on all of the seam bolts. Apply the nuts with the rounded face down to all of the bolts. Do not tighten.
Tighten all of the chime bolts uniformly. Remove the blocking (fig. 9-14); place it under the chime of the bottom. Use a heavy, long timber as a lever and a short timber as a fulcrum to lift the chime. lighten all of the seam bolts. Be careful not to crush the gaskets. Apply a sealing compound to the inside perimeter of the bottom chimes of the staves.
DRESSING TOP CHIME. - Use the scaffold and install the strip gasket to coverall of the bolt holes (fig. 9-15). When one roll of gasket material is used up and a new one is started, the overlap should extend over two bolt holes. Apply a sealing compound at each end of the overlap. Insert a wedge gasket underneath the gasket at each lap, formed by adjoining staves. Insert 1/2- by l-inch bolts through the chime and gasket, in that order. The gasket will hold the bolts in place.
'he ladder consists of a bolted steel angle section. The top of the ladder is fitted with a manhole dome.
The bottom of the ladder is fitted with ladder anchors, flanged, flat steel plates. The small end of the deck plates is bolted to the bottom flange of the manhole dome. Place two ladder rails (fig. 9-16, #1 and #2) with similar bolting legs facing each other on top of several pieces of blocking of sufficient length to support both rails and spaced wide enough apart to insert a ladder
Figure 9-15. - Dressed top chime of the staves
Figure 9-16. - Deck support ladder.
step. Determine which end of the roils will be the bottom. Install the steps from the bottom toward the top of the ladder. Five steps make up the assembled section. Insert 1/2- by l-inch bolts through the ends of the step and rails. Install a nut on each bolt protruding through the rails. Tighten the bolts after all of the steps are installed.
Face the 30 bolt hole flange of the manhole dome and slide it over the top of the rails. Use a driftpin and
Figure 9-17. - First deck plate installed.Continue Reading