ASEISMIC DESIGN WITH PRE DEFINED PLASTIC HINGES- A STUDY

This paper highlights the importance of selection of a suitable ductile composite, incorporating it into the predefined locations, for better seismic performance. Replacement of normal concrete with ductile composites at plastic hinge locations is an idea, which can be well thought for in the conceptual approach to structural design. A simple experimental investigation was carried out to establish this concept. The ability of the structure to sustain levels of inelastic deformation implicit in ductility values is dependent on the material and detailing used. Concrete, which is inherently brittle and weak in tension, were modified by incorporating polymeric materials like natural rubber latex and steel fibers. This improves ductility; strain at peak load and energy absorption capability. The validity of the scheme is proved by a couple of experiments including the stress- strain characteristics of the material as they play a significant role in ductile response of structural elements. Three point bending tests were conducted on four types reinforced concrete beams with different concrete matrixes at the central region and high strength concrete at other regions. As ductility and damage modeling of structural components plays an important role in achieving the performance objectives, they have been quantified using the experimental data by suitable methods. Damage index evaluation was done using one of the well-known damage models, which takes into account the hysteretic energy dissipation along with ductility. A response factor directly related to the damage index is found out in order to get the major design variable displacement ductility, thus helping the design stage calculations.