Ce3100 Str Lab July Nov 2014

5/21/2018 Ce3100 Str Lab July Nov 2014

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CE 3100 Structural Engineering LabJuly- November 2014

Instructors:

Dr. Amlan K

Sengupta

Dr. Arun

Menon

Dr Meher

Prasad A

Dr. Saravanan U Dr Satish Kumar

S R

VI Semester Slot P Monday 14:00 17:00

Timings

Group Lab Report

1 14:00 15:25 15:35 17:00

2 15:35 17:00 14:00 15:25

Experiments to be performed:

1.

Behavior of under-reinforced concrete beams under flexure2.

Behavior of short reinforced concrete columns under axial compression

3.

Behavior of reinforced concrete beams under shear4.

Behavior of reinforced concrete beams under torsion5.

Bending tests on rolled steel joists6.

Symmetrical and unsymmetrical bending7.

Torsion of closed and open sections8.

Plastic behavior of steel beams9.

Buckling of steel angles10.

Lateral buckling of steel H beams11.

Behavior of bolted connectionsDemonstration Experiments:

1.

Bond strength tests

2.

Behavior of over-reinforced concrete beams under flexure

Schedule

Expt

#

August September October November

4 11 18 25 1 8 15 22 13 20 27 3 10 17

1

Introo

fexperiments

a b c d e f g h i j k

Demonstr

ationExperiment

FinalExam

2 b c d e f g h i j k a

3 c d e f g h i j k a b

4 d e f g h i j k a b c

5 e f g h i j k a b c d

6 f g h i j k a b c d e

7 g h i j k a b c d e f

8 h i j k a b c d e f g

9 i j k a b c d e f g h

10 j k a b c d e f g h i

11 k a b c d e f g h i j


2/37

Group Members

Group Roll No. Group Roll No. Group Roll No.

a1

CE08B033

CE11B001

CE11B029CE11B031

CE11B055

e1

CE11B011

CE11B041

CE11B063

CE11B085

i1

CE11B019

CE11B049

CE11B073

CE11B093

a2

CE08B046

CE11B002

CE11B026

CE11B028

CE11B050

e2

CE11B012

CE11B036

CE11B060

CE11B078

CE11B100

i2

CE11B020

CE11B044

CE11B068

CE11B086

b1

CE11B003

CE11B033

CE11B057CE11B079

CE11B099

f1

CE11B013

CE11B043

CE11B067CE11B087

j1

CE11B021

CE11B051

CE11B075CE11B095

b2

CE09B056

CE11B004

CE11B030

CE11B052

CE11B092

f2

CE11B006

CE11B014

CE11B038

CE11B062

CE11B080

j2

CE11B022

CE11B046

CE11B070

CE11B088

c1

CE11B005

CE11B035

CE11B059

CE11B081

g1

CE11B015

CE11B045

CE11B069

CE11B089

k1

CE11B027

CE11B053

CE11B077

CE11B097

c2

CE11B008

CE11B032

CE11B054

CE11B074

CE11B096

g2

CE11B016

CE11B040

CE11B056

CE11B064

CE11B082

k2

CE11B024

CE11B048

CE11B072

CE11B090

d1

CE11B009

CE11B039

CE11B061

CE11B083

h1

CE11B017

CE11B047

CE11B071

CE11B091

d2

CE11B010CE11B034

CE11B058

CE11B076

CE11B098

h2

CE11B018

CE11B042

CE11B066

CE11B084


3/37

Course Evaluation

1.

Session Assessment :75%(Group Report, Viva during the experiment)

2. Final Examination :25%

General Instructions

1.

Always come to the laboratory on time. Shoes are compulsory.2.

Come well-prepared for the experiments. You must bring relevant codes applicablefor concrete/steel code and steel sections hand book.

3.

Maintain a separate observation notebook. Show the observations and get theinstructors signature before you leave the lab after the experiment.

4.

Members of Group 1 will work on the report, after the lab in DCF, on the same dayand submit the completed report (one for each group) before 1700 hours. Membersof Group 2 will work on the report during 1400-1525 hours the next Monday andsubmit the completed report before commencing the experiment for that week at1535 hours.

5.

The report should contain: the title, detailed analysis of experimental data, tabulation

of observations, comparison of theoretical prediction with experimental observation,results and most importantly, discussion of the results and inference.

6.

Reports should be neatly typed.7.

Copying of report will earn zero credits for all the groups that copied.


