INDEX

INTRODUCTION & BASIC LOAD CALCULATION

DESIGN OF BASE PLATE

DESIGN OF PURLIN
INTRODUCTION & BASIC LOAD CALCULATION
1. GENERAL

This report contains the structural analysis and design of steel structure for Store -1
Analysis & design calculation is done in STAAD.Pro -V8i (Consider IS:800 2007 LSD)

2. CODES AND STANDARDS

IS:800 : 2007 : General Construction in Steel.

IS:875 ( Part – 2 ) : Design Loads for Buildings & Structures – Imposed Loads.
IS:875 ( Part – 3 ) : Design Loads for Buildings & Structures – Wind Loads.

3.0 DESIGN LOADS

3.1 Dead Load :

i) Self of whole structure

ii) Load calculation at floor.
Wt. of Chqd Plate = 60 Kg/m2

iii) Load calculation at roof.

Wt of roof sheeting = 15 Kg/m2

Wt of perlin & fixing arrangement = 15 Kg/m2

Total load = 30 Kg/m2

iv)Side Sheeting :- Say total 30 Kg/m2

3.2 Live Load :

a) Live Load on roof (as non-accessible roof) =0.075 t/ m2

Live load intensity on roof for roof slope greater than 100
2
= 0.075-(11.3-10)x0.002= 0.0724 T/m
2/3 of 0.0724 T/m2 =0.049 T/m2
b) Roof Dust Load =0.050 t/m2
= 0.099 t/m2

So considering total load on roof = 0.075+0.050 = 0.125 t/m2

4.3 Wind Load : (As per IS 875-Part-3)

Here Basic Wind Speed 47 m/sec. Detail wind load calculation has done in separate sheet.
 Calculation of Wind Load
WIND LOAD CALCULATION ON WALL
Basic wind speed,Vb = 47 Terrain Category - II
K1 = 1.00 K3 = 1

Calculation of Wind Pressure(Pz)

Pz N/m2
Height Basic Wind K1 K2 (Table 2) K3 Vz
0Range
- 10 HT 47
Speed 1.00 1 1 47.00 1325.4
10 - 15 HT 47 1.00 1.05 1 49.35 1461.3
15 - 20 HT 47 1.00 1.07 1 50.29 1517.5
20 - 30HT 47 1.00 1.12 1 52.64 1662.6

0 - 10 HT 0.135 MT/m²
10 -15 HT 0.149 MT/m²
15 - 20 HT 0.155 MT/m²
20 - 30HT 0.169 MT/m²

WIND LOAD CALCULATION ON WALL

Wind in X Direction :
Ref: TABLE 4, IS : 875 (Part 3) -1987

Max. Length of building = 20.00 m.

w= 10.00 m. Z-wind
A
A B C D A B
X-wind 4.00 m
B
20 m 10.00 m

Shielded Area Enclosed Area = 4 x 5 = 20.00 m2

Mkd. Section Nos Length(m) Width(m) Area(m2)

Column = MB300 2 4.0 0.150 1.200
Considering Diagonal Bracing Member = 2Ls75x75x6 2 4.8 0.075 0.713
Considering Bracing Member = 2Ls50x50x6 2 4 0.05 0.400
Considering Horizontal Bracing Member = 2Ls75x75x6 1 5 0.075 0.375

Total = 2.688
15 % Extra for Gusset Plate = 0.403
Total = 3.091
Wind Solidity Ratio along wind ,Ø = 3.091 / 20 = 0.155
Force-efficient Cf = 1.840

Udl on each column = ( 1.84 x 0.155 x 20 x 0.135107033639144 ) / (2x(4)) ton/m =

0.097 t/m
Frame Spacing ratio= 10/4 = 2.5
Shilding Factor for intermediate frame = 1
Udl on each column = 0.100 t/m
 Calculation of Wind Load
WIND LOAD CALCULATION ON ROOF

X-wind

Z-wind
0 - 10 HT 0.135 MT/m²
10 -15 HT 0.149 MT/m²
15 - 20 HT 0.155 MT/m²
20 - 30HT 0.169 MT/m²

