MEASURES FOR IMPROVING THE LONG-TERM DURABILITY OF A PRESTRESSED CONCRETE BRIDGE USING HIGH-STRENGTH CONCRETE

摘要

The Tan-nowa viaduct is a three-span continuous prestressed concrete box girder bridge. For construction of this bridge with small girder height and long span, high-strength concrete of 60 N/mm2 in design strength was used. High-strength concrete has a dense matrix, inherently excellent in durability. However, as the specific cement content increases, the concrete is more prone to cracking due to shrinkage and larger hydration heat, and workability worsens because of higher viscosity. It was therefore necessary to address many problems to ensure satisfactory durability. For this bridge project, a committee of technology experts was established to study problems and measures to be taken for making the bridge sufficiently durable, fully developing the inherent performance of high-strength concrete. This paper discusses the overview of the bridge, problems studied, measures taken and outline of the construction.