can be severe at the sandline, particularly in a wet-dry tidal area, where 

 steel may deteriorate rapidly. 



Wood is considered less durahle than concrete but its lifespan depends 

 to a great extent on the characteristics of the wood, the usage, and the 

 quality of maintenance. It is an organic material and subject to attack by 

 both plants and animals. It is more subject to damage by fire than other 

 materials . 



Synthetic materials are generally quite durable to chemical attack; 

 however, many will rapidly deteriorate when exposed to sunlight. They 

 require very little maintenance but with most synthetics, because of their 

 short history, their service life relative to the life of the structure is 

 yet to be determined. 



b. Adaptability . For any given coastal structure there is usually 

 more than one material or a combination of compatible materials that can 

 satisfy the performance requirements of the structure. Selecting the 

 proper materials as well as design adaptable to the structure site is 

 important. The size of a structure and the accessibility of construction 

 materials to the site must also be considered. 



Stone and earth structures can assume a wide variety of shapes. The 

 materials are generally available and, forming nonrigid structures, can for 

 example accomodate changes in foundation elevations or slope adjustments 

 without losing structural integrity or ability to perform their function in 

 the structure. Stone can be used under most weather conditions and will 

 accept major and rapid changes in temperature and moisture without major 

 failures. 



Concrete is very adaptable, with or without steel reinforcement. Its 

 use is similar to stone except for the ability to resist abrasion and the 

 cost. Concrete can compete with steel or wood as piles or as sheet pile 

 both in strength and durability. 



Use of steel, because of costs, is generally limited to piles, sheet 

 pile, and beams but is extremely adaptable for use in complex structures. 



Wood is very adaptable except for limitations on the ability to function 

 well against large wave forces or in greater than moderate depths of water. 

 It resists impact and abrasion well, can resist tension, compression or 

 shear, and is easily handled in construction. 



Synthetic and protective coating materials are usually special use 

 items and are not considered as having a wide range of uses. 



c. Fire Resistance . Stone and earth are generally regarded as very 

 fire resistant, especially those that are from igneous or metamorphic 

 sources. Sedimentary stone, because of stratification, is less fire 

 resistant. 



Concrete is generally fire resistant unless exposed to very high 

 temperatures. Reinforced concrete when exposed to extreme temperatures for 



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