Challenge

Project 2

PROJECT-2

  1. Design a Warehouse Building located in Chennai using STAAD Pro Connect Edition. The specification must be as follows:

Width

30m

Length

50m

Eave Height

9m

Bay spacing

6m

Soil type

Medium

Safe Bearing Capacity

200 kN/m2

Roof slope

1 in 12

Assume suitable sections for structural elements. Follow IS800:2007, IS1893 and IS 875

  1. Prepare a Design Basis Report for the project
  2. Create structural model using STAAD Pro Connect Edition
  3. Prepare DL, LL, WL and EQL load calculations as per IS 875 standards
  4. Design using MS – Excel
    1. Steel column

Height of column

h

=

9

m

Yield strength

fy

=

250

N/mm2

Elastic modulus

E

=

200000

N/mm2

Material factor

γm

=

1.1

Step 1

Section classification

Properties of selected section

ISHB

400

A

10466

mm2

h

400

mm

d

374.6

B

250

mm

t

10.6

mm

T

12.7

mm

rx

166.1

mm

ry

51.6

mm

Zp

cm3

Flange criterion

b/T

=

9.84

Web criterion

d/t

=

35.34

Ɛ

=

1.00

b/T

<

10.5

d/t

<

42

The section is classified as COMPACT

Step 2

Effective Length

T7.5

As both ends pin-jointed

KLx

=

9.00

m

KLy

=

9.00

m

KLz

=

9.00

m

Slenderness ratio

KLx/rx

=

54.18

KLy/ry

=

174.42

Non-dimensional effective slenderness ratio

Cl 7.1.2.1

λ

=

=

1.964

Step 3

To calculate φ

φ = 0.5[1+α(λ-0.2)+λ2]

