Bridge synchronous jacking technology is a bridge reconstruction technology that has been used more and more in recent years. Typically, this retrofit technique is used for fairway bridges with insufficient bridge clearance, overpass bridges, and replacement of bridge bearings.
The Technical Principle of Synchronous Jacking System
The synchronous jacking system is composed of an electric motor, high-pressure hydraulic pump, fuel tank, and operation control system, jack and oil pipe, diverter, etc.
The flow of a pump station is output through the diverter, which is provided to each actuator cylinder separately. The displacement control system controls the loading jacking speed of each oil cylinder according to the feedback signal of each different measuring point, so as to realize the synchronous lifting of the entire concrete continuous beam.
Features of Synchronous Jacking Technology
The synchronous jacking control technology is widely used in the lifting and translation of large buildings and the displacement of large equipment structures. Synchronous jacking control equipment can provide sufficient carrying capacity, and hydraulic systems are used at home and abroad.
Building jacking and translation engineering equipment based on distributed control hydraulic system has the following requirements:
(1) Scattered arrangement
(2) Centralized operation
(3) Synchronous lift
(4) Real-time monitoring
(5) Intelligent management
Technical Points and Construction Steps of Synchronous Jacking
Technical Points
(1) The structure of the new bearing should meet the design requirements and relevant industry regulations.
(2) For the overall replacement of the bearing construction plan, the batch of replacement bearings, the displacement of the top and the falling beam and the process should be determined through calculation.
(3) The temporary support of the jacking beam body shall meet the requirements of strength, rigidity and stability.
(4) The lifting and dropping of the beam shall be carried out according to the design requirements.
(5) When the support is replaced, the offset of the support should be checked according to the ambient temperature, and the construction should be selected under favourable temperature conditions.
(6) Measure the height difference between the original support and the new support, and adjust the construction to ensure that the beam and bridge deck elevations meet the reinforcement design requirements.
When the bridge is lifted synchronously, attention should be paid to the influence of various factors such as the installation of the jack, the synchronization accuracy of the jacking, and the installation of the temporary support after falling back, which often causes horizontal deflection during the lifting process, which will directly affect the safety of the bridge in severe cases. Structural limit is the main method to control deflection, and limit generally includes lateral limit and longitudinal limit. The design of the limit device is an essential element to ensure the successful lifting of the bridge.
