Vertical prestressed steel strand tensioning construction method for box girder bridges
A technology of vertical prestressing and construction methods, applied in bridges, bridge construction, erection/assembly of bridges, etc., can solve problems such as unsatisfactory construction quality, and achieve good quality control, small vertical prestress loss, and prevent boxes Effect of oblique cracks in beam web
Inactive Publication Date: 2019-11-05
湖南交通国际经济工程合作有限公司
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Problems solved by technology
[0004] Aiming at the deficiencies in the prior art, the object of the present invention is to provide a construction method for vertically prestressed steel strands of a box-shaped girder bridge, which solves the problem that the steel strands are depressurized by the second tensioning jack and anchored back. The problem of unsatisfactory construction quality after shrinking
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Embodiment
[0042] Embodiment: a kind of vertical prestressed steel strand tensioning construction method of box girder bridge, such as figure 1 , 2 , 3, and 4, including the following steps:
[0043] a. Construction preparation: clean up the debris in the vertical prestressed tensioning slot 6, eliminate the rust and mud on the steel strand 5; install the tensioning anchor cup 3, the tensioning anchor cup 3 and the anchor pad 1 Corresponding positions; check whether the tensioning equipment is normal;
[0044] b. Tensioning for the first time: Install the limit plate 9, the through-hole jack 8, the tool anchor 7 and the tool clip 4 in sequence, and then install the steel strand 5 as a whole according to the process 0→0.1σ con →1.05σ con →Hold the load for 2min→Anchor for tensioning;
[0045] During the stretching process, measure 0.1σ respectively con with 1.05σ con , the jack 8 piston extension value and the tool clip 4 exposed height, and calculate the first tension measured elonga...
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The invention discloses a vertical prestressed steel strand tensioning construction method for box girder bridges, and belongs to the technical field of bridge construction. The method includes the following steps: a step of construction preparation, namely the step of cleaning foreign materials in a vertical prestressed tensioning notch, and eliminating the corrosion and slurry on a steel strand;and installing a tensioning anchor cup which is corresponding to the position of an anchor backing plate, and checking whether tensioning using equipment is normal; a step of first tensioning; a stepof second tensioning, performing second tensioning after the first tensioning is finished for 2-16 h; a step of the verification of the elongation value of the second tensioning, namely the step of calculating the actual elongation value of the second tensioning to compare with a theoretical elongation value, and controlling errors within + / -3%; and a step of the grouting and anchor sealing of ducts. The problems of unideal construction quality of the steel strand after jack pressure relief and anchor retraction of the second tensioning can be solved.
Description
technical field [0001] The invention relates to the technical field of bridge construction, in particular to a construction method for vertically prestressed steel strand tensioning of a box girder bridge. Background technique [0002] The basic concept of the box girder structure is that the entire superstructure becomes an integral hollow beam, and when the main load passes through any position on the bridge, all parts of the hollow beam (beam ribs, roof and bottom plate) participate in the force simultaneously as a whole. The box girder structure can save material, become a thin-walled structure, and improve the torsional strength. Box girder bridges can be divided into single-chamber, double-chamber and multi-chamber bridges. [0003] At present, the vertical prestressing design of box girder bridges generally adopts the secondary tensioning process. Affected by factors such as many tensioning accessories and small anchor groove space, it is always difficult to control...
Claims
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Login to View More IPC IPC(8): E01D21/00E04G21/12
CPCE01D21/00E04G21/12
Inventor 周强吴初平任保军蔡纲杨文志
Owner 湖南交通国际经济工程合作有限公司