FINITE ELEMENT ANALYSIS USING THE MODIFIED COMPRESSION FIELD AND THE CRACKED MEMBRANE MODEL FOR STRUCTURAL CONCRETE SUBJECT TO IN-PLANE STRESS

Resumo

In this paper, the Modified Compression Field Theory (MCFT, Vecchio and Collins, 1986) and
the Cracked Membrane Model (CMM, Kaufmann and Marti, 1998) are developed into a finite element
formulation for the analysis of orthogonally reinforced and prestressed structural elements in plane stress
condition.
MCFT considers orthotropic concrete, distributed and rotating cracks that are normal to the principal
tension stresses. Tension stiffening, aggregate interlock, and interactions between concrete and steel at
surface of cracks use average strains and stress. Use of average constitutive equations relating average
stress and strains are complicated and debatable.
CMM falls into the category of compression field models, combining components from MCFT and
Tension Chord Model (TCM, Kaufmann, 1998) extended to cracked plane stress. In this way, the link
to limit analysis is maintained and there is no need to introduce constitutive equations relating average
stress and average strains in tension: the equilibrium is formulated in terms of stresses at cracks rather
than average stress between cracks. This make easy to evaluated results from practical strut and tie
models (STM).
Two above FE models are verified and compared against experimental results of beams, shear panels
and deep beams.