NKK's minimum maintenance bridges

摘要

NKK has been innovating new concept of minimum maintenance bridge since 1997. As phase 1 project, a rural type testing bridge, using new type of weathering steel, CUPLOY400-CL and CUPTEN490-CL, specially milled by NKK for sea side district, hasbeen designed and constructed inside of NRK for field corrosion test. Long term field test involves measure of salts attached to bridge carried in air from sea, and evaluation of corrosion effect to the weathering steel. As phase 2 project, urban typebridges are proposed and discussed in several view points. Structural members with closed cross section instead of open cross section are proposed for minimum maintenance with several advantages of aesthetics and good rigidity.