Investigation Into The Compression Stress Field Patterns Of D-regions In Concrete Structures

This research is carried out to make a contribution to the design and assessment of the disturbed regions in concrete structures.The research is an investigation of typical D-regions problems using stress field modeling approach,which is sourced from linear elastic stress fields.The motivation is that the implementation of the widely known strut and tie modeling approach for the design and assessment of D-regions is still limited and debatable,and the uniqueness of the strut and tie models remains questionable.This paper incorporates a brief review of strut and tie modeling and stress field modeling,and explores the compression stress field models proposed for predicting the behavior of cracked concrete elements.Next,based on a linear elastic finite element analysis,simplified stress field solutions are proposed for concentric anchorage zones in post-tensioned concrete and deep beams with a unity span to depth ratio.These solutions are justified by the lower bound theorem of plasticity in which the yielding condition is not infringed and the equilibrium and static boundary conditions are fulfilled.Definition procedure of the compression stress fields is established and expressions for calculating the geometric parameters of the stress field are provided.The proposed stress field solutions show that stress fields modeling approach is a very amazingly powerful tool to tackle the D-region problems and provide a further development to visualize the load transfer mechanism within the members.Lastly,conclusions and observations are listed and suggestions for new research paths are given.