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 :-

1) Design Foundations using STAAD Foundation :-

4) Design using MS – Excel

1. a) Steel column :-

Height of column h = 9m

Yield strength fy = 250N/mm^2

Elastic modulus E = 200000N/mm^2

Material factor γm = 1.1

Step :- 1

Section classification

Properties of selected section

ISHB	400
A	10466mm^2
h	400mm
B	250mm
t	10.6mm
T	12.7mm
rx	166.1mm
ry	51.6mm
Zp	cm^3

Flange criterion b/T = 9.84

Web criterion d/t = 35.34

ε = 1

b/T < 10.5

d/t < 42

The section is classified as COMPACT

Step :- 2

Effective length

As both ends pin-jointed

KLx = 9m

KLy = 9m

KLz = 9m

Slenderness ratio

KLx/rx = 54.18

KLy/ry = 174.42

Non-dimensional effective slenderness ratio

λ = 1.964

Step :- 3

To calculate φ

h/bf = 1.60

> 1.2

T = 12.7mm

So, buckling class = b

α = 0.34

φ = 0.5(1+α(λ-0.2)+λ^2)

φ = 2.73

Step :- 4

Calculation of χ

χ = 0.216N/mm^2

Step :- 5

Calculation of fcd

fcd = χfy/γm

= 49.17

Step :- 6

Factored Axial Load

Pd = Afcd

= 514.614kN

1. b) Rafter :-

Span of I beam = 6m

Dead load = 18kN/m

Imposed load = 40kN/m

Length of bearing = 100mm

Yield strength = 250N/mm^2

Step :- 1

Design load calculation

Factored load = 87kN/m

Factored bending moment = 391.5kNm

Step :- 2

Section modulus required

Zreqd = 1722600mm^3

= 1722.60cm^3

Step :- 3

Section classification

Properties of selected section

ISMB	250
A	475.5mm^2
D	250mm
B	125mm
t	6.9mm
T	12.5mm
Izz	5131.6cm^4
Iyy	344.5cm^4
Zp	459.76cm^3

Flange criterion B/2T = 5

Web criterion (D-2T)t = 32.61

ε = 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 = (Zpχfy)/γm

Md = 104.491kNm

< 391.50

Hence section ISMB 250 is adequate for flexure

Step :- 4

Shear resistance of the cross section

Shear capacity Vc = 0.6fyAv/γm

Av = 1725mm^2

Vc = 235.23kN

V = 261kN

V/Vc = 1.11

.> 0.6

Step :- 5

Check for web buckling

Slenderness ratio of web = 2.5d/t

d = 225mm

= 70.33mm

Design compressive stress fc = 203N/mm^2

Pw = 315.16kN

> 261

Hence web is safe against shear buckling

Step :- 6

Check for web crippling at support

Root radius of ISMB250 R = 13mm

tf + R = 25.5mm

Dispersion length n^2 = 63.75mm

Pcrip = 245625N

= 245.63kN

< 261

Hence section adequate for web crippling

Step :- 7

Check for serviceability Deflection

Design load = 58kN/m

Deflection δ = 95.36mm

Allowable deflection = 30mm

Hence serviceability is satisfied

1. c) Base plate :-

Step :- 1

Strength of concrete fcu = 40 N/mm^2

Yield strength of steel fy = 250 N/mm^2

Material factor γm = .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 = 0.4fcu

= 16 N/mm^2

Area required = 93750 mm^2

Let size of plate

Bplate = 350 mm

Dplate = 350 mm

Area of plate = 122500 mm^2

Let projection on each side

a = b

= 25 mm

w = 12.24 N/mm^2

Thickness of slab base ts = 7.7 mm

< 12.70 mm

So use base plate of size 350mmx350mmx12mm.

