SAFIYA HOMES PESHAWAR
COMPUTER AIDED ANALYSIS AND DESIGN OF
STRUCTURES
REPORT ON DESIGN OF ELEVATED WATER TANK HAVING CAPACITY OF
35,000 GALLONS
Submitted By:
Engineering Planners and consultants (Pvt) Limited
Table of Contents
Sr. No
1
2
3
4
5
Description
Structural Design Criteria
3D Model and SAP Input Files, Materials/Section Data etc.
Summary of Time Period and Base Shear
Design of Tank Column , Beam and Above Structure
• Column of Water Tank
• Beam & Bracing Beam
• Water Tank Wall Design
• Bottom Slab
• Top Slab
Foundation Design
Structural Design Criteria
Structural Design Criteria
ELEVATED WATER TANK (35,000 GALLONS)
STRUCTURAL DESIGN CRITERIA
1. INTRODUCTION
A circular-type elevated water tank (EWT) of 35,000 gallons capacity is to be designed. A
minimum hydraulic head of 50'-0" was required by the Public Health Engineer to cover the
area/buildings. The structural analysis and design was started based on concrete outline with 50'0" minimum hydraulic head. SAP2000 / SAFE software's were used to analyze and the design
the EWT.
2. FINAL GEOTECHNICALRECOMMENDATIONS
The recommendations for the site soil by the Geotechnical Engineer are as under:
- Use allowable bearing capacity = 0. 7 TSF at 5-0" below E.G.L
- Soil profile type"SD"
3. LIMITATIONS OF STRUCTURAL ANALYSIS ANDDESIGN
There is no single reference document available to recommend analysis and design
parameters for such tanks for following reasons:
- Prevailing code of practice in Pakistan is Building Code of Pakistan (BCP) - 2007
which referrers mainly to UBC-1997 andACI-318-05.
- One of available ACI documents for Pedestal-mounted steel tanks is ACI 371R-98. The
revised version of this document was released in 2008 (ACI 371R-08) with certain
modifications and encompassing the topic in more detailed manner
- Equivalent static procedure is outlined in ACI 371R-08 and ASCE 7-05 but these codes
suggest site specific acceleration amplification which make it difficult to use ACI 371R-08
strictly for regions outside United States. Therefore, the concept of equivalent static
procedure is taken from ACI 371R-98 and the stepwise procedure to be adopted for
Pakistan region is taken from UBC-1997 (ASCE-7-95) /BCP-2007.
Structural Design Criteria
4. ADOPTED PROCEDURE FOR STRUCTURAL ANALYSIS AND DESIGN
For above said reasons mention in section 3, the following stepwise approach was used:
4.1 Finite element model
Finite element model (FEM) was made in SAP2000 (version 23.1.0) / SAFE (version 2016)
4.2 Loadings
Following loads were considered:
- Deadload
- Live load
- Water load (gravity as well as sloshing effect due to strong ground motions)
- Seismic
V = Cv IW
RT
(Ref: UBC-1997 / BCP-2007)
where Cv = 0.32
(for zone 2B and Soil profile SD)
I = 1.25
R=3
T = 1 sec
(taken from FEM model/based on Raleigh's Method)
W = Dead load + water load (convective and impulsive component)
T > 0.7 sec
4.3 External stability checks
Following checks were made using approximate approach:
4.3.1 Bearing pressure check
Effective allowable bearing capacity = qeffective= 0.7 TSF = 1 x 2.204 = 1.54 ksf Raft
thickness assumed =2 ft
Raft Rectangular Dimension = 34 ft x 34 ft
Raft is modeled in SAFE for checking relatively accurate bearing pressure.
q <qeffective, OK
Structural Design Criteria
4.3.2 Overturningcheck
FOS should be >2
Overturning moment = Mo = 5776 kips-ft
Vertical load of raft, super structure = P =374 kips
Stabilizing moment = Ms = P x raft width / 2
= 374 x 34* / 2
= 6,358 kips-ft
Stabilizing moment by over burden = (1098*4*115/1000)*34/2 = 8586 kip-ft
FOS = Ms / Mo 2.59 > 2 OK
.
