How to replace the bridge bearing?

1, organization establishment

By the project manager unified organization arrangement, leadership and command, set up a special construction command team. In order to ensure the safety of driving, people, equipment and construction, all personnel are required to carefully organize, be responsible for, implement and standardize the operation in strict accordance with the construction safety regulations. Before the bearing adjustment construction, it is necessary to establish and improve the construction scheme, implement the responsibility to the people, and clarify the responsibilities and contact information of each post. All construction personnel are divided into four groups under the unified command of the project manager.

2. Technical preparation

(1) Be familiar with the construction drawings and operating procedures before construction;

(2) Arrange four control points on the top surface of the box girder, all located at the abutment position of the pier, measure and record the original data of the elevation and plane coordinates of the control points, so as to check the changes of the elevation and plane position of the beam body after replacing the abutment.

③ Accurately measure the effective working space distance between the pier and the bottom of the beam, so as to determine the specifications and roof layout method of using special hydraulic roof.

3, the construction site preparation

(1) All machinery, equipment and materials required for the site have been put in place;

(2) chisel away the bearing mortar as much as possible, so that the bearing and bearing mortar can be easily separated after the beam jacking;

(3) Before jacking the box girder, dismantle the beam-falling prevention baffle to install the jack and increase the operating space;

(4) Build a working platform and do a good job in the erection of the working platform on the construction site. It is required to be built around the wharf to facilitate the use of construction operators and monitoring personnel. The working platform should be firm and reliable to ensure the safety of personnel.

(2) the construction process

1, jack arrangement

According to the load of the beam, the mechanical characteristics of the box girder and the self-weight of the box girder, in order to better and reasonably arrange the jacks, jacks are installed at the beam-falling-proof stops next to the four supports of the same pier, and they are lifted synchronously to avoid uneven stress on the bridge and damage to the track slab and mortar layer. In order to ensure the consistent change of the lifting height of the cross beam, each hydraulic jack is arranged with one person to measure the lifting stroke.

2, jack-up system installation

In order to facilitate the jacking operation, all jacks are installed upward, and the oil cylinder is supported at the bottom of the beam bottom. When installing the jack, ensure that the axis of the jack is vertical, so as to avoid the horizontal component caused by the tilt of the jack installation during the jacking process, and ensure that the oil top is firmly installed before connecting the oil circuit.

3, the overall jack-up implementation

(1) Before jacking, loosen the bearing bolts.

Before jack-up, loosen the bearing bolts by 5 mm to leave enough space for jack-up beam.

② Reliability test of jack-up system

In order to observe and evaluate the working state of the whole jacking construction system, before the formal jacking, keep the pressure of the hydraulic system at 50Mpa for five minutes to check the tightness of the hydraulic system and ensure the jacking safety.

③ Formal jacking

(1) Formal jack-up must be carried out according to the following procedures and recorded:

A, operation: loading and jacking according to a preset load;

B observation: each observation point should reflect the measurement situation in time;

C. Measurement: Each measuring point should do a good job of measurement and reflect the measurement data in time;

D. Inspection: submit data to the on-site leading group and compare the difference between measured data and theoretical data;

E. Analysis: In case of data deviation, relevant parties should carefully analyze and adjust in time;

F. Decision-making: When the jacking height reaches 3mm, that is, there is a gap of 3mm between the top surface of the bearing and the bottom surface of the beam, stop jacking, install the pressure relief device 10 minute, and remove and adjust the bearing after there is no abnormality.

⑵ Matters needing attention during jack-up.

A, jack-up is related to the safety of the main structure, and all aspects cooperate closely;

B, in the process of overall jack-up, do a good job of recording.

C, in the process of jack-up, should carry on the cab patrol work, should appoint someone to observe the working situation of the whole system; If there is any abnormality, directly notify the command and control center.

D, in the process of construction, to closely observe the deformation of the structure;

E, in the process of jack-up. Do not enter the construction site without permission;

4. Adjustment of bearing

(1) Chisel the mortar off the lower bearing seat plate.

When the hydraulic jack is compressed, chisel away the bearing mortar around the bottom of the bearing.

② Remove the original bracket.

When the mortar of the lower seat plate of the bearing is chiseled away, the upper plate of the spherical bearing and the lower plate of the bearing are fixed with temporary connecting plates, the connecting bolts of the box girder embedded plate of the upper plate of the spherical bearing are loosened, and the lower plate of the bearing and the anchor bolts are removed.

③ Adjust the bracket.

When removing the bearing, adjust the relative height difference of the four corners of the bearing with the screws of the temporary connecting plate of the bearing, and measure the distance between the upper and lower plates of the bearing with a steel ruler. After repeated adjustment and measurement, the height difference of the four corners of the bearing is controlled within 2mm.

④ Install the bracket.

After the bracket is adjusted, put it back in its original position with a chain, and gradually bring the bolts of the upper plate of the bracket and the embedded plate of the box girder.

5, beam, adjust the elevation

After the bearing is connected with the box girder, operate the hydraulic jack to lower the box girder synchronously, measure the bridge deck elevation and track elevation of the box girder to be consistent with the elevation before jacking, install the lower anchor bolts of the bearing and prepare for grouting.

6, bearing grouting

According to the mortar mixture ratio, the mortar is mixed and poured, and the jacking system is dismantled after the mortar strength reaches 20Mpa.

7, detection

The test shall be carried out at the following process points: (1) After the bearing is grouted, the installation of the bearing shall be tested; (2) After dismantling the jacking system, test the installation of the bearing; (3) After dismantling the jack-up system, test the track elevation. Through the above inspection, it is confirmed that the adjusted bearing meets the standard inspection requirements and the track is restored to the state before adjustment.

(3) Safety measures

① Conscientiously implement the policy of "safety first, prevention first", strictly implement the national laws, regulations, norms, standards and other relevant safety systems related to production safety, and ensure the safety and health of employees during construction and production.

(2) During the period from the beginning of the top beam to the dismantling of the top beam system, the engineering line will be blocked to ensure the safety of the top beam.

(3) Strictly implement safety operation procedures, distribute labor protection articles according to operation requirements, and wear safety helmets when entering the construction site. It is strictly forbidden to direct operations in violation of regulations.

(4) Strengthen the safety protection facilities on the construction site and maintain good, safe and civilized construction conditions.

⑤ Strictly implement the system of safety technical disclosure step by step. Before construction, the technical director shall make a detailed disclosure of the general situation of the project, construction methods and safety technical measures to the project director and foreman. The project leader or foreman shall make a written safety technical disclosure to the monitor, and the written disclosure at all levels shall be signed by the handover person and filed for future reference.

Hubei Chutian Lianfa Road and Bridge Maintenance Co., Ltd. is a professional road and bridge maintenance company, which is mainly responsible for the adjustment, rectification, replacement and jacking of bridge bearings, and sells various construction equipment and accessories (including jacks, expansion joints and bridge bearings) for road and bridge maintenance, crack repair and bridge bearing adjustment.