https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
Analysis and Design of Intze Water Tank by Using STAAD Pro
Chandana Imadabathuni1, Padala Sri Vardhan Goud2, Nalla Ravi Kiran3, Bathula Naveen4
1Assistant
Professor, Dept. of civil Engineering, Gokaraju Rangaraju Institute of Engineering and Technology, Telangana.
civil Engineering Department, GRIET, Hyderabad, Telangana, India.
3 Student civil Engineering Department, GRIET, Hyderabad, Telangana, India.
4Student civil Engineering Department, GRIET, Hyderabad, Telangana, India.
2 Student
Abstract. Water tank is a water storage structured built for long term use. These tanks were utilized
for various uses like distribution of water, firefighting, agriculture, food industry, paper mills etc.
It comes in handy when there is an intermittent supply of water or scarcity of water. Materials like
concrete, pvc Galvanized Iron, fibre is used to manufacture tanks. Water is pumped through pipe
by using pumps from a source. For distribution purpose water can be distributed either gravity or
pump to reach individual with desired pressure and velocity. Volume is calculated based upon
population and their usage and demand. Water demand varies hour to hour. For a continues supply
water tanks are best suited. To meet water demand by public water tanks are to be constructed.
Design and analysis are similar for any liquid present in water tank but is should be crack free to
avoid leakage
1 Introduction
Overhead tanks and reservoirs are liquid storage
containers. These containers are generally used for
storing water for irrigation works, human consumption,
fire, manufacturing units, rainwater harvesting, and for
many purposes. The main purpose of design of tanks are
economical, strength, service life, to provide safe
portable drinking water after storing for a long time and
it also resist special conditions like wind and
earthquakes. Water tanks are generally constructed with
reinforced concrete or steel and design is based on IS
code. Design of tanks depends on the position of tank
i.e, above or below, at the ground level. The overhead
tanks are generally constructed at certain height from the
ground level using columns and braces, for direct
distribution of water by gravity. In any case, the
underground tanks are rest underneath the ground level.
2 Effect of Wind
The wind pressure acting on a Design structure are
processed by method suggested as per the IS code.
Design wind speed (𝑉 ) at any elevation can be
determined as follows:
𝑉
𝑉 𝑥 𝑘 𝑥𝑘 𝑥𝑘
Where, 𝑉 = Design wind velocity for elevation ‘z’ in
m/sec
𝑉 = Basic wind speed based on locations.
𝑘 = Risk coefficient or Probability factor
𝑘 = elevation & construction, Terrain size factor and
𝑘 = Topography factor
𝑘 , 𝑘 and 𝑘 are determined through IS 875 (Part-3)
2015. The design wind pressure for elevation above
mean ground level will be acquired by the
accompanying connection between wind pressing factor
& wind speed
𝑃
0.6 𝑉
Where, 𝑃 is Design Wind pressure (N/m²) at elevation
z,
𝑉 is Design wind speed (m/s) elevation z
3 Intze tank
A German hydraulic engineer is given the name tank as
Intze. The water tower built in accordance with the Intze
precept has a brick shaft on which the water tank sits.
the bottom of the tank is fixed with a hoop anchor (Ring
Anker) manufactured from iron or metal, so that
© The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0
(http://creativecommons.org/licenses/by/4.0/).
https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
handiest vertical, no longer horizontal, forces are
transmitted to the tower. In this project Intze tank is
designed with working stress method and elements of
Intze tank is designed with limit state method.
Tension in bending =2.0 N/𝑚𝑚
Modular ratio =
=9.33
For Rebar stress,
Components of Intze tank:
Indirect tension (Tensile stress) =115 N/𝑚𝑚
Top dome: In general, we provide 100 mm to 150 mm
thick dome at top with reinforcement along the latitudes
and longitudes. Usually, the rise of the dome is l/5th of
the length.
