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
   2. Rafter
   3. Base plate
   4. Pedestal
   5. Z- purlin

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.

Roof Slop Calculations:

Roof Slope  = 1 in 12

Width, b     = 30 m

X / (b/2)    = 1/12

X               = (30/2) / 12  =  15/12

X              = 1.25 m

Total height =9 +1.25 =10.25

Calculation of Design Loads:

1. Calculation of Dead load:

UDL on Rafter (Main frame):

Weight of roof sheeting = 5 Kg/m2

Weight of sag rods and braces = 5 Kg/m2

Collateral load = 10 Kg/m2

Total load = 20 Kg/m2 = 0.2 KN/m2

UDL on Rafters:

Bay spacing = 6m  

UDL = 0.2 X 6 = 1.2 KN/m

UDL on Rafters from purlin:

Choose suitable purlin section for weight of purlin (IS-811)

Say Z = 270 X 75 X 20 X 2.55 = 8.77 Kg/m

weight on rafters from purlin = (Number of purlin X Length of purlin X Weight of Purlin) / Length of rafter

                                          = ( 5 X 6 X 8.77)/15 

                                          = 17.54 Kg/m = 0.175 KN/m

UDL on main frame = 1.2 + 0.175 = 1.375 KN/m 

UDL on gable frame = 1.375/2 = 0.687 KN/m

UDL on Column (Main frame):

Weight of side wall sheeting = 5 Kg/m2

Weight of sag rod and braces = 5 Kg/m2 

Load from sag rods & braces = 10 Kg/m2 = 0.1 KN/m2 = 6 X 0.1 = 0.6 KN/m

Weight of grit (270 X 75 X 20 X 2.55) = 8.77 Kg/m

Weight on column = (5 X 6 X 8.77)/6 = 43.85 Kg/m = 0.438 KN/m

Total Load = 0.6 + 0.438 = 1.038 KN/m

UDL on Column (Gable frame):

Total load = 1.038/2 = 0.565 KN/m

Load on wind column:

Load from sheet and sag rods = 0.1 X 6 = 0.6 kN/m

Weight of grits (230 X 75 X 20 X 2) = 6.32 Kg/m

Load on wind column = (6X 6.32 X 6)/6 = 37.92 Kg/m = 0.38 KN/m

Total load = 0.6 + 0.38 = 0.98 KN/m

Dead Load on eave strut & Gutter:

Point load:-

Weight of Eave strut = CS 270 X 75 X 20 X 3.15 = 10.7 Kg/m

Weight of eave gutter = 0.25 X 0.25 X 0.001 = [0.25 + 0.25 + 0.25] X 0.001 X 7850                  

                                   =5.89 Kg/m

Load due to eave strut & gutter = 10.7 + 5.89 = 16.59 Kg/m 

Load due to eave strut & gutter (Main frame) = 16.59 X 6 = 99.54 Kg 

                                                                        = 0.995 KN

Load due to eave strut & gutter (Gable frame) =0.497 KN

2. Calculation of Live load:

Live load on roof = 0.75 KN/m2 (IS 875- II)

UDL on Rafter:

Main frame rafter = 0.75 X 6 = 4.5 KN/m

Gable frame rafter = 0.5 X 4.5 = 2.25 KN/m

Eave gutter (250 X 250 X 1mm)

Load due to weight of water in gutter:

Main frame = [0.25 X 0.25 X 9 X 6] = 3.375 KN

Gable frame = [0.5 X 3.375] = 1.687 KN

3. Calculation of wind load:

Basic wind speed = 50 m/s for Chennai.

K1 - 1.00

K2 - 1.0

K3 - 1.00

K4 - 1.15

Kd -0.9

Ka (Rafter) - 0.8 or as per tributary area.

Ka (Column) - 0.8245 or as per tributary area.

Ka (Purlin) - 0.9721 or as per tributary area.

