76 



a considerable distance, boring and reeving should be the only method of fastening 

 allowed. 



The ax, the pike pole and pea^•ie also cause much damage. The holes left by 

 sinking an ax into the piling, as is frequently done in handling, are much like those 

 caused by the dog, and are particularly dangerous. The use of pike poles and peavies 

 should only be permitted when their points are blunted. The use of boat hof)ks during 

 inspections by row boat or raft is also a source of considerable damage to treated piles 

 in place, and should be prohibited. 



Driving 



With creosoted piling, again it is necessary to take precautions against the 

 puncturing of the protective shell with pike poles, peavies, axes, etc. Unfortunately 

 men handling creosoted lumber and piling seldom appreciate the necessity for pre- 

 serving the protective shell. Eternal vigilance is the price of a good job in this respect. 



Closely allied to this, one of the most important duties of the pile-driving crew, to 

 drive the piles without puncturing the protective shell, is the necessity of care against 

 the always present danger of checking the piling under the hammer. In using a steam 

 hammer it is well to use piles of a butt diameter of at least 14 inches. This permits the 

 pile to be headed, so that the plate upon which the plunger strikes has a sufTicient 

 bearing entirely on wood whose fibres, below the surface, are supported on all sides 

 by surrounding ones, and it is therefore not so likely to cause checking. On rocky 

 bottoms, where there is little or no mud, great care must be taken not to split the pile 

 (fig. 25). This can be done by avoiding hard drixing, and by the use of various types 

 of steel shoes and plates. 



Much the same precautions apply to the driving of concrete piling as to that of 

 wooden piling, o\'erdriving causing similar, although not, of course, identical troubles. 



Br.-^cing 



The conditions of flexure in the pile will further depend upon its length from 

 wharf to substrata, the pile acting as a colunm with either or both ends fixed. With 

 unsupported lengths averaging from 30 to 50 feet from wharf to substrata, it becomes 

 desirable to reduce this length by cross bracing. This however has been found im- 

 practicable, except to a minor degree. Timber piling protected against borers should 

 not be braced below the high water line for the reason that the framing or other connec- 

 tions of pile bracing will rupture or weaken the protection and the way will be opened 

 for borer attack. Metal pile connections below high water have been found to corrode 

 and break, and connections in concrete piles are likely to develop cracks and expose 

 the reinforcing bars to corrosion, with resultant disintegration of the concrete and 

 destruction of the joint. As a result, bracing, as well as ribbing and other attachments 

 should be made above high water level, (see fig. 24). This restriction of bracing to the 

 restricted space between top of pile and high water, or even wave splash level, is a 

 severe handicap upon mechanical rigidity. For creosoted piling, batter piles having 

 their connections above high tide level will be found the most satisfactory means of 

 securing bracing of the required rigidity. 



Cutting and Fr.aming 

 Creosoted piling should not be cut off below high water line, thus exposing un- 

 treated wood to attack by borers, if it can be avoided. Even tide slopping, where 

 piling is cut near to high water level, may permit Linuwria attack, if water can settle 

 where it does not run off (fig. 26). Furthermore, decay frequently occurs in the un- 

 treated interior of piles when they are cut off at any level above high water. Whenever 



