Discrete optimisation of steel-concrete composite sections in simple girder bridges

Abstract

In this study, the optimisation design problem of steel-concrete composite sections in simple girder bridges is developed. Design variables including the thickness of the desk and the dimensions of the girder section are discrete variables to reflect the realistic design works. The total cost of the desk and the steel girder is the objective function that is minimised. The design requirements of the geometry, load-carrying capacity, and deformation provided in the TCVN 11823:2017 standard are used as the optimisation constraints. The above discrete optimisation is solved by using the Harmony Search (HS) algorithm. A 42(m) simple girder is studied. The numerical results show that the optimal designs save about 15% compared to using the conventional design method. It can be concluded that applying the optimisation in the design of steel-concrete composite beams brings high efficiency and it is easily applied in practice.