In slab there are mainly two types of bars alias main bars and distribution bars. In this construction video tutorial, one can get some useful tips on where to set up theses bars i.e. shorter span or longer span.
Both are mainly utilized as the reinforcements of a slab.
Given below, the characteristics of main bar :
Horizontal bar is main bar and it is mainly arranged in shorter span with longer diameter.
It is applied to withstanding bending moment (sagging).
To resist all the bending moment, tensile stresses, super imposed load (direct load).
It should not be under 8 mm for high yielding strength deformed (Hysds) bars, 10 mm for plain bars.
Main bar should be always under distribution bar. If you view it from top to bottom, the bar should be in second line. On the other hand if you view it from bottom, the bar should be first line.
The characteristics of distribution bar :
Vertical bar is distribution bar and it is arranged in one way slab in longer span with shorter diameter to allocate load to main bars.
Facilitates for allocation of loads (super imposed loads).
To withstand shrinkage stresses that may lead to cracks due to difference in temperature.
Distribution steel is arranged to withstand all the shrinkage stresses because of variance in temperature and shrinkage in concrete (occur owing to hydration reaction) in lateral direction.
The distribution steel performs as a support to bind the reinforcements in a mesh to keep the necessary c/c spacing among the main reinforcements.
To get more information, watch the following construction video tutorial.
Video Source: F&U-FORYOU