Concrete pressure

Concrete pressure
on vertical formwork 3

29
 Concrete pressure

Concrete pressure on vertical formwork

Tables to estimate the concrete pres-

sures based on the concrete tempe- Requirements for accuracy table
rature and rate of placement as per Concrete raw density = 25 kN/m3
3 DIN 18218 (issue 9/80)
Concrete set after 5 hours at the latest
Compaction with internal vibrators

Tight plywood

Pour rate max. 7 m/h = vertical rise of concrete per hour

hs

Definitions Symbol Unit

Concrete pressure Pb kN/m2
5Vb

Pour rate Vb m/h

Hydrostatic pressure hs m
Pb
Vibration depth hr m

Warehouse, Endingen; Ernst Spth, Endingen

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 Concrete pressure

The concrete pressure is ascertained of concrete pressure, depending on grated in the calculation of concrete
as per DIN 18218 (9/80) by differen- consistency. The individual formulae pressure with the factor
tiating between the various consis- are stated below and the resulting
tency ranges. The pour rate vb is inte- values are listed in table form. The kT = 145-3* T
grated differently in the calculation temperature of the concrete is inte- 100
T=temperature in degrees centigrade.

Stiff concrete, KS (K1) Plastic concrete, KP (K2)

Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb
3
Vb 25 C hs 20 C hs 15 C hs 10 C hs 5 C hs Vb 25 C hs 20 C hs 15 C hs 10 C hs 5 C hs
0,5 16,5 0,66 20,0 0,80 23,5 0,94 27,0 1,08 30,6 1,22 0,5 16,8 0,67 20,4 0,82 24,0 0,96 27,6 1,10 31,2 1,25
1,0 18,2 0,73 22,1 0,88 26,0 1,04 29,9 1,19 33,8 1,35 1,0 20,3 0,81 24,7 0,99 29,0 1,16 33,4 1,33 37,7 1,51
1,5 19,9 0,79 24,2 0,96 28,5 1,14 32,8 1,31 37,1 1,48 1,5 23,8 0,95 28,9 1,16 34,0 1,36 39,1 1,56 44,2 1,77
2,0 21,7 0,86 26,4 1,05 31,0 1,24 35,7 1,43 40,3 1,61 2,0 27,3 1,09 33,2 1,33 39,0 1,56 44,9 1,79 50,7 2,03
2,5 23,5 0,93 28,5 1,14 33,5 1,34 38,5 1,54 43,6 1,74 2,5 30,8 1,23 37,4 1,50 44,0 1,76 50,6 2,02 57,2 2,29
3,0 25,2 1,00 30,6 1,22 36,0 1,44 41,4 1,65 46,8 1,87 3,0 34,3 1,37 41,7 1,67 49,0 1,96 56,4 2,25 63,7 2,55
3,5 27,0 1,07 32,8 1,30 38,5 1,54 44,3 1,77 50,1 2,00 3,5 37,8 1,51 45,9 1,84 54,0 2,16 62,1 2,48 70,2 2,81
4,0 28,7 1,14 34,9 1,39 41,0 1,64 47,2 1,88 53,3 2,13 4,0 41,3 1,65 50,2 2,01 59,0 2,36 67,9 2,71 76,7 3,07
4,5 30,5 1,21 37,0 1,47 43,5 1,74 50,1 2,00 56,6 2,26 4,5 44,8 1,79 54,4 2,18 64,0 2,56 73,6 2,94 83,2 3,33
5,0 32,2 1,28 39,1 1,56 46,0 1,84 52,9 2,11 59,8 2,39 5,0 48,3 1,93 58,7 2,37 69,0 2,76 79,4 3,20 89,7 3,59
5,5 34,0 1,35 41,2 1,64 48,5 1,94 55,8 2,23 63,1 2,52 5,5 51,8 2,07 62,9 2,52 74,0 2,96 85,1 3,40 96,2 3,85
6,0 35,7 1,43 43,4 1,73 51,0 2,04 58,7 2,34 66,3 2,65 6,0 55,3 2,21 67,2 2,69 79,0 3,16 90,9 3,63 102,7 4,11
6,5 37,5 1,49 45,5 1,81 53,5 2,14 61,6 2,46 69,6 2,78 6,5 58,8 2,35 71,4 2,86 84,0 3,36 96,6 3,86 109,2 4,37
7,0 39,2 1,56 47,6 1,90 56,0 2,24 64,4 2,57 72,8 2,91 7,0 62,3 2,49 75,7 3,03 89,0 3,56 102,4 4,09 115,7 4,63

Stiff concrete KS (K1): pb = 5* vb + 21 Plastic concrete, KP (K2) pb = 10* vb + 19

Soft concrete, KR (K3) Flowing concrete, KF (flow concrete)

Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb
Vb 25 C hs 20 C hs 15 C hs 10 C hs 5 C hs Vb 25 C hs 20 C hs 15 C hs 10 C hs 5 C hs
0,5 17,5 0,70 21,3 0,85 25,0 1,00 28,8 1,15 32,5 1,30 0,5 17,9 0,72 21,7 0,88 25,5 1,04 29,4 1,19 33,2 1,35
1,0 22,4 0,89 27,2 1,09 32,0 1,28 36,8 1,47 41,6 1,66 1,0 23,8 0,95 28,9 1,16 34,0 1,37 39,1 1,57 44,2 1,78
1,5 27,3 1,09 33,2 1,33 39,0 1,56 44,9 1,79 50,7 2,03 1,5 29,8 1,19 36,2 1,44 42,5 1,70 48,9 1,95 55,3 2,21
2,0 32,2 1,28 39,1 1,57 46,0 1,84 52,9 2,12 59,8 2,39 2,0 35,7 1,42 43,4 1,72 51,0 2,03 58,7 2,33 66,3 2,63
2,5 37,1 1,48 45,0 1,80 53,0 2,12 61,0 2,44 68,9 2,76 2,5 41,7 1,65 50,6 2,00 59,5 2,36 68,5 2,71 77,4 3,06
3,0 42,0 1,68 51,0 2,04 60,0 2,40 69,0 2,76 78,0 3,12 3,0 47,6 1,88 57,8 2,28 68,0 2,69 78,2 3,09 88,4 3,49
3,5 46,9 1,87 57,0 2,26 67,0 2,68 77,1 3,08 87,1 3,48 3,5 53,6 2,11 65,1 2,56 76,5 3,02 88,0 3,47 99,5 3,92
4,0 51,8 2,07 62,9 2,52 74,0 2,96 85,1 3,40 96,2 3,85 4,0 59,6 2,34 72,3 2,84 85,0 3,35 97,8 3,85 110,5 4,35
4,5 56,7 2,26 68,9 2,76 81,0 3,24 93,2 3,73 105,3 4,21 4,5 65,5 2,57 79,5 3,12 93,5 3,68 107,6 4,23 121,6 4,78
5,0 61,6 2,46 74,8 2,99 88,0 3,52 101,2 4,04 114,4 4,57 5,0 71,4 2,80 86,7 3,40 102,0 4,01 117,3 4,61 132,6 5,21
5,5 66,5 2,66 80,8 3,23 95,0 3,80 109,3 4,37 123,5 4,94 5,5 77,4 3,03 93,9 3,68 110,5 4,34 127,1 4,99 143,7 5,64
6,0 71,4 2,85 86,7 3,46 102,0 4,08 117,3 4,69 132,6 5,30 6,0 83,3 3,26 101,2 3,96 119,0 4,67 136,9 5,37 154,7 6,07
6,5 76,3 3,05 92,7 3,70 109,0 4,36 125,3 5,01 141,7 5,66 6,5 89,3 3,50 108,4 4,25 127,5 5,00 146,7 5,75 165,8 6,50
7,0 81,2 3,24 98,6 3,94 116,0 4,64 133,4 5,33 150,8 6,03 7,0 95,2 3,73 115,6 4,53 136,0 5,33 156,4 6,13 176,8 6,93

Soft concrete, KR (K3): pb = 14* vb + 18 Flowing concrete, KF (flow concrete): pb = 17* vb + 17

Consistency range Factor for setting retarder Conversion factor for deviating
concrete raw density
5 hours 15 hours

KS 1,15 1,45
Raw density in kN/m3
KP 1,25 1,80 25 kN/m3
KR/KF 1,40 2,15

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 Concrete pressure

In addition to DIN 18218, other international methods use different parameters for calculating the concrete pres-
sure. The main calculation methods are featured below together with their main factors. The factors are designated
on the basis of DIN 18218. Here it only states the calculation methods for standard concrete; special conditions have
to be observed for concrete with special properties.

1. CIRIA report 108 (United Kingdom)

3 Concrete pressure is calculated according to the CIRIA report 108 as follows:

pb = b x (k1 x vb + k2 x kT x h-k1 x vb) or pb = b x h

whichever is smaller.

This calculation is based on the following parameters:

Flat silo, Sderbrarup;
Max Giese, Bdelsdorf
b raw density of the concrete [kN/m3]
vb pour rate of the concrete [m/h]
h pour height [m]
k1 cross section coefficient k1 = 1,0 for walls
1,5 for columns
(if both edge lengths are smaller
than 2,0 m, the cross sections are
designated to as columns)
k2 additive coefficient k2 = 0,30 for normal concrete
0,45 for concrete with
setting retarder
2
kT temperature coefficient kT = 36
T + 16
Sewage plant, Karlsruhe-Durlach;
with T concrete temperature [C] Dyckerhoff & Widmann AG, Karlsruhe

