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Illustrative Worked Examples: Commentary of Irc: 6-2017

This document provides a worked example to calculate the bending moment, shear force, and torsional moment for a simply supported box girder bridge due to various live load conditions at the support, quarter span, and mid span. It analyzes the maximum loads from Class 70R wheeled and tracked loading, Class A-2 lane loading, special vehicle loading, and congestion factor loading. For each loading case at the support, it calculates the maximum bending moment, shear force, eccentricity that causes maximum torsional moment. It also provides the load position diagrams and influence lines.

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jatin singla
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2K views4 pages

Illustrative Worked Examples: Commentary of Irc: 6-2017

This document provides a worked example to calculate the bending moment, shear force, and torsional moment for a simply supported box girder bridge due to various live load conditions at the support, quarter span, and mid span. It analyzes the maximum loads from Class 70R wheeled and tracked loading, Class A-2 lane loading, special vehicle loading, and congestion factor loading. For each loading case at the support, it calculates the maximum bending moment, shear force, eccentricity that causes maximum torsional moment. It also provides the load position diagrams and influence lines.

Uploaded by

jatin singla
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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COMMENTARY OF IRC: 6-2017

ILLUSTRATIVE WORKED EXAMPLES


CLAUSE NO. & TITLE:

204 - LIVE LOADS


DESIGN CALCULATIONS
WORKED EXAMPLE NO. TITLE OF WORKED EXAMPLE:
LIVE LOAD BENDING MOMENT, SHEAR FORCE & TORSIONAL MOMENT FOR A
204-1 SIMPLY SUPPORTED BRIDGE

PROBLEM STATEMENT 204‐1: FIND OUT BENDING MOMENT, SHEAR FORCE & TORSIONAL 
MOMENT FOR A 2 LANES SIMPLY SUPPORTED BOX GIRDER BRIDGE (OF 7.5 M CARRIAGEWAY) AT 
SUPPORT, QUARTER SPAN & MID SPAN DUE TO FOLLOWING CARRIAGEWAY LIVE LOADS:

a) CLASS 70R (WHEELED) LOADING
b) CLASS 70R (TRACKED) LOADING
c) CLASS A ‐2 LANE LOADING
d) SPECIAL VEHICLE LOADING AS PER CLAUSE 204.5
e) CONGESTION FACTOR LOAD AS PER CLAUSE 204.4

750 750

C VEHICLE
L C VEHICLE
L
C CARRIAGEWAY
L C CARRIAGEWAY
L

1.2m 2.79m 1.2m 2.9m

e=1.155m e=1.1m
7.5m 7.5m
 (A) CLASS 70R (WHEEL)   (B) CLASS 70R (TRACK)
C VEHICLE
L
C CARRIAGEWAY
L
C VEHICLE
L
C CARRIAGEWAY
L

0.15m 2.3m 1.2m 2.3m

e=0.7m e=0.3m
7.5m 7.5m

  (C) CLASS A ‐ 2 LANES (D) SPECIAL VEHICLE

TRANSVERSE ECCENTRICITY OF LIVE LOADS
COMMENTARY OF IRC: 6-2017
ILLUSTRATIVE WORKED EXAMPLES
CLAUSE NO. & TITLE:

204 - LIVE LOADS


DESIGN CALCULATIONS
WORKED EXAMPLE NO. TITLE OF WORKED EXAMPLE:
LIVE LOAD BENDING MOMENT, SHEAR FORCE & TORSIONAL MOMENT FOR A
204-1 SIMPLY SUPPORTED BRIDGE

SOLUTION :
CASE I :‐ FOR  SUPPORT SECTION
L O A D P O S IT IO N F O R M A X . S H E A R F O R C E L O A D P O S IT IO N F O R M A X . B E N D IN G M O M E N T
1 . C L A S S  7 0 R  (W H E E L E D ) L O A D IN G
1KN e = 1 .1 5 5 m
IN F L U E N C E  L IN E 170KN
D IA G R A M
170KN

170KN
170KN
170KN

120KN
120KN

80KN

1 .3 7 3 .0 5 3 .9 6
2.13
1.37

1.52

0 .7 5 3 0 .0 0 .7 5 0 .7 5 3 0 .0 0 .7 5

2 . C L A S S  7 0 R  (T R A C K E D ) L O A D IN G
1KN e = 1 .1 m
(7 0 0 K N /4 .5 7 m )
700KN

4 .5 7
0 .7 5 3 0 .0 0 .7 5 0 .7 5 3 0 .0 0 .7 5

3 . C L A S S  A   L O A D IN G
e = 0 .7 m
1KN 114KN
114KN
114KN

68KN

68KN

68KN

68KN
3 .0 3 .0 3 .0 3 .0
1 .2
0 .7 5 3 0 .0 0 .7 5 0 .7 5 3 0 .0 0 .7 5

4 . S P E C IA L  V E H IC L E   L O A D IN G
1KN e = 0 .3 m
180KN

1 8 0 K N  X  2 0  A X L E

1 .5 0 1 .5 0   (T Y P .) 1 .5 0
0 .7 5 3 0 .0 0 .7 5 0 .7 5 3 0 .0 0 .7 5

LOAD  IMPACT  MAX. BENDING  MAX. SHEAR  MAXIMUM  MAX. TORSIONAL 


S.NO.
DESCRIPTION FACTOR MOMENT ( B.M ) FORCE ( S.F ) ECCENTRICITY ( e ) MOMENT  ( S.F X e )

