Bridge Inspection for Decay and Other Deterioration

Wood is an amazing combination of polymers that exhibits both strength and durability as a structural material. Nevertheless, from the time it is formed in the tree, wood is subject to deterioration by a variety of agents. Damage ranges from relatively minor discolorations caused by fungi or chemicals to more serious decay and insect attack. Wood degradation is beneficial in the ecosystem, returning carbon and other elements to the soil and air, but it becomes detrimental when the deteriorating material is part of a bridge or other structure. Wood outperforms most other materials when used in a properly designed and maintained structure; however, when used in adverse environments, it must be protected to ensure ade­ quate performance. Although the use of pressure-treated wood has signifl­ cantly extended the life of timber, decay is still the primary cause of bridge deterioration.