In this paper, a specified constraint-handling technique for structures is proposed and developed. This new technique is based on fuzzy-logic and some mechanical properties of structures. Compared to commonly used penalty techniques, it does not require pre-tuning in parameters and it shows more stable results and requires considerable fewer iterations to converge without reducing the solution quality. Therefore, the new technique is more user friendly. Also, successful convergence to feasible solutions removes the necessity of using final local search approaches which required the designer to execute some manual try-and-errors to achieve a feasible acceptable design for reporting. Robustness of the proposed fitness function, called Fuzzy Ideal-Feasible-Design (FIFD) technique, is verified on three large scale steel frames using different meta-heuristic methods. Brilliant results show that FIFD is a revolution in handling design criteria that might be a significant step in commercializing optimum design among the practical users in construction markets.