PSI - Issue 64

Carmine Lima et al. / Procedia Structural Integrity 64 (2024) 849–856 Lima et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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in which: - f tk is the ultimate characteristic tensile strength of steel connector; - f cm is the average value of the cylindrical compressive strength of concrete; - E cm is the average Young modulus of the concrete slab; - d and h sc are the diameter and heigh of connectors, respectively; - α is a parameter that depends by the h sc /d ratio as follows = 0,2 ∙ (ℎ ⁄ + 1) 3≤ℎ ⁄ ≤4 =1 ℎ ⁄ >4 .

(3)

Considering the strength of materials obtained by compression tests on cube samples, and the mechanical and geometric characteristics of connectors the expected failure load was evaluated to range between 500 kN and 600 kN.

3. Results and analysis 3.1. Push-out tests results

Fig. 5 reports the resulting force-displacement curves obtained from the push-out tests performed in this study. Fig. 5a highlights that the results of the first push-out test performed on C25/30 test#1 sample demonstrated a failure load higher expected (i.e., range between 500 and 600 kN as described in the previous section). More specifically a maximum load equal to 880 kN was recorded. Subsequently, the test protocol was slightly modified in order to consider the higher strength by applying a load ranging between 40 kN and 320 kN (5% to 40% of the expected strength) for the initial 25 cycles.

Fig. 5 Force-displacement curves from push-out tests