Application of thrust layout optimization to masonry structures

Abstract

A new automated analysis procedure designed to overcome limitations of the traditional thrust line analysis method for masonry gravity structures is presented. The procedure, termed thrust layout optimization (TLO), is capable of automatically identifying admissible thrust lines in masonry gravity structures comprising general arrangements of masonry blocks. The procedure employs a modified truss layout optimization with transmissible loads formulation, which means that an initial thrust line layout does not need to be specified in advance. Highly visual output is generated, allowing areas where tensile strength has been implicitly assumed to be clearly identified, which is beyond the scope of traditional thrust line analysis. Also, sliding failures can be modelled without difficulty. Finally, examples are used to demonstrate the efficacy of the TLO procedure; these show that thrust line bifurcations can be automatically identified in problems involving openings, and that there is no need to estimate the ineffective area in buttress wall problems, both issues for the traditional thrust line analysis method.