Issue 61

M. Khalaf et alii, Frattura ed Integrità Strutturale, 61 (2022) 308-326; DOI: 10.3221/IGF-ESIS.61.21

A tensile test was preformed to plot the load-elongation curve as shown in Fig. 10. The modulus of elasticity was found to be 199075MPa, while the yield stress was equal to 243.2MPa. A direct shear test was also performed which resulted in that the maximum shear capacity of the shear connectors equals 242.2MPa. Fig. 11 shows plotting of load-deflection "shear displacement" gained results. Reinforcing steel bars The British standard recommended the use of a special steel reinforcing mesh where a concentrated or line loads exerted. So, a top mesh of plain steel bar (6.5  6mm/m) in two directions within concrete layer keeping 1.5cm concrete cover was fabricated to resist the negative moments, as shown in Fig.12.

Figure 12: Reinforcing Steel Bars Top Mesh; (M1).

Concrete The concrete mix is designed to give minimum cube strength of 24.5MPa after 28 days. Tab. (4) shows the used concrete characteristics.

Actual Result

Characteristic

M1

M2

M3

Cube Strength after 180 day; f cu (MPa)

32.5

31.8

30.7

Flexural Strength; f r (MPa)

4.88

4.19

4.07

Modulus of Elasticity *; E c (MPa)

24923.6

24542.6

24417

Slump Value (cm)

4.5

4.3

4.4

2377

2370

2390

Concrete Volume Weight;  c (kg/cm 3 )

Table 4: Experimental Models Concrete Characteristics.

*Modulus of elasticity is determined as follows; [17]: E c = 0.043 × ( γ c ) 1.5 × ( f c `) 0.5 where: E c : Concrete modulus of elasticity (MPa). γ c : Concrete volume weight (kg/m 3 ). f c ` : Cylinder compressive strength as a function of f cu (MPa); [15].

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