1 CLASS 70R (W) 1.125 ‐143 KNm 932 KN 1.155 m 1076 KNm


2 CLASS 70R (T) 1.1 ‐47 KNm 711 KN 1.10 m 782 KNm
3 CLASS A ‐ 2LANE 1.125 ‐96 KNm 910 KN 0.70 m 637 KNm
4 SPECIAL VEHICLE 1 ‐135 KNm 1890 KN 0.30 m 567 KNm
NOTE : AXLE LOADS MULTIPLIED BY THE FACTOR OF 10 TO CONVERT FROM TONNES TO KN.
SIGN CONVENTION : (‐)VE MEANS HOGGING & (+)VE MEANS SAGGING.

FOR CONGESTION OF VEHICULAR LIVE LOAD ON CARRIAGEWAY :‐
As per Table‐7, Congestion factor for 30m span  = 1.15
Maximum "SHEAR FORCE" due to Vehicular Load (Except 
= 932 KN
Special Vehicle)
Maximum "SHEAR FORCE" due to Congestion = 932 x 1.15
= 1072 KN
Corresponding "TORSIONAL MOMENT" = 0 KN
As per Clause 204.4,transverse eccentricity not be considered with Congestion factor.
COMMENTARY OF IRC: 6-2017
ILLUSTRATIVE WORKED EXAMPLES
CLAUSE NO. & TITLE:

204 - LIVE LOADS


DESIGN CALCULATIONS
WORKED EXAMPLE NO. TITLE OF WORKED EXAMPLE:
LIVE LOAD BENDING MOMENT, SHEAR FORCE & TORSIONAL MOMENT FOR A
204-1 SIMPLY SUPPORTED BRIDGE

CASE II :‐ FOR  QUARTER SPAN SECTION
L O A D P O S IT IO N F O R M A X . S H E A R F O R C E L O A D P O S IT IO N F O R M A X . B E N D IN G M O M E N T
1 . C L A S S  7 0 R  (W H E E L ED ) LO A D IN G
0 .7 5 K N IN F L U E N C E  LIN E e = 1 .1 5 5 m 5 .6 2 5 K N
D IA G R A M 7 .5
120KN
120KN
170KN
170KN

170KN
170KN

0 .7 5

120KN
120KN
170KN

170KN
170KN
80KN 0 .7 5
0 .7 5 8O KN 0 .7 5
3 .9 6
2.13
1.37

1.52
1.37

3 .9 6
3.05

2.13
1.37

1.37

1.52
3.05
‐0 .2 5 K N 3 0 .0 3 0 .0

2 . C L A S S  7 0 R  (T R A C K ED ) LO A D IN G
e = 1 .1 m 5 .6 2 5 K N
0 .7 5 K N

0 .7 5
700KN 0 .7 5
700KN 0 .7 5
0 .7 5

4 .5 7 1 .1 4 3 .4 3
‐0 .2 5 K N 3 0 .0 3 0 .0

3 . C L A S S  A   LO A D IN G
e = 0 .7 m 5 .6 2 5 K N
0 .7 5 K N
114KN
114KN
114KN
114KN
27KN
27KN

68KN

68KN

68KN

68KN

27KN
27KN

68KN

68KN

68KN
0 .7 5
0 .7 5 0 .7 5 68KN 0 .7 5

1 .1 1 .2 3 .0 3 .0 3 .0 3 .0 3 .2 4 .3 3 .0 3 .0 3 .0
‐0 .2 5 K N
1.10

1.20

3 0 .0
3 0 .0

4 . S P E C IA L  V E H IC L E   LO A D IN G
e = 0 .3 m 5 .6 2 5 K N
0 .7 5 K N
C .G
0 .7 5 1 8 0 K N  X  1 6  A X LE
0 .7 5 1 8 0 K N  X  2 0  A X LE

1 .5   (T Y P .) 1 .5 1 .5   (T Y P .)
‐0 .2 5 K N
3 0 .0 0 .7 5 3 0 .0 0 .7 5

LOAD  IMPACT  MAX. BENDING  MAX. SHEAR  MAXIMUM  MAX. TORSIONAL 


S.NO.
DESCRIPTION FACTOR MOMENT ( B.M ) FORCE ( S.F ) ECCENTRICITY ( e ) MOMENT  ( S.F X e )

1 CLASS 70R (W) 1.125 5010 KNm 651 KN 1.155 m 752 KNm


2 CLASS 70R (T) 1.1 4001 KNm 518 KN 1.10 m 570 KNm
3 CLASS A ‐ 2LANE 1.125 5062 KNm 614 KN 0.70 m 430 KNm
4 SPECIAL VEHICLE 1 10125 KNm 1080 KN 0.30 m 324 KNm
NOTE : AXLE LOADS MULTIPLIED BY THE FACTOR OF 10 TO CONVERT FROM TONNES TO KN.
SIGN CONVENTION : (‐)VE MEANS HOGGING & (+)VE MEANS SAGGING.

