Application of strut-and-tie model for design of interior anchorage zone in post-tensioned concrete structure

This paper presents an application of strut-and-tie model (STM) to design the interior anchorage zone (IAZ) in the post-tensioned concrete structure. The STM theory and range of IAZ are introduced. Then, based on the finite element analysis, a series of simplified equations to calculate internal forces in IAZ are presented. Finally, the STM model for IAZ is given. In the proposed STM model, internal forces in ties vary with the dimension ratio and the eccentricity of load. The U-turn of internal forces is suggested to allocate rebar to resist bearing flexural tensile force. Compared with the FIP (International Federation for Prestressing) model, the proposed STM model is more reasonable and applicable.