CN-121976475-A - Pushing construction method for large-span steel box girder without buttress

CN121976475ACN 121976475 ACN121976475 ACN 121976475ACN-121976475-A

Abstract

The invention discloses a pushing construction method of a large-span steel box girder without a buttress, and relates to the technical field of bridge construction. The invention adopts the asymmetrically arranged inhaul cable, does not need to enlarge the construction range of the pushing platform additionally, can flexibly adapt to the situations of limited sites of the flat curve bridge, the vertical curve bridge and the pushing platform, greatly reduces the occupied space of the pushing platform, reduces the construction quantity and the construction cost of temporary engineering, solves the problem of poor site adaptability of the traditional symmetrical inhaul cable arrangement mode, can be widely applied to pushing construction of various large-span steel box girders without buttresses, particularly adapts to the engineering situations of narrow sites of the flat curve bridge, the vertical curve bridge and the pushing platform, does not need to greatly reform the existing construction equipment, is easy to popularize and apply, and has good practicability and popularization value.

Inventors

ZHANG FAPING
ZHOU YINGCHAO
ZHOU ZELIN
Yi Shouwei
WANG ZELIN
CHEN RUI
BAI WEI

Assignees

中国十九冶集团有限公司

Dates

Publication Date: 20260505
Application Date: 20260319

Claims (8)

1. The pushing construction method of the large-span steel box girder without the buttress is characterized by comprising the following steps of: firstly, constructing a pushing platform at the initial end of a bridge; Secondly, splicing guide beams and part of steel box girder segments on a pushing platform, performing quality detection after splicing, and then pushing the spliced girder body forwards by a preset distance, wherein the preset distance is calculated and determined according to the height of a cable tower and the installation space of a inhaul cable; Step three, installing a cable tower, namely fixing the cable tower on a steel box girder, then installing an inner side cable and an outer side cable on the guide girder side, wherein the arrangement positions, the number and the initial cable forces of the inner side cable and the outer side cable are all determined through construction mechanics calculation, and after the cable tensioning is completed, the connection state between the bottom of the cable tower and the steel box girder is adjusted from initial fixedly connected connection to hinged connection; Continuously pushing the steel box girder forwards, monitoring the posture of the steel box girder, the front-end deflection of the guide girder and the change of the cable force of the cables in real time, when two inner cables and one outer cable are monitored to be incapable of meeting the jacking balance requirement of the steel box girder or when the front-end deflection of the guide girder is monitored to be beyond the allowable range, if the rear-end space of the steel box girder meets the installation requirement of the rest outer cables at the same time, installing the rest outer cables, and adjusting the tensioning tension of the installed cables; Continuously pushing the steel box girder forwards until the steel box girder passes through the adjacent buttress at the front end, then loosening the inner inhaul cable and the outer inhaul cable connected on the cable tower to reduce the cable force, and adjusting the inhaul cable to be in a standby state; step six, continuously pushing the steel box girder forwards until the guide girder passes through the end buttresses, dismantling the outer inhaul cable, and then carrying out sectional dismantling on the guide girder and reserving part sections of the guide girder; Step seven, removing the rest guide beam sections; And step eight, integrally falling the steel box girder, installing bridge decks and removing inner inhaul cables and cable towers.
2. The method for pushing and constructing the large-span steel box girder without the buttress of claim 1, wherein in the first step, the pushing platform is formed by casting reinforced concrete, an anti-slip cushion layer is paved on the surface of the pushing platform, and a protective railing is arranged at the edge of the pushing platform, wherein the height of the protective railing is not less than 1.2m.
3. The pushing construction method of the large-span steel box girder without the buttress is characterized in that in the second step, the guide girder is formed by splicing lightweight steel, the length of the guide girder is calculated and determined according to the span of the steel box girder and the stability requirement of pushing operation, the guide girder is connected with the steel box girder by high-strength bolts in the splicing process, the preliminary pushing distance is 1.5-3 m, the pushing speed is controlled to be 0.2-0.5 m/h, and the displacement and the gesture of the girder body are monitored in real time in the pushing process.
4. The method for pushing and constructing the large-span steel box girder without the buttress according to claim 1, wherein in the third step, synchronous tensioning is adopted for tensioning the inner cable and the outer cable, the cable force change is monitored in real time in the tensioning process of the cables, and the deviation between the real-time cable force and the preset cable force is not more than +/-5%.
5. The method for pushing and constructing the large-span steel box girder without the buttress according to claim 1, wherein in the fourth step, the allowable range of the front end deflection of the guide girder is L/500-L/600, L is the length of the guide girder, when the front end deflection of the guide girder exceeds the allowable range, pushing is stopped, the cable force is adjusted after the rest outside cables are installed, the cable force is adjusted in a step adjustment mode, and the adjustment amount of each step is not more than 10% of the designed cable force.
6. The method for pushing and constructing the large-span steel box girder without the buttress of claim 1, wherein in the fifth step, when the inhaul cable is adjusted to be in a standby state, the cable force is controlled to be 10-20% of the designed tension of the inhaul cable.
7. The method for pushing and constructing the large-span steel box girder without the buttress according to claim 1, wherein in the step six, the length of the reserved guide girder segment is 2-3 m, the reserved guide girder segment is close to the end buttress, and the reserved guide girder segment and the end buttress form a temporary supporting system.
8. The method for pushing and constructing the large-span steel box girder without the buttress according to claim 1, wherein in the step eight, a synchronous girder falling process is adopted when the steel box girder is fallen, the girder falling speed is controlled to be 0.1-0.2 m/h, the elevation and horizontal displacement of the steel box girder are monitored in real time in the girder falling process, and a bilateral symmetry assembling process is adopted for installing bridge decks.

