33KV Rigid Bus Support
33KV Rigid Bus Support
33KV Rigid Bus Support
GENERAL NOTES
QUALITY OF STEEL = ASTM A36 OR A500
QUALITY OF BOLTS & NUTS ‐ ASTM A325 OR A394
DESIGN SHALL CONFORM TO ‐ BS 5950: PART 1
DESIGN WIND SPEED V ‐ 44.40 m/sec
WIND PRESSURE FOR STRUCTURE P ‐ SF X 6.1084 X 10 ‐4 X V2
‐ 4 2
2 X 6,1084 X 10 X 44.4
2.408371 kPa
245.5 kg/sq.Mtr
2.5 kN/m2
WIND PRESSURE ON INSULATOR & CONDUCTOR P = SF X 6.1084 X 10^ ‐4 X V2
0.6 X 6.1084 X 10^ ‐4 X 44.40 2
0.722511 kPa
73.65 Kg/Sq.Mtr
0.74kN/m2
OVERLOAD FACTOR 1.5
STRUNG LINE TUBULAR CONDUCTOR 100mmx5mm AlMgSiO.5 1490 mm2
OVERALL DIAMETER 0.1 m
MASS OF TUBULAR CONDUCTOR 4.03 kg/m
NUMBER OF TUBES 3
SPAN OF TUBE 6m
WIND LOAD PER MTR. OF TUBE 0.1x0.74x1.0 kN/m2 ‐ 0.074 kN/m
FORCE ON OUTER POST INSULATOR 1.1 kN
FORCE ON INNER POST INSULATOR 2.6 kN
CANTILEVER STRENGHT OF POST INSULATOR 8 kN
BENDING MOMENT ON THE BOTTOM OF THE OUTER POST INSULATOR 744.8 N‐m
BENDING MOMENT ON THE BOTTOM OF THE OUTER STEEL STRUCTURE 4.8 KN‐m
BENDING MOMENT ON THE BOTTOM OF THE INNER INSULATOR 1.8 KN‐m
BENDING MOMENT ON THE BOTTOM OF THEINNER STEEL STRUCTURE 11.65 KN‐m
DEFLETION OF TUBE BETWEEN STRUCTURES 2.73 mm
HEIGHT OF POST INSULATOR 0.7 m
HEIGHT OF STEEL STRUCTURE 3.8 m
DIAMETER OF POST INSULATOR 0.185 m
MASS OF POST INSULATOR 8 kg
WIND ON POST INSULATOR 0.74x0.7x0.185 0.1 kN/m2
2
BOND STRESS BETWEEN STEEL & CONCRETE (M:20) t 1.2 N/mm
MECHERINT LTD, ABUJA 31 24th OCTOBER 2017
STEDY ENGINEERING LTD STRUCTURE FOR 33KV RIGID BUS SUPPORT 2X30/40MVA 132/33KV
SUBSTATION OKITIPUPA
B STRUCTURE LOADING CALCULATIONS
I DATA FOR STRUCTURE LOADING CALCULATIONS
REFERENCE STRUCTURE LOADING DIAGRAM
WIND LOAD CALCULATIONS WIND PRESSURE
2
WIND PRESSURE 2.48 Kn/m
BUS SUPPORT LONGITIDUNAL
EXPOSED NO. OF TOTAL
MEMBER
AREA PCS AREA
m m Sq.Mtr
W L
LEG 0.070 3.770 2 0.528
TOP BELT 0.08 2.550 4 0.816
BRACING 0.045 0.311 11 0.154
TOTAL 1.498 m2
WIND ON SUPPORT STRUCTURE 3.7 kN
BUS SUPPORT TRANSVERSE
EXPOSED NO. OF TOTAL
MEMBER
AREA PCS AREA
m m Sq.Mtr
W L
LEG 0.070 3.770 2 0.528
TOP BELT 0.05 0.000 2 0.000
BRACING 0.045 0.311 12 0.168
TOTAL 0.696 m2
WIND ON SUPPORT STRUCTURE 1.7 kN
WEIGHTS
STRUCTURE 298 Kg = 2.9 kN
h
1
BUS
DIRECTION
hs
A B
FIG. 1: OUTLINE DRAWING FOR 132KV RIGID BUS SUPPORT
For the Rigid bus under consideration the tubular buses are supported on three Post Insulators
MECHERINT LTD, ABUJA 32 24th OCTOBER 2017
STEDY ENGINEERING LTD STRUCTURE FOR 33KV RIGID BUS SUPPORT 2X30/40MVA 132/33KV
SUBSTATION OKITIPUPA
which are in turn supported by one lattice steel structures
WEIGHT OF INSULATOR + TUBE ON ONE COLUMN 0.6 kN
Wind load on one column due to Insulators 0.3 kN
Weight of Support structure 2.9 kN
TOTAL VERTICAL LOAD 3.5 kN
WIND LOADS
LONGITIDUNAL DIRECTION
POST INSULATORS 0.3
BUS 0
