en Optimal design Optimal design پژوهشي Research <span style="font-size:11.5pt"><span new="" roman="" style="font-family:" times="">Shape optimization of a double-curved dam is formulated using control points for interpolation functions. Every design vector is decoded into the integrated water-dam-foundation rock model. An enhanced algorithm is proposed by hybridizing particle swarm algorithm with ant colony optimization and simulated annealing. The best experiences of the search agents are indirectly shared via pheromone trail deposited on a bi-partite characteristic graph. Such a stochastic search is further tuned by Boltzmann functions in simulated annealing. The proposed method earned the first rank in comparison with six well-known meta‑heuristic algorithms in solving benchmark test functions. It captured the optimal shape design of Morrow Point dam, as a widely addressed case-study, by 21% reduced concrete volume with respect to the common USBR design practice and 16% better than the particle swarm optimizer. Such an optimal design was also superior to the others in stress redistribution for better performance of the dam system.</span></span><br> &nbsp; Double-curved dam, Concrete infrastructure, Shape Optimization, Particle Swarm Optimization, Graph Theory, Ant Colony Optimization, Simulated Annealing 413 438 http://ijoce.iust.ac.ir/browse.php?a_code=A-10-66-384&slc_lang=en&sid=1 M. Shahrouzi shahruzi@khu.ac.ir 180031947532846002624 180031947532846002624 Yes Civil Engineering Department, Faculty of Engineering, Kharazmi University, Tehran, Iran S.-Sh. Emamzadeh 180031947532846002625 180031947532846002625 No Civil Engineering Department, Faculty of Engineering, Kharazmi University, Tehran, Iran Y. Naserifar 180031947532846002626 180031947532846002626 No Civil Engineering Department, Faculty of Engineering, Kharazmi University, Tehran, Iran