Ref: TABLE 5, IS : 875 (Part 3) - 1987 FOR STATIC WL 10.0m

Roof Slope a (degree) = 11.31 h/w = 0.400 -1.095 -0.4

For transverse wind, Cpe (on windward side) = -1.095

Cpe (on leeward side) = -0.4 WIND Z 4m
For Longitudinal wind, Cpe (max. uplift) = -0.79 Cpi = ± 0.7
For opening area of building less than 20%
Considered Cpi = ± 0.7 10 m
20 m
Design wind pressure, pd = 136 kg/m2

Wind udl [t/m] on roof for wind in Z-dirn: Wind udl [t/m] on roof for wind in X-dirn:

Span (m) Internal Pressure(-0.7) Internal Suction(+0.7) Span (m) Internal Pressure(-0.7) Internal Suction(+0.57)
Windward Leeward Windward Leeward Windward Leeward Windward Leeward
1.00 -0.054 0.041 -0.245 -0.15 1.00 -0.013 -0.013 -0.203 -0.203

h (m.) = 4
Cpi = -0.7 Cpi = +0.7 Cpi = -0.7 Cpi = +0.7

w (m.) = 10
DESIGN OF BASE PLATE
Design of Base Plate on grid For all Col.
Maximum compressive force for Node No 2 Load case 500 DL+LL= 7.292 Ton
Maximum tensile force for Node no.3 Load case no. 516 0.9*DL + WL (-) X (CPI
7.897
= +0.7)=
Ton
Maximum Shear force for Node Number 13 Load case 13= 1.441 Ton
Column Size is MB250
The following configuration is considered for base plate design:
W=250
Grade of Conc= M20 M25
Per. Conc. Bearing stress= 90Kg/cm^2
62.5 Dia of bolt Chosen= 16 mm
L=350 Tension capacity of Bolt= 4.60Ton
p= 125 Thickness of base plate = 20 mm
62.5 Thickness of gusset plate = 8 mm
Tension per bolt = 1.97 ton
g= < Bolt capacity, hence OK
125 Stiffner height = 200 mm
Both side fillet weld size in gusset =6 mm
Concrete bearing Pressure = 7.292X100000/350x250= 8.33 kg/cm2 <Per. Conc. Bearing stress=
90Kg/cm^2Kg/cm^2, Hence OK

i)Moment in base plate from concrete bearing pressure for two adjacent side supported panel as per
Moddy's chart for unifrom pressure as per the following =

a/b= 0.413
Moment Co-efficient α = 0.078
50.0mm =a
Moment per unit centimeter width =
=α x 8.33x12.1^2 kg-cm/cm
= 95.13 kg-cm/cm
Bending capacity of base plate per unit cm= 1.2xfyxZe/ϒm0 =
= Mdp = 1672.7 kg-cm/cm
121.0mm =b
>95.13Kg-cm,OK

ii)Moment in base plate from concrete bearing pressure for three adjacent side supported panel as per
Mukhanov's chart for unifrom pressure as per the following =
a1= 121.6mm
a1/d1 = 1.08
Moment Co-efficient α3 = 0.115
Moment per unit centimeter width =
d1= 113.0mm =α x 8.33x11.3^2 kg-cm/cm
= 122.32 kg-cm/cm
Bending capacity of base plate per unit cm= 1.2xfyxZe/ϒm0 =
= Mdp = 1672.7 kg-cm/cm
>122.32Kg-cm,OK
iii) Checking of base plate thickness for bolt tension is calculated considering the angle of dispersion of load from
bolt to base plate is 45o. The load accumulation per side of three side supported panel is calculated first.
Then the stress in base plate per each side is checked with respect to dispersed width.
 121.6mm Tension per bolt (T) = 1.97425 ton
Considering the Dispersed length and Tensile force
(T3,L3) per side as (T1,L1),(T2,L2) & (T3,L3) as per the
59.1 figure shown, the followins are evaluated:
50.5mm
L1 = 109.6 mm

(T1,L1)
#######
L2 = 121.55 mm
62.5mm o
45 L3 = 101.00 mm

(T2,L2)

Tensile forces are evaluated based on deflection compatibility at bolt location.The following equations
are solved to get the tensile force induced per side.

