Construction Method Of Bridge Prestress Intelligent Tension And Grouting System

2021-04-12 12:16

Process principle

1. Process principle of intelligent tensioning system

Bridge prestress intelligent tensioning system refers to a kind of prestress automatic tensioning equipment and its computer control system. It is mainly composed of a prestressed intelligent tensioning instrument, an intelligent jack, a laptop with its own wireless network card, and high-pressure oil pipes. It takes stress as the control index and elongation error as the proofreading index. The system collects data such as the working pressure of each tensioning device (jack) and the elongation value (including retraction) of each tensioning device (jack), in real time. The data is transmitted to the system host for analysis and judgment, and the tensioning equipment (pumping station) receives system instructions to achieve real-time and accurate control of tensioning force and loading speed. The system also sends instructions from the host computer according to the preset program to synchronously control every mechanical action of each device, and automatically complete the entire tensioning process.

(1) Prestress intelligent tensioning instrument

This equipment is an ultra-high pressure power output device, and its main function is to provide reliable and stable lifting power for the tension device (jack) of the beam body, and has the functions of lifting, pressure holding, and return. The device can accurately implement the commands set by the program, and ensure the reliable interaction of data communication through the wireless communication interface.

(2) Smart jack

The use of new seals, high-pressure self-reinforced cylinder strength, optimized jack structure size, under the premise of ensuring the jack stroke and the same hydraulic pressure, the weight is reduced by 30% to 45% compared with the conventional through-core jack, so that the jack’s weight output ratio can reach 0.6:1. At the same time, the length and outer diameter of the jack are reduced, which can reduce the length of the reserved steel strand, and can be widely used in pre-tensioning and post-tensioning pre-stressed construction. It comes with an electronic displacement sensor for testing the elongation of the inner cylinder of the jack. It has the characteristics of high accuracy, small error, large measuring range, smooth movement, etc. It comes with a high-precision pressure sensor, which can accurately measure the force value output by the jack.

2. Process principle of intelligent large-cycle grouting system

The intelligent grouting system for large-cycle prestressed pipelines refers specifically to the prestressed automatic grouting device and its computer control system. Its main technical principles are as follows:

The system is composed of a system host, a measurement and control system, and a circulating grouting system. The slurry continuously circulates in the loop composed of the prestressed pipeline, the pulp machine, and the squeezing pump to remove the air in the pipeline, find the pipeline blockage in time, and increase the pressure to punch out the impurities and eliminate the squeezing Factors that are not dense.

Precise sensors are installed at the inlet and outlet of the pipeline to monitor the pressure in real time, and feedback to the system host in real time for analysis and judgment. The measurement and control system adjusts the pressure according to the host's instructions to ensure the slurry quality and pressure required by the construction technical specifications for the prestressed pipeline The grouting process is completed under the constraints of important indicators such as, stabilization time, etc., to ensure full and dense grouting.

The main engine judges the filling of the pipeline based on whether the pressure difference between the inlet and outlet ports remains constant within a certain period of time.

After the pre-stressed concrete is stretched, fast-hardening mortar or fast-hardening cement is used to seal the gap between the end pre-stressed tendons and the anchors, and the construction equipment and machinery are arranged at the same time. After the preparation work is completed, start the grouting system for grouting operation.