Inner tensioning pre-stressed concrete double-layer variable section plate box-type structure

The invention relates to an inner tensioning pre-stressed concrete double-layer variable section plate box-type structure of a building. A variable section plate is arranged in the direction parallel to the section of the structure to form a double-layer box-type section, the span range of the variable section plate is 7 to 36 meters, annular prestressed ribs are arranged in a peripheral member, parabolic prestressed ribs are arranged in a flat plate on the middle layer, and tensioning grooves are reserved on the lateral surfaces of a member in the structure; and when concrete reaches the specified strength, the segments of the same prestressed ribs are sequentially connected end to end through middle anchors at the tensioning grooves and tensioned, and then the tensioning grooves are plugged. The structure is characterized in that the tensioning grooves are reserved on the lateral surfaces of the member in the structure, and the prestressed ribs are connected through the middle anchors and tensioned. The structure has the advantages that when the ends of the structural member do not have tensioning and anchoring conditions, prestressed tensioning connection can be realized, high comfort degree, using performance and structural performance can be provided, and the structure is particularly suitable to be used as an underground heavy-duty and large-span double-layer framework box-type structure.