1

Analysis of Test Results

2

What we’ll have to do:

• Load-Deflection curve.

• Load Vs Strain curve for steel and concrete

• Find yield load (s = 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.

3

• 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.

4

Tension Reinforcement and Strain gauges arrangement

T1(1050,845);T2(1260,1020);T3(1460,845);T4(1590,1020);T5(810,1080)

T1

T2

T3

T4T5

1900

1900

5

Compression Reinforcement and Strain gauges arrangement

C6(820,770); C7(1090,820); C8(820,580); C9(820,400)

C9

C8

C7C6

6

Concrete Strain gauge locations

5

4

3

2

1

30, 70, 100, 100

7

Load-Deflection curve

Load vs Central Deflection

0.0

50.0

100.0

150.0

200.0

250.0

-40.0 -30.0 -20.0 -10.0 0.0 10.0 20.0 30.0 40.0

Deflection (mm)

Lo

ad

(K

N)

8

Load vs Central Deflection

0.0

50.0

100.0

150.0

200.0

250.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0

Deflection (mm)

Lo

ad (

NK

)

Load-Deflection curve

9

Load-Deflection curve

Load vs Central deflection

0.0

50.0

100.0

150.0

200.0

250.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0

Deflection (mm)

Lo

ad

(K

N)

10

Load vs Strain curve for steel and concrete

Load vs Strain in Steel (T2)

0.0

50.0

100.0

150.0

200.0

250.0

-500 0 500 1000 1500 2000 2500

Micro-Strain

Lo

ad (

KN

)

11

Load vs Strain curve for steel and concrete

Load vs Strain in steel (T2)

0.0

50.0

100.0

150.0

200.0

250.0

-500 0 500 1000 1500 2000 2500

Micro-Strain

Lo

ad (

KN

)

12

Load vs Strain in steer (T2)

0.0

50.0

100.0

150.0

200.0

250.0

-500 0 500 1000 1500 2000 2500

Mocro-Strain

Lo

ad

(K

N)

Load vs Strain curve for steel and concrete

13

Load vs Strain curve for steel and concrete

Load vs Strain in Concrete(3)

0.0

50.0

100.0

150.0

200.0

250.0

-2500 -2000 -1500 -1000 -500 0

Mocro-strain

Lo

ad

(K

N)

14

Load vs Strain curve for steel and concrete

Load vs Strain in Concrete (3)

0.0

50.0

100.0

150.0

200.0

250.0

-2500 -2000 -1500 -1000 -500 0

Micro-Strain

Lo

ad

(K

N)

15

Load vs Strain curve for steel and concrete

Load vs Strain in Concrete (3)

0.0

50.0

100.0

150.0

200.0

250.0

-2500 -2000 -1500 -1000 -500 0

Micro-Strain

Lo

ad

(K

N)

16

Steel Strain Distribution

100 KN

150 KN

200 KN

17

Concrete Strain Distribution

50 KN

100 KN

150 KN

200 KN

18

• Find yield load (s = 0.002) for flexural rebar and strain at failure load for concrete and rebar.

• First yield load for flexural reinforcement.

19

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)

20

Ductility and Energy Absorption of the Slab

21

Deflection Profile

1 division = 0.01 mm

1 cycle = 1 mm

22

Calculation of Flexural strength

cyyo

oflex

ffdfM

ca

sK

KMP

'2 /59.01

172.08

tesrcylinderfromf

mmd

MPaf

or

c

y

__

120

400

0.15.0

'

23

Calculation of Punching Shear Capacity

dccb

dbfV

o

occu

22

4.0

21

'

24

Compare Test result with Predicted result

Pflex Pv Ppred. Ptest Ptest/Ppred.

25

Show a photograph depicting the crack pattern at failure and Make

comment on the mode of failure of the slab

flex

test

P

P If 1 , Flexural failure

If 1 , Punching Shear failure

From crack pattern

Make comment on mode of failure