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From a design point of view, regions in a structural member can be 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 the present codal provisions recommend well-defined theories for the design of B regions, thumb rule or empirical equations are still being used to design D regions. It has been recently understood that the strut and tie method is an effective tool for the design of both B and D regions. In a deep beam, the distribution of strain across the depth of the cross-section is nonlinear and hence these structural elements belong to D regions. The existing codal provisions for the design of simply supported deep beams are inadequate and are empirical in nature. Among the available codal provisions, there exists a disparity even in the definition of deep beams. Strut and tie models can be developed using load path method, but more than one model is possible for a given problem, and the designer should have a minimum level of experience to identify the appropriate model. In this paper, a methodology has been developed to identify the optimum model among different possible models. Experimental investigations were carried out to validate the optimum strut and tie model. Further, using this method, the limiting value of span to depth ratio for simply supported beams was found out, so that they could be considered as deep beam. [ABSTRACT FROM AUTHOR]

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. A beam whose depth is comparable to span is known as deep beam and these structural elements belong to D regions. It has been recently understood that the strut and tie method (STM) is an effective tool for the design of both B and D regions. The present code recommendations are inadequate for the design of deep beams. In this paper simple equations using STM are developed for finding the area of main steel required to have a balanced type of failure and to find the ultimate capacity of deep beams failing in different failure modes. These equations are compared with experimental results and a good agreement is found. [ABSTRACT FROM AUTHOR]