T1+T2+T3 = T (Eqn 1)
T1 x(59.1)^3 /(3EL1)=T2 x(62.5)^3 /(3EL2)=T3 x(50.5)^3 /(3EL3)Where E = Modulus of Elasticity =
(Eqn 2) =2X10^5 N/mm2

Hence solving the above equation, we get

T1 = 0.6 ton
T2 = 0.5 ton
T3 = 0.9 ton

Hence Bending moment per unit cm in base plate due to T1= 600x5.91/10.96kg-cm/cm= 313.8 Kg-cm
Bending moment in base plate per unit cm due to T2= 500x6.25/12.155kg-cm/cm= 257.1
Bending moment in base plate per unit cm due to T3= 900x5.05/10.1kg-cm/cm= 450.0 Kg-cm
= yxZe/ϒm0 =
Bending capacity of base plate per unit cm width = M dp 1.2xf 1672.7 Kg-cm
The above mements are < Mdp, Hence OK

iv) Design of Gusset plate

There are two types of gusseet plate, one is attached to the flange parallel to web and another is attached to the
wed parallel to flange. The gusset plate and weldings are examined with both tensile load
and compressive load case.

a) Flange stiffner Check from Compression

Height of stiffener So/tg should be < 42 to avoid local buckling

Thickness of gusset plate (tg) = 8 mm

Hence So/tg = 25.0 <42,OK

So= 200mm Influence width of stiffner for resisting pressure

50mm = 125 mm
Bending Moment at face of column
= 8.3x125X0.001x50^2/2 kg-cm
 = 1296.9 kg-cm
Bearing pressure= 8.3kg/cm2
Bending Moment capacity of gusset at face column =
Mtg =1.2xfyxZe/ϒm0 = 139636.4 kg-cm
>1296.9,OK
Shear force in gusset = 518.75 kg
Shear capacity of gst. = 200X8X2400/(√3X1.1x100)=

=20154.80 kg >518.75kg,OK

Check for welding size

Assumed weld size = 6 mm
Permissible weld stress = Where, fwd=fu/(√3 xϒmw) = 1893.7 Kg/cm2

Shear force at the face of column face = 8.3x125x50x0.01 kg= 518.75 kg

Shear stress on both side fillet welding τ= 518.75x100/(2x0.7x151x6)kg/cm2 = 40.9 kg/cm2
Moment at face of column = 1296.9 kg-cm
Section Modulus of both side fillet weld = 2x4.2x151^2/6 mm3 = 31.92 cm3
Bending tensile stress in fillet weld σbt= 1296.9/31.92 kg/cm2= 40.63 kg/cm2
2 2
Combined stress in fillet weld =√σ +1.8τ 68.28 kg/cm2 <1893.7kg/cm2, OK

b) Web Stiffner

200mm 200mm
121.6mm 121.6mm

Bearing pressure= 8.33 kg/cm2 59.1 mm

Bolt tension =2xT3 = 1.7Ton

Check for gusset in compression: Check for gusset in tension:

Thickness of gusset plate = 8 mm
Influence width of stiffner for resisting pressure Bending Moment at the face of column =
= 101 mm 1.7x59.1x100kg-cm= 10047 kg-cm
Bending Moment at face of column
= 8.33x101X0.001x121.55^2/2 kg-cm Bending Moment capacity of gusset at face column =
= 6215.1 kg-cm Mtg =1.2xfyxZe/ϒm0 = 139636.4 kg-cm
> 10047 kg-cm,OK
Bending Moment capacity of gusset at face column =
Mtg =1.2xfyxZe/ϒm0 =139636.4 kg-cm > 6215.1 kg-cm,OK

Shear force in gusset plate = 8.33x121.55x101/100 kg Shear force in gusset plate = 1.7Ton
= 1.02 Ton
Shear capacity of gst. = =20.15 Ton > 1.02 Ton,OK
Shear capacity of gst. = =20.15 Ton
> 1.7 Ton,OK
Check for welding stresses

Maximum shear at face of column from above two conditions= 1.7 Ton
Corresponding bending moment at face of column = 10047 kg-cm
Shear stress in both side fillet weld (τ)= 1.7x10^5/(2x0.7x151x6)kg/cm2 = 134.03 kg/cm2
<1100kg/cm2, OK
Bending stress in tensions in fillet weld (σ) = 10047/31.92 kg/cm2= 314.76 kg/cm2
<1893.7kg/cm2, OK

