Methods of Protecting Timber: 



The three general methods used for the protection of tiUiber are coatings, 

 armors and injected preservatives. No really effective coating has been 

 developed to date. Armors give efficient protraction so long as they remain 

 unbroken and extend from a level above high virater to one belo^T harbor 

 bottom sufficiently far to guard against the possibility of scour. 



Tiie process of protection hj injected preservatives is the most generally 

 used because it has the advantage of affording protection against decay, 

 insects and inarine borers. The preservatives include soluble and. insoluble 

 salts, creosote oil, and creosote coal tar solutions. Soluble salts are 

 not reliable if the timber is exposed to leaching. The best results are 

 obtained from pressure treatments which produce complete penetration by 

 the preservative. Physical damage to pii.es during handling and driving 

 must be avoided in order to realize maxiriium benefit of the preservative 

 treatment r Boring and cuttir-g of piles belov: high water encojrages entry 

 of marine borers. Deterioration is less rapid for pile bents capped with 

 single timbers than for those framed by cutting the pile heads to receive 

 a pair of cap clamps,. 



Abrasion damage applies principally to exposed decking and to the outer 

 faces of fender piles. There is often ample evidence to support the belief 

 that no ext.:-mded usefulness is obtained by treatment of deck timber to 

 prevent decay, on account of the physical destruction caused by wear. 

 Covering of the exposed surfaces with more resistant materials is the only 

 practical solution for abrasion. The life of wood fender piles can often 

 be materially increased by the provision of metal rubbing strips on the 

 contact areas. 



The fire hazard must not be overlooked in design. The principal protection 

 consists in segregating a structure into several units by firewalls or 

 bulkheads extending from the underside of the deck to a level below the 

 low vrater line. The provision of openings in the deck for foam nozzles 

 are often provided for additional -r-rotection. 



Concrete Construction: 



Concrete is generally considered to be the most durable material available 

 for the building of waterfront structures. This idea probably stems from 

 the fact that cement was made in the time of the Romans that remained stable 

 in se". water for hundreds of years. Modern Portland cement apparently 

 lacks such chemical stability in sea water and its use in concrete require 

 careful control. 



The Bureau of Yards and Docks has under test at Portsmouth, New Hampshire, 

 prototype concrete pile specimens ih inches square by 13 feet long. A 

 total of 96 specimens vrere hung in tho tide zone during the years 1925 

 through 1933. Each of these specimens varied in some particular, either 

 in the kind of cement, proportions of the mix, type of aggregate, use of 

 an admixture, surface treatment or special type of reinforcing. Various 



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