Transcript Load vs Strain curve for steel and concrete

Analysis of Test Results
1
What we’ll have to do:
• Load-Deflection curve.
• Load Vs Strain curve for steel and concrete
• Find yield load (es = 0.002) for flexural rebar
and strain at failure load for concrete and
rebar.
• First yield load for flexural reinforcement.
• Ductility of the slab.
• Energy absorption.
• Deflection profile.
2
• Calculate flexural strength and Punching
shear capacity of the slab.
• Compare test result with predicted result.
• Show a photograph depicting the crack
pattern at failure.
• Make comment on the mode of failure of the
slab.
3
Tension Reinforcement and Strain gauges
arrangement
T5
T2
T1
T4
1900
T3
1900
T1(1050,845);T2(1260,1020);T3(1460,845);T4(1590,1020);T5(810,1080)
4
Compression Reinforcement and Strain
gauges arrangement
C6
C7
C8
C9
C6(820,770); C7(1090,820); C8(820,580); C9(820,400) 5
Concrete Strain gauge locations
5
1 3
2
4
30, 70, 100, 100
6
Load-Deflection curve
Load vs Central Deflection
250.0
200.0
Load (KN)
150.0
100.0
50.0
0.0
-40.0
-30.0
-20.0
-10.0
0.0
10.0
20.0
30.0
40.0
Deflection (mm)
7
Load-Deflection curve
Load vs Central Deflection
250.0
Load (NK)
200.0
150.0
100.0
50.0
0.0
0.0
5.0
10.0
15.0
20.0
Deflection (mm)
25.0
30.0
35.0
8
Load-Deflection curve
Load vs Central deflection
250.0
Load (KN)
200.0
150.0
100.0
50.0
0.0
0.0
5.0
10.0
15.0
20.0
Deflection (mm)
25.0
30.0
35.0
9
Load vs Strain curve for steel and concrete
Load vs Strain in Steel (T2)
250.0
200.0
Load (KN)
150.0
100.0
50.0
0.0
-500
0
500
1000
Micro-Strain
1500
2000
2500
10
Load vs Strain curve for steel and concrete
Load vs Strain in steel (T2)
250.0
200.0
Load (KN)
150.0
100.0
50.0
0.0
-500
0
500
1000
1500
2000
2500
Micro-Strain
11
Load vs Strain curve for steel and concrete
Load vs Strain in steer (T2)
250.0
200.0
Load (KN)
150.0
100.0
50.0
0.0
-500
0
500
1000
1500
2000
2500
Mocro-Strain
12
Load vs Strain curve for steel and concrete
Load vs Strain in Concrete(3)
250.0
200.0
Load (KN)
150.0
100.0
50.0
0.0
-2500
-2000
-1500
-1000
-500
0
Mocro-strain
13
Load vs Strain curve for steel and concrete
Load vs Strain in Concrete (3)
250.0
200.0
Load (KN)
150.0
100.0
50.0
0.0
-2500
-2000
-1500
-1000
-500
0
Micro-Strain
14
Load vs Strain curve for steel and concrete
Load vs Strain in Concrete (3)
250.0
200.0
Load (KN)
150.0
100.0
50.0
0.0
-2500
-2000
-1500
-1000
Micro-Strain
-500
0
15
Steel Strain Distribution
100 KN
150 KN
200 KN
16
Concrete Strain Distribution
50 KN
100 KN
150 KN
200 KN
17
• Find yield load (es = 0.002) for
flexural rebar and strain at failure
load for concrete and rebar.
• First yield load for flexural
reinforcement.
18
Ductility and Energy
Absorption of the Slab
Ductility = Ratio of the deflection at 25% of
maximum load (after reaching the maximum
load) to the deflection at the first yielding of
flexural reinforcement.
Energy Absorption = Area under the load
deflection curve up to 25 % maximum load
(after reaching the maximum load)
19
Ductility and Energy
Absorption of the Slab
20
Deflection Profile
1 division = 0.01 mm
1 cycle = 1 mm
21
Calculation of Flexural strength
P flex  KM
o
 s

K  8
 0 . 172 
ac



M o   f y d 1  0 . 59  f y / f
2
'
c

  0 . 5 or 1 . 0
f y  400 MPa
d  120 mm
f
'
c
 from _ cylinder _ tesr
22
Calculation of Punching Shear
Capacity
V u  0 . 4 c 
f
'
c
bo d
b o  2  c1  c 2  2 d 
23
Compare Test result with Predicted result
Pflex
Pv
Ppred.
Ptest
Ptest/Ppred.
24
Show a photograph depicting the
crack pattern at failure and Make
comment on the mode of failure of
the slab
Ptest
If   1 , Flexural failure
P flex
If   1 , Punching Shear failure

 

From crack pattern
Make comment on mode of failure
25