Demolition blasting method for prestress concrete cantilever trussed arch bridge

Abstract

The invention discloses a demolition blasting method for a prestress concrete cantilever trussed arch bridge. The demolition blasting method comprises the following steps: an energy-gathering line cutting blasting method is adopted; firstly, all prestress anchor cable reinforcing steel bars and lower chord girder reinforcing steel bars in a main hole pin section on the main arch of the bridge are cut at the same time; the dose of the thread-loaded explosive of an energy-gathering explosive bag for cutting the pre-stress anchor cable reinforcing steel bars is 40g/cm; a multi-point water pressure blasting method is adopted for demolishing supporting stand columns and arch support stand columns on the piers of the bridge and a hollow body of an edge hole steel structure beam; water pressure explosive bag groups are arranged according to the required positions and heights of cutting openings based on the bridge collapse technology; and the arch top of the bridge and a solid body section between the two edge hole steel structure beams close to a bridge abutment are demolished by a drilling blasting method. By virtue of the above method, the steel structure beam, the arch support stand columns and the plier stand columns are completely demolished, the concrete is crashed and separated, and the bridge is collapsed in an unstable state.

Description

technical field [0001] The invention relates to a blasting method for demolition of highway bridges, in particular to a blasting demolition method for prestressed concrete cantilever truss arch bridges. Background technique [0002] Prestressed concrete cantilever truss arch bridge is a new type of structural bridge developed in the 1980s. This type of structural bridge has better stress conditions than arch truss bridges and has the characteristics of large span. It is one of the main development directions of long-span bridges. In recent years, due to the construction of water conservancy facilities, road widening, etc., there are a large number of such structural bridges that need to be demolished. Traditional bridge demolition blasting generally uses a single shallow hole blasting, hydraulic blasting or energy-gathering cutting blasting for demolition, but the prestressed reinforced concrete cantilever truss arch bridge is a composite structure, and most of the component...

AI Technical Summary

Problems solved by technology

Traditional bridge demolition blasting generally adopts single shallow hole blasting, hydraulic blasting or concentrated energy cutting blasting for demolition, but the prestressed reinforced concrete cantilever truss arch bridge is a composite structure, and most of the components are box-shaped structures with thin walls. Hole or multi-point hydraulic blasting schemes cannot fully realize the design intent, and the cost of fully adopting energy-concentrated wire cutting blasting schemes is relatively high