NON LINEAR ANALYSIS OF RC FRAMED STRUCTURES

Abstract

This study aims to analytically investigate and verify the behaviour of a scaled-down G+2 storey reinforced concrete framed structure (without masonry infill) subjected to monotonic pushover loads, utilizing ABAQUS software. The pushover analysis uses a performancebased approach and increments of horizontal loads applied to the structure while monitoring the corresponding deflection. The main objective is to assess and validate the pushover curve developed analytically with the experimental results available. The work involves conducting a comprehensive finite element analysis of the reinforced concrete frame model, accounting for load conditions, material properties and element sizes. The accurate representation of geometry, cross-sectional properties, and connections within the frame members ensures a realistic simulation of the structure. A simplified geometric modelling approach which uses mixture of 3D wire elements for frame elements and 3D shell elements for slab is used instead of time time-consuming 3D model for each element and then assembled as usually done in ABAQUS. Kent and Park models for stress-strain model of concrete, and steel stress strain curves with and without the post-yielding behaviour are considered in the analysis. The impact of axial force on the moment curvature and the impact of mesh size in altering the response of the structure is thoroughly studied. Additionally, in the simplified geometric modelling approach the degradation of shell elements can be adequately modelled with Concrete Damaged Plasticity Model (CDPM). To understand the behaviour of model for various mesh sizes two 3D joint models were analysed. The findings from this study contribute to enhancing the understanding of the structural behaviour of reinforced concrete frames subjected to monotonic pushover loads. Conclusions gained can be effectively utilized for performance-based assessment and seismic analysis of similar structural systems. Keywords: Non Linear Static Pushover Analysis, Moment Curvature Relationship, Stress- Strain Curve Model for Concrete, Stress Strain Curve Model for Steel, Axial-Flexure Interaction.