2.10 Installation on Existing Structures
Again the lugs welded to the edge of the cell can be used to hold the cell against the structure using nails, lag bolts, tie wire, etc. Even if the surface is smooth, but especially where the surface is rough or irregular a mortar pad between the cell and the structure is required.
Use of lugs on the cell as a template to locate the position for drilling holes for the installation of expanding anchors or install the anchors nearby and use wire to hold the cells in place.
Alternately the cell may be nailed in place using the lugs as a guide. First some quick setting cement mortar or epoxy cement should be mixed up. The surface is trawled and the cell is pushed into the cement so that the excess cement extrudes out of the edges of the cell. The cell is hold in place while the cement sets up, then the installation is completed
|Figure 2.10 - Contact Pressure Cell Installation|
by adding the lag bolts (using the expansion anchors) and tightening or nailing the cell in place. The cell, transducer housing and cable is protected from direct contact with large chunks of rock by covering them with fine grained fill material from which all pieces larger than about 10 mm (0.5") have been removed. This fine material is kept next to the cell and cable as the fill is placed. Additional cable protection can be achieved by using metal conduit strapped to the surface of the structure.