4/37

Expt # 1. Behaviour of reinforced concrete beams under

flexure

Aim:

To study the flexural behaviour of reinforced concrete beams

Details of test specimen:Provide a neat sketch of each test specimen, along with its dimensions and reinforcement.

All dimensions in mm.


5/37

Apparatus used:

List the apparatus used in the experiment and describe them briefly

Background:

Brief description of the response of the reinforced concrete beams under flexure

o Behaviour of singly reinforced beamsUnder-reinforced, over-reinforced,

balanced sections

o Behaviour of doubly reinforced beams

Assumptions in the flexure theory for reinforced concrete beams and their

implications

Brief derivation of the cracking and ultimate moments for singly reinforced sections

o Cracking moment ckcr fbD.M 2120

Here, the mean cube compressive strength of concrete can be substituted forfck(in MPa); b,D(in mm) are the width and depth of the beam, respectively

o

Ultimate moment of resistance )x.(dbxf.M uuckuR 420540

o For an under-reinforced beam,bf.

Afx

ck

sy

u540

o For an over-reinforced beam,

ck

ssckssss

ubf.

EA.bdfEA.)E(Ax

081

00350105671012 326

The material safety factors are neglected.

Obtain the ultimate moment of resistance for doubly reinforced section

Sketch of experimental setup:Neat sketch of the setup showing the location of the steel pellets, dial gauge, point ofapplication of the loads, support condition.

Experimental Setup

Test specimen

Dial gauges

Demec points


6/37

Moment vs. curvature for an under-reinforced section

Moment vs. curvature for an over-reinforced section

Compression failure

First crack (at cracking moment )

MuR

Moment (M)

Curvature ()

MuR

Moment (M)

Curvature

First crack (at cracking moment)

Yield of tension steel(at yielding moment)

Secondarycompression failure


7/37

Procedure:List the procedure followed to collect the required data.

Observation:

1.

Table1: Readings from the DEMEC gauges at various locationsUnder-reinforcedbeam

Load(kg)

DEMEC gauge reading (mm)

1 2 3 4 5

2. Table2: Readings from the dial gauges and crack widthUnder-reinforced beam

Load(kg)

Crackwidth

(mm)

Raw Dial Gauge Reading (mm)

1 2 3

Main Vern Main Vern Main Vern

3.

Table3: Readings from the DEMEC gauge at various locationsOver reinforcedbeam

Load

(kg)


1 2 3 4 5

4. Table4: Readings from the dial gauge and crack widthOver reinforced beam

Load(kg)

Crackwidth

(mm)

Raw Dial Gauge Reading (mm)

1 2 3


5. Figure1: Sketch of Crack pattern Under reinforced beam:

6.

Figure2: Sketch of Crack pattern Over reinforced beam:


8/37

Detailed Calculations:

1. Table5: The value of the strains at various locationsUnder reinforced beam

Load

(kg)

Strain (10-

)

1 2 3 4 5

2. Table6: Deflections at various locationsUnder reinforced beam

Load

(kg)

Observed Deflection (mm) Theoretical Deflection (mm)

1 2 3 1 2 3

3. Table7: The value of the strains at various locationsOver reinforced beam

Load(kg)

Strain (10-

)1 2 3 4 5

4. Table8: Deflections at various locationsOver reinforced beam

Load(kg)

Observed Deflection (mm) Theoretical Deflection (mm)

1 2 3 1 2 3

5. Table9: Various quantities computed from strains tabulated in Tables 5 and 7.

Under reinforced beam Over reinforced beam

Load

(kg)

Moment

(Nm)

Curvature,

Depth

of NA

(mm)

Load

(kg)

Moment

(Nm)

Curvature,

Depth

of NA

(mm)

6. Figure3: Plot of depth vs. strain for various loads

7. Figure4: Plot of load vs. deflection (3 curves, compare theoretical predictions withexperimentally obtained values)

8. Figure5: Plot of moment vs. curvature

9.

Figure6: Plot of moment vs. depth of neutral axis (NA)10.Figure7: Plot of load vs. crack width11.Compare the predicted and observed ultimate capacity and cracking moment.

Discussion:Comment on the results obtained and the observed vs. expected behaviour.


9/37

Expt # 2.Behaviour of axially loaded short column

Aim:To study the behaviour of axially loaded short reinforced concrete column

Details of test specimen:Provide a neat sketch of the test specimen along with its dimensions and relevant

geometric properties

Apparatus used:List the apparatus used in the experiment and describe them briefly

Background:

Brief description of the response of reinforced concrete columns

o Behaviour of a short column

o Behaviour of an eccentrically loaded column

Assumptions in the analysis of reinforced concrete columns and its implications

Brief derivation of the ultimate axial load capacity of short column

o Ultimate axial load,Pu0= 0.67fckAc+ fscAsc

fsc= 0.85fy, approximate stress corresponding to a strain of 0.002

Discuss the role of lateral ties and modes of failure of the column.

