The National Academies Press

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Pages 238-289

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From page 238... ... 238 a p p e N D I x Q testing program The Federal Institute for Materials Research and Testing (BAM) in Germany carried out field testing between October 3 and 12, 2011, in three tunnels in the United States: two in Colorado (Eisenhower Memorial Tunnel and Hanging Lake Tunnel) Read the entire page →
From page 239... ... 239 Table Q.1. Overview of BAM Field-Testing Program, October 2011 Code Tunnel Location Date Technique Size (in.) Read the entire page →
From page 240... ... 240 Figure Q.2. Entrance to the Eisenhower Memorial Tunnel (a) Read the entire page →
From page 241... ... 241 notebook. This simplifies the control and reduces the equipment and weight of the measurement system. Read the entire page →
From page 243... ... 243 lining and detect/locate defects and anomalies within the lining. In the absence of ground truth data, the wave-speed of the lining material was either assumed or estimated from surface measurements. Read the entire page →
From page 244... ... 244 and delaminations directly or indirectly, in real time. Furthermore, it can estimate the strength of the material and estimate the structure thickness. Read the entire page →
From page 245... ... 245 D-Scan Anomaly D-Scan Reinforcement Backwall Weak backwall echo C-ScanD-Scan Reinforcement Anomaly: delamination? Backwall missing portion of the backwall echo Crack (a) Read the entire page →
From page 246... ... 246 Measurement Results for eisenhower Memorial Tunnel Description of the Test Area Measurements in the Eisenhower Memorial Tunnel were performed over two days: October 3 and 4, 2011. The unusually high elevation of the tunnel (11,112 ft) Read the entire page →
From page 247... ... 247 maintaining suction) Read the entire page →
From page 248... ... 248 (because of the positioning and polarization of the probe) and thus could only be vaguely traced at y = 10 in. Read the entire page →
From page 249... ... 249 z = 3 inches Reinforcement z = 16 inches Anomaly Reinforcement y-direction x = 8 inches Anomaly Reinforcement x-direction x = 24 inches Reinforcement y-direction Anomaly y = 4 inches Reinforcement x-direction (a) Read the entire page →
From page 251... ... 251 Figure Q.22. Photograph of construction of Eisenhower Memorial Tunnel sometime between 1968 and 1973 (Colorado DOT 2011) Read the entire page →
From page 252... ... 252 Figure Q.24. Sketch of test area, HL1, Segment 56. Read the entire page →
From page 253... ... 253 led to the rise of amplitudes over an area (Figure Q.26d, Figure Q.27c, Figure Q.28b, and Figure Q.28c) Read the entire page →
From page 254... ... 254 z = 12 in. Because the amplitude spectrum along the profile seemed rather scattered, no reliable conclusions about the nature of the reflector could be drawn. Read the entire page →
From page 255... ... 255 Reinforcement, y-direction y = 22 in. Reinforcement, x-direction Area of beams and dowels y = 12 in. Read the entire page →
From page 256... ... 256 Reinforcement, y-direction Anomaly y = 5 in. Read the entire page →
From page 257... ... 257 dividing segments 56 and 57. Its upper edge (toward the tunnel crest) Read the entire page →
From page 258... ... 258 Figure Q.33. Sketch of test area HL2, Segment 57. Read the entire page →
From page 259... ... 259 In the C-scan at a depth of z = 5 in., a reinforcement bar in the general x-direction could be seen running across the test area roughly from y = 16 in. on the south side of the area to about y = 12 in. Read the entire page →
From page 260... ... 260 z = 5 in. Read the entire page →
From page 261... ... 261 y = 24 in. Read the entire page →
From page 262... ... 262 Ultrasonic Echo The reinforcement mesh could be clearly seen in the ultrasonic echo C-scan at a depth of z = 6 in. (Figure Q.40) Read the entire page →
From page 263... ... 263 a curious finding that the thickness of the lining could not be detected by either method, as the tunnel is relatively recent. IE, however, could provide some hints about the thickness of the tunnel. Read the entire page →
From page 265... ... 265 Figure Q.45. Sketch of test area HL3, segment 58, Hanging Lake Tunnel. Read the entire page →
From page 266... ... 266 z = 6 in. Read the entire page →
From page 268... ... 268 Impact Echo Results No features were resolved on the basis of the IE results, as the frequency peaks were generally too broad to point to any particular resonating feature (Figure Q.51) Read the entire page →
From page 269... ... 269 backwall has a nominal thickness of 24 in., according to the tunnel's blueprints, and has a so-called steel skin. The grid spacing for ultrasonic echo and IE testing was set to 1 in., and for GPR, 2 in. Read the entire page →
From page 271... ... 271 y = 22 in. Read the entire page →
From page 272... ... 272 The B-scans in Figure Q.61 were chosen to represent areas of the test volume with and without anomaly. The left image in Figure Q.61 is a B-scan at x = 3 in., with no anomaly. Read the entire page →
From page 273... ... 273 x = 3 in. Read the entire page →
From page 276... ... 276 Ultrasonic Echo Results Figure Q.69 shows a 3-D image of the volume focusing on the backwall and an anomaly shadowing it. The reinforcement mesh was not clear in the ultrasonic echo C-scans. Read the entire page →
From page 277... ... 277 Figure Q.74) corresponding to the reflector depths of z = 27 in. Read the entire page →
From page 278... ... 278 y = 14 in. Reinforcement y-direction A B x z Figure Q.72. Read the entire page →
From page 279... ... 279 nominal thickness of 24 in. This could be a result of errors in the assumed concrete shear wave velocity used in estimating the reflector depths to analyze the US data of CPB2, as the shear wave velocity was assumed to be 2,710 m/s (from CPB1) Read the entire page →
From page 280... ... 280 extending 22 in. south and 26 in. Read the entire page →
From page 281... ... 281 Ultrasonic Echo Results Three of the four transverse reinforcement bars (in the y-direction) could be detected in the ultrasonic echo C-scan at z = 2-in. Read the entire page →
From page 283... ... 283 z = 25 in. Missing backwall echo due to the shadowing effect of the shallower anomaly x y Figure Q.83. Read the entire page →
From page 284... ... 284 echo, also indicating the presence of shallow delamination. However, the nature of the anomaly could not be confirmed. Read the entire page →
From page 285... ... 285 Anomaly A-Scan x = 6 in. Read the entire page →
From page 286... ... 286 The scanner moved upward and then left (south) Read the entire page →
From page 287... ... 287 z = 1.6 in. Read the entire page →
From page 288... ... 288 Steel bar x-direction Steel bars y-direction y = 2.5 in. Read the entire page →
From page 289... ... 289 Earlier manual measurements indicated that IE is able to evaluate the bonding between tiles and walls when A-scans of individual tiles are analyzed. In the case of automated scanning, the analyzed signal is the average of 20 signals recorded close to the source. Read the entire page →

From page 238...

... 238 a p p e N D I x Q testing program The Federal Institute for Materials Research and Testing (BAM) in Germany carried out field testing between October 3 and 12, 2011, in three tunnels in the United States: two in Colorado (Eisenhower Memorial Tunnel and Hanging Lake Tunnel)