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1 Deltec Engineering LimitedRev 1, July, 2011
Structural Design Calculations for 40,000-Gallon Overhead Water Tank Support Tower & Foundations
-
2 Deltec Engineering LimitedRev 1, July, 2011
Consulting Engineers
Deltec Engineering Limited(Consulting Engineers & Project Managers)
Lagos Office 11, Shasha Road (Opp. Union Bank)
Akowonjo Lagos Tel: 01-7730278
July, 2011
Email: [email protected]
Job No: DEL/2011-134 Date: 09/08/2011 Job Title: DESIGN OF 40,000-GALLON OVERHEAD WATER TANK SUPPORT
TOWER AND FOUNDATIONS S T R U C T U R A L D E S I G N I N F O R M A T I O N INTENDED USE & BRIEF DESCRIPTION OF STRUCTURE The proposed steel tower is to provide support for a 40,000-gallon (181,840 litre-capacity) Braithwaite pressed steel water tank at a height of 12.0m above ground level. The tank measures 6.1mx6.1m on plan and is 4.88m deep. The structural solution consists of a 4-legged lattice tower, 12m high, carrying a platform, which measures 7.9mx7.9m on plan. The platform is made of 356x171x45UB secondary girders `POS 16, placed at 1.22m intervals over 533x210x82UB Main girders `POS 18 which are in turn, supported by the tower legs made of 203x203x46UC `POS 01 at 3.66m centres in the longitudinal and transverse directions. Both the secondary and main girders are extended with 80x80x6RSA sections to carry the walkway and the handrails. For stability the tower is braced horizontally at 3.0m intervals with 100x100x8RSA `POS 02. Cross bracing is made of 80x80x6RSA `POS 03, designed as ties. The Holding Down system consists of 350mmx350mmx25 base plates which are anchored to the concrete base with M20 grade 8.8 galvanized bolts. The foundation is made of 450mm thick reinforced concrete slab at 450mm above ground level, with downturn perimeter containment beams. Further details of the design are given in the accompanying drawings. GENERAL LOADING CONDITION Imposed loading
Self weight of tank = 116.84kN (Braithwaite tank Ref 554).Contents (water) = 1818.4kNOpen flooring system = 0.5kN/m2 (35x5 steel grating)Maintenance load=5.0kN/m2Railing & Posts = 0.35kN/m Wind loading
Basic wind speed, v=35m/s (3-sec gust speed) DURABILITY & FIRE RESISTANCE
Fire resistance-: 1 hour for all elementsMinimum cover to all reinforcement - 50mm substructure CODES OF PRACTICE & REFERENCES
EUROCODE 1: EN199111: 2002: Actions on Structures, EUROCODE 2: EN19921 - 12004: Design of Conceret Structures,EUROCODE 3: EN1993 - 1 - 1: 2005: Design of Steel Structures, EUROCODE 3: EN1993 - 1 - 8: Design of JointsANSI/EIA/TIA-222-G-2003: Structural Standards for Steel Antenna Towers and Antenna Supporting StructuresSubsoil Investigation Report by Otoko Soils, 13 Timbo Close, Off 66 Abuloma Road, Amadi-Ama, Port-Harcourt.
MATERIALS & STRENGTHS Normal Weight Concrete grade 35Characteristic cube strength, fcu = 35N/mm2Characteristic cylinder strength at 28 days, fck = 0.8 xcharacteristic cube strength = 28N/mm2 ReinforcementHigh yield deformed bars type 2 to BS 4449Characteristic strength, fyk = 410N/mm2
Structural Steel Grade S275 (43A)Youngs Modulus, Es =205kN/mm2
BoltsMild steel bolts grade 8.8 Prepared by: Emmanuel Ofovwe Bobor, B.Eng
Date: 11/08/2011 Agreed: Engr. Samson Ivovi, B.Eng, MSc, MNSE, FNIStructE,
Date: 11/08/2011
-
3 Deltec Engineering LimitedRev 1, July, 2011
Job No: DEL/2011-134 Date: 09/08/2011 Job Title: DESIGN OF 40,000-GALLON OVERHEAD WATER TANK SUPPORT
TOWER AND FOUNDATIONS S T R U C T U R A L D E S I G N I N F O R M A T I O N INTENDED USE & BRIEF DESCRIPTION OF STRUCTURE The proposed steel tower is to provide support for a 40,000-gallon (181,840 litre-capacity) Braithwaite pressed steel water tank at a height of 12.0m above ground level. The tank measures 6.1mx6.1m on plan and is 4.88m deep. The structural solution consists of a 4-legged lattice tower, 12m high, carrying a platform, which measures 7.9mx7.9m on plan. The platform is made of 356x171x45UB secondary girders `POS 16, placed at 1.22m intervals over 533x210x82UB Main girders `POS 18 which are in turn, supported by the tower legs made of 203x203x46UC `POS 01 at 3.66m centres in the longitudinal and transverse directions. Both the secondary and main girders are extended with 80x80x6RSA sections to carry the walkway and the handrails. For stability the tower is braced horizontally at 3.0m intervals with 100x100x8RSA `POS 02. Cross bracing is made of 80x80x6RSA `POS 03, designed as ties. The Holding Down system consists of 350mmx350mmx25 base plates which are anchored to the concrete base with M20 grade 8.8 galvanized bolts. The foundation is made of 450mm thick reinforced concrete slab at 450mm above ground level, with downturn perimeter containment beams. Further details of the design are given in the accompanying drawings. GENERAL LOADING CONDITION Imposed loading