STEEL STRUCTURE 3.7
TRANSVERSE DIRECTION
POST INSULATORS 0.1
BUS 0.44
STEEL STRUCTURE 1.7
CASE 1 (TRANSVERSE)
CASE 1 (Along Tube lenght)
Wind Load on
Insulator/TUBE WT of Insulator Wind Load on WT of Insulator
+Tube Insulator +Tube
Moment
Moment
11.65 KN‐m
0 KN‐m
SUPPORT 'A' SUPPORT 'A'
MOMENT CALCULATION (SIZING OF ONE COLUMN OF STRUCTURE)
MECHERINT LTD, ABUJA 33 24th OCTOBER 2017
STEDY ENGINEERING LTD STRUCTURE FOR 33KV RIGID BUS SUPPORT 2X30/40MVA 132/33KV
SUBSTATION OKITIPUPA
MEMBER LEG
FORCE=M/
MOMENT M EFF. WIDTH 2xW
kNm W kN
CASE 1 Wind Parallel to conductor M 0.35
DUE TO HORIZONTAL LOADS Load x Height 0.0193
WIND LOAD ON PI= 0.3 4.15 1.2
WIND ON STRUCTURE 3.7 1.9 7.1
WIND ON RIGID BUS 0.0 4.15 0.0
MOMENT AT BOTTOM OF STRUCTURE 0.0
4.0 TOTAL 8.3 0.3114 13.3 kN
Case 2 Wind normal to conductor
DUE TO HORIZONTAL LOADS Load x Height 0.35
WIND LOAD ON PI= 0.1 4.2 0.4 0.0193
WIND ON STRUCTURE 1.7 1.9 3.3
WIND ON RIGID BUS 0.44 4.15 1.8
MOMENT AT BOTTOM OF STRUCTURE 11.7
2.3 TOTAL 17.2 0.3114 27.6 kN
AXIAL LOAD ON LEG DUE TO VERTICAL LOAD = 0.9 kN
COMPRESSIVE FORCE ON LEG= 28.5 kN
TENSILE FORCE PER LEG= 26.7 kN
MEMBER BRACES
T F=T/nCosα
MEMBER CASE n α Cos α kN kN Length mm
2 1 2 50 0.64 6.1 3.7 405
BELT 1 1 0 1 0.4 0.4 2670
FORCE ACTION POINT
VLE VERTICAL LOAD INSULATOR 0.24 KN m
VLS VERTICAL LOAD STRUCTURE 2.92 KN m
EL ERECTION LOAD 1.5 KN m
LC WEIGHT OF TUBE 0.36 KN 4.2 m
MXL MOMENT X‐DIRECTION 0 KN m
MYL MOMENT Y‐DIRECTION 11.65 KN m
WXC WIND LOAD ON INSULATOR‐X DIRECTION 0.30 KN 4.2 m
WXT WIND LOAD ON TUBE X‐DIRECTION 0.00 KN 4.2 m
WXS WIND LOAD ON STRUCTURE X‐DIRCTION 1.90 KN 3.7 m
WYC WIND LOAD ON INSULATOR‐Y DIRECTION 0.10 KN 4.2 m
WYT WIND LOAD ON TUBE Y‐DIRECTION 0.44 KN 4.2 m
WYS WIND LOAD ON STRUCTURE Y‐DIRCTION 1.73 KN 1.9 m
FV FX FY Mx My
1 VL+MX+WX 3.51 2.00 0 8.3 11.21
2 VL+MY+WY 3.51 0 2.27 11.7 17.19
MEMBER DESIGN
MEMBER LEG BRACING BELT 1
UNIT
MECHERINT LTD, ABUJA 34 24th OCTOBER 2017
STEDY ENGINEERING LTD STRUCTURE FOR 33KV RIGID BUS SUPPORT 2X30/40MVA 132/33KV
SUBSTATION OKITIPUPA
MECHERINT LTD, ABUJA 35 24th OCTOBER 2017
STEDY ENGINEERING LTD STRUCTURE FOR 33KV RIGID BUS SUPPORT 2X30/40MVA 132/33KV
SUBSTATION OKITIPUPA
DESIGN OF BASE 350
BASE PLATE
COMPRESSION DESIGN
L4
90
L3 BOLT
BOLT
Ft = 26.7 KN
600
L3
Check for Shear stress in bolts
(Fs/ps + Ft/pt) = 1.5/98+20.5/116 = 0.35
Shear Stress within limit 0.35 < 1.0 O.K
Embedded Le EMBEDDED LENGTH Ld = ∅fs/(4t)
Where t Design bond stress between steel and concrete
∅ Diameter of the bolt = 20 mm
2
fs Tensile stress on Bolt=20500/245 83.7 N/mm
Ld = 348.75 mm
USE 500mm MINIMUM EMBEDDED LENGTH
FOUNDATION LOADING X Y
MOMENT AT PLINTH LVL 11.7 17.2 kN‐m
SHEAR AT PLINTH LVL 0.0 2.3 kN
VERTICAL LOAD 3.51 3.51 kN
MECHERINT LTD, ABUJA 36 24th OCTOBER 2017