Tensile stress (bending) for liquid face = 115 N/m𝑚 for
t less than 225 mm
Volume = 0.585 𝐷 for (as per) figure
Top ring beam: The top ring beam is subjected to
meridional thrust. The beam is design for hoop tension
which caused due to water load.
D = 8.0 m
Design of Top Dome:
Cylindrical walls: The wall is mainly subjected to hoop
tension which is caused by the water pressure. So, the wall
is designed for hoop tension.
Assuming the rise = 1.5 m
Therefore radius is given by
Bottom ring beam: This ring beam provided between
the cylindrical wall and conical slab. The ring beam is
provided to resist the horizontal component of the reaction
of the conical wall on the cylindrical wall. The bottom
ring beam is designed for the induced hoop tension.
1.5 (2*R -1.50) =
R = 6.08 m
Conical slab: The slab is subjected to both meridional
thrust and hoop tension. The hoop tension is due to fluid
pressure and meridional is due to vertical pressure. So,
the slab should be designed safely.
Bottom dome: The bottom slab may be circular or
domed. This slab is supported on the circular girder
Circular girder: The girder should be designed for the
loads which are coming from the conical slab (inclined
thrust) and from the bottom dome (outward thrust). It
will be placed on the columns and should be designed
for resulting bending moment and torsion.
Fig 2. TOP DOME
Sin∅ =
Cos∅ = 0.7531 and
Columns: The columns are designed for the total
transmitted from the tank. Columns are also designed
for wind and earthquake loads. In columns, bracings
are provided at intervals to resist the wind and
earthquake effects.
∅ =41.14° < 51.8° (Therefore no tension).
Self-weight = 2.4kN/𝑚𝑚
Live load = 1.5 kN/𝑚𝑚
Foundations: In general, to support the all columns
combined footing is adopted. To support a circular
girder and circular slab are design.
Finishes = 0.10 kN/𝑚𝑚
Total load = 5.2 kN/𝑚𝑚
METHODOLOGY
f=
Manual design
0.75
.
hoop stress at crown, ∅
Wind pressure as IS 875- 1200 N/𝑚
f = 4950 ∗
concrete,
.
.
0°
1
f = 0.15 N/𝑚𝑚
For which
10𝑁/𝑚𝑚 , 𝜎
.
∅
f = 0.0564 N/𝑚𝑚
SBC of soil 200 kN/𝑚
𝜎
𝑐𝑜𝑠∅
= 5200 ∗
Capacity of Intze water tank = 0.3 ML
Assuming 𝑀
= 0.6579
.
T=
8𝑁/𝑚𝑚
2
∅
= 4950 ∗
.
.
= 17197.71 N/𝑚𝑚
https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
Compressive stress =
.
compressive stress check (at the bottom of the
cylindrical wall)
= 0.172 N/𝑚𝑚
∗
Top Ring Beam :
11314.37 N/𝑚𝑚
= 12951.59 N/𝑚
Weight of the wall = 0.23 𝑥 5 𝑥25000 = 28750 N/m
Hoop stress in the ring beam = 12951.59 x 8/2
= 51806.38 N
Area of steel required =51806.38/115 = 450.49𝑚𝑚
Provide 4 bars of 12mm diameter
Ring beam
1150𝑁/𝑚
self-weight
Total load 𝑉
41214.37
=
Let cross sectional area = A 𝑚𝑚
9.33
.
𝑥230 𝑥 1000
8.33 ∗ 452.39
Bottom Ring Beam
Let 𝑇
Thrust / meter exerted by the conical wall at
the junction bottom at B
Use a ring beam of size 230mm x 200mm
Area provided = 46000 𝑚𝑚 > 43565.63 𝑚𝑚
𝑇 𝑠𝑖𝑛 ∝
Use 6 mm nominal stirrups at 100 mm c/c
𝑡𝑎𝑛 ∝
Shear stress along edge = T sin∅ = 17197.71 x 0.6579 =
11314.37 N
∝
𝑉
1
45°
.