Self weight of tank = 116.84kN (Braithwaite tank Ref 554).Contents (water) = 1818.4kNOpen flooring system = 0.5kN/m2 (35x5 steel grating)Maintenance load=5.0kN/m2Railing & Posts = 0.35kN/m Wind loading
Basic wind speed, v=35m/s (3-sec gust speed) DURABILITY & FIRE RESISTANCE
Fire resistance-: 1 hour for all elementsMinimum cover to all reinforcement - 50mm substructure CODES OF PRACTICE & REFERENCES
EUROCODE 1: EN199111: 2002: Actions on Structures, EUROCODE 2: EN19921 - 12004: Design of Conceret Structures,EUROCODE 3: EN1993 - 1 - 1: 2005: Design of Steel Structures, EUROCODE 3: EN1993 - 1 - 8: Design of JointsANSI/EIA/TIA-222-G-2003: Structural Standards for Steel Antenna Towers and Antenna Supporting StructuresSubsoil Investigation Report by Otoko Soils, 13 Timbo Close, Off 66 Abuloma Road, Amadi-Ama, Port-Harcourt.
MATERIALS & STRENGTHS Normal Weight Concrete grade 35Characteristic cube strength, fcu = 35N/mm2Characteristic cylinder strength at 28 days, fck = 0.8 xcharacteristic cube strength = 28N/mm2 ReinforcementHigh yield deformed bars type 2 to BS 4449Characteristic strength, fyk = 410N/mm2
Structural Steel Grade S275 (43A)Youngs Modulus, Es =205kN/mm2
BoltsMild steel bolts grade 8.8 Prepared by: Emmanuel Ofovwe Bobor, B.Eng
Date: 11/08/2011 Agreed: Engr. Samson Ivovi, B.Eng, MSc, MNSE, FNIStructE,
Date: 11/08/2011
-
4 Deltec Engineering LimitedRev 1, July, 2011
Job No: DEL/2011-134 Date: 09/08/2011 Job Title: DESIGN OF 40,000-GALLON OVERHEAD WATER TANK SUPPORT
TOWER AND FOUNDATIONS S T R U C T U R A L D E S I G N I N F O R M A T I O N INTENDED USE & BRIEF DESCRIPTION OF STRUCTURE The proposed steel tower is to provide support for a 40,000-gallon (181,840 litre-capacity) Braithwaite pressed steel water tank at a height of 12.0m above ground level. The tank measures 6.1mx6.1m on plan and is 4.88m deep. The structural solution consists of a 4-legged lattice tower, 12m high, carrying a platform, which measures 7.9mx7.9m on plan. The platform is made of 356x171x45UB secondary girders `POS 16, placed at 1.22m intervals over 533x210x82UB Main girders `POS 18 which are in turn, supported by the tower legs made of 203x203x46UC `POS 01 at 3.66m centres in the longitudinal and transverse directions. Both the secondary and main girders are extended with 80x80x6RSA sections to carry the walkway and the handrails. For stability the tower is braced horizontally at 3.0m intervals with 100x100x8RSA `POS 02. Cross bracing is made of 80x80x6RSA `POS 03, designed as ties. The Holding Down system consists of 350mmx350mmx25 base plates which are anchored to the concrete base with M20 grade 8.8 galvanized bolts. The foundation is made of 450mm thick reinforced concrete slab at 450mm above ground level, with downturn perimeter containment beams. Further details of the design are given in the accompanying drawings. GENERAL LOADING CONDITION Imposed loading
Self weight of tank = 116.84kN (Braithwaite tank Ref 554).Contents (water) = 1818.4kNOpen flooring system = 0.5kN/m2 (35x5 steel grating)Maintenance load=5.0kN/m2Railing & Posts = 0.35kN/m Wind loading
Basic wind speed, v=35m/s (3-sec gust speed) DURABILITY & FIRE RESISTANCE
Fire resistance-: 1 hour for all elementsMinimum cover to all reinforcement - 50mm substructure CODES OF PRACTICE & REFERENCES
EUROCODE 1: EN199111: 2002: Actions on Structures, EUROCODE 2: EN19921 - 12004: Design of Conceret Structures,EUROCODE 3: EN1993 - 1 - 1: 2005: Design of Steel Structures, EUROCODE 3: EN1993 - 1 - 8: Design of JointsANSI/EIA/TIA-222-G-2003: Structural Standards for Steel Antenna Towers and Antenna Supporting StructuresSubsoil Investigation Report by Otoko Soils, 13 Timbo Close, Off 66 Abuloma Road, Amadi-Ama, Port-Harcourt.
