ABSTRACT
Owing to its particularity in geometry, loading, and boundary conditions, the design of any D-region generally requires the development of a particular strut-and-tie model (STM). Nevertheless, in some cases, known models can be adapted to suit specific conditions of D-regions into consideration. In this chapter, two approaches for developing an STM are presented: either the load path method or employing elastic finite element analysis to determine the flow of forces for best serviceability. Accounting for practical detailing in developing an STM in addition to model optimization is discussed. The STMs of some basic discontinuous stress fields, which are frequently encountered in different versions and combinations, even in apparently different structures, are developed. Moreover, practical examples of discontinuous stress fields are modeled. These include local pressure, a beam with a dapped end, a beam with a recess, a deep wall-like column with a recess, walls with openings, a deep beam with an eccentric large opening, and B-regions with web reinforcement. The chapter also explains how to handle three-dimensional reinforced concrete blocks such as pile caps, with either two-dimensional or three-dimensional modeling.
