Optimal strut-and-tie models in structural concrete members

The strut-and-tie modeling is a simple, unified, rational and safe approach for the design of structural concrete members. Conventional methods are not efficient in finding optimal strut-and-tie models in concrete members with complex geometry and loading conditions. In this paper, the Evolutionary Structural Optimization (ESO) method for continuum structures with displacement constraints is briefly outlined and used to develop optimal strut-and-tie models in structural concrete members. By treating prestressing forces as external loads, prestressed concrete members can be analyzed, optimized and dimensioned like reinforced concrete ones. By slowly removing a small number of elements with the least contribution to the stiffness from the discritized concrete member, the load-transferring mechanism in the member can be gradually chacreterized by the resulting topology. Numerical examples are presented to show the effectiveness of the proposed evolutionary material removal procedure in automatically generating optimal strut-and-tie models in reinforced and prestressed concrete members. Optimal strut-and-tie models obtained by using the ESO method are verified by the existing experimental evidence and analytical solutions