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
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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
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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.
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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.
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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
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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
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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)
DEMEC gauge reading (mm)
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
Main Vern Main Vern Main Vern
5. Figure1: Sketch of Crack pattern Under reinforced beam:
6.
Figure2: Sketch of Crack pattern Over reinforced beam:
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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.
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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.
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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)
DEMEC gauge reading (mm)
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
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Detailed Calculations:
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.
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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
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Experimental Setup
Cross-section(All dimensions in mm)
Procedure:List the procedure followed to collect the required data.
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
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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
Detailed Calculations:
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.
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Expt # 4.Behaviour of reinforced concrete beams under torsion
Aim:To study the behaviour of beam under pure torsion.
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 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
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Sketch of experimental setup:
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
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Procedure:List the procedure followed to collect the required data.
Observations:
1. Figure - 1: Sketch the crack pattern
2. Table1: Readings from dial gauges.
Load(kg)
Readings ofDial Gauge 1
Readings ofDial Gauge 2
Detailed Calculations:
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
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Expt # 5.Bending tests on steel rolled joists
Aim:To study the bending behavior of steel rolled joists
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:
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
Sketch of experimental setup:
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
Main Vern Main Vern Main Vern
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
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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.
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Expt # 6.Symmetrical and unsymmetrical Bending
Aim: To study the behavior of a section subjected to symmetrical and unsymmetrical
bending
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:
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
Sketch of experimental setup:
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
Raw Strain Gauge Reading, (*10-
)
1 2 3
10.Table2: Readings from the dial gaugeSymmetrical bending
Load,
kg
Raw Dial Gauge Reading, (mm)
x y
Main Vern Main Vern
11.Table3: Readings from strain gauge at various locationsUnsymmetrical bending
Load,
kg
Raw Strain Gauge Reading, (*10-
)
1 2 3
12.Table4: Readings from the dial gaugeUnsymmetrical bending
Load,
kg
Raw Dial Gauge Reading, (mm)
x y
Main Vern Main Vern
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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.
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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
Apparatus used:List the apparatus used in the experiment and describe them briefly
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.
Sketch of experimental setup:
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
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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)
Location 1 Location 2
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)
Location 1 Location 2
Detailed Calculations:1. Table5: Strains at various locations for open section
Load,
kg
Strains (*10-
)
Location 1 Location 2
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
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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.
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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:
List the apparatus used in the experiment and describe them briefly
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:
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
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
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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
Detailed Calculations:
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
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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.
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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.
Details of test specimen:
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.
Sketch of experimental setup:
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
20 mm20 mm
8.35mm
20 mm
20 mm
20mm
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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
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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)
Detailed Calculations:
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.
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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.
Details of test specimen:
Provide a neat sketch of the test specimens along with its dimensions and relevant
geometric properties.
Apparatus used:
List the apparatus used in the experiment and describe them briefly
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
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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
Detailed Calculations:
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.
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Expt # 11.Behaviour of Bolted connectionsAim:To study the different failure modes and to determine the capacity of the given bolted
connections.
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 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
Detailed Calculations:
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
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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
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 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
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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
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3. Table2 : Readings from dial gauge for plain bar
Load ( kg) Dial Gauge Readings in mm
at loaded end at free end
Detailed Calculations:
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.