Joist type cable arch bridge structure and its construction method

Abstract

A truss-type cable-arch bridge structure, its lower chord main arch ring is composed of multiple arched steel pipes or steel boxes filled with concrete to form a concrete truss-type main arch ring, and the steel pipe concrete column is vertically fastened to the lower knot of the lower chord main arch ring At this point, the upper end of the steel pipe concrete column is fastened to the upper node of the upper chord roadway beam, and the two ends of the stay cables equipped with adjustable anchor clamps are respectively anchored to the upper node and the lower node of the adjacent steel pipe concrete column. Point. The construction method is to hoist the first unit’s concrete truss-type main arch ring, steel pipe columns and carriageway beams from the bridge abutments on both sides of the bank using stay cables with adjustable anchor clamps, and assemble them into one; then hoist the second unit, By analogy, until the arch bridge is closed, concrete is poured into each arched steel pipe or steel box truss from the lower end; after the bridge is completed, the stay cables at each node are adjusted to make the entire arch evenly stressed. The invention can comprehensively utilize the characteristics of synergistic combination and complementary advantages of various materials such as high-strength steel cables, steel materials and concrete, and is suitable for building bridges with large spans in V-shaped valleys in mountainous areas.

Description

technical field [0001] The invention relates to an arch bridge structure and a construction method, in particular to a truss-type cable-arch bridge structure and a construction method suitable for inconvenient and difficult transportation conditions such as steep mountainous areas and V-shaped valley terrains. Background technique [0002] From the ancient stone arch bridge in my country --- Zhaozhou Bridge to the reinforced concrete arch bridge in the 20th century, it has gone through a thousand years of development. The cast-in-place reinforced concrete arch bridge needs to be made on site, which is only suitable for small arch bridges; Concrete arch bridges have gone through three stages of development: box arch, steel pipe concrete arch and truss composite arch. [0003] 1. Prefabricated thin-walled box-shaped concrete arch bridges—Before the 1990s, long-span arch bridges in mountainous areas in my country mostly used prefabricated thin-walled box-shaped arch bridges. It...

AI Technical Summary

Problems solved by technology

It is divided into 3-7 sections vertically, each section weighs 40-60t, and cable cranes are often used for erection. The installation of 200-500t of equipment and the erection of arch ribs take up to one year; A large amount of manpower is used, which increases the project cost. In addition, the mountainous terrain is steep, and there is no place for prefabrication and hoisting of long components, so that the maximum span of the box arch bridge stays at the level of L<150m

[0004] 2. Steel pipe concrete arch bridge--In 1990, Sichuan Wangcang Bridge built a steel pipe concrete arch. Its lower chord main arch ring is an arched steel pipe with concrete injected inside. Due to the light weight of the steel pipe, it can be used as both a support and a formwork. Great convenience Therefore, it has promoted the rapid development of long-span arch bridges in China. At present, the largest span is Wushan Bridge in Sichuan, which has reached 460m; According to the requirements, the large-scale cable crane equipment used in it uses as much as 500-800t of steel, and the construction facilities such as cables and buckle frames must be removed after the main arch ring is closed, resulting in high costs. Except for professional teams, general construction It is difficult for units to complete the construction task of long-span concrete-filled steel pipe arch bridges

However, after 20 years of operation practice, the weakness of the reinforced concrete material used in the truss composite arch has gradually been exposed; for example, the truss joints and the post-cast part of the main arch ring have cracks to varying degrees under repeated loads, which affects durability In addition, when the span increases, the weight of reinforced concrete prefabricated components is too large, which brings many technical difficulties to demoulding, moving, turning over, and hoisting

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