40 



The difficulties of this type of construction, however, are of such a 

 nature that the probability of securing a maximum length of life is 

 less than in the case of precast concrete piles or pile casings. [No. 

 (6) in last year's summary.] 



(8) Copper sheathed piles have given very satisfactory service 

 in locations where (towage from abrasion and theft can be minimized. 

 s itclt piles care full y prepared and li an died fall into the class of best sur- 

 face ])rotectionf>, U'hen used under the conditions indicated. 



(9) The selection of a type of piling or pile protection for a given 

 structure must be made upon the basis of cast and permanence of the 

 materials under consideration, the character of the structure and the 

 probable need for future alterations to meet the changing requirements 

 of commerce. When a comparatively short increase over the life of 

 untreated wooden piling is sufficient, the surface protections will often 

 be found economical in waters not exposed to severe storm action; 

 if a moderately long physical life approximating the average economic 

 life of marine structures in this harbor is desired, a good creosote treat- 

 ment will provide it at the lowest annual cost, so far as present knowl- 

 edge goes; if conditions warrant building for the greatest permanence, 

 with less regard fof first cost, concrete construction has shown a Jiigh 

 value in this harbor. For the protection from further damage of 

 wooden piles already in place and showing attack by borers, not yet 

 severe enough to require condemnation, the concrete casing, precast 

 or poured in place, is the only means of salvage so far found by the 

 Committee. 



AVHAHF rONSTKK TIOX SKCT1OX 



Following this Committee's report of last year an insistent demand 

 arose for the formulation by the Committee of definite advice respect- 

 ing practical measures which should be taken to avoid, for example, 

 the damage to creosoted piling in careless handling and construction 

 which the report of the Committee so strongly condemned. This led 

 to the creation for this year of the sub-committee on Wharf Construc- 

 tion. 



Specifications and Inspections 



It should be obvious that specifications and inspections should be 

 co-extensive. The best specification is comparatively valueless unless 

 inspection is both thorough, and of sufficient scope to insure that 

 the specification has been complied with. With respect to piling this 

 should follow through the supply and preparation of the piles, their 

 transfer from source of supply to site, their handling to pile driver, 

 and finally their driving and fastening in the completed structure. 

 The suggestions herein offered are confined to creosoted piling, for 



