Descripción: Project on the design of a concrete box culvert, contains introduction, methodology and lit review
Project on the design of a concrete box culvert, contains introduction, methodology and lit reviewDescription complète
Project on the design of a concrete box culvert, contains introduction, methodology and lit review
DESIGN OF PIPE CULVERT 1.0
2.0
DATA Discharge through pipe culvert
Q
=
1.57 cum/sec
Velocity of flow through pipe
V
=
2.00 m/sec
Width of road
B
=
7.50 m
Bed level of flow
H1
=
100 m
Top level of embankment
H2
=
103 m
Wheel load
W
=
62.50 kN
Impact factor
I
=
Q
= AxV
1.50
DIAMETER OF PIPE Discharge
= ∏/4 x d2 x V d
=
1.00 m
Adopt RCC NP3 heavy duty non pressure pipe for carrying heavy road to traffic. Ref. IS: 458-1971, For pipe of Internal Diameter = 1.00 m Outer Diameter = 1.20 m
3.0
LOAD BY EARTH FILL Total height
=
3m
Considering height of culvert
=
1m
Height of embankment over pipe
=
2m
=
59.50 kN/m
W
=
62.50 kN
Cs
=
0.032
From Table 1 Load by earth fill
4.0
LOAD BY VEHICLE WHEEL Load by vehicle wheel From Table 2
Load on pipe
= 4 x Cs x I x W =
5.0
CHECK FOR STRENGTH FACTOR
12.00 kN/m
The type of non pressure pipe and bedding should be so chosen that under Maximum combination of field loading a factor of safety = (3-Edge Bearing Strength in kN/m / Factor of safety) = (Load on pipe by earthfill in kN/m / Corresponding strength factor) + (Load on pipe by wheel Load in kN/m / Strength factor) Ref. IS:458-1971 code Three edge beam strength of NP-3 class 1000 mm diameter of pipe is
111
59.50
=
1.50 Strength Factor (S.F)
+
S.F =
0.902
For First class prepared ground bedding, S.F = 2.3 For concrete cradle bedding, S.F = 3.7 So, Providing any of these two the S.F is more than its required value of S.F.
6.0
REINFORCEMENT IN PIPE Ref. IS:458-1971, Spiral reinforcement of hard drawn steel wire with permissible stress of 140 N/sq.mm is 44 kg/m Longitudinal reinforcemet of mild steel with a permissible stress of 126.5 N/sq.mm is 5.8 kg/m Using 12 mm dia bars @ 60 mm centre as Spiral reinforcement average diameter of spiral
=
1.1 m
Weight of one spiral of 12 mm dia
=
3.072 kg
No. of Spirals in 1 m
=
16.67
Weight of Spiral reinforcement per meter length of pipe =
51.20 kg/m
So, Spiral steel provided 51.20 kg/m is more that minimum reinforcement of 44 kg/m as specified in IS:485-1971.
7.0
LONGITUDINAL REINFORCEMENT Providing 6 mm dia mild steel bars as Longitudinal Reinforcement. Weight of each bar
=
No. of bars required
=
0.22 kg/m 26.10
Spacing
=
Adopt 130 mm spacing for the longitudinal reinforcements.
132.40 mm
1.50
111 kN/m 12.00 1.50
Table 1 : Load on Pipe due to Earthfill Pipe Size (d) Outer Dia (D) in mm in mm
Embankment loading on pipe in kN/m for various de 1
2
3
4
5
500
650
16.8
34.9
54.0
65.3
99.0
600
760
18.7
42.6
62.4
75.5
103.0
700
860
20.0
48.0
68.0
86.5
118.5
800
980
24.2
55.3
79.5
107.0
136.5
900
1100
28.3
58.7
91.5
122.0
150.0
1000
1200
28.6
59.5
101.0
132.0
163.0
1200
1430
33.4
74.0
115.0
159.0
200.0
due to Earthfill pipe in kN/m for various depths H in metres 6
7
8
9
10
118.5
150.0
171.0
191.0
212.0
133.0
160.5
186.0
197.0
230.0
154.5
174.0
209.0
228.0
246.0
163.0
202.0
230.0
260.0
288.0
185.0
209.0
257.0
297.0
338.0
202.0
228.0
259.0
324.0
357.0
226.0
274.0
315.0
352.0
427.5
Table 2 : Influence Coeffcients 'Cs' for Concentrated Surface Pipe Size (d) Outer Dia (D) in mm in mm
Embankment loading on pipe in kN/m for various de 0.1
0.2
0.3
0.4
0.5
500
650
0.246
0.228
0.198
0.169
0.117
600
760
0.247
0.234
0.210
0.182
0.131
700
860
0.247
0.236
0.215
0.186
0.140
800
980
0.249
0.240
0.220
0.196
0.149
900
1100
0.249
0.241
0.225
0.202
0.156
1000
1200
0.249
0.242
0.228
0.205
0.162
1200
1430
0.249
0.242
0.230
0.209
0.171
r Concentrated Surface Loads pipe in kN/m for various depths H in metres 0.6
