The document discusses the design of a gantry girder to support a traveling crane. It provides details on load calculations, including wheel loads and impact loads. A preliminary trial section of ISWB 600 is selected. Calculations are shown for moment of inertia, plastic modulus, and checking bending and shear capacities. The section is determined to be adequate to support the factored bending moment of 651.81 kNm and maximum shear of 427.96 kN.

1. Presented by: Ghawsudin Mayar

2. GANTRY GIRDER
 Gantry girders are laterally unsupported beams to carry heavy
loads from place to place at the construction sites, mostly these are
of steel material.
2

3. INTRODUCTION TO THE GANTRY
GIRDER
 Profiles used for Gantry Girder
3

4.  Wheel Base
 Wheel base means the distance between the two wheels resting on
one gantry girder.
 This depends upon the span of the crane across the shop. The wheel
base may be taken as follows.
4

5.  Support
Gantry girders may be supported on brackets attached to columns or
stepped columns or on a separate column set on the inner side of the
main columns.
5

6.  Allowances for Impact of Wheel Loads
The following allowances are made to cover all forces caused by
vibration, shock from slipping of slings, kinetic action of acceleration
and retardation and impact of wheel loads.
6

7.  Load on Gantry Girder
 Vertical loads transmitted by the crane.
 Lateral forces transmitted due to sudden stopping or starting of the
crab on the crane.
 Longitudinal forces transmitted due to sudden stopping or starting
of the crane.
7

8. DESIGN PROCEDURES FOR GANTRY
GIRDER
1. Determination of the Maximum Wheel Load
2. Determine Maximum vertical shear force and maximum vertical
bending moment for the gantry girder
3. Determine Corresponding to the wheel loads the appropriate
lateral forces
4. Analysis of the Selected Girder Section
5. Checking
8

9. PROBLEM
Design a gantry girder to be used in an industrial building carrying a manual
operated travelling crane for the following data:
• Crane capacity: 200 KN
• Self-weight of the crane girder excluding trolley: 200 KN
• Self-weight of the trolley etc.: 40 KN
• Approximate minimum approach of the crane hook: 1.2m
• Wheel base: 3.5m
• Distance between gantry rails: 36m
• Distance between the columns: 8m
• Self-weight of rail section: 300N/m
• Diameter of crane wheel: 150mm
9

10. STEP (1): PARTIAL SAFETY FACTORS
10

11. STEP (2): DESIGN FORCES
 Maximum Wheel Load
Maximum concentrated load on crane:
Maximum factored load on crane:
Factored uniform distributed load:
11
200 40 240KN 
240 1.5 360KN 
200
1.5 8.33
36
KN 

12. Taking moment about (B)
Load on each wheel:
• Total weight of Sections: I section + Channel section + rail section
• Factored load =
12
8.33 36 36
* 36 360 (36 1.2) 498
2
* 161.88
RA RA KN
RB KN
 
      

498
249
2
KN
1432.4 351.2 300 2.3KN
m
  ;
1.5 2.3 3.45KN
m
 

13. 13
* 8 249 (8 1.375) 249 (3.125) 303.46
* 8 249 (1.375) 249 (4.875) 194.5
3.125
* 194 3.125 3.45 3.125 591
2
RC Rc KN
RD Rc KN
Moment KN m
       
      
       

14.  Maximum Shear
Taking moment about (D)
14
8 249 8 249 4.5 389.06RC Rc KN      

15.  Impact load
Vertical force to rails
• Machine operated 25% of wheel load
• Hand operated 10% of wheel load
• Total Moment =
15
10
249 24.9
100
KN 
* ' 8 24.9 6.25 24.9 3.125 ' 30.34
* ' 8 2 24.9 30.34 ' 19.46
* 19.46 3.125 60.81
RC RC KN
RD RD KN
Moment KN m
      
     
   
591 60.81 651.81KN m  

16. Horizontal Force to rail
Factored lateral force:
Lateral force on each wheel:
Maximum B.M due to lateral force by proportion:
16
5
240 12
100
KN 
5
240 1.5 12
100
KN  
18
9
2
KN
9 60.81
2.2
249
KNm


3 3
1.2
1 824.76 10 250 1.2 800.4 10 250
1.1 1.1
187.44 218.29
y y
z
o o
z
Zp f Ze f
Md
m m
Md
KNm KNm

 
   
 
     
 


17. STEP (3): PRELIMINARY TRIAL
SECTION
According IS 800:2007 (Table 46), I select ISWB 600 with
17
6
31.4 651.81 10
1.4 (3650.136 )
250
Mz
Zp cm
fy
 
