Development of strut and tie models for simply supported deep beams using topology optimization

Generally, structural members can be broadly divided into two regions, namely B, or Bernoulli regions, where the strain distributions are linear and D, or Disturbed regions, where the strain distributions are nonlinear While well defined theories are available for designing B regions, rules-of-thumb or empirical equations are still being used to design D regions although B and D regions are equally important. It has been recently understood that the strut and tie model is an effective tool for the design of both B and D regions. Since this method is a realistic approach, this has found place in many codes like Euro code, American code, Canadian code, Australian code, New Zealand code etc. In a deep beam, the distribution of strain across depth of the cross section will be nonlinear and hence these structural elements belong to D regions. The existing code provisions for the design of simply supported deep beams are inadequate and are empirical in nature. In this paper,the development of strut and tie models for simply supported deep beams using topology optimization is discussed. The design of deep beams using topology optimization is illustrated using an example and is compared with available code recommendations.