Simulation of Crack Propagation in Some Self-Compacting Concrete Structures and Determination of Their Strength and Ductility Performances

Abstract

A study on the crack propagation, strength and ductility performances of some self-compacting concrete (SCC) structures with and without steel fibers can be made through experiments. But testing is laborious. For large structure like dam, testing is impossible. Sometimes, there could be insufficient laboratory facilities. Under such circumstances, the non-linear analysis of concrete structures became a novel design tool. It employs the power of computer simulation using finite element method (FEM) based software to support the structural engineers. The ATENA software uses smeared crack approach and is based on the Bazant’s crack band theory. The experimental total fracture energies of both SCC and steel fiber reinforced SCC (Steel fibers of length 25mm@ 0.6% by volume of mix) beams of strength M50 determined by RILEM’s work of fracture method, corresponding material properties and tension softening behavior are used as input data in the software. The simulated load-deflection/CMOD curve could be used to access the strength and ductility performances of the structures. The strength is identified by peak load and ductility by extension of tail end of this curve beyond yield load. Hence, this paper presents an appropriate methodology to determine the performances by simulation. Ductility is the desired property required for structures during earthquake. This can be improved by increasing the main steel reinforcement, incorporate fiber reinforced plastic (FRP) and steel tubes to impart it. But this could be uneconomical. In such cases, it is to be investigated that ductility can be improved by incorporating steel fibers of appropriate aspect ratio and volume in the mix. The ductility ratio (μ) determined from the load-deflection/CMOD curves is further used to evaluate the response reduction factor(R) by an empirical formula as established in earlier investigation. The R used in base shear formula of IS 1893(Part-I)-2002 code considers the ductility property of the structures that are subjected to lateral base shear during earthquake. Thus this study is carried out to identify the usefulness of simulation technique which is a new and robust tool to assess these performances of the structures using ATENA software that avoid the tedious testing procedures. This study investigates the influence of steel fibers in SFRSCC structures to improve their strength and ductility performances compared to SCC structures.