4.4 Loadcombinations
Service and factored load combinations were taken from UBC-1997, ACI-371R-98 / BCP – 2007
because of compatibility of seismic loadings within these codes.
4.5 Materialproperties
Following material properties were taken for concrete design:
*fc' = 3000 psi for raft, beam and tank top bottom slab
fc’ = 4000 psi for water tank column
fy = Grade 60 for main and transverse reinforcement
4.6 Size of Water Tank
Internal Dia of Bowl = 23 feet dia
Water Height 13'-3'' feet
Free Board = 0'-9'' feet
Gross Height = 14 feet
Wall Thickness of Bowl = 12 inch
Volume of Water = 35,000 gallon
3D Models and SAP2000 Input
Files Materials/Section
Data
3D Model of EWT
Grid System Data
Concrete Properties
Bracing Beam Section Along With
Modifiers
Top and Bottom Beam of Water Tank
With Modifiers
Column Section of Water Tank Along
with Modifiers
Water Tank Top & Bottom Slab Section
Load Patterns
Summary of Time Period and
Base Shear
2. Material properties
This section provides material property information for materials used in the model.
Table 7: Material Properties 02 - Basic Mechanical Properties
Table 7: Material Properties 02 - Basic Mechanical Properties
Material
UnitWeight
UnitMass
E1
G12
U12
Kip/in3
Kip-s2/in4
Kip/in2
Kip/in2
3000Psi
8.6806E-05 2.2483E-07
3122. 1300.83
0.2
3
4000Psi
8.6806E-05 2.2483E-07
3600.
1500.
0.2
A416Gr270
2.8356E-04 7.3446E-07
28500.
A615Gr60
2.8356E-04 7.3446E-07
29000.
A992Fy50
2.8356E-04 7.3446E-07
29000. 11153.8
0.3
46
Table 8: Material Properties 03a - Steel Data
Table 8: Material Properties 03a - Steel Data
Material
Fy
Fu FinalSlop CoupMod
e
Type
Kip/in2
Kip/in2
A992Fy50
50.
65.
-0.1
Von
Mises
Table 9: Material Properties 03b - Concrete Data
Table 9: Material Properties 03b - Concrete Data
Material
Fc
eFc FinalSlop CoupMod
e
Type
Kip/in2
Kip/in2
3000Psi
3.
3.
-0.1 Modified
DarwinPecknold
4000Psi
4.
4.
-0.1 Modified
DarwinPecknold
A1
1/F
5.5000E-06
5.5000E-06
6.5000E-06
6.5000E-06
6.5000E-06
Table 10: Material Properties 03e - Rebar Data
Table 10: Material Properties 03e - Rebar Data
Material
Fy
Fu FinalSlop CoupMod
e
Type
Kip/in2
Kip/in2
A615Gr60
60.
90.
-0.1
Von
Mises
Table 11: Material Properties 03f - Tendon Data
Table 11: Material Properties 03f - Tendon Data
Material
Fy
Fu FinalSlop CoupMod
e
Type
Kip/in2
Kip/in2
A416Gr270
245.1
270.
-0.1
Von
Mises
3. Section properties
This section provides section property information for objects used in the model.
3.1. Frames
Table 12: Frame Section Properties 01 - General, Part 1 of 4
Table 12: Frame Section Properties 01 - General, Part 1 of 4
SectionName
Material
Shape
t3
t2
Area TorsCon
st
in
in
in2
in4
12x21
3000Psi
Rectangular
21.
12.
252. 7780.13
12x27
3000Psi
Rectangular
27.
12.
324. 11211.6
C21x21
4000Psi
Rectangular
21.
21.
441. 27389.4
1
C30
4000Psi
Circle
30.
706.86 79521.5
6
Table 12: Frame Section Properties 01 - General, Part 2 of 4
Table 12: Frame Section Properties 01 - General,
Part 2 of 4
SectionName
I23
AS2
AS3
in4
in2
in2
12x21
0.