𝑇
Shear stress = 11314.37/100*1000 = 0.113 N/𝑚𝑚
58285.92N/𝑚𝑚
Resolving horizontally at B
Design of cylindrical wall
𝐻
Pressure intensity = 5 x 9810 = 49050 N/𝑚𝑚 (at the
bottom of cylindrical wall)
𝑇 cos 𝛼
58285.92
The lateral load (𝐻
- beam B
= 947.83 𝑚𝑚
will create hoop tension in the ring
Hoop tension through 𝐻 = 𝐻
Provide 10 nos of 12 mm dia bars
= 41214.37
Area provided = 1130.97 𝑚𝑚
Spacing of 12mm dia bar = 1000 𝑥 𝜋
=164857.48 N
.
Assume the depth of ring beam be 500 mm deep
= 200mm
Pressure due to water at ring beam = 9810 5
Hence provide 12mm at 200 mm c/c spacing at both
directions
=24525 N/m
Assume thickness of wall = 230 mm
.
230 𝑥 1000
cos 45°
=41214.37 N/m
Hoop tension = 49050 x 8/2 = 196200 N
Distribution steel =
552𝑚𝑚
Provide 12 bars of 8 mm diameter of spacing 100 mm
c/c
1 𝐴
Concrete Cross sectional area,51806.38/2 =43171.98
𝑚𝑚
.
0.18N/𝑚𝑚
Nominal vertical stress is equal to 0.24% gross area
Dimensions of the ring beam:
𝐴
0.23 𝑥 0.2 𝑥 25000
=
.
Compressive stress =
𝐴 provided = 452.39 𝑚𝑚
=𝐴
𝑇 𝑠𝑖𝑛∅ = 17197.71 x
=
= 17197.71*0.7531
Equivalent concrete area = 𝐴
𝑉
Vertical component of 𝑇
sin41.14
Horizontal component of T = cos∅
Hoop tension due to water = 24525
= 552 𝑚𝑚
= 98100 N
Total hoop tension = 98100 +164875.48 =262957.48 N
Provide 10mm dia rebars of spacing 100mm b/w the
Steel for hoop tension =
3
.
.
1270.32 𝑚𝑚
https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
Provide 6 bars of 18 mm ∅
1526.81 𝑚𝑚
𝐴
9.33
=𝐴
1 𝐴
=𝐴
8.33 ∗
Effective depth = 200 – 25 – 8 = 167 mm
12718.33
262957.48
12718.33
Provide 250 𝑚𝑚
Distance between center of section (x) = 𝑑
100 = 67 mm
2
21611760.64
167 230 0.9
𝐴
Conical Slab
𝑊
2𝜋
𝑇 𝑥 = 17706.6040
625.177 𝑚𝑚
Provide 4 no’s bars, 16 mm diameter
𝑊
𝑡𝑎𝑛𝛼
2𝜋
Design of bottom dome
Where,
𝑊
weight of water resting on conical slab
R is the radius of dome, rise = 1.2 m
𝑊
weight of the conical slab
Then, 2.5
𝛼
slop of conical slab
.
𝑋
.
Sin 𝜃
𝜃
Self -weight of water
𝑊
9810
1.2
Let 2𝜃 be the angle subtended by the dome
0.72 𝑚
.
1.2 2 𝑅
R = 3.20 m
8.625 𝑚
.
8.625
2𝜋 2.5
0.72
.
0.78 ,
51.37°
Cos𝜃
2.121 𝑚
.
51.8°
0.624
Length of the conical slab = 2121 mm
Thickness of dome = 0.2 m
Thickness of the slab as 200 mm
Loads:
Self- weight 𝑊 = 0.2
216557.83 𝑁
2.121
2500
.
Hoop
tension
579362.697 𝑁
Dead load = 25000 x 0.2 = 5000 𝑁/𝑚𝑚
.
2𝜋
.
Weight of water resting on the dome = 𝑟 𝜋𝑟
3𝑅 ℎ
.
