A double-fold composite beam structure and its construction method

Abstract

The invention discloses a double-folded combined beam structure and a construction method thereof. The combined beam structure comprises an I-shaped main beam, a steel transverse separation plate, a combined bridge deck panel and a bridge deck pavement layer, wherein the bridge deck pavement layer is paved on the combined bridge deck panel; the I-shaped main beam comprises a main beam folded steel web plate, a main beam upper flange steel plate welded above the main beam folded steel web plate and a main beam lower flange steel plate welded below the main beam folded steel web plate; the combined bridge deck panel comprises a folded steel bottom plate and an ultrahigh-performance concrete layer poured on the folded steel bottom plate; the steel transverse separation plate comprises a transverse separation plate folded steel plate, a transverse separation plate upper flange steel plate welded above the transverse separation plate folded steel plate and a transverse separation plate lower flange steel plate welded below the transverse separation plate folded steel plate; and the main beam upper flange steel plate and the transverse separation plate upper flange steel plate are welded with a folded steel bottom plate. The combined beam structure disclosed by the invention does not need bracket construction and is good in stressing performance, high in bearing capability and high in structural reliability.

Description

technical field [0001] The invention relates to the technical field of bridge structures, in particular to a double-fold composite beam structure and a construction method thereof. Background technique [0002] Small and medium-span bridges (30m~50m) used on highways (including expressways, first-class highways and low-grade highways) and municipal roads have a wide demand in my country. According to statistics from the Ministry of Transport, by the end of 2014, the national The number of highway bridges is about 757,100, of which bridges with a span of less than 40m account for more than 90% of the total. Due to the constraints of economic conditions and the huge demand for traffic, most of the small and medium-span bridges built in the past used prefabricated concrete girder bridges and prestressed concrete girder bridges, which have the advantages of low direct cost, simple structure, and high construction technology. It has many advantages such as maturity, and has been ...

AI Technical Summary

Problems solved by technology

[0007] However, this traditional steel plate composite girder bridge has the following deficiencies in design, construction and operation: 1. In the traditional steel plate composite girder bridge, the web is made of flat steel plates. In order to ensure the stress and stability of the web, it is often necessary to There are many horizontal and vertical stiffeners on the web, and the structure is relatively complicated, which causes inconvenience to construction and processing

In order to ensure the local stability of the web, thicker steel plates are often used, and the material utilization efficiency of steel is not fully utilized

2. For the traditional steel plate composite girder bridge, the construction of the concrete bridge deck needs to set the formwork first, and then pour on-site on the formwork

Such construction steps lead to a large amount of form work and on-site wet work, and slow construction speed. The formwork cannot be completely supported by steel beams, and a full floor of scaffolding needs to be set up, resulting in high temporary construction costs.

Especially in the construction of municipal bridges with heavy traffic flow, the support construction will have a serious impact on the existing urban traffic, which is not in line with the current construction concept of "bridge prefabrication and rapid construction" actively advocated in China, and the construction time and cost are high. Poor benefit

3. In the traditional steel plate composite girder bridge, the bridge deck is made of ordinary concrete, which has low tensile strength

The concrete cracking of the bridge deck often occurs, which affects the durability and performance of the structure, and at the same time reduces the axial stiffness and bending stiffness of the composite section

In order to control the tensile stress of the bridge deck concrete in the negative moment zone, the method of adjusting the concrete pouring sequence, lifting the middle support point, and applying longitudinal prestress is often used, which is not very effective and causes complicated construction procedures.

Images