Several important steps for bridge bearing replacement

 The main function of the bridge bearing is to reliably transmit the reaction force of the superstructure to the pier and complete the deformation (horizontal displacement and turning angle) required by the beam structure at the same time. Due to the quality problems of the bearing itself, as well as the improper design, installation and use of the bearing, the bearing is damaged prematurely, which affects the normal use of the bridge. For the irreparable damage in the bearing disposal technology, the bearing needs to be replaced. During the replacement process, the replacement method has a great impact on the safety of the bridge structure. Therefore, during the replacement process, it is necessary to The main stress-bearing parts of the bridge structure are monitored to ensure the safety and control of the replacement process.

Determination of support disposal plan

First of all, according to the structural characteristics of the bridge, if it is the left and right sides, the left and right sides can be operated separately when replacing, and the equipment used for roof lifting should comprehensively consider the influence of various unfavorable factors, so as not to damage the bridge deck structure.

The steps of the replacement of the bearing

1 Construction preparation

(1) According to the determined construction plan, do a good job in the construction of the construction site working platform. It is required to set up two brackets for each replacement set of supports, which is convenient for construction operators and monitoring personnel to use. The working platform should be firm and reliable to ensure the safety of personnel.

(2) Carry out the matching calibration of the jacks and oil pumps used. Two additional sets are added as spares.

(3) Select a new bearing of the same type as the original bearing, and do a good job in the test and inspection of the new bearing.

(4) Carefully clean up the sundries at the support and remove the redundant constraints near the support.

(5) The jack is installed in place.

(6) Arrange the stress and deflection observation points required for monitoring. Displacement observation points are set at the bridge piers to observe the displacement changes of the consolidation piers; two displacement observation points are set at the expansion joints of the bridge deck to observe the displacement changes at the expansion joints of the bridge deck.

(7) Organization and arrangement of construction personnel: The personnel entering the site are determined according to the needs of the project, including a project leader who is responsible for the unified arrangement and command of the project; a project technical leader who is responsible for the technical, task disclosure and Technical training; two experts, responsible for emergency treatment of temporary situations during the construction process, and several monitoring personnel.

2 jacking construction

(1) If the bridge width to be constructed should be temporarily closed before being jacked up to avoid construction accidents.

(2) After the preparation work is completed, the jack will be lifted under the unified command of the project leader. Control the jacking speed of the beam until all jacking is in place, and the support can be taken out smoothly. During the whole lifting process, the main girder, bridge deck and ancillary facilities must be carefully observed. If there is any abnormality, the lifting should be stopped immediately and adjusted, and then lifted again.

(3) After the jacking is in place, temporary support is required. The support should be firm and reliable, and the jack should not be loosened during the support process.

(4) After the support pad is taken out of the old support, before placing the new support, it is necessary to locate the original support to ensure the correct position after the support is replaced.

(5) Before installation, fill the silicone grease in the oil storage tank on the surface of the PTFE board in the PTFE board support to ensure that the surface of the PTFE board and the stainless steel surface are clean, and there should be no damage or scratching.

(6) When the bridge support is replaced and the main beam is in place, it should also be carried out in a distributed manner. First, the temporary support at the bottom of the beam is lifted, and then the beam body is dropped in place in sequence.

3 Conclusion

There are many bridges in use in my country, and the number of new bridges is increasing. Through our investigation, at least 20% of the bridge supports have serious diseases and need to be replaced and adjusted, otherwise the structural safety of the bridge itself will be affected. Through several years of construction, we have summed up a set of suitable lead bearing replacement and disposal methods and control technologies, which have broad application prospects.



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