9810 𝜋
.
Hoop steel on the entire section
2798.85 𝑚𝑚
Area of dome surface
2814.86 𝑚𝑚
.
Maximum bending
17706.604 𝑁𝑚
1.2
3 3.2
3
1127757.6 𝑁
2𝜋𝑅ℎ
2
𝜋
1.2
1.2
3.2
Load intensity due to weight of water =
46736.74 𝑁/𝑚𝑚
Load/meter width of conical slab
.
𝜋
= 24.13 𝑚
Design for Flexure
.
2.5
=
.
Provide 14 bars of 16 mm diameter
𝐴
= 167 -
= 21611760.64 N-m
500 𝑚𝑚 𝑠𝑖𝑧𝑒
𝑊
𝑀
Resultant bending moment
58285.92 67
10
118760.41
𝐴
5285.92 𝑁
Provide 16 mm rebar, at the clear cover =25 mm
Limiting tensile stress for net concrete area = 2 N/𝑚𝑚
𝐴
41214.37
sin 45°
𝑇
Net concrete area = 𝐴
1526.81
𝑇 sin 𝛼
Axial compression 𝑉
= 94435.22 N
moment
Meridional thrust
.
.
46736.74
= 92092.098 N/m
4
.
.
.
.
https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
.
Meridional compressive stress =
Hoop stress at the crown 𝜃
Hoop
.
.
0.624
.
Load at each support
0°
𝑐𝑜𝑠𝜃
stress
= 274089.11 N
0.46
= 548178.22 N
46736.74
Design of support section:
.
Moment of resistance= bending moment at support
= 0.006
0.913𝑏𝑑
Max.
hoop
46736.74
.
.
𝑐𝑜𝑠𝜃
stress
90997.585
𝑑
1
499.17 𝑚𝑚
Clear cover = 40 mm, adopt D = 550 mm, d = 510 mm.
= 0.374 𝑁/𝑚𝑚
Equivalent shear force = 𝑉
Provide nominal 0.3 % of steel
𝑉
Design circular girder:
Total water weight 𝑤
dome water weight
300401.66 𝑁
Maximum shear stress 𝜏 max
𝜏 max
𝜏
= 1035830.096 N
Weight of ring beam at B 𝑊
2𝜋 4 = 78539.82 N
0.25
0.5
𝜏
Longitudinal reinforcement:
25000
𝑀
216557.83 𝑁
𝑇 1
𝑀
5000 24.13
0.4
0.6
25000
1.7
𝐷
𝑏
(Assume size of girder 100 x 600) = 94247.78 N
6578.139
1000 1
1.7
9190047.132 𝑁𝑚𝑚.
90997.585
𝐴
Let us provide 8 columns
Maximum bending moment at supports = 0.0083Wr
230
550
400
1000
9190047.132
𝑀
0.9
100187632.1
𝑑 230 0.9 510
949.02 𝑚𝑚
Transverse reinforcement:
2.5
𝐴
= 90997.585 Nm
Maximum bending moment at center = 0.00416Wr
4385425.806
𝑀
= 100187632.1 Nm
Total load (W) = 4385425.806 N
= 0.0006
𝑀
M = moment at cross section
2𝜋
𝑀
43854525.806
𝜏
2.2 𝑁/𝑚𝑚
=120650 N
Weight of circular girder
2.5
.
= 1.47
Weight of the dome + cylindrical wall + ring beam at A
𝑊
41214.37 2𝜋 4
Weight of lower dome 𝑊
.
Equivalent nominal shear stress 𝜏
conical slab water weight +
= 1711842.68 + 1127757.6 =2839600.28 N
Weight of conical wall 𝑊
.
.