Ka (Side Runner) - 0.978 or as per tributary area

Kc -0.9

Design wind pressure = pd = kd x ka x kc x 0.6 x (Vb x k1 x k2 x k3 x k4)^2= 0.652 kN/m2

But should not be less than 0.7 Pz = 0.7 x 1.006 = 0.704 kN/m2

Cpe - As per table 5 & 6 of IS: 875 (Part 3) – 2015

Cpe On wall:

Direction	A	B	C	D
0 deg.	0.7	-0.25	-0.6	-0.6
90 deg.	-0.5	-0.5	0.7	-0.1

Cpe On Roof:

Roof angle = 2.86

Direction	EF	GH	EG	FH
0 deg.	-0.86	-0.4
90 deg.			-0.8	-0.4

Cpi = 0.2

Wind Load on Column in (+X)-direction:

Wind Load on Columns = (Cpe – Cpi) x A x Pd

Wind about X Direction + Cpi = (0.7 – 0.2) x 8 x 0.704 = 2.816 kN/m on Wall A

Wind about X Direction + Cpi = (-0.25 – 0.2) x 8 x 0.704 = -2.534 kN/m on Wall B

Wind about X Direction + Cpi = (-0.6 – 0.2) x 6.75 x 0.704 = -3.802 kN/m on Wall C & D

Wind Load on Column in (-X)-direction:

Wind about X Direction - Cpi = (0.7 + 0.2) x 8 x 0.704 = 5.069 kN/m on Wall A

Wind about X Direction - Cpi = (-0.25 + 0.2) x 8 x 0.704 = -0.282 kN/m on Wall B

Wind about X Direction - Cpi = (-0.6 + 0.2) x 6.75 x 0.704 = -1.9 kN/m on Wall C & D

Wind Load on Column in (+Z)-direction:

Wind about Z Direction + Cpi = (-0.5 – 0.2) x 8 x 0.704 = -3.942 kN/m on Wall A

Wind about Z Direction + Cpi = (-0.5 – 0.2) x 8 x 0.704 = -3.942 kN/m on Wall B

Wind about Z Direction + Cpi = (0.7 – 0.2) x 6.75 x 0.704 = 2.376 kN/m on Wall C

Wind about Z Direction + Cpi = (-0.1 – 0.2) x 6.75 x 0.704 = -1.425 kN/m on Wall D

Wind Load on Column in (-Z)-direction:

Wind about Z Direction - Cpi = (-0.5 + 0.2) x 8 x 0.704 = -1.689 kN/m on Wall A

Wind about Z Direction - Cpi = (-0.5 + 0.2) x 8 x 0.704 = -1.689 kN/m on Wall B

Wind about Z Direction - Cpi = (0.7 + 0.2) x 6.75 x 0.704 = 4.276 kN/m on Wall C

Wind about Z Direction - Cpi = (-0.1 + 0.2) x 6.75 x 0.704 = 0.475 kN/m on Wall D

Wind Load on Rafters in (+X)-direction:

Wind Load on Rafters = (Cpe – Cpi) x A x Pd

Wind about X Direction + Cpi = (-0.86 – 0.2) x 8 x 0.704 = -5.970 kN/m on Side A Rafter

Wind about X Direction + Cpi = (-0.4 – 0.2) x 8 x 0.704 = -3.378 kN/m on Side B Rafter

Wind Load on Rafters in (-X)-direction:

Wind about X Direction - Cpi = (-0.86 + 0.2) x 8 x 0.704 = -3.716 kN/m on Side A Rafter

Wind about X Direction - Cpi = (-0.4 + 0.2) x 8 x 0.704 = -1.125 kN/m on Side B Rafter

Wind Load on Rafters in (+Z)-direction:

Wind about Z Direction + Cpi = (-0.8 - 0.2) x 6.75 x 0.704 = -4.752 kN/m Side C Rafter

Wind about Z Direction + Cpi = (-0.4 - 0.2) x 6.75 x 0.704 = -2.851 kN/m Side D Rafter

Wind Load on Rafters in (-Z)-direction:

Wind about Z Direction - Cpi = (-0.8 + 0.2) x 6.75 x 0.704 = - 2.851kN/m Side C Rafter

Wind about Z Direction - Cpi = (-0.4 + 0.2) x 6.75 x 0.704 = -0.950 kN/m Side D Rafter

Wind Load on Canopy:

Cp - As per table 8 of IS: 875 (Part 3) – 2015

Roof Angle 2.86 deg.

Cp -ve = 1.08

Cp +ve = 0.35

Wind Load on Canopy (Upward) = 1.08 x 8 x 0.704 = 6.082 kN/m

Wind Load on Canopy (Downward) = 0.35 x 8 x 0.704 = 1.971 kN/m

3. Seismic Load:

As per IS: 1893 - 2016

Seismic zone - III - Z = 0.16

Rf - 4.0

I - 1.0

SS - 3.0

25% of Live Load on roof considered for calculation of seismic forces.

100% of collateral load on roof considered for calculation of seismic forces.

50% of (Live load + Collateral load) on mezzanine floor considered for calculation of seismic forces.

