To evaluate the real-world performance of corrugated steel web box girders in modern bridges, this study investigates their structural design and mechanical behavior using a three-dimensional finite element modeling approach. The main girder scheme and corrugated steel web box girder configuration are defined, and two representative loading cases are considered: Case 1 with symmetric loading and Case 2 with eccentric loading. A prestressing system is incorporated and a spatial finite element model is established to assess key performance indicators, including ultimate flexural capacity, shear buckling behavior, and shear-stress resistance of the corrugated steel web. Results show that the vehicle-load eccentricity amplification factor is essentially unchanged (M2/M1 = 1.002), indicating near-identical responses between the two loading cases. With a positive-stress bias amplification factor of 1.20 and a shear-stress bias amplification factor of 1.51, the designed bridge demonstrates strong overall stability. Moreover, the computed shear stresses in the corrugated steel web remain below the allowable design limits, confirming that its mechanical behavior satisfies current bridge design standards. These findings support the practical adoption of corrugated steel web box girders and highlight their relevance for sustainable bridge construction.