= 274089.11
Provide 8 mm diameter bars at 100mm c/c spacing
= 0.0083
1000
2.5
= 6578.139 Nm
550
80
𝐴
𝑠
𝑇𝑠
𝑏𝑑 𝜎
𝑏
400
470𝑚𝑚
320
𝑉𝑠
2.5𝑑 𝜎
80
6578139
470 230
320 𝑚𝑚, 𝑑
274089.11
2.5 470 230
Providing 4-legged 10 mm stirrups, 𝐴
Shear force at supports =
Therefore 𝑠
.
5
315 𝑚𝑚
261.55 𝑚𝑚 , 𝑡𝑎𝑘𝑒 𝑠 𝑎𝑠 250𝑚𝑚
https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
𝐴
𝜏
𝜏 𝑠 .
𝑏
𝜎
1.37 0.2
400
𝑠
400
Weight
of
water
tank
354950.035 𝑁 𝑜𝑛 𝑒𝑎𝑐ℎ 𝑐𝑜𝑙𝑢𝑚𝑛
𝑠
154.81 𝑚𝑚
.
=
In case of empty tank
Provide 150 mm spacing c/c.
Load on column = 573545.95 – 354950.035
Steel due to sagging moment = 45608.428
432.02𝑚𝑚
= 218595.915 N
Provide 4 bars of 12mm diameter
Corresponding axial load =
.
𝐴
452.39 𝑚𝑚
Let 𝐴
.
219694.387 𝑁
.
= steel requirement without wind effect
Hoop stress:
Then
𝑐𝐴
𝑡𝐴
573545.95 𝑁
𝑇
5
190
𝐴
573545.95
thrust on girder acted by conical slab
𝑇 𝑠𝑖𝑛𝛼 2𝜋𝑟
𝑊
𝑊
𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑐𝑦𝑙𝑖𝑛𝑑𝑟𝑖𝑐𝑎𝑙 𝑤𝑎𝑙𝑙 𝑎𝑛𝑑 𝑢𝑝𝑝𝑒𝑟 𝑑𝑜𝑚𝑒
𝑇 𝑠𝑖𝑛𝛼
2𝜋𝑟
𝐴
.
17111842.68 216557.83
1035830.096
Horizontal component of 𝑇
𝐻
𝐻
40861.8 𝑁 acting at 14.37 m from the base
Wind thrust on circular wall
0.7
Hoop stress = 131216.72 x 2.5 = 328041.81 N
.
1884.95 𝑚𝑚
Wind thrust on top dome & cylindrical walls
.
5
8.46 1200 0.7
92092.098
131216.72 𝑁
Hoop compressive stress =
720 𝑚𝑚
Take reduction factor as 0.7
= 57492.06 N
𝐻
300
Analysis for wind pressure:
266874.52 cos45
Horizontal component due to dome 𝐻
𝑐𝑜𝑠51.37°
300
Provide 6 bars of 20 mm diameter 𝐴
= 188708.78 N
.
.
1.5
0.6
Wind thrust on the circular girder
1200 0.7
Wind thrust on columns & bracings
1200 0.7
3
0.3 1200
Let 𝛼 = Angle made by column with vertical axis
1
,α
10
5°42°, sinα
0.0995, cosα
0.995
Actual length of column = √10
1
.
0. 10
Total moments due to wind pressure at the base =
40861.8 14.37
8731.8 10.75
2721.6
10
20160 5
809066.92 𝑁𝑚
√101
10.05 𝑚
Vertical load on column by wind load
22500 𝑁
∈𝑥
Total load = 548178.22+22500 = 570678.22 N
.
5
= 20160 N acting at 5 m from the base
10
Providing 300mm x 300mm column size
Self - weight = 10 ∗ 0.3 ∗ 0.3 ∗ 25000
5.4
2721.6 𝑁 acting at 10 m from the base
.