MATERIALS & STRENGTHS Normal Weight Concrete grade 35Characteristic cube strength, fcu = 35N/mm2Characteristic cylinder strength at 28 days, fck = 0.8 xcharacteristic cube strength = 28N/mm2 ReinforcementHigh yield deformed bars type 2 to BS 4449Characteristic strength, fyk = 410N/mm2
Structural Steel Grade S275 (43A)Youngs Modulus, Es =205kN/mm2
BoltsMild steel bolts grade 8.8 Prepared by: Emmanuel Ofovwe Bobor, B.Eng
Date: 11/08/2011 Agreed: Engr. Samson Ivovi, B.Eng, MSc, MNSE, FNIStructE,
Date: 11/08/2011
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5 Deltec Engineering LimitedRev 1, July, 2011
DELTEC
DELTEC ENGINEERING LTD Job No.
Calculation Sheet DEL /2011 - 134
Member/LocationJob Title: Design of 40,000-Gallon Overhead Water Tank Support Drg Ref.
Tower Made by
REFERENCE CALCULATIONSBASIC ASSESSMENT OF OVERHEAD WATER TANK
STRUCTURAL DESIGN INFORMATIONTankType:Reference Code:Length of Tank, L:Breadth of Tank, B:Depth of Tank, D:Volume of Tank:Gravity LoadsMaintenance load on walkway:Self weight of Tank:Weight of water in Tank:Open Flooring system:Railings and posts:PLATFORM LOADING
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6 Deltec Engineering LimitedRev 1, July, 2011
INTERNAL TANK BEARER 'SG 1'From tank own weight = 65.53/(4.88 x 4)Water = 872.83/(4.88 x 4)Open Flooring System: = 0.5x1.22Maintenance Load: = 5x1.22Railings + Posts = 0.35x1.22EXTERNAL TANK BEARER 'SG 2'From tank own weight: = 65.53/(2x4.88x4)Water: = 872.83/(2x4.88x4)
At cantilever: = 0.5x0.5x1.22At Span: = 0.5x0.5x0.9At cantilever: = 5.0x0.5x1.22At Span: = 5.0x0.5x0.9
Railings + Posts = 0.35x1.22PERIMETER BEAM 'SG 3'Open Flooring At cantilever: = 0.5x0.5x1.22
At Span: = 0.5x0.9Maintenance LAt cantilever: = 5.0x0.5x1.22
At Span: = 5.0x0.9At cantilever: = 0.35x1.22At Span:
Open Flooring System:Maintenance Load:
Railings + Posts
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7 Deltec Engineering LimitedRev 1, July, 2011
DELTEC
DELTEC ENGINEERING LTD Job No.
Calculation Sheet DEL /2011 - 134
Member/LocationJob Title: Design of 40,000-Gallon Overhead Water Tank Support Drg Ref.
Tower Made by
REFERENCE CALCULATIONSINTERNAL TANK BEARER 'SG 1'
1.35
22.459 98.50649.128 118.762
123.7539.1585.49109.105
EXTERNAL TANK BEARER 'SG 2'
72.7435.25912.93354.551
PERIMETER BEAM 'SG 3'
6.0221.4164.606
Calculations in accordance with BS EN 1993- 1- 1: 2005All loads and moments are factored
Factors of Safety: G = Q =
TYPICAL TANK BEARER 'SG': I - SectionBS EN 1993- 1- 1: 2005
Z
Gk1 = 0.427 KN
610 3660
MVRSRDRL
900
gk2 = 0.61 KN/mqk2 = 6.1 KN/m
gk1 = 3.357KN/mqwk1 = 44.715KN/m
RW
Gk2 = 0.427KN
610 3660
RSRDRL
900
gk4 = 0.305KN/mqk4 = 3.05 KN/m gk3 = 1.679KN/mqwk3 = 22.357 KN/m
RW
gk5 = 0.305KN/m, qk5 = 3.05KN/m
Gk2 = 0.427KN
1510 3660
RSRDRL
gk6 = 0.35KN/m
gk7 = 0.305KN/m, qk7 = 3.05KN/m
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8 Deltec Engineering LimitedRev 1, July, 2011
Design Info:Design bending moment about major axis, Design shear force,Force through flange
Preliminary Sizing:Deflection: For the beam above, the maximum deflection occurs at the mid-span of SG1, thus:
where 48.0726.71610
L = 3660Thus: 91,176,217Check Moment:
From Table 3.1
Try 356 x 171 x 45kg/m UB
Steel Designer's Manual - 6th Edition (1996)
Actual deflection, = L2/384EI [w1(5L2 - 24N12) - 48w2L2N2(0.5N2 + N1)2 - 48P(N1 + N2)]Limiting deflection, lim = span/720 = L/720
Equating both to ensure deflection is within the limit gives; Ireq = 720L/384E [w1(5L2 - 24N12) - 48w2N2(0.5N2 + N1) - 48P(N1 + N2)]
w1 = 1.0gk1 + 1.0qwk1 = w2 = 1.0gk2 + 1.0qk2 =
N1 =
Ireq =
Applied moment, Msd = Assume t > 40mm; fy =
Plastic Modulus Required, Wpl,y reqd = Msd/fy =
h
b
tw
tf
Y Y
Z
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9 Deltec Engineering LimitedRev 1, July, 2011
DELTEC
DELTEC ENGINEERING LTD Job No.