h/bf

=

1.60

>

1.2

T

=

12.7

mm

T 7.1

so, buckling class

=

b

α

=

0.34

φ

=

2.73

Step 4

Calculation of χ

χ =

χ

=

0.216

N/mm2

Step 5

Calculation of fcd

fcd

=

χfy/γm

=

49.17

Step 6

Factored Axial Load

Pd

=

Afcd

=

514.614

kN

    1. Rafter

Span of I beam

=

3

m

Dead Load

=

18

kN/m

Imposed Load

=

40

kN/m

Length of bearing

=

100

mm

Yield strength

=

250

N/mm2

58

3

Step 1

Design load calculation

Factored Load

=

87.00

kN/m

Factored bending moment

=

97.88

kNm

Step 2

Section modulus - Required

Z reqd

=

430650.0

mm3

=

430.65

cm3

Step 3

Section classification

Properties of selected section

ISMB

250

A

475.5

mm2

D

250

mm

B

125

mm

t

6.9

mm

T

12.5

mm

Izz

5131.6

cm4

Iyy

344.5

cm4

Zp

459.76

cm3

Flange criterion

B/2T

=

5

Web criterion

(D-2T)/t

=

32.61

Ɛ

=

1

B/2T

<

9.4

(D-2T)/t

<

83.9

The section is classified as PLASTIC

Step 3

Moment of resistance of the cross section

Moment

Md

=

(Zpxfy)/γm

Md

=

104.491

kNm

>

97.88

Hence section ISMB 250 is adequate for flexure

Step 4

Shear resistance of the cross section

Shear capacity

Vc

=

0.6fyAv/γm

Av

=

1725

mm2

Vc

=

235.23

kN

Factored shear

V

=

130.50

kN

V/Vc

=

0.55

<

0.6

Step 5

Check for Web Buckling

Slenderness ratio of web

=

2.5d/t

d

=

225

=

70.33

Design compressive stress

fc

=

203

N/mm2

Pw

=

315158

=

315.16

kN

>

130.50

Hence web is safe against shear buckling

Step 6

Check for web crippling at support

Root radius of ISMB 250

R

=

13

mm

tf + R

=

25.5

mm

Dispersion length

n2

=

63.75

mm

Pcrip

=

245625

N

=

245.63

kN

>

130.50

Hence section adequate for web crippling

Step 7

Check for serviceability - Deflection

Design load

=

58

kN/m

Deflection

δ

=

5.96

mm

Allowable deflection

=

15

mm

Hence serviceability is satisfied

    1. Base plate Design

Step 1

Strength of concrete

fcu

=

40

N/mm2

Yield strength of steel

fy

=

250

N/mm2

Material factor

γm

=

1.1

kN

Factored load

=

1500

kN

Step 2

Steel column section

Thickness of flange

T

=

12.7

mm

Step 3

Area required

Bearing strength of concrete

=

0.4 fcu

=

16

N/mm2

Area required

=

93750

mm2

Let size of plate

Bplate

=

350

mm

Dplate

=

350

mm

Area of plate

=

122500

mm2

Let projection on each side

a = b

=

25

mm

w

=

12.24

N/mm2

Cl 7.4.3.1

Thickness of slab base

ts

=

7.7

mm

<

12.70

mm

So use base plate of size 350mm x 350mm x 12mm

    1. Pedestal
  1. d) Pedestal :-
  2. Grade of concrete = 40N/mm^2 Load = 123kN
  3. Moment = 116kNm
  1. Horizontal shear = 13kN Yield strength = 250N/mm^2
  2. Length of base plate L = 450mm Width of the base plate B = 350mm
  3. C/C distance of (Ld) of bolt group in Z = 300mm C/C distance of (Ld) of bolt group in X = 180mm Bearing strength of concrete fc = 16N/mm^2 Depth of column D = 300mm
  4. Width of column W = 250mm

14. Step :- 1

  1. Anchor Bolt Details
  2. Dia of anchor bolt = 24mm
  3. No of anchor bolt on each side = 4 Total number of anchor bolt,n = 8
  4. Gross area of the bolt 'Asb' = 452.16mm^2 Net area of the bolt 'Anb' = 352mm^2
  5. Ultimate tensile strength of the bolt fub = 400N/mm^2 Fyb(Anchor bolt) = 240N/mm^2

23. Step :- 2

  1. Base plate details
  2. Ultimate tensile strength of a plate,fu = 490N/mm^2 Thickness of plate = 16mm
  3. Yield stress of plate = 330N/mm^2

30. Step :- 3

  1. Anchor bolt design
  2. Area of the plate = 157500mm^2
  3. Stress Max pressure ζ1 = F/A+6*Mz/BL^2
  4. = 10.60N/mm^2
  5. < 16
  1. OK
  2. Min pressure ζ2 = F/A-6*Mz/BL^2
  3. = -9.04N/mm^2
  4. < 16
  5. C = L*ζ1/(ζ1+ζ2)
  6. = 242.89mm
  7. a = L/2-C/3
  8. = 04mm e = (L-Ld)/2
  9. = 75mm
  10. y = (L-C/3-e)
  11. = 294.04mm
  12. Tension in anchor bolts along the length of plate FT = (Mz-Fxa)/y
  13. = 364.38
  14. Tension per bolt = 91.10kN shear per bolt,V = 1.63kN

65. Step :- 4

  1. Shear check
  2. Factored shear force Vsb = 1.63kN
  3. Vd,sd = 81290.9N
  4. = 21.291kN
  5. Factored Vd,sb = 65.03kN

77. Step :- 5

  1. Tensile check
  2. Factored tensile force in bolt Tb = 91.10kN Tensile strength of bolt Td,b = Tnb/γmb
  3. Tn,b = 0.9fubAn
  4. = 126720N
  5. = 72kN
  1. Tn,b = fybAsb(γmb/γmo)
  2. = 123316N
  3. = 123.316kN
  4. Lesser of two =123.32kN So, Td,b = 65kN

94. Step :- 6

  1. Combined unity check
  2. (Vsb/Vdb)^2+(Tb/Tdb)^2
  3. Vsb/Vdb = 0.025
  4. Tb/Tdb = 0.92 Unity check = 0.85
  5. < 1
  6. Hence OK

107. Step :- 7

  1. Anchor bolt length
  2. Bond strength in tension bd = 1.4N/mm^2 Anchor length required = Tb/(3.14*d*ηbd)
  3. = 863.44mm
  4. Let anchor bolt bolt length = 900mm
  1. Z- purlin

e) Purlin :- Step :- 1

Span of the purlin = 7m Spacing of the purlin = 1.5m Number of sag rods = 1 Slope of the roof = 5deg