Sketch of experimental setup:

Neat sketch of the setup showing the location of the steel pellets and loading.


10/37

Experimental Setup

Procedure:

List the procedure followed to collect the required data.

Observation:1. Table1: Readings from the DEMEC gauge at various locations

Load

(kg)


Face A Face B Face C Face D

1 2 3 4 5 6 7 8 9 10 11 12

2. Figure1: Sketch of crack pattern on the four faces of the column:

Face A Face B Face C Face D

P

P

3 @ 200950

225

225


11/37


1. Table2: The value of the strains at various locations

Load

(kg)

Strain at various locations (10-

)

Face A Face B Face C Face D1 2 3 4 5 6 7 8 9 10 11 12

2. Figure2: Plot of load vs. mean strain (Compare theoretical prediction with that

observed experimentally)

3. Figure3: Plot of load vs. strain at level1 for various faces

4. Figure4: Plot of load vs. strain at level2 for various faces5. Figure5: Plot of load vs. strain at level3 for various faces

6. Figure6: Plot of load vs. strain at various levels in faceA

7. Figure7: Plot of load vs. strain at various levels in faceB

8.

Figure8: Plot of load vs. strain at various levels in faceC9. Figure9: Plot of load vs. strain at various levels in faceD

In Figures 3 to 9, plot the mean strains as well.

Discussion:

Comment on the observed vs. expected behaviour, the nature of the moments on thecolumn (if any), variation of strains at various levels of a given face and crack pattern.


12/37

Expt # 3.Behaviour of reinforced concrete beams under shear

Aim:To study the behaviour of beams under shear, with and without shear reinforcement.

Details of test specimen:Provide a neat sketch of the test specimen along with its dimensions and geometric

properties

Apparatus used:List the apparatus used in the experiment and describe them briefly.

Background:

Brief description of the response of reinforced concrete beams under shear

1. Behaviour of a beam without shear reinforcement

2. Behaviour of a beam with shear reinforcement

Brief review of shear strength of reinforced concrete beams.

1. Design strength of a beam without shear reinforcement:

0.85 0.8 1 5 16

ck

c

f

Where0.8

6.89

ck

t

f

p or 1 whichever is greater.

Shear strength Vc=c

bd.

2.

Design strength of a beam with shear reinforcement:

Shear strength VuR= Vc + Vs

Where Vc = shear resisted by concrete

Vs= shear resisted by stirrups.

Discuss the typical shear failure modes in RC beams.

Sketch of experimental setup:Neat sketch of the setup showing the location of steel pellets, dial gauge, point of

application of the load, support conditions.

v

svy

ss

dAfV


13/37

Experimental Setup

Cross-section(All dimensions in mm)


Observations:

1. Table1: Readings from the dial gaugebeam without shear reinforcement

Load (kg) Dial gauge reading (mm)

2. Table2: Readings from the DEMEC gaugebeam without shear reinforcement

Load (kg)DEMEC gauge reading

Diag 1 Diag 2

150

25

200

(3) 16

6stirrups


14/37

3. Table3: Readings from the dial gaugebeam with shear reinforcement

Load (kg) Dial gauge reading (mm)

4. Table4: Readings from the DEMEC gaugebeam with shear reinforcement

Load (kg)DEMEC gauge reading

Diag 1 Diag 2

5. Figure - 1 : Sketch of crack pattern


1. Table5 : Deflectionsbeam without shear reinforcement

Load (kg) Deflection (mm)

2.

Table6 : Deflectionsbeam with shear reinforcementLoad (kg) Deflection (mm)

3. Table7 : Values of average shear stress and shear strain

Load

(kg)

Shear stress

(N/mm2)

Strain (1) Strain (2) Shear Strain

4.

Figure -2: Plot of load vs. deflection for both the cases

5. Figure -3: Plot of shear stress vs. shear strain for both the cases

6. Compare the deflection responses of the beams, with and without shear

reinforcement

Discussions:Comment on the results obtained and the observed vs. expected behaviour.


15/37

Expt # 4.Behaviour of reinforced concrete beams under torsion

Aim:To study the behaviour of beam under pure torsion.


properties

Apparatus used:List the apparatus used in the experiment and describe them briefly.

