TOPOLOGY OPTIMIZATION OF DOUBLE LAYER GRIDS FOREARTHQUAKE LOADS USING A TWO-STAGE ESO-ACOMETHOD

A two-stage optimization method is presented by employing the evolutionary structuraloptimization (ESO) and ant colony optimization (ACO), which is called ESO-ACO method.To implement ESO-ACO, size optimization is performed using ESO, first. Then, theoutcomes of ESO are employed to enhance ACO. In optimization process, the weight ofdouble layer grid is minimized under various constraints which artificial ground motion isused to calculate the structural responses. The presence or absence of elements in bottom andweb grids and also cross-sectional areas are selected as design variables. The numericalresults reveal the computational advantages and effectiveness of the proposed method.