Calculation Sheet DEL /2011 - 134
Member/LocationJob Title: Design of 40,000-Gallon Overhead Water Tank Support Drg Ref.
Tower Made by
REFERENCE CALCULATIONS
Section Properties: 356 x 171 x 45kg/m UBDepth of Section h = 356mmWidth of Section b = 171mmWeb Thickness 6.9mmFlange Thickness 9.7mmDepth Between d= 312.3mmRoot Radius r = 10.2mm
8.8145.8
121,000,000mm48,120,000mm4
Classify Section:9.7mm
0.9248.81< 10 'Flange is at least compact'45.8< 83 'Web is at least compact'
Shear Buckling:51.6 Column flange thickness Ok
mm < 40mm 275 Plate thickness Ok259.270mm259.270mm
4c2 + 1204.6c + 5793.16fyp = N/mm2fck = N/mm2
fcd = ccfck/c = N/mm2fjd = 0.67fcd = N/mm2Ap' = NEd/fjd = mm2
mm2
ts req = 16.616mmts prov = 25mm
fyp = N/mm2Dpmin = 2c + hc = Bpmin = 2c + bc = Baseplate 350 x 350 x
25mm
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81 Deltec Engineering LimitedRev 1, July, 2011
Job No. Sheet No Rev.
DEL /2011 - 134 20 OF 23
EOB Date: 09/08/2011 Chd. SAI
CALCULATIONS OUTPUTCalculations in accordance with BS EN 1993- 1- 8: 2005
69.428KN19.521KN
KN
mmmm
KN
KN
Bolt Tension Capacity OkKN Tensile Capacity Ok
KNKNKN
Bolt Shear Capacity OkKN Shear Capacity Ok
< 1.0
Column to baseplate welds:mmmm
Ft,Ed = Fv,Ed =
N/mm2Ft,Ed = 17.07 KN
Ft,Ed = 147 KN
Fv,Ed = 4.88 KNFv,Ed = 98 KN
Bolt size and number chosen are suitable
Holding down bolts should be anchored into the foundation by washer plate or other load distributing member embedded in the
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82 Deltec Engineering LimitedRev 1, July, 2011
mm
N/mmN/mmmmN/mmN/mm
N/mmN/mmN/mm
N/mm
N/mm
Weld Capacity OkN/mm Weld chosen is suitableSUMMARY OF BASEPLATE REQUIREMENTS
Size 350mm x 350mm x 25mmGradeS275 steel
Edge distance50mmBolts4 Nos. 20mm, Grade 8.8
Welds6mm fillet weld all round
fw,Ed = 881.38 KN
N/mm2Table 10.12; Fillet Weld Resistances,
IStructE Manual, Page 116
fw,Rd = 903 KN
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83 Deltec Engineering LimitedRev 1, July, 2011
Job No. Sheet No Rev.
DEL /2011 - 134 21 OF 23
EOB Date: 09/08/2011 Chd. SAI
CALCULATIONS OUTPUT
Wind at 450
DL = 273.347 KNLL = 31.356 KNWk = +118.488 KN
DL = 273.347 KNLL = 31.356 KNWk = 0
B
3660
DL = 273.347 KN LL = 31.356 KN+Wk = +52.51 KN
B
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84 Deltec Engineering LimitedRev 1, July, 2011
Wind normal to face
DL = 273.347 KN LL = 31.356 KN+Wk = +52.51 KN
3660
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85 Deltec Engineering LimitedRev 1, July, 2011
Job No. Sheet No Rev.
