IMPACT ECHO (IE)
www.olsoninstruments.com www.olsonengineering.com
Experimental Results from the North Wall
North Wall – Top Duct: The IE results from the North Wall with the actual defect design of the top duct
placed above the IE results of the top duct are shown in Figure 8. Several pieces of stepped Styrofoam
were inserted inside this duct ranging from depth lost of 23% to 94% or circumferential lost of 32% to
84%. All the results from four ducts from the North wall are presented with normalized thickness
tomogram. The results are interpreted to indicate that the grout defect started to appear at the west end of
the girder although there was not Styrofoam inside the duct for the first 6.10 m (24 inches) from the west
end. However, visual inspection indicated there was honeycomb around the top duct of the north wall.
Figure 8 showed that the IE test was able to detect the grout defect of 23% depth lost or 32%
circumferential lost. The location that the grout defect is more evident corresponds to void with 50%
depth and 50% circumferential contact diameter lost.
Figure 8 - IE Results from the North Wall with Actual Design Defects of Top Duct and the Normalized
Thickness Scale
North Wall – Second Duct from Top:
Several pieces of stepped Styrofoam were inserted inside this duct
ranging from depth lost of 6% to 87% or circumferential lost of 16% to 76%. Review of Figure 9 shows
that the grout defect started to appear at a length of 1.62 m (64 in) from the west end of the girder. This
length corresponds with location with voids of 13% lost in depth or 24% circumferential lost.
North Wall - Review of Figure 10 shows that the grout defect started to appear at a length of 2.59 m
(102”) from the west end of the girder. This location corresponds to void of 11% depth lost or 19%
circumferential lost. In this case, the grout defect appear to be apparent (full depth void) right at a length
of 3.35 m (132 in) from the west end. This location corresponds to void of 35% depth lost or 39%
circumferential lost.
Length of Wall (inches)
48 96 144 240 16 32 64 80 112 128 160 224 0
West End East End
176 192 208
0
4.8
4
3.2
2.4
1.6
0.8
Wall Height (ft)
Grout defects start to appear at the west end
Grout defect becomes clear
To Next Page
Loading...