In this paper, a hybridmethod combining simulated annealing with
glowworm swarm optimization (SAGSO) algorithms is presented and
employed to optimize PC precast road bridges formed by two isostatic
beams with a double U-shaped cross-section. Two objective functions
are considered: the CO2 emissions and cost of the PC bridge at the different
stages of material production, transportation and construction. The
extensive computational experiments with a set of five span lengths
for the bridge indicate that SAGSO is an efficient algorithm for the advanced
automatic design of real PC precast bridges used in road construction
that reduced the CO2 emissions and the cost. The analysis
reveals that CO2 emissions and cost are closely related and, as a rule of