Background:

Brief description of various types of torsion in reinforced concrete beams.

Comment on cracking and ultimate torque.

Relevant code provisions.

1. Cracking torsion moment (torque),2

,max2 3

cr t

b bT D

Where,max

0.2t ck

f .

b = width of the beam, in mm

D = depth of the beam, in mm

ckf = characteristic compressive strength of concrete in N/mm2

.Use mean strength instead of characteristic strength.

2. Ultimate torsional moment: When only the ties yield before failure

Where

At= area of cross-section of one leg of stirrup

b1= shorter distance between longitudinal barsd1= longer distance between longitudinal bars

fyt= yield strength of transverse steelsv= spacing of stirrups.

v

ytt

uRs

fAdbT 112


16/37


Neat sketch of the setup showing the location of steel pellets, dial gauge, point ofapplication of the load, support conditions.

Experimental Setup

Cross-section(All dimensions in mm)

150

25

(4) 12

6stirrups200


17/37


Observations:

1. Figure - 1: Sketch the crack pattern

2. Table1: Readings from dial gauges.

Load(kg)

Readings ofDial Gauge 1

Readings ofDial Gauge 2


1. Cracking torque,Tcr.

2. Ultimate torsional moment TuR

3. Table2: Calculation of angle of twist from experimental data.

Load

(kg)

Torque

(kN-m)

Net

deflection

(mm)

Angle of

twist

(rad)

4. Figure -2: Plot of torque vs. angle of twist

Discussions:

Comment on the results obtained and the behaviour observed.

fron

side

topside

back

side

bott

side


18/37

Expt # 5.Bending tests on steel rolled joists

Aim:To study the bending behavior of steel rolled joists


properties


Background:

Assumptions in the theory of beam bending and its implications for this experiment

Brief derivation of the flexure formula

Theoretical estimate of the shear stresses at neutral axis of Isection

List the methods available to determine the deflection of a beam Obtain an equation for the deflected shape of a simply supported beam subjected to

two-point loading

Theory of strain-rosetteExpressions to determine the components of the straintensor, principal strains and principal direction


Neat sketch of the setup showing the location of the strain gauges, dial gauge, point ofapplication of the loads, support condition and the orientation of the chosen coordinate

system

Procedure:

List the procedure followed to collect the required data

Observation:7. Table1: Readings from the strain gauge at various locations

Load,

kg

Raw Strain Gauge Reading, (*10-

)

1 2 3 4 5 6 7 8 9 10

8. Table2: Readings from the dial gauge

Load,

kg

Raw Dial Gauge Reading, (mm)

1 2 3


Detailed Calculations:12.Table3: The value of the strains at various locations

Load,

kg

Strain, (*10-

)

1 2 3 4 5 6 7 8 9 10


19/37

13.Table4: Deflections at various locations

Load,

kg

Deflection, (mm)

1 2 3

14.Table5: Various quantities computed from strains tabulated in Table3.

Load,

kg

Moment,

Nm

Curvature,

Depth

of NA,mm

Principal strain

@ loc 2

Principal

direction@ loc 2,

Shear strain @

loc 3 from1

p

2

p 9 10

15.Figure1: Plot of depth vs. strain for various loads

16.Figure2: Plot of load vs. deflection (3 curves)

17.Figure3: Plot of moment vs. curvature

18.

Figure4: Plot of moment vs. depth of neutral axis19.Figure5: Plot of load vs. principal direction

20.Figure6: Plot of load vs. shear strain (2 curves)21.Estimate the flexural rigidity from:

a. Load vs. deflection curve (3 values)

b. Moment vs. curvature curve22.Compute the theoretical flexural rigidity and compare it with that obtained in

the experiment

23.Estimate the shear rigidity from the load vs. shear strain plot and compare it

with the theoretical value

Discussion:Comment on the results obtained and the observed vs. expected behavior.


20/37

Expt # 6.Symmetrical and unsymmetrical Bending

Aim: To study the behavior of a section subjected to symmetrical and unsymmetrical

bending


properties


Background:

Assumptions in the theory of beam bending and its implications for this experiment

Conditions under which we can superpose solutions and its applicability for this

experiment

Brief derivation of the flexure formula for unsymmetrical bending Obtain an equation for the deflected shape of a simply supported beam subjected to

one-point loading


Neat sketch of the setup showing the location of the strain gauges, dial gauge, point ofapplication of the loads, support condition

Procedure:

List the procedure followed to collect the required data

Observation:

9.

