Download - Pipe Support Columns at Bridge Crossing
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1.0 DESIGN INFORMATION
1.1 Material Properties
Density of Concrete 24 kN/m3
Density of Water 9.81 kN/m3
Concrete Grade 30 N/mm2
Characteristic Strength of high yield Steel 460 N/mm2
Characteristic Strength of Mild Steel 250 N/mm2
1.2 Durability Requirement
Exposure Condition -Severe
Clear cover to r/f 50 mm
1.3 Foundation
Assumed bearing capacity 125 kN/mm2
Soil parameters c= 0 kN/mm2
(cohesionless soil) j= 300
g= 20 kN/m3
(Where c is cohesion,jis friction angle and gis the density.)
2.0 REFERENCES
BS 8110 Part 1 (1985)
British Standard Structural Use of Concrete
BS 8007 (1987)
Design of concrete structures for retaining aqueous liquids
BS 4466 (1981)
Reinforced Concrete Designers Hand Book
R.E.Renolds and James C. Steedman - 10 th Edition
Standard Method of Detailing Structural Concrete
By Institution of Structural Engineers UK
Specification for Bending Dimensions and Scheduling of Reinforcement for Concrete.
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Design Data and Parameters
Material Properties
Density of Concrete kN/m3
Density of Water kN/m3
Concrete Grade N/mm2
Characteristic Strength of high yield Steel N/mm2
Durability Requirement
Exposure Condition - Severe
Clear cover to r/f mm
Foundation
Bearing capacity (assumed) kN/m2
Soil parameters c= kN/m2
j=
g= kN/m3
(Where c is cohesion,jis friction angle and gis the density.)
460
50
100
5
18
10
OutputCalculations
30 0
1.0
24
25
Reference
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OutputCalculationsReference
Design of the Column Support (Intermediate)
Height of the support = m
Pipe diameter = m
Length of a pipe = m
Self wt of pipe (One pipe length) = kN
Column size = m
Clear height = m
End condition at top =
End condition at bottom =
=
Effective height (Lexor Ley) =
Lex/h or Ley/b =
> 15
The column is slender
Minimum eccentricity = mm
2.1 Load Calculation
Wt of water inside = kN
Self wt of the column = kN
Additional imposed load (0.5kN/m) = kN
Impact force at top = kN
Moment at the base due to impact force = kNm
Moment due to eccentricity = kNm
0.35
0.30
4.00
3.05
1
25.14
2.2
2.0
6.00
4.00
4
11.76
6.10
24.40
8.80
0.65
3.00
20
4.24
Assume an impact load due to pipe hitting at
top at 2.0m/s during handling
Assume that the pipe will not be submerged. The maximum flood
level is about 2000 above the ground level. The pipe is placed
500mm above the maximum flood level. Each pipe is supported by
a concrete column. Foundation of each column will be placed at a
depth of 1500 below the ground.
Cl.3.8 BS
8110 P-1
200 DI Pipe
Column
Max.water level
GL h Max.=3500mm
6000
Min.500mm
1500mm
300DI Pipe
Min 500mm
hmax= 4000mm
6000 mm
Column
1500mm
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OutputCalculationsReference
Water pressure inside the pipe = bars
= kN
Moment at base due to the bend at top = kNm
Assume a log impact during flood
Weight of log assumed = Tons
Velocity of flood (assumed) = m/s
Force at top of column due to log impact =
= kN
Moment acting on the column base = kNm
Total axial load during construction (Ult) = kNm
(Self wt of pipe+column+Imposed load)
Total moment during construction (Ult) = kNm
(Due to eccentricity+Impact force)
Total axial load during functioning (Ult) = kNm
(Self wt of pipe+column+Imposed load+water load)
Total moment during functioning (Ult) = kNm
(Due to eccentricity+pipe pressure+Log impact)
2.2 Design of the column
Cover = mm
b = mm
h = mm
Vertical r/f bar diameter = mm
Stirrups = mm
d = mm
k =
Z = mm
Zcorrect = mm
As = mm
Provide 4 T 16 + As = mm2
(Per face)
Design of Stirrups
Stirrups size = 6mm or
(1/4)*vertical bar dia
= mm
Spacing = 12xBar dia
= mm
Use stirrups as R-06 @ 175
25.53
6.00
24.00
50
39.95
32.32
74.85
242.87
242.87
770.1
805
350
16
282
0.108
350
2.00
3.00
0.1*W*v
15
5.55
Column is subjected to very low axial load. Therefore it can be
designed as a cantilever beam.
10
Assume that the pipe line it straight and no bends. Force due to
water pressure due to 30rotation at top
22.21
4.0
192
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OutputCalculationsReference
Check for minimum area of r/f
sc c =
sc = mm2
Satisfactory
2.3 Design of the base
Total axial load during construction (Ser) = kNTotal moment during construction (Ser) = kNm
Total axial load during functioning (Ser) = kN
Total moment during functioning (Ser) = kNm
Max axial force at the base (Service) = kN
Max moment at the base (Service) = kN
Assumed bearing capacity = kN/m2
Assumed "B" = m
Assumed"L" m
assumed "h" = m
Pressure under the base (SLS) = kN/m2
Pressure under the base (ULS) = kN/m2
Hence ok.
