The construction method of prestress staged stretching based on the elimination of concrete creep

Abstract

The invention relates to a prestress staged tensioning construction method for eliminating concrete creep. The method includes the steps of S1, acquiring a relational graph between concrete creep deformation and concrete loading age; S2, after hollow plate hoisting is completed, tensioning prestress load for the first time to allow the lower-edge stress of a hollow plate to be close to zero underself-weight and prestress or appropriately increasing prestress to allow a hollow plate beam to have a small amount of upward reverse creep deformation; S3, during second-stage paving, tensioning prestress again to allow the prestress effect to balance out the effect of the second-stage paving, wherein the creep deformation direction of the whole new bridge is upward at the moment; S4, after the deck construction of the whole bridge is completed, tensioning the prestress for the third time before the bridge is open to traffic to apply all the residual prestress during design in one step so asto complete the tensioning work. The method has the advantages that the staged prestress tensioning can partially balance out the creep effect, and the creep deformation can be effectively reduced byappropriately prolonging the loading age of the concrete beam.

Description

technical field [0001] The invention relates to the field of bridge construction, and more specifically relates to a construction method based on prestress staged tensioning for eliminating concrete creep. Background technique [0002] At the end of the 20th century, the country experienced large-scale engineering construction. After more than 20 years of rapid development, the speed of new urban bridges tended to slow down, and the scale gradually shrank. With the rapid development of the economy, the problem that gradually emerged in the later stage of large-scale construction is that the original bridge will soon be unable to meet the traffic demand, resulting in traffic congestion and structural overload, reducing the service life and safety performance of urban bridges. Therefore, the existing bridge needs to be reconstructed and widened. [0003] Concrete structures, however, suffer from shrinkage deformation and creep deformation that increases with time. Due to the...

AI Technical Summary

Problems solved by technology

With the rapid development of the economy, the problem that gradually emerged in the later stage of large-scale construction is that the original bridge will soon be unable to meet the traffic demand, resulting in traffic congestion and structural overload, reducing the service life and safety performance of urban bridges

However, in actual projects, most of this method cannot be implemented due to the limitation of the construction period.

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