DEL /2011 - 134 22 OF 23
EOB Date: 09/08/2011 Chd. SAI
CALCULATIONS OUTPUTSTABILITY ANALYSIS
15.52KN19.88KN
17.27KN34.79KN
OVERTURNING MOMENT AT TOWER BASE (AT SERVICE)Service Moment,
(17.27 x 6) + (34.82 x (16.462 - 3.66/2) 609.335KNm
A Z
h = 350mmw = 25 x h = 8.75
Maximum Service Load,1218.811KN
m
Minimum Service Load,
to Tower) (At Service)Mo = 613.297 KNm
KN/m2
Total axial load (At service), = 4 x (21.611 + 31.356 + 218.209) Pmax = 1218.811 KN
- 1218.811L - 5203.99 = 0KN/m2KN/m2
Total axial load (At service), = 4 x (21.611 + 31.356) + 134.107
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86 Deltec Engineering LimitedRev 1, July, 2011
KN
m
47.61
At ultimate,1645.39KN N = 1645.39 KN573.130KNm
Ultimate stresses,
166.235KN/m
345.975 + 8.75L2 P min = 345.975 + 8.75L2
- 345.975L + 5203.99 = 0KN/m2 (To ensure that the base remains in contact
with the soil)m2
Provide 6.9 x 6.9 x 350mm Base Area prov,
Aprov = m2 Base Area = 47.61 m2
Total axial load, N =[ 4(1.35*50.669) +
Mo = 576.526 KNm
net = 2891.45 6 x 855.464 6.9 6.92 fmax = 311.119KN/m
fmin = fmin = 165.807KN/m
1620
311.119 KN/m
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87 Deltec Engineering LimitedRev 1, July, 2011
Job No. Sheet No Rev.
DEL /2011 - 134 23 OF 23
EOB Date: 09/08/2011 Chd. SAI
CALCULATIONS OUTPUT Total
999.281KN = 1645.394
1.62
276.775 310.691
475.848
523.433
-466.021Bending Moment Diagram
410
999.281KN
fyk = N/mm2
NEd = NEd = 1000.429 KN
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88 Deltec Engineering LimitedRev 1, July, 2011
h = 350mmc = 40mm = 16mm
294mmu = 4 x 350 = 1400mm
1852.200kN
KN Shear Resistance Ok
6600mm = 588mm
Soil pressure per unit width at 2.0d from column face, 289.09KN/m309.48kN0.15951.4628
582.268
M = 466.021kNmd = h - c - /2 = 302mm
0.9719 0.95 la = 0.954170.303 33 T16 @ 200 BB & BT
deff. = 0.5(dy + dz) = h - c - =
VRd,max = 0.5ud[0.6 (1 - fck/250)]fck/1.5 = VRd,max = 1852.20 KN
bv =
f2.0d = f2.0d = 524.06 KN/mVEd = 0.5(1.5-2d)(f2.0d + 549.87)=
Ed = VEd/bd = N/mm2k = (1+(200/d)0.5) = mm-1
Asv = (vEd/(0.12k))3(bd/(100fck)) = mm2 Asv = 949.777 mm2/m
Use la = As = M/(0.95fyklad) = mm2
6633 mm2/m
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89 Deltec Engineering LimitedRev 1, July, 2011
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90 Deltec Engineering LimitedRev 1, July, 2011
Job No: DEL/2011-134 Date: 09/08/2011 Job Title: DESIGN OF 40,000-GALLON OVERHEAD WATER TANK SUPPORT
TOWER AND FOUNDATIONS S T R U C T U R A L D E S I G N I N F O R M A T I O N INTENDED USE & BRIEF DESCRIPTION OF STRUCTURE The proposed steel tower is to provide support for a 40,000-gallon (181,840 litre-capacity) Braithwaite pressed steel water tank at a height of 12.0m above ground level. The tank measures 6.1mx6.1m on plan and is 4.88m deep. The structural solution consists of a 4-legged lattice tower, 12m high, carrying a platform, which measures 7.9mx7.9m on plan. The platform is made of 356x171x45UB secondary girders `POS 16, placed at 1.22m intervals over 533x210x82UB Main girders `POS 18 which are in turn, supported by the tower legs made of 203x203x46UC `POS 01 at 3.66m centres in the longitudinal and transverse directions. Both the secondary and main girders are extended with 80x80x6RSA sections to carry the walkway and the handrails. For stability the tower is braced horizontally at 3.0m intervals with 100x100x8RSA `POS 02. Cross bracing is made of 80x80x6RSA `POS 03, designed as ties. The Holding Down system consists of 350mmx350mmx25 base plates which are anchored to the concrete base with M20 grade 8.8 galvanized bolts. The foundation is made of 450mm thick reinforced concrete slab at 450mm above ground level, with downturn perimeter containment beams. Further details of the design are given in the accompanying drawings. GENERAL LOADING CONDITION Imposed loading
Self weight of tank = 116.84kN (Braithwaite tank Ref 554).Contents (water) = 1818.4kNOpen flooring system = 0.5kN/m2 (35x5 steel grating)Maintenance load=5.0kN/m2Railing & Posts = 0.35kN/m Wind loading
Basic wind speed, v=35m/s (3-sec gust speed) DURABILITY & FIRE RESISTANCE
Fire resistance-: 1 hour for all elementsMinimum cover to all reinforcement - 50mm substructure CODES OF PRACTICE & REFERENCES
EUROCODE 1: EN199111: 2002: Actions on Structures, EUROCODE 2: EN19921 - 12004: Design of Conceret Structures,EUROCODE 3: EN1993 - 1 - 1: 2005: Design of Steel Structures, EUROCODE 3: EN1993 - 1 - 8: Design of JointsANSI/EIA/TIA-222-G-2003: Structural Standards for Steel Antenna Towers and Antenna Supporting StructuresSubsoil Investigation Report by Otoko Soils, 13 Timbo Close, Off 66 Abuloma Road, Amadi-Ama, Port-Harcourt.