210.
210.
12x27
0.
270.
270.
C21x21
0.
367.5
367.5
I33
I22
in4
9261.
19683.
16206.7
5
39760.7
8
in4
3024.
3888.
16206.7
5
39760.7
8
Table 12: Frame Section Properties 01 - General,
Part 2 of 4
SectionName
I23
AS2
AS3
in4
in2
in2
C30
0.
636.17
636.17
Table 12: Frame Section Properties 01 - General, Part 3 of 4
Table 12: Frame Section Properties 01 - General, Part 3 of 4
SectionName
S33
S22
Z33
Z22
R33
in3
in3
in3
in3
in
12x21
882.
504.
1323.
756.
6.0622
12x27
1458.
648.
2187.
972.
7.7942
C21x21
1543.5
1543.5 2315.25 2315.25
6.0622
C30
2650.72 2650.72
4500.
4500.
7.5
R22
in
3.4641
3.4641
6.0622
7.5
Table 12: Frame Section Properties 01 - General, Part 4 of 4
Table 12: Frame Section Properties 01 - General, Part 4 of 4
SectionName
AMod A2Mod A3Mod
JMod
I2Mod
I3Mod
12x21
12x27
C21x21
C30
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
0.35
0.35
0.7
0.7
0.35
0.35
0.7
0.7
MMod
WMod
1.
1.
1.
1.
1.
1.
1.
1.
Table 13: Frame Section Properties 02 - Concrete Column, Part 1 of 3
Table 13: Frame Section Properties 02 - Concrete Column, Part 1 of 3
SectionName
RebarMatL
RebarMatC
ReinfConfig LatReinf
Cover NumBars
Circ
in
C21x21
A615Gr60
A615Gr60
Rectangular
Ties
1.5
C30
A615Gr60
A615Gr60
Circular
Ties
2.
8
Table 13: Frame Section Properties 02 - Concrete Column, Part 2 of 3
Table 13: Frame Section
Properties 02 - Concrete
Column, Part 2 of 3
SectionName
NumBars
2Dir
C21x21
C30
3
NumBars
3Dir
3
Table 13: Frame Section Properties 02 - Concrete Column, Part 3 of 3
Table 13: Frame Section Properties 02 - Concrete Column, Part 3 of 3
SectionName BarSize BarSize
Spacing NumCBar NumCBar
L
C
C
s2
s3
in
C21x21
#9
#4
6.
3
3
C30
#9
#3
6.
Table 14: Frame Section Properties 03 - Concrete Beam, Part 1 of 2
Table 14: Frame Section Properties 03 - Concrete Beam, Part 1 of 2
SectionName
RebarMatL
RebarMatC
TopCover BotCover
in
in
12x21
A615Gr60
A615Gr60
2.
2.
12x27
A615Gr60
A615Gr60
2.5
2.5
Table 14: Frame Section Properties 03 - Concrete Beam, Part 2 of 2
Table 14: Frame Section Properties 03 - Concrete Beam, Part 2
of 2
SectionName TopLeftA TopRghtA BotLeftAr BotRghtA
rea
rea
ea
rea
in2
in2
in2
in2
12x21
0.
0.
0.
0.
12x27
0.
0.
0.
0.
3.2. Areas
Table 15: Area Section Properties, Part 1 of 3
Table 15: Area Section Properties, Part 1 of 3
Section
Material
AreaType
Type
DrillDOF Thickness
RAFT
3000Psi
Shell
S12
3000Psi
Shell
S6
W12
3000Psi
3000Psi
Shell
Shell
ShellThick
ShellThick
Shell-Thin
ShellThick
F11Mod
Yes
in
24.
BendThic
k
in
24.
Yes
12.
12.
1.
Yes
Yes
6.
12.
6.
12.
1.
1.
1.
Table 15: Area Section Properties, Part 2 of 3
Table 15: Area Section Properties, Part 2 of 3
Section
F22Mod
F12Mod M11Mod M22Mod M12Mod
RAFT
S12
S6
W12
1.
1.
1.
