IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

The load versus deformation behavior of a reinforced concrete (RC) panel element under membrane stresses can be predicted by the modified compression field theory (MCFT) and the softened truss model (STM). In these theories, the stress-strain relationships for reinforcing bars are derived from tests under uniaxial tension. When these relationships are applied to an element under biaxial stresses, the Poisson'S effect is usually neglected. This leads to an overestimate of the shear resistance offered by the element. The present research investigated Poisson'S effect in RC panels subjected to biaxial stresses. To incorporate Poisson'S effect in the analysis of panels, an orthotropic formulation was developed, based on the concept of apparent Poisson'S ratio (APR). The APRs were quantified by testing panels under biaxial tension-compression. Poisson'S effect is incorporated in the STM to rectify the overestimate of the shear resistance of a panel element.

Department Of Civil Engineering

World University root node

ACI Structural Journal

Modeling effect of biaxial stresses on average stress-strain relationship of reinforcing bar in reinforced concrete panels

The average stress-strain relationships of the steel reinforcing bars (rebars) used in the analysis and design of reinforced concrete (RC) panels are derived from uniaxial tension tests. This tends to overestimate the overall resistance of the panels, especially in the post-yield range. The biaxial stress field within a panel results in a reduction of the average stresses in the rebars. This paper presents qualitatively the biaxial effect on the average stress-strain relationships of the rebars.