MATERIALS & STRENGTHS Normal Weight Concrete grade 35Characteristic cube strength, fcu = 35N/mm2Characteristic cylinder strength at 28 days, fck = 0.8 xcharacteristic cube strength = 28N/mm2 ReinforcementHigh yield deformed bars type 2 to BS 4449Characteristic strength, fyk = 410N/mm2
Structural Steel Grade S275 (43A)Youngs Modulus, Es =205kN/mm2
BoltsMild steel bolts grade 8.8 Prepared by: Emmanuel Ofovwe Bobor, B.Eng
Date: 11/08/2011 Agreed: Engr. Samson Ivovi, B.Eng, MSc, MNSE, FNIStructE,
Date: 11/08/2011
-
91 Deltec Engineering LimitedRev 1, July, 2011
Job No: DEL/2011-134 Date: 09/08/2011 Job Title: DESIGN OF 40,000-GALLON OVERHEAD WATER TANK SUPPORT
TOWER AND FOUNDATIONS S T R U C T U R A L D E S I G N I N F O R M A T I O N INTENDED USE & BRIEF DESCRIPTION OF STRUCTURE The proposed steel tower is to provide support for a 40,000-gallon (181,840 litre-capacity) Braithwaite pressed steel water tank at a height of 12.0m above ground level. The tank measures 6.1mx6.1m on plan and is 4.88m deep. The structural solution consists of a 4-legged lattice tower, 12m high, carrying a platform, which measures 7.9mx7.9m on plan. The platform is made of 356x171x45UB secondary girders `POS 16, placed at 1.22m intervals over 533x210x82UB Main girders `POS 18 which are in turn, supported by the tower legs made of 203x203x46UC `POS 01 at 3.66m centres in the longitudinal and transverse directions. Both the secondary and main girders are extended with 80x80x6RSA sections to carry the walkway and the handrails. For stability the tower is braced horizontally at 3.0m intervals with 100x100x8RSA `POS 02. Cross bracing is made of 80x80x6RSA `POS 03, designed as ties. The Holding Down system consists of 350mmx350mmx25 base plates which are anchored to the concrete base with M20 grade 8.8 galvanized bolts. The foundation is made of 450mm thick reinforced concrete slab at 450mm above ground level, with downturn perimeter containment beams. Further details of the design are given in the accompanying drawings. GENERAL LOADING CONDITION Imposed loading
Self weight of tank = 116.84kN (Braithwaite tank Ref 554).Contents (water) = 1818.4kNOpen flooring system = 0.5kN/m2 (35x5 steel grating)Maintenance load=5.0kN/m2Railing & Posts = 0.35kN/m Wind loading
Basic wind speed, v=35m/s (3-sec gust speed) DURABILITY & FIRE RESISTANCE
Fire resistance-: 1 hour for all elementsMinimum cover to all reinforcement - 50mm substructure CODES OF PRACTICE & REFERENCES
EUROCODE 1: EN199111: 2002: Actions on Structures, EUROCODE 2: EN19921 - 12004: Design of Conceret Structures,EUROCODE 3: EN1993 - 1 - 1: 2005: Design of Steel Structures, EUROCODE 3: EN1993 - 1 - 8: Design of JointsANSI/EIA/TIA-222-G-2003: Structural Standards for Steel Antenna Towers and Antenna Supporting StructuresSubsoil Investigation Report by Otoko Soils, 13 Timbo Close, Off 66 Abuloma Road, Amadi-Ama, Port-Harcourt.