1.
1.
1.
1.
1.
1.
0.25
0.25
0.35
1.
0.25
0.25
0.35
Table 15: Area Section Properties, Part 3 of 3
Table 15: Area Section Properties, Part
3 of 3
Section
MMod
WMod
RAFT
S12
S6
W12
1.
1.
1.
1.
1.
1.
1.
1.
3.3. Solids
Table 16: Solid Property Definitions
Table 16: Solid Property Definitions
SolidProp
Material
MatAngle MatAngle
A
B
Degrees
Degrees
Solid1
3000Psi
0.
0.
4. Load patterns
This section provides loading information as applied to the model.
4.1. Definitions
Table 17: Load Pattern Definitions
Table 17: Load Pattern Definitions
LoadPat
DesignType SelfWtMu
AutoLoad
lt
DEAD
LIVE
WATER
Dead
Live
Live
1.
0.
0.
MatAngle
C
Degrees
0.
1.
0.25
0.25
0.35
V13Mod
V23Mod
1.
1.
1.
1.
1.
1.
1.
1.
Table 17: Load Pattern Definitions
LoadPat
DesignType SelfWtMu
AutoLoad
lt
EQX
EQY
Quake
Quake
0.
0.
UBC97
UBC97
4.2. Auto seismic loading
Table 18: Auto Seismic - UBC97, Part 1 of 3
Table 18: Auto Seismic - UBC97, Part 1 of 3
LoadPat
Dir
PercentEc
Ct
R
c
EQX
EQY
X
Y
0.05
0.05
0.03
0.03
3.
3.
SoilType
SD
SD
Table 18: Auto Seismic - UBC97, Part 2 of 3
Table 18: Auto Seismic - UBC97, Part 2 of 3
LoadPat
Z
Ca
Cv SourceTy SourceDis
pe
t
km
EQX
0.2
0.28
0.4
B
0.
EQY
0.2
0.28
0.4
B
0.
Table 18: Auto Seismic - UBC97, Part 3 of 3
Table 18: Auto Seismic - UBC97, Part 3 of 3
LoadPat
I
TUsed WeightUs BaseShear
ed
Sec
Kip
Kip
EQX
1.
1.03 1010.924
130.864
EQY
1.
1.03 1010.924
130.864
5. Load cases
This section provides load case information.
5.1. Definitions
FtUsed
Kip
9.435
9.435
Na
Nv
1.3
1.3
1.6
1.6
Table 19: Load Case Definitions, Part 1 of 2
Table 19: Load Case Definitions, Part 1 of 2
Case
Type
InitialCond
ModalCase
BaseCase
DEAD
MODAL
WATER
EQX
EQY
LIVE
LinStatic
LinModal
LinStatic
LinStatic
LinStatic
LinStatic
Zero
Zero
Zero
Zero
Zero
Zero
Table 19: Load Case Definitions, Part 2 of 2
Table 19: Load Case
Definitions, Part 2 of 2
Case
DesignAct
DEAD
MODAL
WATER
EQX
EQY
LIVE
NonComposit
e
Other
ShortTerm
Composit
e
ShortTerm
Composit
e
ShortTerm
Composit
e
ShortTerm
Composit
e
5.2. Static case load assignments
MassSour
ce
DesActOp
t
Prog Det
Prog Det
Prog Det
Prog Det
Prog Det
Prog Det
Table 20: Case - Static 1 - Load Assignments
Table 20: Case - Static 1 - Load Assignments
Case
LoadType
LoadName
LoadSF
DEAD
WATER
EQX
EQY
LIVE
Load pattern
Load pattern
Load pattern
Load pattern
Load pattern
DEAD
WATER
EQX
EQY
LIVE
1.
1.
1.
1.
1.
5.3. Response spectrum case load assignments
Table 21: Function - Response Spectrum - User
Table 21: Function - Response Spectrum - User
Name
Period
Accel FuncDam
p
Sec
UNIFRS
0.
1.
0.05
UNIFRS
1.
1.
6. Load combinations
This section provides load combination information.