Actual load on each column at top =
548178.22 𝑁
1200
8731.8 𝑁 acting at 10.75 from the base
= 1.5 𝑁/𝑚𝑚
Columns:
Axial load =
667.82 𝑚𝑚
Min requirement of steel = 0.8% Gross area
𝑇
266874.52 𝑁
tanα
𝐴
2
4
4
4
√2
∈
64 𝑚
Max. wind thrust in most leeward side & the most
windward side
573545.95 𝑁
809066.92
Tank full condition = 573545.95 N
6
√
https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
= 35756.04 N
2
8179.63
Consider windward column 1
Provide 300 x 300 mm beam
Dead load + wind load = 570678.22+50566.682
Area of steel =
= 621244.902 N
23135.49 𝑁𝑚
√2
508.02𝑚𝑚
.
Use 4 rebars of 18mm diameter
.
Corresponding axial load =
624366.74 𝑁
.
S.F. for brace =
Horizontal component of the axial force due to wind
action = 2 50566.682 0.0995 4 35756.04
0.0995
20125.54 𝑁
√
Actual horizontal force at base = 40861.8
2721.6 20160 20125.54
Horizontal shear column =
𝑠𝑖𝑛22°30°
.
Shear force for brace =
8731.8
.
2.678 𝑚
17278.18 𝑁
.
.
Nominal shear stress 𝜏
52349.66 𝑁
.
.
Span of brace = 2
0.22
Provide nominal stirrups, 2 legged - 10 mm diameter
stirrups 200mm spacing c/c
6543.71 𝑁
FOUNDATION Design
Maximum bending moment for the column =
.
8179.63 𝑁𝑚
6543.71
Axial load
4588367.6 𝑁
Column section:
on
573545.95
column
8
Axial load = 624366.74 N
Self- weight of footing (10% of column load) =
458836.76 N
B.M. = 8179.63 Nm
Total load = 5047204.36 N
Provide 300 x 300 mm size
SBC = 200 k𝑁/𝑚𝑚 .
Use 6 rebars, 20 mm  at effective cover of 50 mm
Area
𝐴
1884.95 𝑚𝑚
Net concrete area = 𝐴
𝑚
.
Provide outer diameter of 9.0 m & inner diameter of 6.0
m
1 𝐴
9.0
= (300 x 300) +(8.33 x 1885) = 105702.05 N
For net concrete section the polar moment of inertia
𝑚𝐴
8.33 1885
10 𝑚𝑚
150
416.01
Direct
𝑑𝑖𝑟𝑒𝑐𝑡
stress
50
Bending stress in concrete =
2.95 𝑁/𝑚𝑚
83985.48 𝑁-m
concrete
=
.
5.91 𝑁/
.
< 200 86 k𝑁/
Maximum negative B.M. occurs at supports
Maximum
5047204.36
.
𝑚𝑚
142.82 86 k𝑁/𝑚𝑚
Design at Circular Girder
10 𝑚𝑚
in
.
35.34 𝑚
6.0
142.82 8686 k𝑁/𝑚𝑚
𝑚𝑚 , hence ok.
Equivalent moment of inertia about full section =
832
.
Net intensity
𝑒𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝑑𝑒𝑝𝑡ℎ 𝑓𝑟𝑜𝑚 𝑐𝑒𝑛𝑡𝑟𝑒
832.02
25.24 𝑚
0.00416
0.0006
𝑊
𝑟
Maximum stress = 5.91+2.95 = 8.86 𝑁/𝑚𝑚
Maximum shear force at support
315450.27 N
Design of braces:
Design at Support Section:
Moment in braces = 2
𝑠𝑒𝑐45°
𝑚𝑜𝑚𝑒𝑛𝑡 𝑓𝑜𝑟 𝑡ℎ𝑒 𝑐𝑜𝑙𝑢𝑚𝑛
4
0.0083
positive
bending
4 83985.480 N-m
Maximum torsion
m
150
5047204.36
12113.29 N.
Moment of resistant
maximum bending moment at
support assume b = 500 mm
7
https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
0.913 𝑏𝑑
167567.18
1000
STAAD Pro design
605.86 𝑚𝑚, adopt 610 mm
d
Procedure
Equivalent shea stress,
𝑉
𝑉
1.6
𝑉
1.
