msi05 shear force influence lines(1)

Faculty : Civil And EnvironmentEngineering

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Department : Structure And MaterialEngineering

Edition 2Checking No

Title :

SHEAR FORCE INFLUENCE LINES

Effective Date 11/07/2005AmendmentDate

5/7/2005

1.0 OBJECTIVE

1.1 Part 1: To plot Shear force influence line.1.2 Part 2: To verify the use of a shear force influence on a simply supported

beam

2.0 LEARNING OUTCOME

2.1 The application the engineering knowledge in practical application2.2 To enhance technical competency in structural engineering through

laboratory application.2.3 To communicate effectively in group2.4 To identify problem, solving and finding out appropriate solution through

laboratory application

3.0 INTRODUCTION

Moving loads on beams are common features of design. Many road bridges areconstructed from beam, and as such have to be designed to carry a knife edge load,or a string of wheel loads, or a uniformly distributed load, or perhaps the worstcombination of all three. The method of solving the problem is to use influencelines.

Prepared by:Name: Ahmad Zurisman bin Mohd Ali

Singnature:

Date:


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4.0 THEORY

Defination: Shear influence line is defined as a line representing the changesin shear force at a section of a beam when a unit load moves on the beam

Part 1: This Experiment examines how shear force varies at a cut section as aunit load moves from one end to another ( see Figure 1). From the diagram,shear force influence line equation can be writen.

For 0 ax a shear line is given by :

LxSy …………… (1)

For bxa shear line is given by:

LxSy 1 . ……………(2)

1 (unit load ) x ‘cut’x Sy

RA Sy RB

a b

L

Figure 1

Part 2: If the beam are loaded as shown in Figure 2, the shear force at the ‘cut’can be calculated using the influence line. (See diagram 2).

Shear force at ‘cut’ section 332211 yFyFyF … (3)

(y1 , y2 and y3 are ordinates derived from the influence line in terms of

x1, x2, x3 ,a , b and L)


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F1 F2 F3 Lba

x1x2

x3

Shear Force Influenceline for cutsection.

y1 y2 y3

Figure 2

4.0 APPARATUS

Sketch the apparatus used in this experiment and named the essential components


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5.0 PROCEDURES

Part 1:1. Check the Digital Force Meter reads zero with no load.2. Place hanger with any mass range between 100g to 300g at the first

grooved hanger support at the left support and record the Digital Forcereading in Table 1.

3. Repeat the procedure to the next grooved hanger until to the lastgrooved hanger at the right hand support

4. Complete the calculation in Table 1.Part 2:

1. Place three load hangers with 100g. 200g and 300g massrespectively at any position between the supports. Record thepositions and the Digital Force Display reading in Table 2.

2. Repeat the procedure with three other locations.3. Complete the calculation in Table 2

6.0 RESULTPart 1:

Location of loadfrom left handsupport (m)

Digital ForceDisplay

Reading (N)

Shear Forceat cut section

(N)

Experimental Influenceline value

TheoreticalInfluencelines value

0.040.060.080.100.120.140.160.180.200.220.240.260.340.360.380.40

Table 1


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Notes:1. Shear force at cut section is the same value given by Digital force reading. Add –ve

sign to the value for positions 320mm to 380mm.

2. Experimental Influence line values =)(

)(NLoad

NShearForce

3. Calculate the theoretical value using the equation 1 for load position 40 to 260 mmand equation 2 for load position 320mm to 380mm.

Part 2 :

Location Position of hanger from left handsupport (m)

Shearforce

DigitalReading

(N)

TheoreticalShear(Nm)

100g 200g 300g

1234

Table 2Notes:

1. Theoretical Shear Force is calculated using Equation (3)

7.0 DISCUSSIONS

Part 1

1. Derive equation 1 and 2.………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….……………………………………………………………………………………………………………………………………………………


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2. On the same graph paper, plot the theoretical and experimental valuesagainst distance from left hand support.

3. Comment on the shape of the graph. What does it tell you about how shearforce varies at the cut section as a load moved on the beam.…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

4. Comment on the experimental result compared to the theoretical result…………………………………………………………………………..…………………………………………………………………………..…………………………………………………………………………..…………………………………………………………………………..…………………………………………………………………………..…………………………………………………………………………..………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………


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Part 2

1. Comment the experimental result and the theoretical result in Table 2.…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………..………………………………………………………………………..………………………………………………………………………..………………………………………………………………………..………………………………………………………………………..………………………………………………………………………..

8.0 CONCLUSIONS

What can you prove from the experiment

Part 1:

……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….

Part 2:

………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

msi05 shear force influence lines(1)

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