At the end of May 2014, Xiamen implemented the reconstruction and upgrading project of Xianyue Road viaduct. By October 26, the deck of the Xianyue Road Viaduct, which landed at the intersection of Taiwan Street, was quietly raised by 1 cm. After transformation, the viaduct is like a seesaw, downhill into uphill. Among them, the shortest pier was 11.261 meters long. It is reported that this is the most elevated viaduct in China. In this process, the construction side used displacement sensors, so that the accuracy of the bridge deck error measurement in the jacking process reached 0.01 mm.
Errors in jacking up should not exceed 2 mm
The deck of a section of Taiwanese Street connected by Higher Education Bridge is about 225 meters long. There are six spans and seven piers. The first three spans are a steel box girder, weighing about 2200 tons, and the last three spans are a concrete box girder, weighing about 6400 tons. During the test jacking process before the formal jacking, each pier is surrounded by a group of orange cylindrical jacks, which will temporarily replace the pier as the fulcrum of the bridge.
To ensure that the bridge is in good condition during jacking up, the jack must be lifted in proportion and synchronously without any error. Otherwise, if the force is not uniform, the bridge body may be damaged, and the error can not exceed 2 mm. On-site technicians use computers to refuel the pumping station for the jacks, while controlling the lifting height of each jack. In the jacking process, the displacement sensor will ensure the accuracy of jacking up, the measurement accuracy can reach 0.01 mm.
How to install and operate displacement sensors better in jacking stroke monitoring?
From the above cases, it can be seen that displacement sensors are widely used in many bridge deck construction and measurement, especially in jack lifting stroke monitoring. Next, we will have a detailed understanding of how to better install and operate displacement sensors in the use of bridge synchronous hydraulic jacks.
1. When installing Jack and displacement sensor device, the installation of Jack must ensure that the ground is flat, and the installation of displacement sensor should ensure that the pull line is vertical.
2. After connecting the power cable and inserting the plug into the pump station, the displacement detection device and the displacement detection port on the hydraulic jack-up pump station should be connected with the signal cable according to the distribution of the control points.
Finally, before the synchronous Jack lifts, it is necessary to check the accuracy of the displacement sensor reading, and arrange the field personnel to pull out the displacement sensor rope, whether the reading on the display screen is the same as the displacement reading pulled out by the field rope. Only in this way can displacement sensors be better installed and used in the process of bridge jacking.
Extracted from: Sensor Expert Network（摘自：传感器专家网，翻译而来）