Double-deck multi-span bridge construction method

Abstract

Disclosed in the present disclosure is a double-deck multi-span bridge construction method. According to the double-deck bridge construction method of the present disclosure, construction is carried out by using a method of disassembling a support jig frame in a graded and span-separated mode, an upper chord jig frame and a lower chord jig frame can be used in a recycle manner, and construction costs are reduced. In addition, a construction period of building the support jig frame is shortened, and other construction operations can be synchronously carried out on a span in which the jig frame is disassembled, for example, fire retardant coating construction can be carried out on a mounted bridge deck after the jig frame is disassembled, and the construction period of a double-deck multi-span bridge is effectively shortened. Additionally, according to the double-deck multi-span bridge construction method in embodiments of the present disclosure, the upper chord jig frame and the lower chord jig frame are disassembled in a graded manner, thereby ensuring that a bridge structure can be smoothly and safely transitioned to a designed stress state.

What is claimed is: 
     
         1 . A double-deck multi-span bridge construction method, comprising:
 construction of a first span:
 mounting a lower chord jig frame of the first span, and mounting a lower-deck bridge structure of the first span by using the lower chord jig frame of the first span as a support; and 
 mounting an upper chord jig frame of the first span, and mounting an upper-deck bridge structure of the first span by using the upper chord jig frame of the first span as a support; 
   construction of a second span:
 mounting a lower chord jig frame of the second span, and mounting a lower-deck bridge structure of the second span by using the lower chord jig frame of the second span as a support; and 
 mounting an upper chord jig frame of the second span, and mounting an upper-deck bridge structure of the second span by using the upper chord jig frame of the second span as a support; 
 demounting the upper chord jig frame of the first span; 
   performing construction of the remaining spans of the bridge in sequence by adopting a construction manner of demounting a jig frame in a span-separated mode, and after construction of all spans of the double-deck multi-span bridge is completed, disassembling the remaining upper chord jig frames and lower chord jig frames;   wherein the construction manner of demounting a jig frame in a span-separated mode comprises the following steps of:
 mounting an upper chord jig frame of a currently constructed span, and mounting an upper-deck bridge structure of the currently constructed span by using the upper chord jig frame of the currently constructed span as a support; and 
 demounting an upper chord jig frame of a span adjacent to the currently constructed span, and demounting a lower chord jig frame of a span which is separated from the currently constructed span by one span. 
   
     
     
         2 . The double-deck multi-span bridge construction method according to  claim 1 , wherein the double-deck multi-span bridge is constructed from both ends to the middle, and joined at any span in the middle, spans at both ends of the double-deck multi-span bridge adopt the construction manner of the first span, spans adjacent to spans at both ends of the double-deck multi-span bridge adopt the construction manner of the second span, and the remaining spans of the double-deck multi-span bridge adopt the construction manner of demounting a jig frame in a span-separated mode. 
     
     
         3 . The double-deck multi-span bridge construction method according to  claim 1 , wherein a process of mounting a lower-deck bridge structure by using the lower chord jig frame as a support comprises: mounting a lower chord at the top of the lower chord jig frame, and mounting the lower-deck bridge structure on the lower chord. 
     
     
         4 . The double-deck multi-span bridge construction method according to  claim 3 , wherein a process of mounting an upper-deck bridge structure by using the upper chord jig frame as a support comprises: mounting a portal frame on the lower-deck bridge structure, mounting a support distribution beam between the top of the portal frame and the top of the upper chord jig frame, mounting an upper chord upon the support distribution beam, and mounting the upper-deck bridge structure on the upper chord. 
     
     
         5 . The double-deck multi-span bridge construction method according to  claim 4 , wherein a process of mounting the upper chord upon the support distribution beam comprises: mounting a positioning stopper on the support distribution beam, and positioning and mounting the upper chord by using the positioning stopper. 
     
     
         6 . The double-deck multi-span bridge construction method according to  claim 5 , wherein the lower-deck bridge structure of one or more spans of the double-deck multi-span bridge is made to have an arched structure. 
     
     
         7 . The double-deck multi-span bridge construction method according to  claim 1 , wherein, before mounting the upper chord jig frames and the lower chord jig frames, jig frame abutments are constructed at mounting positions of the upper chord jig frames and the lower chord jig frames. 
     
     
         8 . The double-deck multi-span bridge construction method according to  claim 7 , wherein, before mounting the upper chord jig frames and the lower chord jig frames, the jig frame abutments are pre-compressed.