2 2
Combined stress in fillet weld =√σ +1.8τ 362.5 kg/cm2 <1893.7kg/cm2, OK

V) Design of Shear Key

14.41 kg/cm2
50mm
(TOC) (TOC)

=100mm 20mm

200

Type -I OR Type-II

Shear force to be resisted= 1.441 Ton

Thickness of grout = 50 mm
Depth of shear key below TOC =100mm
Width of shear key = 200 mm
Thickness of Shear key =20mm
Type of shear Key= Type -I .
Maximum Concrete Bearing pressure at the face of shear key 14.41 kg/cm2 <90kg/cm2,OK

Maximum Bending Moment at the bottom of base plate = 1.441x(0.33x100+50)x1000/200 kg-cm = 598 kg-cm

Bending Capacity of Shear key = Mts =1.2xfyxZe/ϒm0 = 1672.7 kg-cm >598kg-cm,OK

Hence provide Star Shear Key of depth 150mm X200mm wide X 20mm which is butt welded with each other and butt
welded to bottom of base plate
DESIGN OF PURLIN
Design of Purlin

Design Wind Pressure = 135 kg/m2 Dead load of sheeting = 20.1 kg/m2
Pressure Co-efficient = 1.3 Live Load on sheeting = 160 kg/m2
Roof Slope = 1 in 3

Y
z

z
Y
θ WL
DL+LL

Major axis moment (Mx)is calculated for three cases:

4
Case I: Single span Mz(span) ==wzLz2/8, δ = 5Wz L /384EI
4
Case II: Double span continious Mz(supp) ==wzLz2/8, Mz(span) =wzLz2/10, δ = Wz L /185EI
4
Case III: Triple span continious Mz(supp) ==wzLz2/10, Mz(span) =wzLz2/12, δ = Wz L /185EI

Minor axis moment is claculated based on same equation, where the support is counted by no of sag rod support. i.e

Case I: Single span My(span) ==wyLy2/8, (i.e No sag rod or Single central Sagrod support.)
Case II: Double span continious My(supp) ==wyLy2/10, (Two or More equidistance sag rod support)

A) Design of Purlin with span Lx= 5 m & Spacing = 1.40 m C/C

Section Chosen: MC125 ;No. of Sag Rod = 1 ; Section Type= Rolled

Major Axis Span Type= Double span Ly = 2.5 m Section class= semicompact

Iy= 61.1 cm4 λLT = 0.292 ϒm0= 1.1

ry = 1.91 cm αLt = 0.210 Vp = 8693.1 kg (as per 8.4.1)
LLT = 250.0m cm φLt= 0.552 d/tw= 23.6 <67 (as per 8.4.1)
hf= 11.68 cm χLt = 0.979 fbd = 2225.65 kg/cm2
tf= 8.2 cm Mdz = 176338 kg-cm (as per cl.8.2.2) = 1.76 T-m
It= 29.28 cm4 Mdy = 30455 kg-cm (as per cl.8.2.1.2) = 0.30 T-m
Iw= 0 cm4
βb= 1
Zpz= 79.23 cm3
Zez= 68.1 cm3
Mcrz = 2318356.1 kg-cm
fy = 2500 kg/cm2
S/Weight(w)= 13.1 kg/m
Shear Area 6.625 cm2
Zpy= 29.96 cm3
Zey= 13.4 cm3

UDL Load intencity about major (i.e about z axis) & about minor axis(i.e about Y axis) are as follows:
Wz(dead) =39.13kg/m Wz(live) =212.51kg/m Wz(wind) =245.70kg/m Wy(dead) =13.04kg/m Wy(live) =70.84kg/m

Hence factored Minor Axis Moment Due to Dead and Live load (My) = 7864.5 kg-cm
Factored Major Axis moment due to Dead and Wind load = Mzsupport) = 96984 kg-cm
Hence =My/Mdy+Mz/Mdz = 0.81 < 1.0, OK
Deflection of purlin at span due to Wind load & Dead Load δ = 8.21 mm <Lx/200,OK
Hence provideMC125as purlin with 1 no sag rod for span 5m