Calculation Method for Flexural Capacity of High Strain Hardening UHPC T-Beams

Abstract:

In order study the calculation method for flexural capacity of high strainhardening ultrahigh performance concrete (UHPC) Tbeams, a fourpoint loading experiment of five girder specimens was conducted and the loaddeflection curve of reinforcement and high strain strengthening UHPC was drawn. The Tbeam failure process was divided into the elastic stage, the fracture development stage, and the loadtofailure stage. Different from common concrete, when the force of high strainhardening UHPC beam reach the ultimate load carrying capacity, the relationship between stress and strain of UHPC of compressive region is still linear. Meanwhile, since the contribution of UHPC tensile strength of tensile region to flexural capacity, after UHPC cracking, should be considered, an equivalent rectangular stress coefficient β of UHPC of tensile region is proposed. The calculation method for flexural capacity of reinforced UHPC Tbeams is deduced, based on the flat section assumption. This method is compared with the foreign calculation method and the accuracy of each method is analyzed. The results show that the calculated value of the proposed method fits the test value well, providing reference for theory analysis and structural design of reinforced UHPC T-beams.

Key words:ultrahigh performance concrete; high strainhardening; flexural capacity; method comparison