Modelling of deep concrete beams strengthened with Ultra-High Performance Fiber Concrete jacket

Abstract

Deep beams are defined as having small shear-span-to-depth ratio and are used as trans-fer girders in high buildings, cap beams in bridges. The modelling of deep beams cannot bedone on the basis of the theory plane sections remain plane (Hooke theory) because theydevelop complex deformation patterns.The subject of this thesis is the modeling of a deep beam reinforced by an ultra-high per-formance fibers concrete (UHPFC) jacket. What is of interest in this project is to determinethe shear resistance and to have the effect of the fibers. This is based on the two-parameterkinematic theory for shear behaviour of deep beams developed by Mihaylov et al. (2013).The main goal of this thesis is to introduce and define the fundamental theory of the kin-ematic model (2PKT), for deep beams and extend it for the case of adding an ultra high per-formance fiber jacket. The key feature of this theory are the compatibility conditions whichare derived from a simplified kinematic representation of the deformation patterns observedin deep beams. The shear capacity of the deep beam is the sum of the four components ofshear resistance across the critical diagonal crack, the shear demand curve is derived fromthe tension force in the flexural reinforcement by using the moment equilibrium of the shearspan,the intersection of these two curves gives the shear strength of the deep beam.The two-parameter kinematic theory (2PKT) is capable of predicting the shear failure load,the crack widhts near failure, and the complete deformed shapes of diagonal cracked point-loaded deep beams subjected to single curvature the case of ultra-high performance fiberconcrete jacket (UHPFC)