MODEL 4420 VIBRATING WIRE CRACKMETER
| 3D MONITORING |
23
4.
Insert the provided setting tool into the anchor, small end first. Expand the
anchor by hitting the large end of the setting tool with several sharp
hammer blows.
5.
Remove the PVC slotted sleeve or dowel pin securing the transducer shaft.
6.
Push the cap screws through the swivel bearings and spacers on each end
of the crackmeter and then tighten the cap screws into the anchors.
7.
Check and record the reading with a portable readout.
Z-AXIS
The Z-axis, as shown above, measures vertical movement along the crack
utilizing two brackets: one to transfer movement across the crack, and one to
mount the sensor vertically. The 5-5/8" long stainless steel angle iron is mounted
across the crack by installing an expansion anchor with a spacer approximately
two inches from the break. The vertical element is then aligned so that a
crackmeter with U-joints on both ends will be upright in relation to the break.
Two expansion anchors are supplied with this part located 1-1/4" apart, and no
spacers are required. A percentage of the transducer’s range can be established
by tightening or loosening the nuts on the long threaded rod.
The actual height of the crackmeters above the surface is determined by the
spacers and is proportional to the range of the sensor, to accommodate the
maximum amount of movement.
The 3D hardware comes standard with expansion anchors, but is designed to be
interchangeable with groutable anchors.
For installation steps, refer to the instructions in Section 2.2.3 for groutable
anchors and Section 2.2.4 for drop-in expansion anchors.
D.3 MODEL 4420-3 CANTILEVER 3D ARRAY ALTERNATIVE
You can use the Model 4420-3 cantilever crackmeter to construct an alternative
version of this 3D array, where the 4420-3 monitors the vertical Z-axis in a
cantilever arrangement.
The 4420-3 employs a Model 4150 strain gauge to measure vertical movements.
This version, shown below, is available in a one-inch range only.
15:
FIGURE 15:
Cantilever 3D Array - Top View