The Strengthening Technology about External Prestressing of Large Span Concrete Bridge

Problems with prestressed long-span concrete bridge in China are beam cracks and time-dependent deflection in midspan,which result in higher cost for bridge maintenance and poor sense of beauty,influence structure durability and traffic safety.External prestressing system adopted for long-span concrete bridge strengthening has obvious effect to control cracks and deflection.Based on the strengthening practice of two bridges with main span of over 200m,This paper puts forward relevant measures and some useful suggestion for external prestressing system.