Results Compared with HAZUS

From Table 10 we observe that comparable levels of damage will be produced at much lower drift ratios when the wall behavior is dominated by shear, as opposed to flexure. This implies that a basing damage estimates on a single drift ratio for all low-rise masonry walls, as does HAZUS, is not likely to be particularly accurate.

Table 8. Drift ratio – Eikanas.

No

H

(in)

Yd

(in)

DR

Avg

Sd

(in)

DR

Avg

Ud

(in)

DR

Avg

Dd

(in)

DR

Avg

i(p)

52

0.10

0.19

0.20

0.16

0.31

0.46

0.73

1.40

1.57

1.12

2.15

2.18

1(N)

0.11

0.21

0.31

0.60

0.90

1.73

1.15

2.21

2(P)

84

0.19

0.23

0.34

0.13

0.15

0.42

1.58

1.88

1.53

1.99

2.36

2.16

2(N)

0.37

0.44

0.58

0.69

0.99

1.18

1.65

1.96

3(P)

84

N/A

N/A

0.57

N/A

N/A

0.22

N/A

N/A

3.80

N/A

N/A

5.95

3(N)

0.48

0.57

0.19

0.22

3.19

3.80

5.00

5.95

4(P)

52

0.16

0.31

0.48

0.28

0.54

0.75

0.57

1.10

1.24

0.69

1.33

1.53

4(N)

0.34

0.65

0.50

0.96

0.70

1.35

0.90

1.73

5(P)

84

0.28

0.33

0.33

0.38

0.45

0.54

0.99

1.18

1.30

1.38

1.64

1.88

5(N)

0.28

0.33

0.53

0.63

1.19

1.42

1.78

2.12

6(P)

84

0.23

0.27

0.29

0.48

0.57

0.73

1.12

1.33

1.34

2.24

2.67

2.41

6(N)

0.25

0.30

0.75

0.89

1.13

1.35

1.81

2.15

7(P)

52

0.08

0.15

0.18

0.20

0.38

0.38

0.50

0.96

0.96

0.70

1.35

1.45

7(N)

0.11

0.21

0.20

0.38

0.50

0.96

0.80

1.54

Table 9. Drift ratio – Ibrahim.

No

H

(in)

Yd

(in)

DR

Avg

Md

(in)

DR

Avg

Ud

(in)

DR

Avg

Dd

(in)

DR

Avg

i(p)

55

0.13

0.24

0.26

0.23

0.41

0.36

0.31

0.57

0.82

0.59

1.07

1.25

1(N)

0.15

0.27

0.17

0.30

0.59

1.07

0.79

1.43

2(P)

55

0.16

0.29

0.27

0.20

0.36

0.33

0.59

1.07

0.89

N/A

N/A

1.07

2(N)

0.13

0.24

0.16

0.29

0.39

0.71

0.59

1.07

3(P)

55

0.16

0.29

0.29

0.18

0.32

0.31

0.39

0.71

0.59

N/A

N/A

0.71

3(N)

0.16

0.29

0.16

0.29

0.26

0.46

0.39

0.71

4(P)

55

0.15

0.27

0.28

0.18

0.32

0.34

0.22

0.39

0.48

0.63

1.14

1.10

4(N)

0.16

0.29

0.20

0.36

0.31

0.57

0.59

1.07

5(P)

55

0.10

0.18

0.20

0.12

0.21

0.25

0.26

0.46

0.52

0.59

1.07

1.07

5(N)

0.12

0.21

0.16

0.29

0.31

0.57

0.59

1.07

Table 10. Quantitative damage states.

Damage States

Flexurally Dominated Behavior

Shear Dominated Behavior

Drift Ratio (AR = 1.0)

Drift Ratio (1.0 < AR < 2.6)

Drift Ratio (AR = 1.0)

Drift Ratio (AR < 1.0)

Slight

<0.25

0.20-0.50

<0.25

0.20-0.30

Moderate

0.25-0.70

0.40-0.80

0.25-0.55

0.25-0.35

Extensive

0.70-1.20

1.20-1.60

0.55-0.80

0.40-1.00

Complete

1.10-1.75

1.50-2.40

0.80-1.50

1.00-1.25

(c) Flexurally critical behavior (1.0 < AR < 2.6) (d) Shear critical behavior (AR < 1.0)

Fig. 1. Drift ratio versus damage states.

Table 11. Drift ratio comparison with HAZUS.

Damage States

HAZUS

Flexure

Shear

High-

Code

Moderate-

Code

Low-

Code

Pre­

Code

AR = 1.0

1.0 < AR < 2.6

AR = 1.0

AR < 1.0

Slight

0.40

0.40

0.40

0.30

<0.25

0.20-0.50

<0.25

0.20-0.30

Moderate

0.80

0.70

0.60

0.50

0.25-0.70

0.40-0.80

0.25-0.55

0.25-0.35

Extensive

2.40

1.90

1.60

1.30

0.70-1.20

1.20-1.60

0.55-0.80

0.40-1.00

Complete

7.00

5.30

4.40

3.50

1.10-1.75

1.50-2.40

0.80-1.50

1.00-1.25

Table 11 compares HAZUS drift ratios with those selected in this paper, as discriminated by qualitative damage state. Note that HAZUS predicts much larger drift ratios than do experimental results. The difference is quite high in the Extensive and Complete damage states. Current HAZUS methodology compares best with high aspect ratio, flexurally-critical walls.

Conclusions

In this study, quantitative and qualitative damage states for low-rise reinforced masonry walls are defined based on experimental results. Drift ratio is used as the quantitative damage indicator, and separate classifications are provided depending on whether the behavior of the wall is dominated by flexure or by shear. Comparison of the drift ratios selected in this paper indicates large differences when compared to the HAZUS methodology, which does not differentiate based on wall behavior mode. Current HAZUS provisions best correlate with high aspect ratio, flexurally critical walls.

While it is certain that masonry wall damage is significantly influenced by behavior mode, lim­itations of the experimental database restrict the confidence that can be place in any classification system. Although the authors do believe classification system presented in this paper is superior to the current HAZUS methodology, more testing is required before any classification system can be made reliable.

specimen number

value in positive test direction

value in negative test direction

aspect ratio

wall height, in

drift ratio, %

average drift ratios in positive and negative directions

wall vertical steel, %

wall horizontal steel, %

lateral load at first yield of vertical steel, k

wall displacement at Y, in

lateral load at major diagonal crack, k

wall displacement at M, in

lateral load when masonry achieved compression strain of 0.0025, k

wall displacement at S, in

maximum lateral load attained, k

wall displacement at U, in

lateral load at 20% degradation, k

wall displacement at D, in

axial stress, psi

value is not available