Table1: Readings from strain gauge at various locationsSymmetrical bendingLoad,

kg


)

1 2 3

10.Table2: Readings from the dial gaugeSymmetrical bending

Load,

kg


x y

Main Vern Main Vern

11.Table3: Readings from strain gauge at various locationsUnsymmetrical bending

Load,

kg


)

1 2 3

12.Table4: Readings from the dial gaugeUnsymmetrical bending

Load,

kg


x y

Main Vern Main Vern


21/37

Detailed Calculations:24.Table5: The value of the strains at various locationsSymmetrical bending

Load,

kg

Observed Strain, (*10-

) Theoretical Strain, (*10-

)

1 2 3 1 2 3

25.Table6: Deflections at various locationsSymmetrical bending

Load,

kg

Observed Displacement, (mm) Theoretical Displacement, (mm)

x y x y

26.Table7: The value of the strains at various locationsUnsymmetrical bending

Load,

kg

Observed Strain, (*10-

) Theoretical Strain, (*10-

)

1 2 3 1 2 3

27.

Table8: Deflections at various locationsUnsymmetrical bendingLoad,

kg

Observed Displacement, (mm) Theoretical Displacement, (mm)

x y x y

28.Figure1: Plot of load vs. theoretical and observed displacement along xdirection

for both symmetrical and unsymmetrical bending

29.Figure2: Plot of load vs. theoretical and observed displacement along ydirectionfor both symmetrical and unsymmetrical bending

30.Figure3: Plot of load vs. theoretical and observed axial strain at location 1 for both

symmetrical and unsymmetrical bending

31.

Figure4: Plot of load vs. theoretical and observed axial strain at location 2 for bothsymmetrical and unsymmetrical bending

32.Figure5: Plot of load vs. theoretical and observed axial strain at location 3 for both

symmetrical and unsymmetrical bending

Discussion:

Comment on the results obtained and the observed vs. expected behavior.


22/37

Expt # 7.Torsion of closed and open sections

Aim:To compare and study the behavior of a closed and open section subjected to torsion

Details of test specimen:Provide a neat sketch of the test specimens along with its dimensions and relevant

geometric properties


Background:

Definition of open and closed section

Brief description of the theories of TorsionCoulomb theory and St. Venant theory

Assumptions in the theories of torsion and its implications

Brief derivation of the expression:

J

T

r

zfor closed sections

For circular tube with a slit along the meridian subjected to a pure torque, T:

)cosh(

)sinh()tanh()(

3l

xlxl

EC

T

w

,

)cosh(

)cosh(1'

2l

x

EC

T

w

,

)cosh(

)sinh(''

l

x

EC

T

w

,

)cosh(

)cosh('''

l

x

EC

T

w

,

where is the angle of twist,)6(

24

22

r

t

E

G, 52 )6(

3

2trC

w

,E= 71

GPa, G= 27 GPa, lis the length of the tube,xis the distance measured from the

torque applied end, tis the thickness of the tube, ris the mean radius of the tube.

The only non-zero components of the stress in cylindrical polar coordinates are:

'''2

))cos(1(2'2

3

ErtGz

, ''))sin(2(2 Er

zz , where

varies from to + ( at split end); = 0 at exactly opposite to split end.

Derive the expressions for the principal strain for the above state of stress, assumingthe material obeys Hookes law with Youngs Modulus,E(= 71 GPa) and Poisson

ratio, )32.0( . Also, obtain an expression for the principal direction with respect to

a fixed Cartesian coordinate basis for the above state of stress.


Neat sketch of the setup showing the location of the strain gauges, orientation of thechosen coordinate system and loading

Procedure:List the procedure followed to collect the required data


23/37

Observation:13.Table1: Readings from the strain gauge at various locations for open section

Load,

kg

Raw Strain gauge reading

Location 1 Location 2

0o

45o 90

o 0

o45

o 90

o

14.Table2: Rotation at various locations for open section

Load,

kg

Rotation (degrees)


15.Table3: Readings from the strain gauge at the given location for closed section

Load,kg

Raw Strain gauge reading

0o

45o 90

o

16.Table4: Rotation at various locations for closed section

Load,kg

Rotation (degrees)


Detailed Calculations:1. Table5: Strains at various locations for open section

Load,

kg

Strains (*10-

)


0o

45o 90

o 0

o45

o 90

o

2. Table6: Comparison of strains at various locations for open section

Torque,Nm Location1(Observed) Location1(Calculated) Location2(Observed) Location2(Calculated)

Principal

strain

Principal

direction

Principal

strain

Principal

direction. Principal

strain

Principal

direction. Principal

strain

Principal

direction.