  
3
3986.66Zp cm
ISWB 600@133.7 Kg/m ISMC 300@351N/m
bf 250mm 90mm
tf 21.3mm 13.6mm
tw 11.2mm 7.6mm
R1 17 13
Ixx 106198.5cm^4 6362.6cm^4
Iyy 4702.5cm^4 310.8cm^4
Area 17038mm^2 4564mm^2

18. 18

19.  Moment Inertia of Gantry Girder
 Izz gross = I beam + I channel
19
17038 (300 7.6) 4564 23.6
247.59
4564 17038
AY
y mm
A
   
  



106198.5 × 104
+ 17038 × 307.6 − 247.59 2
+ 310.8 × 104
+ 4564 × 274.59 − 23.6 2
= 135543 × 104
𝑚𝑚4

20. • A1+A2+A3+A4=A5+A6
• Equal Area Axis
20
(250 21.3) (300 7.6) (90 7.6 13.6) 2 (557.4 ) 11.2 ( 11.2) (250 21.3)
( 480.83 )
t t
t mm
             
 
600 2 21.3 480.83 76.57mm   

21.  Plastic Modulus of Section
21
3
7.6
* 300 7.6 (76.57 21.3 )
2
90 7.6
2 13.6 (90 7.6) (76.57 21.3 7.6 ( 7.6)
2
21.3
250 21.3 (76.57 )
2
76.57
76.57 11.2
2
480.83
480.83 11.2
2
21.3
250 21.3 (480.83 )
2
4767935.97
z
z
Zp
Zp mm
    

        
   
  
  
   
 
3 31356033064
* 3766.98 10
600 7.6 247.59
Iz
Ze mm
y
   
 

22. CLASSIFICATION OF SECTION
 Outstanding of flange of I-Section, b=bf/2<8.4ꜫ
 Outstanding flange of channel section, b=bf – tw/tf <8.4 ꜫ
 Web of I section d/tw
22
125
5.86 8.4
2
 
90 7.6
6.05 8.4
13.6


 
2( 1) 600 2(21.3 17)
46.73 84
11.2
f
w
D t R
t

   
  
Hence, the entire section is plastic.

23.  Check for moment capacity
Hence, moment capacity of the section
 Combined check for local Moment
23
3 3
1.2
1 824.76 10 250 1.2 800.4 10 250
1.1 1.1
1083.63 1026.81
y y
z
o o
z
Zp f Ze f
Md
m m
Md
KNm KNm

 
   
 
     
 

1026.81 651.81zMd KNm KNm 
1
651.81 2.2
0.64 1.......
1026.81 187.44
My Mz
Mdy Mdz
ok
 
  

24.  Buckling Resistance Check
24
0.5
2
2
2
4 4 5 4
2
5
1
1 ( )
2 20
8000
607.6
21.3 7.6 28.9
4702.5 10 6362.6 10 1106.51 10
17038 4564 21602
1106.5 10
71.56
21602
LT
y
f
f
L
y f
cr h
tLT
LT
f
f
y
y
EI h
M
L
L mm
h
t mm
I mm
A mm
Iy
A


  
  
  


  
     
  

  
0.5
2 5 4
2 6
2
8000
2 10 11065.1 10 607.6 1 71.561 ( ) 1610.78 10
607.62 8000 20
28.9
crM Nmm

 
     
     
  
 

25.  Non Dimensional Slender ratio
 Design Bending Compressive Stress
25
3
6
2
2
2 2 0.5
2 2 0.5
1 4767.977 10 250
0.86
1610 10
0.5 1 ( 0.2)
0.5 1 0.21 (0.86 0.2) 0.86 0.93
1
( )
1
0.77
0.93 (0.93 0.86 )
b pz y
LT
cr
LT LT LT LT
LT
LT LT LT
Z f
M


  


    
  

      
       

   
 
 
2
0.77 250
175
1.1
LT y
bd
o
f N
f
m mm


 
  

26.  Design Bending Strength
26
3
1 4767.977 10 175 834.39
dz b pz bd
dz
M Z f
M KNm
  
    
So 834.39 > 651.81 ………………………………………ok

27. STEP (4): CHECKING
 Shear Capacity Check
Maximum shear force due to wheel load= 389.06 KN
Impact Load=
Design Shear force= 389.06+38.90 = 427.96KN
So 881.77 > 427.96 ……………………….............ok
27
0.1 389.06 38.90KN 
600 11.2 250
881.77
3 3 1.1
w y
d
mo
h t f
V KNm

   
  
 

28.  Web Bearing Check
So 626.18 > 427.96 ………………………………ok
28
2
2 1
( 1 )
* 1 (100 150)
* 2.5( ) 2.5(21.3 17) 96
(150 96) 11.2 250
626.18
1.1
w y
w
o
f
w
b n t f
F
m
b
n t R
F KN

  

 
    
  
 

29. ANALYZE AND DESIGN BY STAAD
PRO
29

30. 30

31. 31