

Strain ɛ × 10 -3 (mm/mm)

Figure 10: Lateral and vertical deformation state of short tubes T2 and T3 according to the model proposed by Tao et al [12] for confined concrete. Fig.11 shows the FE failure modes of empty steel tubes (f e = 240 MPa) in the elasto-plastic state with multilinear hardening (tubes T1, T2 and T3) for which an instability appears in the three tubes with an important blistering on the periphery of the tube T1 (shortest tube) which increases until the middle of the tube, on the other hand we do not observe any buckling in its lower part.

(a)

(b)

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