Step :- 2

Dead loads

Weight of sheeting = 5kg/m^2 Self weight of purlin = 4.22kg/m^2

Additional load = 10%

= 0.42kg/m^2 Total dead load = 0.096kN/m^2

Live loads

Live load on roof = 75kg/m^2

= 0.75kN/m^2

Wind loads

Basic wind spped = 50m/s Terrain category = 2 Building class = B

k1 = 1

k2 = 1

k3 = 1

Design wind speed Vz = 57m/s

Design wind pressure Pz = 1949.40N/m^2

= 1.95kN/m^2 Length of the building I = 50m Breath of the building w = 30m Height of the building h = 10.5m Height of the building at eaves = 9m

h/w = 0.35

I/w = 1.67

External pressure coefficient Maximum downward Cpe = -0.4 Maximum upward Cpe = -0.7

Internal pressure coefficient Maximum positive Cpi = 0.5 Maximum negative Cpi = -0.5

For maximum upward wind force

Maximum upward Cpe = -0.7

Cpi = -0.5

Cpe + Cpi = -1.2

Pz = 1.95

Wind pressure for purlin design = -2.339kN/m^2

For maximum upward wind force

Max upward Cpe = -0.4

Cpi = 0.5

Cpe + Cpi = 0.1 Pz = 1.95

Wind pressure for purlin design = 0.195kN/m^2

Step :- 3

Design load calculation

Spacing of purlin = 1.5m Slope of roof = 5deg

Total dead load = 0.096kN/m^2

DL normal component = 0.144kN/m DL tangential component = 0.013kN/m Total live load = 0.75kN/m^2

LL normal component = 1.121kN/m LL tangential component = 0.098kN/m WL1 wind load = -2.339kN/m^2

WL normal component = -3.496kN/m WL2 wind load = 0.195kN/m^2

WL normal component = 0.291kN/m

Summary of loads

WL2

ad

l load

WL1)

LL+WL2)

ad

l load

Maximum normal component = 1.265kN/m

Step :- 4

Purlin section

Section selected = Zx200x6x2.3

Yield stress of material = 2400kg/cm^2 Flange width b = 60mm

Depth of section d = 200mm Thickness t = 2.30mm Length of Lip lip_I = 20mm

Internal bending radius = 3mm

Area = 8.07cm^2 Zxx = 47.72cm^3 Zyy = 10.22cm^3 Ixx = 477.18cm^4 Iyy = 61.34cm^4

Weight of purlin = 6.335kg/m

=4.223kg/m^2

Check for basic properties

t = 2.30mm

w = 49.40mm

Fy = 2400kg/cm^2 w/t = 21.48

< 60

OK

Check for stress

Span major axis = 7m Span minor axis = 2m

BM coefficient for Mxx = 10

BM coefficient for Myy = 10

WL2

ad

l load

)+(Myy/Zyy)

Maximum compressive stress = 344.80N/mm^2

1435/sq.root of f = 24.44

> 21.48

Hence section OK

Step :- 5

Combined Bending And Shear stresses in web

h/t = 84.96

WL2

Actual stress

m of squares

Maximum combined stresses = 0.511

< 1

OK

Step :- 6

Check for deflection

Number of spans = 3 Deflection = (3/384)(wl^4/EI)

w = 3.351kN/m Span = 6m

E = 207400N/mm^2

Ixx = 477.18cm^4

δ = 34.29mm Allowable deflection δ = Span/180

= 33.33mm

> 34.29

Not OK

  1. Design Foundations using STAAD Foundation.
  2. Attach necessary sketches and drawings wherever required.
  3. All stipulations, assumptions and design parameter must adhere to Indian Standards.

  1. Design a simply supported gantry girder to carry electric overhead travelling crane

Given:

Span of gantry girder = 7 m

Span of crane girder = 9 m

Crane capacity = 250 kN

Self-weight of trolley, hook, electric motor etc. = 40 kN

Self-weight of crane girder excluding trolley = 100 kN

Minimum hook approach = 1.0 m

Distance between wheels = 3 m

Self-weight of rails = 0.2 kN/m

Step 1

Span of gantry girder

=

7

m

Span of crane girder

=

9

m

Crane capacity

=

250

kN

Self weight (trolley,hook,motor)

=

40

kN

Self weight of crane girder

=

100

kN

Minimum hook approach

=

1

m

Distance between wheels

=

3

m

Self weight of rails

=

0.2

kN/m

Step 2

Maximum moment due to vertical load

Weight of trolley + Weight of load lifted

=

290

kN

Self weight of crane girder

=

100

kN

For maximum reaction on girder, the moving load should be as close to the gantry as possible