2. ACI 347R (USA): For columns For walls

According to ACI the concrete pres- the concrete pressure is taken to be: we differentiate between ranges of
sure is calculated according to the 785*vb pour rate.
cross section form, differentiating pb = 7,19 +
17,78 + T
between ranges of concreting speed. vb < 2,14 m/h:
The calculations include: The limits of concrete pressure for The same formula is used as for columns
columns are defined as follows:
the cross section form 2,14  vb  3 m/h:
the pour rate pmin = 28,74 kN/m2
the concrete temperature
1155 244* vb
pmax = 143,7 kN/m2 oder 23,5 * h pb = 7,19 + +
and the pour height (whichever is smaller) 17,78 + T 17,78 + T
vb > 3 m/h: pb = 23,5* h
The raw weight of the concrete is taken
to be 2400 kg/m3. The concrete pressure limit values for
walls are defined as follows:
pmin = 28,74 kN/m2
pmax = 95,8 kN/m2 oder 23,5 * h
(whichever is smaller)

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 Concrete pressure

3. CIB-FIB-CEB (France)
This method differentiates between three table values which integrate the various criteria. The following parameters
are integrated in the table:

the pour height

the wall thickness d [mm]
the pour rate of the concrete
the slump [mm] according to standard P 18-305 3
the concrete temperature

The weight of the concrete is taken to be 2400 kg/m3.

The following tables can be used to read the values of the concrete pressure:
The smallest of the 3 values is to be taken as concrete pressure!

Table 1 for ascertaining P1 (hydrostatic pressure):

h [m] 1 2 3 4 5 >6
P1 [kN/m2] 25 50 75 100 125 150

Table 2 for ascertaining P2 (arch effect of the slightly thickened concrete):

V [m/h]
d [mm]
1 2 3 4 5 6 8 10 15 20 30 >=40
150 P2=35 35 40 45 45 50 55 60 75 90 120 150
200 40 40 45 50 50 55 60 65 80 95 125 150
300 50 50 55 60 60 65 70 75 90 105 135 150
400 60 60 65 70 70 75 80 85 100 115 145 150
500 70 70 75 80 80 85 90 95 110 125 150 150

Table 3 for ascertaining P3 (setting off the concrete):

Slump Concrete V [m/h]

[mm] temperature [C]
1 1,5 2 2,5 3 4 5 6 7 >=8
5 P3=50 70 95 115 135 150 150 150 150 150
50 10 40 55 70 85 100 135 150 150 150 150
15 40 45 55 65 75 100 125 150 150 150
20 35 40 45 50 55 70 90 105 125 150
5 60 85 110 140 150 150 150 150 150 150
10 50 65 85 105 125 150 150 150 150 150
75
15 40 50 65 80 95 125 150 150 150 150
20 35 40 50 60 70 90 115 135 150 150
5 70 100 130 150 150 150 150 150 150 150
10 55 75 100 120 150 150 150 150 150 150
100
15 45 60 75 90 110 150 150 150 150 150
20 35 45 55 70 80 110 130 150 150 150

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 Concrete pressure

Two examples are used to illustrate

Example 1: how to calculate the concrete pres-
Example 2:
Wall formwork Column formwork
sure using the different methods.
Pour height/wall height: H = 4 m Pour height/wall height: H = 4 m
Pour rate: vb = 3,0 m/h Pour rate: vb = 6.0 m/h
Concrete temperature: T = 15C Concrete temperature: T = 15C
Wall thickness: d = 300 mm Column cross section: 0.5 x 0.5 m

3 General data: normal concrete,

As per DIN 18218: plastic consistency (K2), concrete raw As per DIN 18218:
density b = 25 kN/m3 unless other-
145-3*15 wise stated. 145-3*15
kT = =1 kT = =1
100 100
pb = 1*(10*3,0 + 19) pb = 1*(10*6,0 + 19)

= 49,0 kN/m2 = 79,0 kN/m2

As per CIRIA-Report 108: As per CIRIA-Report 108:

k1 = 1,0 k1 = 1,5

k2 = 0,3 k2 = 0,3
2 2

kT =
36 =1,35
kT =
36
=1,35
15 + 16 15 + 16

pb = 25 x (1x 3 + 0,3 x 1,35 x 4-1 x 3) pb =25 x (1,5 x 6 + 0,3 x 1,35 x 4-1,5 x 6)

Grain building, Rostock; ZBO, Grevesmhlen

= 58,5 kN/m2 = 97,6 kN/m2

As per ACI 347R: As per ACI 347R:

1155 244 * 3 758*6
pb = 7,19 + + pb = 7,19 +
17,78 + 15 17,78 + 15 17,78 + 15
= 64,8 kN/m2 = 150,9 kN/m2

pmin < 64,8 kN/m2 < pmax pmin < 150,9 kN/m2 > pmax = 23,5 * h
pb = 64,8 kN/m2 pb = 94,0 kN/m2

As per CIB-FIB-CEB: As per CIB-FIB-CEB:

P1 = 100 kN/m2 P1 = 100 kN/m2
P2 = 55 kN/m2 P2 = 85 kN/m2
P3 = 95 kN/m2 Sewage plant, Bottrop; Kster Bau, Melle P3 = 150 kN/m2
Whichever is smaller! Whichever is smaller!

pb = 55 kN/m2 pb = 85 kN/m2

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en 1065 celik dikme.tif (1728x2262x2 tiff)