A Macro-model for Nonlinear Analysis of 3D Reinforced Concrete Shear Walls

Architectural limitations in many situations make it necessary for the RC shear walls to be extended in plan in different directions at a single location that makes them a 3D configuration. Analysis of such walls is very challenging. In this research about 450 cases of 3D shear walls are considered with different shapes and heights. L, T and H-shape walls are studied. They are nonlinearly analyzed in Abaqus using a micro-model, i.e. the finite element modeling and analysis. A meso-modeling approach using fiber elements is also examined in Opensees. It is shown that the meso-model is both accurate enough and much faster than the micro modeling approach. To go further, a macro-model is developed in bending in which the nonlinear behavior is assumed to be concentrated at the base of the wall using a rotational spring. The axial force, shape of the cross section, percentage of the longitudinal reinforcement and the aspect ratio of the wall are recognized to be the main parameters defining characteristics of the rotational spring. Using regression, semi-analytical formulas are suggested for rapid determination of the moment-rotation curve of the rotational spring. Comparison with micro-model and experimental results confirm the good accuracy of the developed macro-model.

Keywords:

micro model , meso model , macro model , Nonlinear analysis , 3D RC shear wall