Extraction of strut and tie model from 3D solid element mesh analysis

Abstract

Strut-and-tie model (STM) method is a lower bound method based on the theory of plasticity, which can be used especially for the design of structural concrete members in D- Region. An approach for automatically finding an appropriate STM for structural concrete members modeled and analyzed by using solid element mesh is introduced in this study. The finite element analysis can be performed in any FEA computer program that has the solid element meshing capability. The solid element principle stress trajectories of the concrete member are obtained and struts and ties are extracted based on the direction cosines and magnitude and graphically displayed. The algorithm includes two main important features: (1) to extract and display an appropriate STM from the output of FEA; and (2) to refine, analyze and design the extracted appropriate STM. As a sample application, concrete pile cap configuration is used in demonstrating the capability of the proposed method in finding an appropriate strut-and-tie model and compared with the previous theoretical and experimental studies that deal with STM for the purpose of verification of the results.