In this paper, a nonlinear finite element model (FEM) was developed using ABAQUS 
6.14 to study the effect of the upper steel mesh on the behaviour of mono-symmetric steel-concrete 
composite (SCC) beams provided with channel shear connectors. Moreover, the FEM will be used 
to calculate the effective width of the concrete slab against the existence of upper steel reinforcement 
mesh and compare the results with the calculation of the effective width in the universal codes (i.e., 
AISC 360-15, CSA S16-14 and the Eurocode 4; CEN 2004). In this respect, six (SCC) beams were 
modeled to study the effect of the upper steel mesh on SCC beams' behaviour. The results of this 
study showed that the increase in the ratio of the upper steel reinforcement mesh is affecting the 
value of the ultimate load, mid-span deflection value and slip value at the steel-concrete interface. 
The presence of upper steel reinforcement mesh with a ratio of 0.91% from the area of the concrete 
slab leads to decreased vertical deflection by 32.5 % at the ultimate load of the beam without upper 
steel reinforcement mesh for beams. Also, the slip value decreased by 60 % at the ultimate load. 
Also, the effective width of the concrete slab for beams provided with the channel shear connectors 
increases with the increase in the ratio of the upper steel reinforcement mesh.