Prevention and treatment of bellows leakage and plugging
Only the pipe with sufficient compressive strength and stiffness can be used as the slag pipe, and the damaged pipe is strictly prohibited.
Select the matching pipe and connect the pipe according to its number, and seal the joint gap with waterproof cloth or adhesive cloth to ensure tightness.
Beam concrete before the initial setting with through the hole to check, pull, dredge work, if the pre-prestressed element, pull the prestressed steel line or steel wire bundle during construction can be, concrete pouring after the through hole inspection, and do the corresponding treatment.
If you encounter a blocked hole that can not be dredged, you should first clear the location of the blocked hole, and then cut open, dredged.
The choice of stretching time
Some construction units in order to rush the construction period, in the concrete mixed with early strength agent, in the pouring of concrete 3 days after the tensioning operation. This method cannot guarantee the quality requirements, because the growth of elastic modulus and strength is not synchronized, the early strength agent accelerates the growth rate of strength, but does not accelerate the growth rate of elastic transverse quantity. In this way, when the mixed ship soil is stretched at the early stage when the deformation is large, the prestress loss will increase, the bearing capacity will not meet the requirements and cracks will appear. Therefore, in the construction process, the tensioning time should be selected strictly according to the requirements.
Control tension
If the tension force is not strictly controlled, the quality of prestressed Bridges will be greatly affected. Usually the tensile force and the elongation of prestressed tendons are used to control the stretching operation at the same time, which is called "double control method". In this method, the tensile force is mainly controlled, and the elongation value is used to check the tensile force. The key to determine whether the prestress is accurate or not is to see whether the tensile force is consistent with the elongation value.
Conclusion
To ensure the structure's safety and efficacy, the following steps should be taken during prestressing construction:
First and foremost, prestressed buildings should be designed with load, environmental conditions, and long-term performance in mind.
Material quality control: Use high-grade materials like prestressed steel strands or rebar. To ensure strength and longevity, these materials must comply with particular norms and requirements.
To avoid damage or corrosion, prestressed materials should be handled and kept carefully. Moisture and contamination should be avoided, as they will impair the material's quality.
If post-tensioning is employed, suitable grouting should be applied to the reinforcement. This guarantees that prestress is spread equally throughout the structure.
Regular inspection and monitoring: During construction, prestressed structures should be inspected and monitored on a regular basis to identify any issues.
Following the guidelines outlined above can reduce the danger of prestressing construction while also ensuring the overall quality and safety of the project.
In the construction, we should continue to improve the control of prestress, only perfect this work, in order to make the prestress play a full role, better meet the requirements of construction and use.