100% of Dead load considered for calculation of seismic force.

Modeling in staad pro:

Step 1: create model in staad pro

Step 2: Assign section to the drawing

Step 3: Give specifications

• Assign tension member
• Release moment

Step 4: Input all load cases

Step 5: Assign values in load cases

Step 6: Generate seismic definition

Step 7: Input wind load

Step 8: Define parameters

Step 9: Define commands

Step 10: Run analysis

Step 11: In result : Setup report : Print report

Step 12 : Click on Staad foundation

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Design of Steel Column:

Flange thickness = T = 12.7 mm.

Overall height of Column ISMB400 = h = 400 mm.

Clear depth between flanges = d = 400 – (12.7 x 2)

= 374.6 mm.

Thickness of web = t = 10.6mm.

Flange width = 2b = bf = 250 mm.

Hence, half Flange Width = b = 125 mm.

Self –weight = w = 0.822 kN/m.

Area of cross-section = A = 10466 mm2.

Radius of gyration about x = rx = 166.1 mm.

Radius of gyration about y = ry = 51.6 mm.

Type of section:

b/T = 125/12.7= 9.8 < 10.5

d/t =374.6/10.6 =35.3 < 42

(Table 3.1 of IS: 800)

Hence, cross-section can be classified as “COMPACT”.

Effective Sectional Area:

Ae = 10,466 mm2

(Since there is no hole, (Clause 7.3.2 of IS: 800)

no reduction has been considered)

Effective Length:

As, both ends are pin-jointed effective length, KLx = KLy = 3m

Slenderness ratios:

KLx/rx = 9000/166.1 =54.1

KLy/ry = 9000/51.6 =174.41

Non-dimensional Effective Slenderness ratio, λ">λ:

         = (sqrt2.5X(174)^2)/(pi^2X2X10^5)= 3.83

Value of ϕ">ϕ from equation: 

Hence, α">α = 0.34 for buckling class ‘b’ will be considered.

Hence, ϕ">ϕ= 0.5 x [1+0.34 x (0.654-0.2)+0.6542] = 0.791

Calculation of x:

     =   0.809

Calculation of fcd from the following equation:

= 0.809 x 250/1.1 = 183.86 N/mm2

Factored axial load in kN.

pd = Ag fcd

    = 10466 x 183.86/1000 = 1924.28 kN.

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Design of Rafter:

Span of Rafter = 6 m

Dead load = 18KN/m

Imposed load = 40KN/m

support bearing = 100mm

yield strength = 250N/mm2

Design load calculation:

Factores load 1.5(DL+LL) =87 KN/m

Factores Bending moment = 65.25 KN/m

Section modulus Required:

Z reqd = (65.25 x 10^6 x1.1) /250 =287100 mm3 = 287.1 cm3

Section classification:

ISMB-200

A = 323.3 mm2

D = 200mm

B = 100mm

t = 5.7 mm

T = 10.8 mm

Ixx = 2235.4 cm4

Iyy = 150 cm4

Zp = 375.35 cm3

Moment of resistence of the cross-section:

Md = 

      = (1 x 375.35 x 250) / ( 1.1)

Md = 85.306 > 65.25 KN/m.

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Design of Base Plate:

Strength of concrete, Fcu = 40 N/mm2

Yield strength of steel, fy = 250 N/mm2

Material factor, γm">γm= 1.1 KN

Factoresl Load = 1500 KN

Steel column section:

Thickness of flange, T = 12.7 mm

Area required:

Bearing strength of concrete = 0.4fcu = 0.4 x 40 = 16 N/mm2

                                          = (1500x1000) /( 16)

                                          = 93750 mm2

Let size of plate , Bplate = 450 mm

                          Dplate = 300 mm

                 Area of plate= 135000 mm2

projection on each side = a=b =25mm

W = (1500x1000) /( 450 x 300)

     = 11.11 N/mm2

Therefore, Thickness of Base Plate, clause 7.4.3.1

ts= 7.3 mm < 12.7 mm

Size of Base plate 450 x 350 x 16 mm

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Design of Pedestal:

Grade of concrete = 40 N/mm2

Load                    = 200 KN

Moment               = 120 KN

Horizontal shear   = 20 KN

Yield strength       = 250 N/mm2

Length of base plate = 450 mm

Width of base plate = 350 mm

C/C distance of bolt in group-Z = 300 mm

C/C distance of bolt in group-X = 180 mm

Bearing strength of concrete Fc = 16 N/mm2

Depth of Column = 300 mm

Width of Column = 250 mm

Anchor Bolt Details:

