Automated Finite-Element-Based Validation of Structures Designed by the Strut-and-Tie Method

Abstract

Several codes of practice now support the use of the strut-and-tie method (STM) for the design of complex regions in structural concrete. In this method, a load-resisting truss is idealized and designed to carry the applied forces through these regions to their supports. The method assumes that the load can be carried in the manner envisioned by the designer and that the nominal design strength is at least equal to the calculated capacity of the idealized plastic truss. These assumptions are not always valid, particularly for nonductile and complex structures, as revealed by experiments in which some of STM designed structures have exhibited poor performance at service load levels and/or not been able to support their calculated nominal design strength. Thus, there is clearly a need for a convenient and reliable means of assessing the likely performance of complex regions designed using the STM. This paper presents an integrated STM design and computational framework that was developed to overcome the barriers to efficient design by the STM and effective design validation by nonlinear finite-element analysis.