Open STAAD.pro.
Click on new project > add file name>Select
‘space’.
Length (in m), Force (in KN).
Select add beam option and click on finish.
2. Geometry>Run structure wizard > select
surface/plate model > cylindrical surface. Close it to
transfer to modelling
Length :12
Division along length: 1
Start radius: 3.5
Division along periphery: 8(column)
End radius: 2.5
3. Using Add beam selecting top node and bottom
node. Repeat along periphery for required number
of columns.
4. Copy all vertical members using ctrl + C and paste
aside using ctrl + V.
5. Add intermediate nodes along length to add
required number of beams in horizontal direction.
Connect all node in a plane to form a circular beam.
6. Repeat the same process at top to get circular girder.
7. Geometry>Run structure wizard> select surface/plate
model >Spherical cube
Select spherical cap (Bottom dome). Close it to
transfer to modelling
Diameter of sphere:
Base Diameter:
8. Shift the obtained Spherical cap to top beam
Measure distance using ‘display node to node
distance’ tool
Select all plates > Right click mouse>Move >
add (-) sign to above distance to rest on top beam.
1. Geometry>Run structure wizard > select
surface/plate model > cylindrical surface
Length: 2.12
Division along length: 1
Start radius: 35
Division along periphery: 8(column)
End radius: 2.5
2.
Shift the obtained Conical dome to top beam
Measure distance using ‘display node to node
distance’ tool
Select all plates > Right click mouse>Move > add
(-) sign to above distance to rest on top beam.
3. Geometry>Run structure wizard > select
surface/plate model >
cylindrical surface
Length: 2.12
Division along length: 1
Start radius: 35
Division along periphery: 8(column)
End radius: 2.5
4. Shift the obtained cylindrical surface to top beam
Measure distance using ‘display node to node
distance’ tool
Select all plates > Right click mouse>Move > add
(-) sign to above distance to rest on top beam.
.
354212.8 N
.
𝜏
2.2 𝑁/𝑚𝑚
𝜏
.
315450.27
Hence, 𝜏
1.16 𝑁/𝑚𝑚
but
𝜏 .
Longitudinal reinforcement:
𝑀
𝑀
𝑀 ,
.
𝑀
m
.
16531078.12 N-
.
𝑀
(167567.18 1000
𝑀
184098.26
16531078.12)
10 N
184098.26 10
230 0.9 610
𝐴
1457.97 𝑚𝑚
Provide 9 bars of 16 mm diameter bars
Hence 𝐴
1810 𝑚𝑚 .
Transverse reinforcement
.
𝐴
.
.
𝐴
4
420 𝑚𝑚,
𝑑
660
314.16
10
314.16 𝑚𝑚 , 𝑏
120
540 𝑚𝑚
.
.
.
𝑆
500
80
𝑆
251.7 𝑚𝑚
Let us provide 200 mm clear cover spacing
Steel for hogging moment 𝐴
665.13 𝑚𝑚
Provide 4 bars of 16 mm diameter
Fig 3. INTZE WATER TANK MODEL
8
https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
5.
6.
7.
Geometry>Run
structure
wizard>
select
surface/plate model >Spherical cube
Select spherical cap (Top dome). Close it to transfer
to modelling
Diameter of sphere:
Base Diameter:
Shift the obtained Conical dome to top beam
Measure distance using ‘display node to node
distance’ tool
Select all plates > Right click mouse>Move > add
(-) sign to above distance to rest on top beam.
Finally Check dimensions of tank using ‘display
node to node distance’ tool to verify. Any
corrections to be made are rectified.
GENERAL PROPERTIES
8.
9.
Click ‘property’ at left of screen> Define required
dimensions for respective elements. Assign the
property for various elements using any of the
options present according to your convenient.
Click ‘Support’ > Create >Select ‘fixed’ >click
Add> assign at bottom part of beam.