Description

Pushing construction method for large-span steel box girder without buttress Technical Field The invention relates to the technical field of bridge construction, in particular to a pushing construction method for a large-span steel box girder without a buttress. Background The bridge pushing method is a construction method that a prefabricated field is arranged behind a bridge abutment along the longitudinal axis direction of a bridge, the prefabricated field is prefabricated Liang Tihou in stages, the beams are pushed forward section by a sliding device and a pushing device through the force application of a horizontal jack, and the beams fall down and a formal support is replaced after the beams are in place. The current common pushing construction process comprises a cable-stayed buckling pushing construction process and a temporary buttress pushing construction process. The temporary buttress pushing construction process needs to arrange a plurality of temporary buttresses before pushing work so as to support the steel box girder. Compared with the temporary buttress pushing construction process, the temporary engineering investment can be greatly reduced to reduce the construction cost, so that the application is more common, such as the large-span continuous span steel beam buckle tower pushing construction device and method disclosed in China patent application with the publication number of C119571733A and the combined beam non-buttress pushing construction method disclosed in China patent application with the publication number of CN116254773A, and the technical scheme of the patent adopts the symmetrically-arranged inhaul cable pushing construction process with the cable pulling buckling method. When the bridge has a flat curve, a vertical curve or a limited pushing platform field, the existing pushing construction process adopting a cable-stayed buckling method with symmetrical arrangement of cables is difficult to meet construction requirements, and mainly has the problems that firstly, if the cable-stayed mode is adopted when the pushing platform field is limited, in order to ensure the installation space and the stress balance of the cables, the construction range of the pushing platform is usually required to be additionally enlarged, the construction amount and the cost of temporary engineering are increased, and in addition, the cable-stayed mode is difficult to adapt to the curve form of the bridge for the flat curve and the vertical curve bridge, the cable-stayed mode is easy to cause uneven stress of the cables to influence the pushing stability, secondly, in the pushing process of the flat curve bridge, the beam body is influenced by uneven distribution of vertical loads, if the symmetrical cable-stayed mode is adopted, the stress imbalance at two sides of a steel box beam is caused, additional torque and rolling moment are generated, the beam body is easy to cause deflection or instability, potential safety hazards are caused, and particularly, the support of the temporary support pier is lack of the beam body is more outstanding, in order to solve the problem that the balance of the cable-stayed, in addition, in order to solve the problem that the balanced stress is easy to be arranged, the conventional mode is easy to adjust the stress balance, the cable-stayed mode is easy to be adopted, but the construction efficiency is easy to be adjusted, the conventional problem is easy to be out of the balance is easy to be solved, and the problem is that the stress is frequently is easy to be adjusted is caused by the stress balance in the bridge is in the stress-balanced in the stress mode, and the stress-balanced mode is in the construction mode is too has is easy to be adjusted. Disclosure of Invention The invention aims to solve the technical problem of providing a pushing construction method for a large-span steel box girder without a buttress, which can reduce temporary construction structures and improve construction efficiency and construction safety. The technical scheme adopted by the invention for solving the technical problems is that the pushing construction method of the large-span steel box girder without the buttress comprises the following steps: firstly, constructing a pushing platform at the initial end of a bridge; Secondly, splicing guide beams and part of steel box girder segments on a pushing platform, performing quality detection after splicing, and then pushing the spliced girder body forwards by a preset distance, wherein the preset distance is calculated and determined according to the height of a cable tower and the installation space of a inhaul cable; Step three, installing a cable tower, namely fixing the cable tower on a steel box girder, then installing an inner side cable and an outer side cable on the guide girder side, wherein the arrangement positions, the number and the initial cable forces of the inner side cable and the outer side cable are all determin