In case heavy loads exceeding current design load passes the bridge, pre-structural analysis that reflects the axle load and the distance between Axles are being performed. Then, Measures regarding passing heavy loads are established based on the result of pre-structural analysis. However, when requirements of serviceability of bridge have not met or failure to obtain structural design report or shop drawing due to lack of maintenance occurs, section modulus should be reasonably estimated. Especially, in case of Pre-stressed Concrete Girder Bridge, if detailed information on tendon is inadequate, imposing vehicle weight restriction should be considered thoughtfully. The purpose of this study is to establish rational approach about passing heavy loads targeting PSC Girder Bridge that has failed to secure the details of cross section. In order to do it, tendon's profile was estimated and its estimated result was verified through pre-monitoring. Furthermore, by conducting a nonlinear analysis, the reliability of the analysis was determined in simulating the stiffness of a member and based on proven section modulus; the behavior of a special cargo (U-EA101) that weighs 5,136.15kN was reasonably predicted