Detailing of reinforcement J. Arrieta As ,max 0,04 Ac
where Ac is the transverse area of the column. For transverse reinforcement (9.5.3) the minimum diameter ϕt,min and the maximum spacing st,max are:
1 4
t ,min max 6 mm ; long st ,max min 20 long ; bmin ; 400 mm
The maximum spacing is reduced by a factor 0,60 in zones near a beam or a slab, and in lapped joints if the diameter of bars is greater than 14 mm. In this case a minimum of 3 bars must be present. No longitudinal compression bar can be at a clear distance greater than 150 mm from a restrained bar; restraining is obtained using transverse reinforcement or splices When there is a change of direction in a longitudinal bar, the lateral forces may be ignored if the slope of the change is less or equal to 1:12, otherwise pushing forces have to be considered. 4.2.4.2
Column B2 - case 2
The column considered corresponds to case 2 - flat solid slab. Geometrical data are in figure 20. The materials used have the following properties: o
Concrete:
fck = 30 N/mm2;
γc = 1,50;
o
Steel:
fyk = 500 N/mm2;
γs = 1,15
fctm 0,30fck 2 / 3 2,90 N/mm 2
Applying the actual values of the column to the previous expressions we obtain: o
Longitudinal reinforcement
min 8 mm As,min max 0,23NEd ;500 mm2 As,max 10000 mm2 o
Transverse reinforcement
t ,min
6 mm if long 24 mm long if long 24 mm 4
st ,max min 20long ;400 mm
125