1

p

2

p

1

p

2

p

1

p

2

p

1

p

2

p

3. Table7: Rotation at various locations for open section

Load,

kg

Torque,

Nm

Observed Rotation (deg.) Calculated Rotation (deg.)

Location 1 Location 2 Location 1 Location 2

4. Table8: Strains at the given location for closed section

Load,

kg

Strains (*10-

)

0o

45o 90

o


24/37

5. Table9: Comparison of strains at various locations for closed section

Torque,Nm

Location1(Observed)

Location1(Calculated)

Principalstrain

Principal

direc

tion

Principalstrain

Principal

direc

tion.

1

p 2

p 1

p 2

p

6. Table10: Rotation at various locations for closed section

Load,kg

Torque,Nm

Observed Rotation (deg.) Calculated Rotation (deg.)

Location 1 Location 2 Location 1 Location 2

7. Figure1: Torque vs. angle of twist per unit length for closed and open section8. Figure2: Torque vs. principal direction for open section

9.

Figure3: Torque vs. major principal strain for open section

10.Figure4: Torque vs. minor principal strain for open section11.Figure5: Torque vs. principal direction for closed section

12.Figure6: Torque vs. major principal strain for closed section

13.Figure7: Torque vs. minor principal strain for closed section Figures 2 to 4 contains 2 curves corresponding to different locations

Discussion:Comment on the observed vs. expected behavior and the results obtained.


25/37

Expt # 8.Plastic Behaviour of Steel Beams

Aim:To study the plastic behavior of steel beams and to determine the collapse load of the

beam.

Details of test specimen:

Provide a neat sketch of the test specimen along with its dimensions and geometric

properties

Apparatus used:


Background:

Brief description of the plastic theory and its importance in steel construction.

Brief description of the plastic hinge concept and plastic collapse load

Brief derivation of the formula for finding the plastic moment capacity of a proppedcantilever with a concentrated load.

Experimental setup and procedure:


system

A square rod of span L is restrained against translation and rotation at one end (A) and

against vertical translation at the other end (C). It is subjected to a concentrated load at B,

at a distance a from the rotationally restrained end. A pair of strain gauges at top andbottom fibres are provided at sections P and Q at distance c and d from A and B

respectively. A load cell is provided at C to measure the vertical reaction at the right

support. A dial gauge is located at B to measure vertical deflection.

The load is applied at point B from a hanger rod at 10 kg increments. All the readings

(strain gauges, load cell and dial gauge) are taken after each load increment. The

increment in load is reduced to 5 kg closer to failure load in order to obtain failure load

accurately and more readings closer to the failure load. Failure is indicated by largeincrease in deformation and continuous increase in deformation with time. After failure

take a piece from the undisturbed portion and do tension test to obtain the yield strength

of the material.1. Measure the cross-section of the rod at several places with a vernier and also

determine the span and the load position with a scale.

2. Calculate the expected collapse load by assuming the mechanism and by drawing thebending moment diagram at collapse. Assume mild steel of yield strength 250 MPa.

cd

a b

L

QBP

A C


26/37

3. Apply the load by means of weights and note the reaction as well as strains and

deflections.

4. In the tension test, note the failure mode and the yield and ultimate stresses and thecorresponding strains.

Observation:

17.

Table1: Readings from the load cell and strain gauges

Load,kg

Load cellreadings

Strain gauge readings

At P At Q

Top Bottom Top Bottom

18.Table2: Readings from the dial gauge below the load

Load

Kg.

Raw Dial Gauge reading (mm)

Main Vern


33.Table3: The value of the strains at various locations

Load,

kg

Strain, (*10-

)

At P At Q

Top Bottom Top Bottom

34.Table4: Deflection at B

Load,kg

ObservedDeflection, (mm)

TheoreticalDeflection, (mm)

35.Table5: Reaction at C

Load,

kg

Observed

Reaction

Theoretical

Reaction

36.

Table6: Bending moment at A and B

Load, kg

Bending moment at A Bending moment at B

Elastic

analysis

Based on

Strains

Based on

observedreaction

Elastic

analysis

Based on

Strains

Based on

observedreaction


27/37

37.Figure1: Experimental and theoretical load versusdeflection plots

identifying the yield and ultimate load levels

38.Figure2: Experimental and theoretical load versusreactions plots39.Figure3: Load versusmoment at A (3 curves)

40.Figure4: Load versusmoment at B (3 curves)

41.

Compare the yield and collapse loads obtained from the test with thepredictions.

