The Composition Of The Bridge Hydraulic Lifting System

2021-04-08 12:30

Jacking technology is a new type of bridge construction technology, which used to be mainly used in housing construction engineering correction and bridge jacking construction technology. In recent years, with the rapid development of the transportation industry, jacking technology has been mostly used in the technical transformation of existing bridges and the correction of bridge deviations due to various reasons. In many cases, for example, due to the improvement of waterway standards, bridges need to be elevated, bridge reconstruction caused by insufficient clearance of overpasses on highways, existing overpass landing ramps in cities are elevated to elevated, large-span steel bridges, and extra-high pier bridges. The jacking in place, the correction of construction errors, and the replacement of bridge supports, etc., all require the use of synchronous jacking technology to change the position of the main girder. It does not affect the stress characteristics of the upper structure of the original bridge, the cost is relatively low, the construction period is short, and the normal traffic flow is not affected. It has advantages that other construction methods cannot match. The use of jacking technology for construction will bring good social and economic benefits.

The bridge hydraulic jacking system is the core part of the entire bridge jacking. At present, most of the domestically used are PLC systems. The PLC control hydraulic synchronization system is composed of the PLC hydraulic overall synchronization control system (oil pumps, cylinders, etc.), monitoring sensors, computer control systems, etc. It consists of several parts.

1) PLC hydraulic integral synchronous lifting control system

The working principle of the PLC hydraulic integrated synchronous lifting control system is: the PLC hydraulic control room inputs hydraulic pressure and displacement instructions to the hydraulic pump station and displacement monitoring system according to the pre-programmed control program. After the hydraulic pump station receives the instructions, it delivers the corresponding hydraulic pressure to the hydraulic pressure. Jack, the jack will produce corresponding displacement according to the hydraulic value and jacking force; the displacement monitoring system will promptly feed back to the PLC hydraulic control room according to the displacement of each jack, and the control software program will timely modify the hydraulic and displacement commands according to the displacement feedback information. The closed loop of force and displacement is regulated and controlled, so that the systematic error of the displacement of each jack in each cycle is controlled within 2 ram.

2) Monitoring sensor system

The monitoring and sensing system is very important in the whole jacking system, and it is our main source of data information. The monitoring equipment mainly involved in jacking includes a jacking force monitoring system (mainly presented by an oil pressure gauge system), a stress monitoring system (mainly presented by a stress sensor), and a displacement monitoring system (mainly presented by a displacement sensor).

3) Computer system

The core control device of the computer system adopts button operation and displays the force parameters of each jacking cylinder through the touch screen. It can also be connected to a printer to record the jacking process data. The system is equipped with a UPS power supply, even if the power is unexpectedly cut off, data and engineering can also be performed. The computer system is the core of the entire PLC system. It analyzes and processes the data collected by the monitoring and sensor system, and feeds the processed data back to the hydraulic system. The hydraulic system adjusts the hydraulic pressure of each jack, thus the entire item lift system Synchronicity.