Durability Design Approaches For Bridge Structures

Poor durability, short service life and low economical efficiency of bridges have become a worldwide difficult problem. The construction of bridges, roads and other infrastructural projects in China is on the instant development period, numerous bridges will be built in recent years. Therefore, how to increase the durability, safety and economical efficiency of infrastructures has been an important and valuable issue in our country. This dissertation mainly focuses on the following aspects:1. The principles and approaches for durability grade classify of bridge members are bring forward, durability grade standard and maintenance characteristic for typical bridge members are given, the design service life for bridge components is established.2. The serious durability defects of bridges are outlined, main reasons are analyzed, and integral design method frame for bridge durability is proposed which will comprised of three levels with two aspects (determined and quantified aspects). For material level, the concept of carbon durability and calculate formula is bring forward for the carbon effect in normal atmospheric environment, which can be easily used for carbon life rule design. For section and member level, design service life calculation formula based section durability ultimate limit is given. The durability design life that implied in the recommended durability measures of the Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts in typical atmospheric environment in China is analyzed, and section durability with different concrete and design parameters are compared. For member and structural safety durability level, simple and practical control formula for bending resistance members is deduced and the thoughts for determining correction factor of time depended resistant capacity is put forward. An example for showing the calculation procedure is given.3. The important influence of structure detailing for bridge durability is discussed, and durability design principles based on structural detail, waterproof...