Mixed-Type Modeling of Structures with Slender and Deep Beam Elements

The nonlinear analysis of reinforced concrete frame structures with slender members can be performed accurately and efficiently with 1D elements based on the plane-sections-remain-plane hypothesis. However, if the frame also includes deep beams which require 2D high-fidelity finite element procedures, the analysis of large structures can become very costly. To address this challenge, this paper proposes a mixed-type modeling framework which integrates 1D slender beam elements with a novel 1D macroelement for deep beams. The framework is implemented in an existing nonlinear analysis procedure and is used to model 18 deep beam tests and a 20-story frame. It is shown that the proposed framework provides similarly accurate predictions to the 2D high fidelity procedures but requires a fraction of the time for modeling and analysis. Furthermore, the macroelement improves the post-peak predictions, and therefore the framework is suitable for evaluating the resilience of structures under extreme loading.