Click ‘Load and Definition’
To apply wind load first we have to define it in first
section. Enter your values. Keep exposure as –1.
Click ‘Load case details’ to add DL, LL & WL.
Add self-weight as DL
Add Water load as LL
Add Wind Load
Select material as concrete and assign for entire
tank
Analysis
10. Click ‘Analysis and print’> Run analysis >Check
for Zero errors>Post processing
Apply given loads to see deflected shape of
structure, beam moments and forces.
Design
11. Click on ‘Design’ >Select parameters to include in
our design.
Define parameters with respective values
Select the required command to instruct software
to design according to IS code.
Detailing of reinforcement and quantity of
concrete is present in output file.
Design in STAAD Pro
Step 1: Geometry of Structure
9
https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
Step 2: Material and Property
Step 4: Assign Support
Step 3: Loads and Definitions
Step 5: Run Analysis
10
https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
Bending moments of beam
Step 6: Go to Post processing
Stresses in Beam
Max absolute and max Principal stress
Step 8: Design
Step 7: Analysis Drawings
11
https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
Reinforcement Details
RESULTS
Ring Beam
Manual design of Intze tank as per IS: 3370
Top dome:
Thickness of the dome = 100mm
Force = 5.2k𝑁/𝑚𝑚
Hoop stress = 0.15 𝑁/𝑚𝑚
Meridional stress = 0.17 𝑁/𝑚𝑚
Area of steel = 300 𝑚𝑚
Top ring beam:
Size = 230 x 200 mm
Meridional thrust = 12.95 kN
Hoop tension = 51.81kN
Shear stress = 0.113 𝑁/𝑚𝑚
Area of steel = 452.39 𝑚𝑚
Cylindrical wall:
Height = 4m
Thickness of wall = 230mm
Hoop tension = 196.2kN
Tensile stress = 0.18 𝑁/𝑚𝑚
Area of steel = 1130.97 𝑚𝑚
Columns:
Ring beam at bottom:
Size = 250 x 500mm
Hoop tension = 262.95kN
Area of steel = 1526.81 𝑚𝑚
Conical slab:
Thickness of the slab = 200mm
Hoop tension = 579.36kN
Area of steel = 2814.86 𝑚𝑚
Bottom dome:
Thickness of the dome = 200mm
Meridional thrust = 92.09kN
Hoop tension = 230kN
Tensile stress = 0.374 𝑁/𝑚𝑚
Area of steel = 600 𝑚𝑚
Circular girder:
Size = 400 x 600mm
Load = 4385.4kN
Hoop stress = 1.5 𝑁/𝑚𝑚
Hoop compression = 328kN
12
https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
Area of steel = 949.02 𝑚𝑚
Design and analysis in staad pro
13
https://doi.org/10.1051/e3sconf/202130901178
E3S Web of Conferences 309, 01178 (2021)
ICMED 2021
Conclusion




An Intze water is designed with 300000 litres
capacity with 12m staging has designed with M30
grade of concrete.
We design the tank by both manually and using
STAAD Pro, the program results shown that design
is safe
After completion of Intze water tank design in
STAAD Pro and from manual calculations we
conclude that design is safe.
Though design is safe but we observed that
reinforcement is less when compared with manual
calculations.
References
1.
2.
3.
4.
5.
6.
7.
14
Text book: Design of Reinforced Concrete
Structures by S. Ramamrutham.
I.S-3370 (Part IV-1967). Code of Practice for
Concrete Structures for the storage of liquids.
I.S-3370 (Part II-1967). Code of practice for
concrete structures for the storage of liquids.
Manchalwar, Atulkumar, and S. V. Bakre.
International Journal of Dynamics and Control
(2020): 1-10.
I.S:456-2000. Indian Standard Code of Practice for
Reinforced Concrete.
I.S:875-1987 Part-III code design of wind loads.
Manchalwar, A., and S. V. Bakre. Soil Mechanics
and Foundation Engineering 57.2 (2020): 170-177