FOR CONGESTION OF VEHICULAR LIVE LOAD ON CARRIAGEWAY :‐
As per Table‐7, Congestion factor for 30m span  = 1.15
Maximum "SHEAR FORCE" due to Vehicular Load (Except 
= 651 KN
Special Vehicle)
Maximum "SHEAR FORCE" due to Congestion = 651 x 1.15
= 749 KN
Corresponding "TORSIONAL MOMENT" = 0 KN
As per Clause 204.4,transverse eccentricity not be considered with Congestion factor.
COMMENTARY OF IRC: 6-2017
ILLUSTRATIVE WORKED EXAMPLES
CLAUSE NO. & TITLE:

204 - LIVE LOADS


DESIGN CALCULATIONS
WORKED EXAMPLE NO. TITLE OF WORKED EXAMPLE:
LIVE LOAD BENDING MOMENT, SHEAR FORCE & TORSIONAL MOMENT FOR A
204-1 SIMPLY SUPPORTED BRIDGE

CASE III :‐ FOR  MID SPAN SECTION
L O A D P O S IT IO N F O R M A X . S H E A R F O R C E L O A D P O S IT IO N F O R M A X . B E N D IN G M O M E N T
1 . C L A S S  7 0 R  (W H E E L E D ) L O A D IN G
IN F L U E N C E  LIN E e = 1 .1 5 5 m 7 .5 K N
0 .5 K N D IA G R A M
170KN

120KN
120KN
170KN
170KN
170KN
170KN
120KN

80KN
8O KN
0 .7 5 0 .7 5

3 .9 6

2.13

3.05
1.52

1.37

1.37
‐0 .5 K N
0 .7 5 3 0 .0 0 .7 5 3 0 .0

2 . C L A S S  7 0 R  (T R A C K E D ) L O A D IN G
0 .5 K N e = 1 .1 m 7 .5 K N

700KN

4 .5 7 700KN

‐0 .5 K N 4 .5 7
0 .7 5 3 0 .0 0 .7 5 0 .7 5 3 0 .0 0 .7 5

3 . C L A S S  A   L O A D IN G
0 .5 K N e = 0 .7 m 7 .5 K N
114KN
114KN
27KN
27KN

68KN

68KN

68KN

68KN

114KN
114KN

68KN

68KN

68KN

68KN
27KN
27KN

‐0 .5 K N 1 .1 3 .2 4 .3 3 .0 3 .0 3 .0
0 .7 5 3 0 .0 0 .7 5 1 .2
0 .7 5 3 0 .0 0 .7 5

4 . S P E C IA L  V E H IC L E   L O A D IN G
0 .5 K N e = 0 .3 m 7 .5 K N
1 8 0 K N  X  1 0  A X LE C .G
1 5 .0

1 .5  (T Y P .) 1 8 0 K N  X  2 0  A X LE

‐0 .5 K N 1 .5  (T Y P .)
0 .7 5 3 0 .0 0 .7 5 0 .7 5 3 0 .0 0 .7 5

LOAD  IMPACT  MAX. BENDING  MAX. SHEAR  MAXIMUM  MAX. TORSIONAL 


S.NO.
DESCRIPTION FACTOR MOMENT ( B.M ) FORCE ( S.F ) ECCENTRICITY ( e ) MOMENT  ( S.F X e )

1 CLASS 70R (W) 1.125 6613 KNm 370 KN 1.155 m 427 KNm


2 CLASS 70R (T) 1.1 5335 KNm 326 KN 1.10 m 359 KNm
3 CLASS A ‐ 2LANE 1.125 6201 KNm 302 KN 0.70 m 211 KNm
4 SPECIAL VEHICLE 1 13500 KNm 495 KN 0.30 m 149 KNm
NOTE : AXLE LOADS MULTIPLIED BY THE FACTOR OF 10 TO CONVERT FROM TONNES TO KN.
SIGN CONVENTION : (‐)VE MEANS HOGGING & (+)VE MEANS SAGGING.

FOR CONGESTION OF VEHICULAR LIVE LOAD ON CARRIAGEWAY :‐
As per Table‐7, Congestion factor for 30m span  = 1.15
Maximum "SHEAR FORCE" due to Vehicular Load (Except 
= 370 KN
Special Vehicle)
Maximum "SHEAR FORCE" due to Congestion = 370 x 1.15
= 426 KN
Corresponding "TORSIONAL MOMENT" = 0 KN
As per Clause 204.4,transverse eccentricity not be considered with Congestion factor.

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