Discussion:Comment on the results obtained and the observed versusexpected behavior.


28/37

Expt # 9.Buckling Strength of Concentrically Loaded Angle struts

Aim:To study the buckling behavior and to determine the limit point load and the

elastic buckling load (Pcr) of single and double angle steel compression members, and to

compare with the theoretical values obtained from Eulers equation.


Single and double angle column specimens (20mm20mm3mm)

Apparatus used:

Single and double angle column specimens (20mmx20mmx3mm)

Steel scale

Dial gauges (L.C= 0.01mm)

Vernier calipers (L.C= 0.02mm)

Two hemi-spheres

Plumb bob

Plate with circular groove

Background:

Assumptions in the theory of Eulers theoryand its implications for this experiment

Brief derivation of the Eulers Buckling equation

Brief description of the effect of initial imperfections, residual stresses and

eccentricity on the buckling load capacity of columns

Brief description about Southwells Plot.



system

20 mm20 mm

8.35mm

20 mm

20 mm

20mm


29/37

Procedure:List the procedure followed to collect the required data

Observation:

Table1: Single angle under uniaxial compression

Table 1:Calculation for Single Angle Strut

Sl. No.Load(P) Dial Gage Reading Deflection Deflection/Load

d1/P (mm/kg)Micron kg D1 D2 d1 (mm) d2 (mm)

Test Floor

Concrete Pedestal

Test Specimen

Semi Hemispherical Iron PiecePiston For Application of Vertical Load

Dial Gauges (1 & 2)

Horizontal Beam of Self-Straining

Frame

Hydraulic Jack

End Plates

Fig . Experimental Setup for Compression testing of members


30/37

Double angle under uniaxial compression

Table 2:Calculation for Double Angle Strut

Sl. No.Load

Dial Gage

ReadingDeflection

Deflection/Load

d1/P (mm/kg)

Micron kg D1 D2 d1 (mm) d2 (mm)


42.Figure1: Load versusmaximum lateral displacement43.Figure2: Southwell plot of P versus/P to obtain the critical load

44.Compare experimental results with the code (IS 8002007) provisions and

comment on the discrepancy if any.

Discussion:Comment on the observed versusexpected behavior and the results obtained.


31/37

Expt # 10.Lateral Buckling of Steel I Beams

Aim:To study the lateral buckling behaviour of steel I-beams and to determine the critical

moment.


Provide a neat sketch of the test specimens along with its dimensions and relevant

geometric properties.

Apparatus used:


Background:

Description of lateral- torsional buckling of beams

Brief Description of Southwell plot.

Lateral buckling strength Mcr( IS: 800 - 2007)

2

2

2

2

)()( KL

EIGI

KL

EIM wt

y

cr

where,E = Youngs modulus =2 x 10

5MPa; G = Shear modulus =0.769 10

5MPa

Iy = Moment of inertia about the weak axis in (mm4)

hf = Center to center distance between the flanges in mm

KL = Effective laterally unsupported length of the member in mmry = Radius of gyration of the section about the weak axis in mm

It = St.Venants torsion constant=3

tb 3ii (for open cross section)

Iw =Warping constant = 2yyff hI1 ; ( 5.0f for I section ,hy = (d - tf )

Using Mcr, the nominal bending strength of laterally unsupported beam as

governed by lateral torsional buckling can be calculated as follows using mo= 1.0

bdpbd fZM moyLTbd ff / 2

)2.0(15.0LTLTLT

0.11

5.022

LTLTLT

LT

cr

ypb

LTM

fZ

LT = Imperfection factor = 0.21 for rolled steel section

For top flange loading the code recommends an increase in effective length by 20%.

Sketch of experimental setup:Neat sketch of the setup showing the location of the strain gauges, orientation of the

chosen coordinate system and loading


32/37

Procedure:

Two simply supported I-sections (ISMB 100) are loaded by a concentrated load at theirmid-span using weights on a hanger. The vertical and lateral deflections are measured

using circular dial gauges. One is loaded at the level of the top flange and the other is

loaded at its centroidal axis level.

1. Calculate the nominal bending strength for both beams (code value).

2. Practice reading the dial gauges by slackening the string (do not pull the strings) and

identify its least count.3. Carryout the test by applying the load in increments of 40 kg and recording the dial

gauge readings.

4. Note or take a picture of the buckling mode from one end of the beam.

Observation:19.Table1: Readings from the Dial gauges

Load,kg Dial gauge readingsVertical Horizontal


14.Table2 Vertical and lateral deflections

Load,

kg

Deflections (mm)

Vertical Horizontal

15.Figure1: Load versuslateral displacement

16.