Design for moment
Maximum moment at base = kNm
Assume r/f bar diameter = mm
dmin = mm
dmax = mm
davg = mm
k =
Z = mm
Zcorrected = mm
As required = mm2
Provide T 10 - As = mm2/m
Design for Shear
Shear force at a distance d = kNShear stress = N/mm
ear capac ty vc = N/mm2
Vertical line shear is not critical
Consider the shear perimeter at 1.5d
Shear stress = N/mm
Punching shear is not critical
100.00
190
518
0.027
116.56
36.42
185
195
179.4
1.600
83.26
0.250
46.86
37.41
1.600
Cl.3.11 BS8110 P-1
0.50
10
175.8
150 524
46.86
33.1725.05
37.41
0.29
Table 3-27
BS 8110 P-1
0.4
490.0
82.060.28
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OutputCalculationsReference
Design of the Column Support (At the End)
Height of the support = m
Pipe diameter = m
Length of a pipe = m
Self wt of pipe (One pipe length) = kN
Column size = m
Clear height = m
End condition at top =
End condition at bottom =
=
Effective height (Lexor Ley) =
Lex/h or Ley/b =
> 15
The column is slender
Minimum eccentricity = mm
2.1 Load Calculation
Wt of water inside = kN
Self wt of the column = kN
Additional imposed load (0.5kN/m) = kN
Impact force at top = kN
Moment at the base due to impact force = kNm
Moment due to eccentricity = kNm
Water pressure inside the pipe = bars
The pipe line has a 450downward bend
Force due to the bend (perpendicular ) = kN
= 2*P*A*Sin(/2)
Horizontal component of the force = kN
Moment at base = kNm
Assume a log impact during flood
Weight of log = TonsVelocity of flood (assumed) = m/s
Force at top of column due to log impact =
= kN
Moment acting on the column base = kNm
Total axial load during construction (Ult) = kNm
(Self wt of pipe+column+Imposed load)
Cl.3.8 BS
8110 P-1 0.30
6.00
4.00
4.00
3.05
0.35
3.00
0.1*W*v
6.00
2.00
24.00
25.53
6.10
Assume an impact load due to pipe hitting at
top at 2.0m/s during handling
11.76
3.00
229.62
15
81.18
24.38
0.65
57.41
4.24
1
8.80
25.14
20
2.2
4
3.0
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OutputCalculationsReference
Total moment during construction (Ult) = kNm
(Due to eccentricity+Impact force)
Total axial load during functioning (Ult) = kNm
(Self wt of pipe+column+Imposed load+water load)
Total moment during functioning (Ult) = kNm
(Due to eccentricity+pipe pressure)
2.2 Design of the column
Cover = mm
b = mm
h = mm
Vertical r/f bar diameter = mm
Stirrups = mm
d = mm
k =Z = mm
Zcorrect = mm
As = mm
Provide 4 T 25 + As = mm2
(Per face)
Design of Stirrups
Stirrups size = 6mm or
(1/4)*vertical bar dia
= mmSpacing = 12xBar dia
= mm
Use stirrups as T10 @300
Check for minimum area of r/f
sc c =
sc = mm2
Satisfactory
2.3 Design of the base
Total axial load during construction (Ser) = kN
Total moment during construction (Ser) = kNm
Total axial load during functioning (Ser) = kN
Total moment during functioning (Ser) = kNm
Max axial force at the base (Service) = kN
Max moment at the base (Service) = kN
Assumed bearing capacity = kN/m2
Assumed "B" = m
Assumed "H" = m2.650
254.27
100.00
2.650
1964
10.0
300
76.80
81.04
81.04
25.03
254.27
Cl.3.11 BS
8110 P-1
1440.0Table 3-27
BS 8110 P-1
0.4
600
32.32
Column is subjected to very low axial load. Therefore it can be
designed as a cantilever beam.
483.93
483.93
1901.7
25
10
527.5
0.068
368.30
600
50
39.92
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OutputCalculationsReference
assumed "h" = mm
Pressure under the base (SLS) = kN/m2
Pressure under the base (ULS) = kN/m2
Hence ok.
Design for moment
Maximum moment at base = kNm
Assume r/f bar diameter = mm
dmin = mm
dmax = mm
davg = mm
k =
Z = mm
Zcorrected = mm
As required = mm2
Provide T 16 - As = mm2/m
Design for Shear
Shear force at a distance d = kN
Shear stress = N/mm
ear capac ty vc =
Vertical line shear is not critical
Consider the shear perimeter at 1.5d
Shear stress = N/mm2
Punching shear is not critical
182.26
93.52
130.93
110 1829
259.87
0.350
0.36
0.036
264.4
262.2
1737
16
276
292
284
N/mm20.60
0.39
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OutputCalculationsReference
Check the Column head
Total axial load (Ult) = kN
(Pipe wt+Water wt+Imposed Load)
Plan area = mm2
Stress on the column head = N/mm2
Stress that can be resisted by concrete = N/mm
Hence Satisfactory
0.137
10
4.0
10.29
75250
215
350
150 150
200
100