Optimisation of strut-and-tie model in deep beams with openings

Reinforced concrete deep beams find useful applications in tall buildings and foundations. Over the past two decades, as the need for deep beams continued to grow throughout the construction industry, numerous design models for deep beams have been suggested. However even the latest design codes still offer little insight into the design of deep beams in particular when complexities exist in the beams like openings. A method commonly suggested for the design of deep beams with openings is the strut-and-tie model which is primarily used to represent the actual load transfer mechanism in a structural concrete member under ultimate load. In this study, the development of the strut-and-tie model is transformed to the topology optimisation problem of continuum structures. The optimal strut-and-tie model is generated by gradually removing inefficient material from an over-designed area. During the optimisation process, both the stress and displacement constraints are satisfied and the performance of progressive topologies is evaluated. The influence on the strut-and-tie model in relation to different size, location and number of openings in deep beams is examined herein.