Influence Line Diagrams-I

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Influence Line Diagrams-I

• Theory of Structures - I

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Contents

• Introduction
• Influence lines for Beams
• Reactions
• Shear
• Moments

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Introduction

• In normal shear force and bending moment
  diagrams, load remains static and cross-section
  of beam changes for various values.

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• In influence line diagrams for various functions
  (i.e. shear, bending moment, reactions),
  x-section remains static and load moves.

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Influence lines for Beams
6
12
Unit load at x 3
Unit load at x 6
Unit load at x 9
Unit load at x 12
Unit load at x 0
1
1
1
1
1
RA1
RB0
RA0
RB1
RA0.75
RB0.25
RA0.5
RA0.25
RB0.5
RB0.75
0.75
0. 5
0.25



-
-
-
0.25
0. 5
0.75
3.0
2.25
2.25
1.5
1.5
6
x RA 1-x/12 RB x/12 V6L -x/12 V6R 1-x/12 M6L x/2 M6R 6-x/2
0 1.0 0.0 0.0 0
3 0.75 0.25 -0.25 1.5
6 0.50 0.50 -0.50 3.0
6 0.50 0.50 0.50 3.0
9 0.25 0.75 0.25 1.5
12 0.0 1.0 0.0 0
7
1.0
0.5
ILD for RA
0.5
ILD for Shear at 6 from A
3.0
1.0
ILD for Moment at 6 from A
ILD for RB
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Practice Problems

• Example 6-1 to 6-8
• Chapter 6
• Structural Analysis by R C Hibbeler

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Thank You