MATERIALS & STRENGTHS Normal Weight Concrete grade 35Characteristic cube strength, fcu = 35N/mm2Characteristic cylinder strength at 28 days, fck = 0.8 xcharacteristic cube strength = 28N/mm2 ReinforcementHigh yield deformed bars type 2 to BS 4449Characteristic strength, fyk = 410N/mm2
Structural Steel Grade S275 (43A)Youngs Modulus, Es =205kN/mm2
BoltsMild steel bolts grade 8.8 Prepared by: Emmanuel Ofovwe Bobor, B.Eng
Date: 11/08/2011 Agreed: Engr. Samson Ivovi, B.Eng, MSc, MNSE, FNIStructE,
Date: 11/08/2011
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92 Deltec Engineering LimitedRev 1, July, 2011
Job No: DEL/2011-134 Date: 09/08/2011 Job Title: DESIGN OF 40,000-GALLON OVERHEAD WATER TANK SUPPORT
TOWER AND FOUNDATIONS S T R U C T U R A L D E S I G N I N F O R M A T I O N INTENDED USE & BRIEF DESCRIPTION OF STRUCTURE The proposed steel tower is to provide support for a 40,000-gallon (181,840 litre-capacity) Braithwaite pressed steel water tank at a height of 12.0m above ground level. The tank measures 6.1mx6.1m on plan and is 4.88m deep. The structural solution consists of a 4-legged lattice tower, 12m high, carrying a platform, which measures 7.9mx7.9m on plan. The platform is made of 356x171x45UB secondary girders `POS 16, placed at 1.22m intervals over 533x210x82UB Main girders `POS 18 which are in turn, supported by the tower legs made of 203x203x46UC `POS 01 at 3.66m centres in the longitudinal and transverse directions. Both the secondary and main girders are extended with 80x80x6RSA sections to carry the walkway and the handrails. For stability the tower is braced horizontally at 3.0m intervals with 100x100x8RSA `POS 02. Cross bracing is made of 80x80x6RSA `POS 03, designed as ties. The Holding Down system consists of 350mmx350mmx25 base plates which are anchored to the concrete base with M20 grade 8.8 galvanized bolts. The foundation is made of 450mm thick reinforced concrete slab at 450mm above ground level, with downturn perimeter containment beams. Further details of the design are given in the accompanying drawings. GENERAL LOADING CONDITION Imposed loading
Self weight of tank = 116.84kN (Braithwaite tank Ref 554).Contents (water) = 1818.4kNOpen flooring system = 0.5kN/m2 (35x5 steel grating)Maintenance load=5.0kN/m2Railing & Posts = 0.35kN/m Wind loading
Basic wind speed, v=35m/s (3-sec gust speed) DURABILITY & FIRE RESISTANCE
Fire resistance-: 1 hour for all elementsMinimum cover to all reinforcement - 50mm substructure CODES OF PRACTICE & REFERENCES
EUROCODE 1: EN199111: 2002: Actions on Structures, EUROCODE 2: EN19921 - 12004: Design of Conceret Structures,EUROCODE 3: EN1993 - 1 - 1: 2005: Design of Steel Structures, EUROCODE 3: EN1993 - 1 - 8: Design of JointsANSI/EIA/TIA-222-G-2003: Structural Standards for Steel Antenna Towers and Antenna Supporting StructuresSubsoil Investigation Report by Otoko Soils, 13 Timbo Close, Off 66 Abuloma Road, Amadi-Ama, Port-Harcourt.
MATERIALS & STRENGTHS Normal Weight Concrete grade 35Characteristic cube strength, fcu = 35N/mm2Characteristic cylinder strength at 28 days, fck = 0.8 xcharacteristic cube strength = 28N/mm2 ReinforcementHigh yield deformed bars type 2 to BS 4449Characteristic strength, fyk = 410N/mm2
Structural Steel Grade S275 (43A)Youngs Modulus, Es =205kN/mm2
BoltsMild steel bolts grade 8.8 Prepared by: Emmanuel Ofovwe Bobor, B.Eng
Date: 11/08/2011 Agreed: Engr. Samson Ivovi, B.Eng, MSc, MNSE, FNIStructE,
Date: 11/08/2011
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93 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
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94 Deltec Engineering LimitedRev 1, July, 2011
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95 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
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96 Deltec Engineering LimitedRev 1, July, 2011
Msd = 98.506 KNmVsd = 118.76KNFsd= 167.89KN
Ireq = 91,176,217mm4
Wpl,y req = 386,298mm3
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97 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
Section Ok
Iprov = 121,000,000mm4
Wpl,y prov = 774,000mm3
Section is ok, Class 2
Full lateral restraint assumed
Msd = 98.506 KNVsd = 118.76KN
Vpl,Rd = 386.29 KN
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98 Deltec Engineering LimitedRev 1, July, 2011
Shear Capacity Ok
Moment Capacity OkMpl,Rd = 202.71 KN
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99 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
Web bearing capacity Ok
Fsd = 270.81 KN
Ry, Rd = 270.55 KN
Ra, Rd = 278.68 KN
Web crippling capacity is Ok
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100 Deltec Engineering LimitedRev 1, July, 2011
Web buckling capacity Ok
356 x 171 x 45kg/m UB
