Application of post-casting belt in deformation joint 1. Solve the settlement difference. The structure and foundation of the high-rise building and the podium are designed as a whole, but the two parts are temporarily disconnected during the construction. After the main structure is completed, most of the settlement (more than 50%) will be re-watered. Concrete, the high and low layers are integrated into one. The design time base should consider the different stress states in two stages and perform strength check separately. The calculation after the integration into the whole should consider the additional internal force caused by the late settlement difference. This practice requires that the foundation soil is better, and the settlement of the house can be basically completed during the construction period. Double Bolts Hose Clamp,Double Bolt Hose Clamp,Heavy Duty Double Bolt Clamp Cixi Chengtuo Hardware Parts Factory , https://www.ibccoupling.com
2. Reduce the effect of temperature shrinkage. The newly poured concrete will shrink during the induration process, and the completed structure will be expanded by heat and contracted by cold. Most of the concrete induration shrinkage will be completed in the first 1-2 months after construction, and the effect of temperature changes on the structure is frequent. When the deformation is constrained, temperature stress is generated inside the structure, and in severe cases, cracks appear in the member. In the construction of the post-casting belt, in the long building, every 30 to 40 meters, the width is 700-1000 mm, and the steel bars in the joint are lapped or straight-through and curved. After leaving the post-casting strip, the concrete can shrink freely during the construction process, thus greatly reducing the shrinkage stress. The tensile strength of concrete can be used mostly to resist temperature stress and improve the structure's ability to resist temperature changes. The retention time of the post-casting belt is generally not less than one month, during which the shrinkage deformation can be completed by 30% to 40%. The pouring time of the post-casting belt should be selected when the temperature is low (but should be positive temperature). The concrete with a small amount of aluminum powder mixed with cement or cement should be used. The strength grade should be higher than the strength of the component to prevent the new and old concrete. Cracks appear, causing weak parts.
The premise of the post-casting belt must be that the bearing capacity of the foundation soil of the project site is relatively high and the compression ratio is relatively small. The post-casting strip should be placed at the location where the beam bending moment and the bearing bending moment of the beam or plate are small, especially the beam, which must be considered as the main factor. The specific location of the rear wrap should also be determined in conjunction with the specific project.
Each building has its own different characteristics. Whether it needs deformation joints or how to set up deformation joints should be considered according to different construction requirements, structural forms and geographical environment of each project, and reasonable and simple practices should be adopted as much as possible. Achieve more desirable results. The key point in the deformation joint is the settlement joint. The above is a little experience of the author in dealing with the settlement joint of the building over the years. I hope that by summarizing the previous experience, the deformation joint can be processed more perfectly in the future structural design work. 