Structure and method for turning over large box component in workshop

The invention discloses a structure and a method for turning over a large box component in a workshop. The invention is characterized in that the structure for turning over the large box component in the workshop comprises a bridge bottom slab and a bridge deck slab; a steel box girder is provided with a main lifting lug, an auxiliary lifting lug and a conversion lifting lug; and the method for turning over the large box component in the workshop comprises the following steps of connecting a large crane main hook to the main lifting lug, connecting a large crane auxiliary hook to the conversion lifting lug, and connecting a small crane main hook to the auxiliary lifting lug positioned on the side of the bridge bottom slab; ascending the large crane main hook, descending the small crane main hook, and when the large and small crane main hoists are horizontal, ascending the large crane auxiliary hook and separating the small crane main hook; ascending the large crane main hook, descending the large crane auxili