Method for testing cable force of long and large cable-stayed bridge based on space line shape

The invention relates to a long and large cable-stayed bridge cable force test method based on a space line shape, and belongs to the technical field of bridge engineering, and the method comprises the steps: building a stay cable nonlinear finite element model, and calculating a stay cable space line shape according to a designed cable force; sequentially calculating stay cable space line shapes of different design cable forces under the same cable force gradient change to obtain a curve cv1 of the deflection changing along with the cable force; the space line shape of the stay cable is tested on site, and actually-measured coordinates and actually-measured deflection ft of anchoring points at the two ends of the stay cable are calculated; comparing ft with the curve cv1, and determining a preliminary actually measured cable force result T0; the nonlinear finite element model of the stay cable is updated, the midspan maximum deflection ffimax of the stay cable is calculated in a refined mode, and an updated