Bridge vertical prestress loss compensation method based on embedding and pasting of prestress batten in surface layer

Abstract

The invention discloses a bridge vertical prestress loss compensation method based on embedding and pasting of prestress batten in a surface layer. The bridge vertical prestress loss compensation method comprises the steps that firstly, a prefabrication groove is cut in a concrete protection layer of a bridge structure web; secondly, batten clamps and a tensioning device are installed, the fixed end batten clamp and the tensioning device are fixed to the protection layer of the web at the fixed end and the tensioning end correspondingly, and the tensioning end batten clamp and a sensor are installed; thirdly, the batten is anchored and tensioned; fourthly, the prefabrication groove is filled with a bonding agent; and fifthly, tensioning is finished, and after the bonding agent reaches thecuring strength, the prestress applied by the tensioning device is released, the tensioning end clamp and the fixed end clamp slide, and the prestress on the batten is released. The bridge vertical prestress loss compensation method has the advantages that durability is good, construction convenience and simpleness are good, and web cracking load and anti-shearing bearing capacity can be improved.

Description

technical field [0001] The invention mainly relates to the technical field of bridge reinforcement, in particular to a method for compensating vertical prestress loss of bridges based on embedding prestress slats on the surface. Background technique [0002] In the prior art, prestressed concrete box girders generally apply preload to the web by setting vertical prestressed steel bars to offset part of the main tensile stress caused by self-weight and external loads, so as to curb the occurrence of oblique cracking of the web . However, due to the limited height of the box girder, the length of the vertical prestressed tendons is relatively short. When the tensile control stress is reached, the elongation of the high-strength finish-rolled thick steel bar is limited. If there is a slight carelessness in anchoring, the steel bar will shrink. Too much vertical prestress is lost due to the large amount, and the shrinkage and creep of concrete often leads to serious prestress l...

AI Technical Summary

Problems solved by technology

[0004] In the traditional technology, the existing reinforcement methods include applying external prestressed reinforcement, pasting carbon fiber cloth or steel plate, the former is complex in construction, needs to install special anchor blocks on the bridge, and there is a risk of insufficient durability of the external cable system; the latter belongs to passive reinforcement It cannot close the oblique cracks, and has a limited inhibitory effect on the continued development of oblique cracks, and it does not solve the problem of oblique cracking of the web caused by the loss of vertical prestress.

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