Demolition construction method for overpass existing line arch bridge

Abstract

The invention discloses a demolition construction method for an overpass existing line arch bridge. The demolition construction method comprises the steps: 1, erecting a protective shed frame; 2, carrying out static crushing demolition on the arch blasting demolition structure; 3, manually removing the blasting protection layer; 4, cutting the removed arch ring; 5, hoisting the arch ring to be hoisted; and 6, dismantling the under-arch structure. The method is simple, reasonable in design, easy and convenient to construct and good in using effect; the protection shed frames fixed to the frontside and the rear side of the removed arch bridge are adopted for effective protection, meanwhile, the structure on the arch of the removed arch bridge is removed in the mode that static crushing andmanual chiseling are combined, it is guaranteed that a plain concrete arch ring cannot be damaged in the static crushing process, and an existing spanned railway line cannot be disturbed. After the arch ring is exposed, the removed arch ring is cut and decomposed through a rope saw and then hoisted and removed, then the under-arch structures on the left side and the right side are rapidly removed,the construction period can be effectively shortened, the arch bridge removing efficiency is improved, and the removing process is safe and reliable.

Description

technical field [0001] The invention belongs to the technical field of bridge construction, and in particular relates to a construction method for demolishing an arch bridge with an upper span existing line. Background technique [0002] At present, my country's existing electrified railways have many additional second-line projects and renovation projects. Most of the newly-built second-line lines are built next to the existing railways. The existing railways are built with low standards. Due to planning and investment restrictions, no second-line lines are reserved. Most of the existing railway bridges on the upper span need to build new bridges and dismantle the old bridges when building the second line, so as to meet the construction needs of the new second line foundation project. When upgrading highways and municipal projects, when rerouting is limited, when upgrading highway bridges in situ, the existing bridges also need to be demolished, and when seriously diseased h...

AI Technical Summary

Problems solved by technology

However, when the highway arch bridge (that is, the public-span iron arch bridge) built in the early 1970s over the existing railway line was demolished, due to the special structure of the demolished arch bridge and the lack of steel materials at that time, the arch bridge was demolished. The use of an open-hole structure consisting of plain concrete arch rings and masonry rubble pavement structures to meet the traffic needs of highways crossing railway overpasses was the mainstream and product of the times to solve the problem of crossing railway overpasses on national and rural roads at that time, but it was not possible. The overall hoisting and dismantling is very difficult, especially when the demolished arch bridge is located in a mountainous area or in a river valley, the construction site is narrow, and the overall dismantling is more difficult and basically impossible

However, when the in-situ demolition method based on the construction of temporary convenience lines is used for demolition, temporary convenience lines need to be constructed, and after the temporary convenience lines are opened, the existing railway traffic needs to be interrupted, and then the upper span bridges should be dismantled in situ. Due to constraints such as the difficulty of demolition of villager settlements along the line and the difficulty of demolition, the implementation conditions for in-situ demolition of temporary convenience lines are not available, and when the in-situ demolition of temporary convenience lines is adopted, the investment in rerouting is large

Therefore, when demolishing an arch bridge with upper spans and existing lines that cannot be temporarily rerouted because the construction site is limited, it can only be carried out in situ by using the "skylight point" for daily maintenance under the condition of ensuring that the existing operating railway transportation and driving safety are not affected. demolition construction

[0004] The in-situ demolition of the existing line arch bridge with upper span is very difficult, mainly in the following four aspects: First, the concrete arch ring has no reinforcement after radar monitoring, the arch ring is plain concrete arch ring, and the construction site site It is too narrow to support large-tonnage lifting equipment. The catenary catenary cables and wires are located in the arc of the arch ring. There are many existing equipment such as catenary pillars and optical cables on both sides of the arch bridge and the lower part of the arch bridge. The overall hoisting plain concrete arch ring is broken and damaged Most of the equipment has caused serious accident consequences, so it does not have the conditions for overall hoisting and dismantling. The blasting method is used, and the existing operating equip

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