A new design capability for automated formulation of optimal truss models (strut-and-tie models) is presented and illustrated with example designs of a variety of disturbed regions of reinforced and pre-stressed concrete structures, including deep beams with holes, continuous beams, and corner joints. The design method selects the optimal geometry of the strut-and-tie layout, determining the proper positioning of tensile ties and compressive struts to minimize the amount of reinforcing steel needed in the tension ties of the truss model for the region being designed. Two "practical" parameters are under control of the design engineer running the computer program-a reinforcement layout practicality factor which can be used to force the reinforcement layout into strictly horizontal and vertical bars (which will require additional reinforcement volume beyond the true optimal value), and a stress redistribution factor which can be used to control the amount of redistribution needed in developing the full capacity of the truss model after cracking has occurred.
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