1. d) Pedestal :-

Grade of concrete = 40N/mm^2

Load = 123kN

Moment = 116kNm

Horizontal shear = 13kN

Yield strength = 250N/mm^2

Length of base plate L = 450mm

Width of the base plate B = 350mm

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

Width of column W = 250mm

Step :- 1

Anchor Bolt Details

Dia of anchor bolt = 24mm

No of anchor bolt on each side = 4

Total number of anchor bolt,n = 8

Gross area of the bolt 'Asb' = 452.16mm^2

Net area of the bolt 'Anb' = 352mm^2

Ultimate tensile strength of the bolt fub = 400N/mm^2

Fyb(Anchor bolt) = 240N/mm^2

Step :- 2

Base plate details

Ultimate tensile strength of a plate,fu = 490N/mm^2

Thickness of plate = 16mm

Yield stress of plate = 330N/mm^2

Step :- 3

Anchor bolt design

Area of the plate = 157500mm^2

Stress Max pressure σ1 = F/A+6*Mz/BL^2

= 10.60N/mm^2

< 16

OK

Min pressure σ2 = F/A-6*Mz/BL^2

= -9.04N/mm^2

< 16

C = L*σ1/(σ1+σ2)

= 242.89mm

a = L/2-C/3

= 144.04mm

e = (L-Ld)/2
= 75mm

y = (L-C/3-e)

= 294.04mm

Tension in anchor bolts along the length of plate

FT = (Mz-Fxa)/y

= 364.38

Tension per bolt = 91.10kN

shear per bolt,V = 1.63kN

Step :- 4

Shear check

Factored shear force Vsb = 1.63kN

Vd,sd = 81290.9N

= 21.291kN

Factored Vd,sb = 65.03kN

Step :- 5

Tensile check

Factored tensile force in bolt Tb = 91.10kN

Tensile strength of bolt Td,b = Tnb/γmb

Tn,b = 0.9fubAn

= 126720N

= 126.72kN

Tn,b = fybAsb(γmb/γmo)

= 123316N

= 123.316kN

Lesser of two =123.32kN

So, Td,b = 98.65kN

Step :- 6

Combined unity check

(Vsb/Vdb)^2+(Tb/Tdb)^2

Vsb/Vdb = 0.025

Tb/Tdb = 0.92

Unity check = 0.85

< 1

Hence OK

Step :- 7

Anchor bolt length

Bond strength in tension bd = 1.4N/mm^2

Anchor length required = Tb/(3.14*d*τbd)

= 863.44mm

Let anchor bolt length=900mm

1. 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

	DL+LL	DL+WL1	DL+LL+WL2
Normal load	1.265	-3.351	1.556
Tangential load	0.111	0.013	0.111

	DL+LL	0.75(DL+WL1)	0.75(DL+LL+WL2)
Normal load	1.265	-2.514	1.167
Tangential load	0.111	0.009	0.083

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

	DL+LL	DL+WL1	DL+LL+WL2
Normal load	6.198	16.422	7.625
Tangential load	0.060	0.007	0.060
Mxx/Zxx	129.878	344.133	159.789
Myy/Zyy	5.895	0.672	5.895
(Mxx/Zxx)+(Myy/Zyy)	135.773	344.805	165.684

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

	DL+LL	DL+WL1	DL+LL+WL2
Fbw	506.539	673.697	637.697
Fv	735.223	977.847	977.847

Actual stress

fbw	129.878	344.133	159.789
fv	5.895	0.672	5.895
fbw/Fbw	0.256	0.511	0.237
fv/Fv	0.008	0.001	0.006
Sqrt of sum of squares	0.257	0.511	0.237

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

2) Design a simply supported gantry girder to carry electric overhead travelling crane