240 kN

200 kN

A

1

14

B

15 m

Reaction at A

RA

=

501

kN

Load on gantry girder from each wheel

=

251

kN

Factored wheel load

=

375.833

kN

RD

=

281.875

kN

Maximum moment

ME

=

634.22

kNm

let self weight of girder

=

2

kN/m

Dead load (self weight + rails)

=

2.2

kN/m

Factored DL

=

3.30

kN/m

M due to DL

=

20.21

kNm

M due to impact load

=

158.55

kNm

Factored moment due to all vertical loads

M

=

812.99

kNm

Step 3

Maximum moment due to lateral load

Hzl. Force transferred to rails

=

29

kN

Horizontal force on each wheel

=

7.25

kN

Factored horizontal force

=

10.875

kN

Maximum moment

=

18.35

kNm

Vertical shear due to

wheel loads

=

563.75

kN

impact

=

140.94

kN

self weight

=

9.90

kN

Total shear

=

714.59

kN

Lateral shear due to surge

=

20.68

kN

Step 4

Preliminary section determination

Minimum economic depth

D

=

L/12

=

583.333

mm

Width of compression flange

b

=

L/40 to L/30

=

175

233

Required plastic modulus

Zp

=

1.4 x M / fy

=

4552721

=

4552.72

x103 mm3

Let us try

ISMB 600 with ISMC 400 on compression flange

Step 5

Properties of selected section

ISHB

450 @ 0.92 kN/m

ISMC

400 @ 0.49 kN/m

A

11789

mm2

A

6380

mm2

h

600

mm

h

400

mm

b

250

mm

b

100

mm

tf

20.3

mm

tf

15.3

mm

tw

11.3

mm

tw

8.8

mm

Izz

40350

x104mm4

Izz

15200

x104mm4

Iyy

3045

x104mm4

Iyy

508

x104mm4

R

18.5

mm

Cyy

2.42

mm

Step 6

Determination of section modulus

Let the distance of N.A from the tension range by y'

y'

=

y'

=

407.58

mm

Izz

=

797.166

x106mm4

Zez

=

1955830

mm3

For compression flange about y-y axis

I

=

17843.2

x104mm4

Zey

=

892161

mm3

Total area of section

=

18169

mm2

Let plastic NA be at a distance Yp from tension flange.

Yp

=

375.12

mm

Zpz

=

5261194

mm3

For top flange

Zpy

=

1171868

mm3

Step 7

Section classification

For ISMB

b/t

=

5.88

<

9.4

d/t

=

46.23

<

84

For ISMC

b/t

=

5.96

<

9.4

Hence section is plastic

Step 8

Check for local moment capacity

Local moment capacity for bending in vertical plane

Mdz

=

fyZp / 1.1

=

1195.73

kNm

=

1.2 Zefy / 1.1

=

533.41

kNm

Mdz

=

533.41

kNm

For top flange

Mdy

=

266.33

kNm

=

243.317

kNm

Mdy

=

243.32

kNm

Step 9

Check for combined local capacity

1.60

>

1

Step 10

Check for buckling resistance

Md

=

βb Zp fbd

For plastic section

βb

=

1

LLT

=

7000

mm

E

=

200000

N/mm2

hf

=

597.5

mm

Iy

=

18245

x104mm4

A

=

18169

mm2

ry

=

100.21

mm

fcr,b

=

503.24

N/mm2

λ

=

0.705

ϕ

=

0.91

X

=

0.99

N/mm2

fbd

=

166.591

Mdz

=

876.47

kNm

Mdy

=

207.33

kNm

Hence

1.02

>

1

Hence section is unsafe against torsional buckling

Step 11

Check for shear

Vz

=

714.59

kN

Shear capacity

=

Av*fyw / √3 *1.1

=

889644

N

=

889.644

kN

>

714.59

Now

=

533.787

kN

low shear

Step 12

Check for web buckling

b

=

175

mm

n1

=

232.6

mm

d

=

522.4

mm

t

=

11.3

mm

λ

=

111.877

For buckling Class a

Table 9a

Fcd

=

128.6

N/mm2

Buckling resistance

=

592316

kN

>

714.59

kN

Step 13

Check for deflection at working load

Vertical deflection

Serviceability vertical wheel load

=

251

kN

Deflection at mid span

a

=

2000

mm

Izz

=

797.17

x106mm4

δ

=

42.82

mm

Horizontal deflection

I

=

17843.23

x104mm4

δ

=

4.58

mm

L/750

=

9.33

mm

Unsafe in vertical direction

Safe in lateral direction

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