I
MPACT
E
CHO
(IE)
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downshift in frequencies from lengths of 5.49 to 6.1 m (216 to 240 in), indicating voids at duct locations
where no discontinuities were intentionally placed. It is likely that grout did not flow into the higher east
duct end due to the big voids in front of it. Radiographic tests will be performed in the future to verify the
design versus actual conditions of the simulated defects.
Figure 5 – IE Results from the South Wall with Actual Design Defects of Top Duct
South Wall – Second Duct from Top: Review of Figure 6 shows that there are three grout defect zones.
The first grout defect zone correlates with the end defect (13% depth lost or 24% circumferential lost).
The second defect zone shows minor grout problem from lengths of 0.91 – 1.67 m (36 – 66 in) from the
west end of the duct. However, there is no actual defect placed in this area. Radiography is required to
confirm the realization of defect designs. The third defect zone appears at a length of 3.35 m (132 in)
which corresponds to defect of 9% in depth lost or 18.5% in circumferential lost. The most apparent
grout defect appears at a length of 5.18 m (204 in) corresponding to the location of the largest Styrofoam
in the duct (87% depth lost or 76% circumferential perimeter lost). Similar to the results from the top
duct, the interpretation of the Impact-Echo Scanner results, however, shows a downshift in frequencies
from lengths of 5.18 to 6.1 m (204 to 240 in), indicating major voids at duct locations where actual defect
shape tapers down toward the east end. It is likely that grout did not flow into the east end due to the
large voids in front of it.
South Wall – Third Duct from Top: Figure 7 shows three zones of grout defects. The first area is
located at the west end where Styrofoam Defect ID# 3 (see Table 1) is in place. However, the IE results
show that the duct is fully grouted between lengths of 0.45 – 2.13 m (18 – 84 in) from the west end where
there are actual Styrofoam defects placed in these locations. The grout defect appears again between
lengths of 2.13 – 3.2 m (84 – 126 in). The starting location of the second defect zone corresponds to
actual defect of 49% depth lost or 48% circumferential lost. The end location of the defect zone
0
60
120
180
240
20
40
80
100
140
160
200
220
Length of Wall (inches)
0
4.8
4
3.2
2.4
1.6
0.8
Wall Height (ft)
72
144
180
216
16%, 6%”
84%, 94%
76%, 87%
68%, 77%
Defect appears at length of 76 inches (from West end) – defect size of 20%, 11%
Defect can be identified clearly at length of 115 inches (from West end)
- Defect Size of 57%, 59%
West End
East End
8.0
8.75
9.5
10.25
11.0
11.75
12.5
13.25
14.0
8.0
8.75
9.5
10.25
11.0
11.75
12.5
13.25
14.0
IES Thickness Echo Scale (inches)
