Minimal clear spacing of bars - Code chapter 8.2(2)
The main principles which are checked are mainly satisfying minimal distances between bars which should be arranged in such a way that concrete can be placed and compacted satisfactorily so that adequate bond will develop between the bars and concrete.
The procedure of calculation is running for each distances between bars and verification of the minimal distance among them towards the limited value from the code. The distances are evaluated as the minimal clear distance for all member types mentioned before (beam, column and beam slab) . Check looks as follows.
Minimal clear distance between longitudinal bar ss-s,min is calculated from practical reinforcement (REDES).
Furthermore minimal allowed clear distance between bars from all bars in cross-section is calculated according to chapter 8.2(2) as
ss-s,min,lim=max (k1 ∙ ϕ; dg+k2; slb,min)
where:
- k1 and k2 are coefficients defined in NA. For standard Eurocode k1= 1 and k2= 5
- ϕ is diameter of maximal longitudinal reinforcement
- dg - maximal stone diameter in concrete mixture
- slb,min is minimal clear distance defined as fixed value in chapter 8.2(2)
Finally unity check is calculated as follows:
UC8.2(2) = ss-s,min,lim/ ss-s,min
Clause 8.2.(2) - Coefficients used for National annex parameters
There are the following differences in particular NA.