KNKNKNmKNmKNKNKN
Nb, Rd = 290.99 KN
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101 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
Msd = 215.6 KNmVsd = 251.84 KN
Fsd= 370.79 KN
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102 Deltec Engineering LimitedRev 1, July, 2011
Ireq = 132,508,207mm4
Wpl,y req = 845,490mm3
Iprov = 337,400,000mm4
Wpl,y prov = 1,702,000mm3
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103 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
Section is ok
Section is ok, Class 2
Section is Ok for lateral torsional buckling
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104 Deltec Engineering LimitedRev 1, July, 2011
Shear Capacity Ok
Moment Capacity Ok
Msd = 215.60 KNVsd = 251.84 KN
Vpl,Rd = 665.21 KN
Mpl,Rd = 445.76 KN
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105 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
Fsd = 370.79 KN
Ry, Rd = 431.14 KN
Web bearing capacity is Ok
Ra, Rd = 501.54 KN
Web crippling capacity is Ok
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106 Deltec Engineering LimitedRev 1, July, 2011
356x171x45 UB
KNKNKNmKNmKNKNKN
Nb, Rd = 581.75 KN
Web buckling capacity is Ok
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108 Deltec Engineering LimitedRev 1, July, 2011
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109 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
Try HE 160 B
Try 100 x 100 x 8 RSA
Try 80 x 80 x 6 RSA
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OUTPUT
= 19.90 KN = 34.82 KN
= 15.52 KN = 17.27 KN
= 384.35 KNm
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= 613.30 KNm
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OUTPUT
WL = +/- 118.488 KNDL = 273.347KNLL = 31.356 KN
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115 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
Slenderness Ok
NEd = 589.081 KN
Section is ok, Class 2
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116 Deltec Engineering LimitedRev 1, July, 2011
Slenderness OkSlenderness Ok
HE 160 B
KNKN
NEd = 589.081 KN
Nb, Rd = 982.71 KN
Compressive Capacity Adequate
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117 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
NEd = 41.289 KN
Class 3, Do a strength reduction or use an effective area
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118 Deltec Engineering LimitedRev 1, July, 2011
NEd = 641.289 KN
Nb, Rd = 84.20 KN
Compressive Capacity Adequate
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119 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
Deflection ok
Tensile Capacity Adequate
100 x 100 x 8 RSA
KNKNKNmKN
Use two bolts M20 at each end
NEd = 41.289 KN
Nu, Rd = 455.467 KN
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121 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
Section is ok, Class 2
NEd = 51.007 KN
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122 Deltec Engineering LimitedRev 1, July, 2011
Slenderness Ok
Tensile Capacity Adequate
80 x 80 x 6 RSA
KNmKN
Use two bolts M20 at each end
NEd = 51.007 KN
Nu,Rd = 261.8 KN
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OUTPUT
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124 Deltec Engineering LimitedRev 1, July, 2011
Plate thickness Ok
ts req = 16.616mmts prov = 25mm
Baseplate 350 x 350 x 25mm
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OUTPUT
Bolt Tension Capacity Ok
Bolt Shear Capacity Ok
Ft,Ed = 17.07 KN
Ft,Ed = 147 KN
Fv,Ed = 4.88 KNFv,Ed = 98 KN
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126 Deltec Engineering LimitedRev 1, July, 2011
Weld Capacity Ok
350mm x 350mm x 25mmS275 steel50mm4 Nos. 20mm, Grade 8.86mm fillet weld all round
fw,Ed = 881.38 KN
fw,Rd = 903 KN
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127 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
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128 Deltec Engineering LimitedRev 1, July, 2011
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129 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
Service Moment,
Maximum Service Load,
Minimum Service Load,
Mo = 613.297 KNm
Pmax = 1218.811 KN
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130 Deltec Engineering LimitedRev 1, July, 2011
At ultimate,N = 1645.39 KN
Ultimate stresses,
P min = 345.975 + 8.75L2
Provide 6.9 x 6.9 x 350mm
Base Area = 47.61 m2
Mo = 576.526 KNm
fmax = 311.119KN/mfmin = 165.807KN/m
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131 Deltec Engineering LimitedRev 1, July, 2011
OUTPUT
KN
NEd = 1000.429 KN
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132 Deltec Engineering LimitedRev 1, July, 2011
la = 0.95 33 T16 @ 200 BB & BT
VRd,max = 1852.20 KN
f2.0d = 524.06 KN/m
Asv = 949.777 mm2/m
6633 mm2/m
Sheet2