Step :- 1

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 :- 2

Maximum moment due to vertical load

Weight of trolley + weight of load lifted = 290kN

Self weight of crane girder = 100kN

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

Reaction at A RA = 501kN

Reaction at B RB = 281.875kN

Load on gantry girder from each wheel = 251kN

Factored wheel load = 375.833kN

Maximum moment ME = 634.21kNm

Let self weight of girder = 2kN/m

Dead load = 2.2kN/m

Factored DL = 3.3kN/m

M due to DL = 20.21kNm

M due to impact load = 158.55kNm

Factored moment due to all vertical loads

M = 812.99kNm

Step :- 3

Maximum moment due to lateral load

Horizontal force transferred to rails = 29kN

Horizontal force on each wheel = 7.25kN

Factored horizontal force = 10.875kN

Maximum moment = 18.35kNm

Vertical shear due to wheel loads = 563.75kN

Impact = 140.94kN

Self weight = 9.90kN

Total shear = 714.59kN

Lateral shear due to surge = 20.68kN

Step :- 4

Preliminary section determination

Minimum economic depth D = L/12

= 583.333mm

Width of compression flange b = L/40 to L/30

= 175 to 233

Required plastic modulus Zp = 1.4M/fy

= 4552721

= 4552.72x10^3

Let us try ISMB600 with ISMC400 on compression flange.

Step :- 5

Properties of selected section

ISMB	[email protected]/m
A	15600mm^2
h	600mm
b	210mm
tf	20.3mm
tw	12mm
Izz	91800x10^4mm^4
Iyy	2650x10^4mm^4
R	20mm

ISMC	[email protected]/m
A	6380mm^2
h	400mm
b	100mm
tf	15.3mm
tw	8.8mm
Izz	15200x10^4mm^4
Iyy	508x10^4mm^4
Cyy	2.42mm

Step :- 6

Let the distance of N>A> from, t,he tensio,n range by y'

y' = 388.93mm

Izz = 1348.13x10^6mm^4

Zez = 3466240mm^3

For compression flange about y-y axis

I = 16766.7x10^4mm^4

Zey = 838333mm^3

Total area of section = 21980mm^2

Let plastic N>A> be at a distance

Yp = 580.88mm

Zpz = 4410317mm^3

For top flange Zpy = 1078488mm^3

Step :- 7

Section classification

For ISMB b/t = 4.90

< 9.4

d/t = 43.28

< 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

= 1002.34kNm

Mdz = 1.2Zefy/1.1

= 945.34kNm

For top flange

Mdy = 245.11kNm

Mdy = 228.64kNm

In the above which ever the minimum value is taken

Mdz = 945.34kNm

Mdy = 228.64kNm

Step :- 9

Check for combined local capacity

(812.99/945.34)+(18.35/228.64)<1

0.947<1

Step :- 10

Check for buckling resistance

Md = βbZpfbd

βb = 1

Lt = 7000mm

E = 200000N/mm^2

hf = 597.5mm

Iy = 17850x10^4mm^4

A = 21980mm^2

ry = 90.12mm

fcr,b = 417.43N/mm^2

λ = 0.744

φ = 0.95

= 0.97N/mm^2

fbd = 166.591

Mdz = 734.72kNm

Mdy = 202.84kNm

Hence 1.20>1

Hence section is unsafe against torsional buckling

Step :- 11

Check for shear

Vz = 714.59kN

Shear capacity = Avfyw/(3^0.5x1.1)

= 944755N

= 944.755kN

> 714.59

Now = 566.853kN

Low shear

Step :- 12

Check for web buckling

b = 175mm

n1 = 232.6mm

d = 519.4mm

t = 12mm

= 104.746

Fcd = 128.6N/mm^2

Buckling resistance = 629008kN

> 714.59kN

Step :- 13

Check for deflection at working load

Vertical deflection

Serviceability vertical wheel load = 251kN

Deflection at mid span a = 2000mm

Izz = 1348.13x10^5mm^4

δ = 25.32mm

Horizontal deflection

I = 16766.65x10^4mm^4

δ = 4.88mm

L/750 = 9.33mm

Unsafe in vertical direction.

Safe in lateral direction.