UHPC box girder torsion stress analysis system and method based on unbalance loading deformation characteristics

According to the UHPC box girder torsion stress analysis system and method based on the unbalance loading deformation characteristics, three-dimensional full-field strain measurement is conducted on a UHPC box girder, three-dimensional space displacement of all section feature points in the beam length direction is obtained, and therefore the section strain change of the box girder in the beam length direction in the nonlinear stress stage is determined; therefore, the most unfavorable torsion stress section of the box girder is identified and positioned; then, in combination with the three-dimensional space displacement and geometric characteristics of the feature points on the most unfavorable section of torsion stress, the deformation and strain distribution rule of the section is obtained, then the torsion and distortion deformation states of the box girder under unbalance loading are determined, and the torsion distortion effect is quantitatively recognized; and the torsion stress state of the box girder