Dia of anchor bolts =24 mm

No:of anchor bolts in each side = 4

Total no:of anchor bolts, n = 8

Gross area of the bolt ;Asb' = 452.16 mm2

Net area of bolt 'Anb' = 352 mm2

Ultimate tensile strength of bolt 'fub' = 400 N/mm2

Fyb (anchor bolts) = 240 N/mm2

Base plate Details:

Ultimate tensile strength of plate 'fu' = 490 N/mm2

Thickness of plate = 16 mm

Yield stress of plate = 330 N/mm2

Anchor bolt design:

Area of the plate =  157500 mm2

Stress,   Maximum pressure =

                                         = 10.6 N/mm2 < 16 Hence OK

             Minimum pressure =

                                         = -9.04 N/mm2 < 16 Hence OK

 Centroid = = 242.89 mm

a =L/2-C/3 = 144.04 mm

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

y = (L - C/3-e) = 294.04 mm

Tension in anchor bolt along the length of plate, FT = (Mz - Fa)/Y

                                                                          = 364.38

Tension per bolt                                                   = 91 KN

Shear per bolt                                                     = 1.63 KN

Shear Check:

Factored shear force = Vsb = 1.63 KN

                                 Vd,sb = 81290.9 N

                                          = 81 KN

Factored                      = 65.03 KN

Tensile Check:

Factored tensile force in bolt, Tb = 91.1 KN

Tensile strength of bolt       

Ts,b = Tn,b /$\gamma mb$= 126 KN

Td,b = 98.65 KN

Combined Unity Check:

Vsb/Vdb = 0.025

Tb/Tdb = 0.92

Unity check = 0.85 <  1, Hence OK

Anchor Bolt Length:

 Bond strength in tension, $\tau bd$= 1.4 N/mm2

Anchor length required = Tb(3.14*$\tau bd$)

                                  = 863.44 mm

Let Anchor Bolt Length = 900 mm

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Design of Z-Purlin:

Span of the purlin = 6 m

spacing of purlin = 1.5 m

No:of sag rods = 1

slope of the roof = 4.76 = 5 degree

Dead load:

Weight of sheeting = 6kg/m2

self weight of purlin = 4.22 kg/m2

Additional load = 10% = 0.42 kg/m2

Total Dead load = 0.106 kg/m2

Live load:

Live load on roof = 75 kg/m2

Wind Load:

Basic wind speed = 50 m/s

Terrain caterogy  = 2

Building class      = B

               K1      = 1

               K2      = 1

               K3      = 1

Design wind speed, Vz = 57 m/s

Design wind pressure, Pz = 1949.9 m/s = 1.94 KN

Length of building, L = 50 m

Breadth of building, W = 30 m

Height of building, H = 10.25 m

Height of eaves, = 9 m

                      h/w = 0.34

                      L/w = 1.667

External Pressure Co-eeficient:

Maximum downward =Cpe =  -0.4

Maximum upward =Cpe =  -0.7

Internal Pressure Co-eeficient:

Maximum positive =Cpi =   0.5

Maximum negative =Cpi =  -0.5

For Maximum upward wind force:

Max upward Cpe = - 0.7

Cpi = - 0.5

Cpe+Cpi = -1.2

Pz = 1.95

Wind Pressure for Purlin Design = - 2.339 KN/m2

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 = 0.195 KN/m2

Design Load Calculation:

spacing of purlin 1.5 m

slope of roof = 5degree

Total dead load = 0.096

DL Normal component = 0.144 KN/m

DL Tangential component = 0.013 KN/m

Total Live load = 0.75

LL Normal component = 1.121 KN/m

LL Tangential component = 0.098 KN/m

Total Wind load = -2.339 

WL Normal component = - 3.496 KN/m

WL2 WL load = 0.195 KN/m

WL Normal component = 0.291 KN/m

Maximum Normal component = DL+LL = 1.265 KN/m

Purlin section:

Selected section Z200 x 6 x 2.3

Area = 8.07 cm2

Weight of purlin = 6.335 kg/m

_______________________________________________________________________________________________________________________________________________________

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

Step : 1

Given Data:

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

Letr 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	600@1.22kN/m
A	15600mm^2
h	600mm
b	210mm
tf	20.3mm
tw	12mm
Izz	91800x10^4mm^4
Iyy	2650x10^4mm^4
R	20mm

 

ISMC	400@0.49kN/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

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 classfication:

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 whichever 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.

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