Auxiliary construction method for longspan cantilever entire laminated Vierendeel truss structure

The invention provides an auxiliary construction method for a longspan cantilever entire laminated Vierendeel truss structure. The method includes the steps that 1, a cantilever reinforced concrete Vierendeel truss is constructed; 2, a steel structure column temporary supporting system is constructed, wherein the system is composed of a plurality of steel structure columns, one steel structure column is erected at the position corresponding to a supporting column under each cantilever beam, each steel structure column is formed by connecting three sections of steel columns, and the installation process includes the steps of pasting a steel base plate on the first layer of floor, marking steel column installation locations on the steel base plate, hoisting the upper sections of steel columns to abut against the cantilever beams, hoisting the middle sections of steel columns to be in butt joint with the upper sections of steel columns, hoisting the lower sections of steel columns to be in butt joint with the middle sections of steel columns, enabling the steel structure columns to just fall off onto the steel column installation locations of the steel base plate, jacking up the steel structure columns to abut against the cantilever beams, enabling the gaps between the steel structure columns and the steel base plate to be filled with steel plates and conducting full welding; 3, laminated layers above the Vierendeel truss are continuously constructed; 4, the steel structure column temporary supporting system is removed. By the adoption of the method, the effectiveness and safety of constructing the entire laminated Vierendeel truss which is high in cantilever height and large in span can be guaranteed.