Fig. 20
By wedging the inner end of the putlog into the wall, some stability is given to the scaffold, but the connection cannot be considered satisfactory, as the putlog would draw under very little strain. Greater stability can be gained if the outer frame of the scaffold is supported by one of the three methods given as follows.
Fig. 21.—Shores and Ties for Dependent Scaffolds
A shore or tie can be fixed between the erection and the ground as shown in [fig. 21], or, if there are openings in the wall, supports can be fixed as ties shown in the same diagram.
The ties or struts should be placed to every third or fourth standard at about 25 feet from the ground, and their fastenings made good. Additional ties should be carried within the building at a greater height where possible. The stability of the scaffold under loads and cross wind pressure, depends greatly upon the ties or shores, and their fastenings should be well made and kept in good order. The historical instance of the mechanic who, to escape a shower of rain, stood upon the inner board of the platform, and by leaning against the building pushed the scaffold over, should have no opportunity of recurrence.
Fig. 22
To stiffen the scaffold longitudinally braces are tied on the outside of the scaffold in the form of a St. Andrew’s cross (see [fig. 13]).
They start from the lower end of one standard and rise obliquely across the scaffold to near the top, or some distance up a standard in the same run. Tied at their crossing-point, connections are made to all the main timbers of the scaffold with which they come in contact. Braces are fixed in all exposed situations, and generally where the scaffold is more than one pole (30 feet) in height.