Table 22: Combination Definitions
Table 22: Combination Definitions
ComboName ComboType
CaseName
ScaleFact
or
S2
S2
S3
S3
S3
S4
S4
S4
SENV
SENV
SENV
DCON1
DCON2
Linear Add
Linear Add
Linear Add
Envelope
Linear Add
Linear Add
WATER
DEAD
WATER
DEAD
EQX
WATER
DEAD
EQY
S2
S3
S4
DEAD
DEAD
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.
1.4
1.2
Table 22: Combination Definitions
ComboName ComboType
CaseName
ScaleFact
or
DCON2
DCON2
DCON3
DCON3
DCON3
DCON3
DCON4
DCON4
DCON4
DCON4
DCON5
DCON5
DCON5
DCON5
DCON6
DCON6
DCON6
DCON6
DCON7
DCON7
DCON8
DCON8
DCON9
DCON9
DCON10
DCON10
Linear Add
Linear Add
Linear Add
Linear Add
Linear Add
Linear Add
Linear Add
Linear Add
WATER
LIVE
DEAD
WATER
LIVE
EQX
DEAD
WATER
LIVE
EQX
DEAD
WATER
LIVE
EQY
DEAD
WATER
LIVE
EQY
DEAD
EQX
DEAD
EQX
DEAD
EQY
DEAD
EQY
1.6
1.6
1.3
1.
1.
1.
1.3
1.
1.
-1.
1.3
1.
1.
1.
1.3
1.
1.
-1.
0.8
1.
0.8
-1.
0.8
1.
0.8
-1.
Design of Tank Column , Beam & Above
Structure
o
o
o
o
o
Column of water Tank
Beam & Bracing Beam
Water Tank Wall Design
Bottom Slab
Top Slab
Column Of Water Tank
Column Section
Column Reinforcement Detail
Bottom Slab
Top Slab
BRACING BEAM , WATER TANK
BOTTTOM AND TOP BEAM
BRACING BEAM AT PLINTH REINFORCEMENT DETAIL
BRACING BEAM AT LEVEL -1 REINFORCEMENT DETAIL
BRACING BEAM AT LEVEL -2 REINFORCEMENT DETAIL
BRACING BEAM AT LEVEL -3 REINFORCEMENT DETAIL
TANK BOTTOM BEAM REINFORCEMENT DETAIL
Water Tank WALL DESIGN
OVER HEAD WATER TANK
DESIGIN OF WALL
Thickness of Wall
Cover
=
=
12.00 in
2.00 in
d
Height of wall
Water pressure
Pw
Lx
=
=
=
=
=
10.00
14.00
0.850
5.68
33.00
(-)Moment
=
2.Pw.H
in
ksf
kip
ft
4.85
kip-ft
2.18
kip-ft
15.00
(+)Moment
=
3.Pw.H
50.00
(-) As
(+) As
Asmin (0.2%bh)
=
=
=
0.1664
0.0749
0.216
1/2 "Ø
1/2 "Ø
1/2 "Ø
@
@
@
14.2 in
31.5 in
10.9 in
Use Min
Use Min
Use
"Ø
@
PROJECT:
Free Board
1/2
@
@
10.9 in c/c
9 ft
1/2 "Ø
"Ø
10.9 in
4.04 KIPS
0.850 Ksf/ft
0.85
ksf/ft
Foundation Design
DESIGN OF RAFT FOR E.W.T
Introduction
The Rectangular raft foundation of size 34’x 34' is to be designed for E.W.T having capacity of
35,000 gallons. The tank is located in seismic zone 2B with soil type S D and bearing capacity of
soil is taken as 0.7 tons/sft.
Safe Modeling
Exporting base reaction file from SAP2000 to SAFE V2016.
Defining Material Properties
Defining Area Properties
Defining Soil Properties
Subgrade modulus
DESIGN PREFFERENCE
Deformed Shape
Soil Pressure
Slab Resultant Moment Diagram
Raft Bottom Reinforcement detail in one direction
Raft Bottom Reinforcement detail in two direction