Figure2: Southwell plot of W versusdelta/W to obtain the critical moment4. Compare experimental results with the code (IS 8002007) provisions and comment

on the discrepancy if any.

Discussion:Comment on the observed versusexpected behavior and the results obtained.


33/37

Expt # 11.Behaviour of Bolted connectionsAim:To study the different failure modes and to determine the capacity of the given bolted

connections.


properties


Background:

Brief description about different types of bolts

Brief description of different types of bolted connections and their behaviour.

Brief derivation of the formula for finding out their strength.

Sketch of experimental setup:Neat sketch of the setup showing the location of the strain gauges, dial gauge, point of

application of the loads, support condition and the orientation of the chosen coordinate

system

Procedure:

Two lap joints are to be tested. In the first test, a single bearing bolt is put on one side of

a double cover plate lap connection. The grade of the bolt is indicated on its head. Thethickness of the connecting plates is to be noted. As the load is increased, the elongation

is measured by dial gauges. Strain in the plates is also measured by means of dial gauges.

The bolt usually fails under double shear.

In the second test , high strength friction grip bolts are used. These are pre-tensioned to

the proof stress by the turn-of-the-nut method wherein 3/4th

of a turn is given after thesnug tight condition. The increase in the length of the bolt will be by 3/4

thof the pitch.

This can be used to calculate the force in the bolt. The lap connection is the tested as

before and the failure is usually by slip followed by the rupture of the section.

Observation:

Bearing Bolt

20.Table1: Readings from the dial gauge at various locations

Load,

kg

Dial Gauge Reading, (mm)

1 2 3 4


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Friction Grip bolt

21.Table2: Readings from the dial gauge

Load,

kg

Dial Gauge Reading, (mm)

1 2 3 4


45.Table3: The value of the strains at various locations

Load,

kg

Strain, (*10-

)

1 2 3 4 5 6 7 8 9 10

46.

Figure1: Load versusdeflection curve for both the cases47.Calculate the capacity of the bearing bolt in shear and in bearing, and compare

with the observed capacity.

48.Obtain the slip and net section rupture capacities, and compare with theobserved values. The load-slip graph for the bolt can be obtained from

experiment.

Discussion:Comment on the results obtained and the observed versusexpected behavior


35/37

Demo # 1.Bond Strength Tests

Aim:

1 To plot the load versus slip curves for the loaded and free ends in each specimen

2

To record the loads at slips of 0.025 mm at the free end and 0.25 mm at the loadedend of the in each specimen

3 To record the maximum load at failure and type of failure for each specimen

4 To compare the bond strengths of the two types of reinforcing bars5 To record the cube strength


Provide a neat sketch of the test specimen along with its dimensions and geometric

properties

Apparatus used:

List the apparatus used in the experiment and describe them briefly.

Background:

Brief description of various types of bond in reinforced concrete members.

Brief description of the mechanisms by which bond resistance is mobilized in reinforced

concrete.

Describe the factors affecting the bond strength

Comment on the significance of development length

Comment on load at which slipping occurs

Relevant code provisions.

Bond Stress /( )e

P l

Where Pe= Load at which slip occured

= Diameter of rod usedl = Length of embedment

Sketch of experimental setup:Neat sketch of the test setup


36/37

Procedure:

List the procedure followed to collect the required data.

Observations:

1. Cube Strength of Concrete2. Table1 : Readings from dial gauge for deformed bar

Load ( kg) Dial Gauge Readings in mm

at loaded end 1 at loaded end 2 at free end


37/37

3. Table2 : Readings from dial gauge for plain bar

Load ( kg) Dial Gauge Readings in mm

at loaded end at free end


1. Table3 : Bond stress in deformed bar

Load in kgAverage slip at

loaded end in mm

Slip at free end in

mm

Bond stress in

N/mm2

2.

Table4 : Bond stress in plain bar

Load in kgSlip at loaded end in

mm

Slip at free end in

mm

Bond stress in

N/mm2

3. Figure -1: Plot of load vs slip for deformed bar

4. Figure -2: Plot of load vs slip for plain bar

5. Load at slip of 0.025 mm at free end for

a) Plain bar

b)

Deformed bar6. Load at slip of 0.25 mm at loaded end for

c) Plain bar

d) Deformed bar

7. Maximum load at failure for

e) Plain bar

f) Deformed bar

Discussions:Comment on the results and the behavior observed.

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Ce3100 Str Lab July Nov 2014

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