Comparative study of interior and exterior wall-floor connections

Abstract

Current practice in the design of connections of precast reinforced concrete structures is based on empirical relationships that often do not reflect the complexity of real geometric configuration and response to load conditions. However, recent developments in numerical modeling of such connections now allow for realistic and accurate description of the failure mechanism, produced by extreme loading conditions. In this study a numerical model of different joint failure mechanisms in precast concrete structures is presented in detail. The type of joints considered in this study consists of reinforced interior or exterior wall-to-floor connections with or without reinforced grout filler material. The model is assumed to be two-dimensional corresponding to plane strain condition. In the implementation of the nonlinear finite element analysis, multiaxial stress-strain laws are used to describe fracture phenomena with proper allowance for complex loading and unloading cycles. A rotating crack model is used to reach the needed accuracy to numerically describe fracturing of the reinforced concrete medium. In this model, it is assumed that the crack follows the principal strain direction and, therefore, varies with time. An iterative approach is used to solve the nonlinear problem. The numerical solution includes the generation of stress contours in the connection and the graphical representation of the crack patterns.