Use of UHPC Jackets in Coastal Bridge Piles

Concrete deteriorates for a variety of reasons, but corrosion of steel reinforcement has been one of the most prevalent mechanisms of deterioration since concrete structures were introduced in the early 1900s. It affects many types of concrete elements, especially the substructures of coastal bridges. Steel reinforcement used in coastal bridge piles has exhibited corrosion damage within twenty years of construction. Therefore, it degrades the durability and reduces the service life of the bridges severely. As a result, it costs billions of dollars in rehabilitating or repairing the deficient components. The recent development of UHPC can mitigate these deficiencies because of its exceptional properties. However, the cost of UHPC is significantly higher than that of the conventional concrete. Therefore, it appears to be attractive to use UHPC jackets in coastal bridge piles, which allows to taking advantage of the superior properties of UHPC without using excessive amount of UHPC in the full section. This paper presents a study of the structural design of piles using UHPC jackets, including the working stress design and strength design. A numerical example of a square pile using a UHPC jacket is included to show how the flexural strength design can be handled.