Method for releasing stress of large-span concave three-dimensional pipe truss structure

The invention relates to a stress releasing method for a large-span downward-concave type three-dimensional pipe truss structure, and belongs to the technical field of steel structure building construction. According to the method, a stress releasing device is additionally arranged at the joint of a concrete filled steel tubular column and a concave three-dimensional pipe truss support, the stress releasing device comprises two hydraulic jacks arranged on the two sides of the joint, the concave three-dimensional pipe truss is jacked up through the two hydraulic jacks, two polyfluortetraethylene plates are arranged between the top of the column and the support in a cushioned mode, and the concave three-dimensional pipe truss support is supported by the two polyfluortetraethylene plates. And then the two hydraulic jacks are synchronously unloaded, and the column top and the support generate relative sliding between the two polyfluortetraethylene plates, so that the horizontal stress generated by the concave thr