BOLTS 



m 



^ 



WOOD PLANKS 



Figure 61. Wakefield sheet piling. 



spruce, hemlock, redwood, cedar, and a number of species of pine, including 

 lodgepole, ponderosa, and white. Hardwoods are less commonly used not 

 because of inferior quality but because of cost or availability. Hard- 

 woods, generally, are more difficult to treat with preservatives. However, 

 special situations may call for hardwoods. For instance, an imported 

 hardwood called greenhart is gaining some acceptance for use as fender 

 piles because it appears to be fairly resistant to marine borers in its 

 untreated state. Tables 31 and 32 list significant characteristics of 

 domestic softwoods and hardwoods, respectively. 



6. Destructive Biota . 



a. General. 



Although there are many life forms that may eat, live in, or make use 

 of wood in a way that may be called destructive, many are so rare or do so 

 little damage during the useful life of wood structures that they can be 

 ignored relative to the use of wood in the coastal zone. Those that most 





Table 31. 



Domestic 



softwoods 







General 



Douglas 









Southern 



characteristics 



Fir 



Redwood 



Cedar 



Spruce 



Pine 



Shrinkage in 



10.9 



11.5 



11.2 



10.4 



12.4 



volume from green 













to ovendry (pet) 













Modulus of rupture 



43.7 



51.4 



41.6 



31.4 



44.1 



MPa 



(green) 



(green) 



(green) 



(green) 



(green) 



Modulus of 



7.798 



7.591 



5.199 



5.971 



7.860 



Elasticity 



(green) 



• (green) 



(green) 



(green) 



(green) 



GPa 













244 



