Large-span bridge steel girder closing construction method

Abstract

The invention relates to a construction method of steel girder closure in large span bridges, and is characterized in that: a lower chord is closed firstly, an upper chord is closed secondly, and slant rods are closed finally. In construction, a structure method of 'a long round hole plus a round hole closure hinge' is adopted. The Z-direction of a left lower chord rod and a right lower chord rod of the closure point is adjusted at first to go through two trusses midline; then the Y direction is adjusted to close the long round hole on the lower chord closure with nails punched; and the X direction is adjusted after the closure of the long round hole and then a high bolt goes through the round hole in the lower chord closure point to close. If Z direction deviation is not big, a jack can be arranged on the top face and bottom face of the left lower chord rod of the closure point and the right chord rod of the closure point and tension adjustment is conducted in the two sides of the closure segment. According to calculation, every cable release tension at different tons to diminish the deviations in Y and Z directions to be close to closure requirements. The lower chord rod and the slant rod are closed in order. The invention has the advantages that by adopting the structure method of 'a long round hole plus a round hole closure hinge', the steel girder closure precision is high and zero error closure is achieved; the construction risk of field operation is lowered; and field construction progress is quickened.

Description

technical field [0001] The invention relates to a construction method for mid-span closure of a steel girder of a main span of a long-span bridge, and belongs to the technical field of construction of long-span and steel girder bridges. Background technique [0002] The following characteristics exist in the steel girder design of long-span bridges: [0003] 1. Due to the high rigidity of the mid-span closure. [0004] Usually, the height of the tower above the bridge deck of the short-tower cable-stayed bridge is relatively small, which is about half of the general cable-stayed bridge. The ratio of the side span to the main span is 0.58, which is larger than that of ordinary cable-stayed bridges, and the height-span ratio of the main girder is very large. It belongs to the continuous steel truss girder reinforced by cable-stayed cables. The highway bridge deck is connected to the steel girder by shear nails Forming a combined beam is much more rigid than ordinary cable-st...

AI Technical Summary

Problems solved by technology

[0005] 2. There are many closing positions

[0011] 5. High precision requirements for closing

[0012] Reaming is not allowed during the construction process. Such a complex large-scale steel structure is multi-point closed in the air, and the error is less than 0.075 mm, which makes the construction difficult.

[0013] The existing Zhonghelong construction methods cannot effectively solve the difficulties and problems caused by the above-mentioned many factors.

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