Sample 2

Sample 3

Sample 4

class of loading/kN

average height/cm

class of loading/kN

average height/cm

class of loading/kN

average height/cm

class of loading/kN

average height/cm

20

7.50

20

8.57

20

11.62

20

11.88

30

11.94

30

12.67

30

14.57

30

14.31

40

13.81

40

13.13

40

15.14

40

15.15

50

15.31

50

13.75

50

15.29

50

16.00

60

15.75

60

16.13

60

15.43

60

16.00

70

16.50

65

18.00

68

16.36

70

17.15

80

16.81

-

-

-

-

-

-

84

20.13

-

-

-

-

-

-