RU2630940C2 - Pedestrian span structure of bridge with multi-braced main trusses of composite materials - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: pedestrian span structure of the bridge with multi-braced main trusses of composite materials includes at least two multi-braced main trusses, the belts of which are made of angles and strips of the rectangular cross-section. The braces are made of one or more strips of the rectangular cross section, located on their wide sides in vertical planes parallel to the common plane of the truss, so that in the joints the parts of the belts and the braces are layered in different planes and bolted directly, without gussets; at least two transverse connections connecting the multi-braced main trusses; bearing bridge bed elements supported by the multi-braced main trusses and consisting of longitudinal ribbed panels fastened together and transverse beams. The bearing bridge bed elements are located at the structure bottom level, are made of composite materials, and the longitudinal ribbed panels are connected to the lower belts of the multi-braced main trusses and the transverse beams.

EFFECT: increasing the structure reliability and durability.

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Description

The invention relates to the field of bridge construction and can be used in the construction of spans of pedestrian bridges made of polymer composite materials.

Known pedestrian spans with two main trusses, the elements of which are made of composite material, which is used fiberglass pultrusion profile building, hereinafter referred to as SPPS. (“Bridge constructions made of fiberglass” // Collection of articles “Introduction of the experience of applied advanced technologies of aircraft building in industry and transport”, under the editorship of A.E. Ushakov, issue 1, M., 2001, pp. 135-140; “ The use of composite materials for bridge structures ”// Collection of articles“ Introduction of the experience of applied advanced aircraft building technologies in industry and transport ”, edited by A.E. Ushakov, issue 3, M., 2004, pp. 5-12).

Elements of these spans, namely the elements of the main trusses, bond trusses and bearing structures of the bridge, are made up of shaped sections. The main span trusses have a simple diagonal grating, the main truss belts are composed of one or two channel profiles, and the braces and racks consist of single channel or square profiles with a longitudinal section cavity. Elements of the main trusses are connected in nodes with ordinary bolts along one or two contact planes through metal gussets. The load-bearing structures of the bridge web consist of shaped cross-section beams transmitting pressure to the nodes of the main trusses and longitudinal ribbed floor panels lying on the transverse beams and directly perceiving the temporary load. Connections are made in the form of farms having a simple diagonal or cross pattern.

One of the largest span structures of this type is installed on the bridge over the M7 highway in the Nizhny Novgorod region (see http://www.apatech.ru/pira.html “Pedestrian bridge at Pyra, 378 km of the M7 Volga highway”). The span of the main farms is 33.0 m, the size of the pedestrian walkway is 3.0 m, the weight of the span is 30.9 tons.

Constructed spans of bridges of this design are lightweight, low construction height, high speed of work at the construction site, high corrosion and chemical resistance, moderate operating costs.

The disadvantages of these composite spans:

- the main trusses are used with a simple diagonal lattice and with elements from single profiles transmitting forces in nodes in no more than two attachment planes; due to these structural solutions, significant lateral forces and nodal bending moments appear poorly perceived by the material at the ends of the elements;

- the appearance in the nodes of the main trusses of large transverse forces and bending moments requires a large number of bolts, the use of metal gussets and a corresponding increase in cross sections;

- the design of the load-bearing elements of the bridge web does not allow them to be included in the operation of the main farms and thereby reduce the effort in them, deflections and the total consumption of materials;

- nodal connections of the supporting elements of the bridge fabric are complex and difficult to access during installation and current maintenance;

- the presence of metal elements in the nodes of the main farms and load-bearing elements of the bridge web does not allow to take full advantage of the performance characteristics of the composite material due to the need for regular inspection and painting of the metal.

Closest to the proposed invention is a hybrid road span with multi-span main trusses made of fiberglass SPPS and a reinforced concrete slab of the carriageway located on top of the main trusses and included in their work (Journal of Building Materials, Equipment, Technologies of the 21st Century, No. 12, 2014 g. // article by B.V. Pyrinov “Construction of the first road bridge in Russia using polymer composite material”, pp. 24-28). The span of a bridge with multi-diagonal main trusses made of composite materials has: at least two multi-diagonal main trusses, the belts of which are made of corners and stripes of rectangular section, and the braces are made of one or several stripes of rectangular cross section, located with their wide sides in vertical planes, parallel to the common plane of the truss so that in the nodes the details of the belts and braces are layered in different planes and are bolted directly; at least two cross-links connecting multi-diagonal main trusses; reinforced concrete slab, acting as the supporting structure of the bridge, connected to the upper belts of the main trusses with anchor-rod stops. Connections of all elements of the span are made on ordinary bolts.

The advantages of the prototype design are:

- the inclusion in the work of the main farms of the supporting structure of the bridge web - reinforced concrete slab, which allows to reduce the consumption of expensive fiberglass;

- compliance with the requirements of the current Norms for the deflection of road spans at a building height that is consistent with the dimensions of typical reinforced concrete spans,

- direct attachment of the elements of the main trusses and connections to each other without auxiliary metal parts,

- simplicity of connections and their availability for inspection, maintenance and repair,

- uniformity of the current content of the carriageway with the most common typical bridge spans on highways.

The disadvantages of the prototype are:

- significant construction height, making it difficult to use this design in pedestrian bridges,

- an increase in construction time compared with structures made entirely of composite materials due to the construction of reinforced concrete slabs.

The objective of the proposed technical solution is to create a quickly erected pedestrian span of low construction height, with simple nodal joints, reducing the effort in the elements of multi-span main trusses and reducing the total weight of the structure.

To achieve the technical result, the pedestrian span of the bridge with multi-span main trusses made of composite materials has at least two multi-span main trusses, the belts of which are made of corners and strips of rectangular cross section, and the braces are made of one or several strips of rectangular cross section, their wide sides in vertical planes parallel to the common plane of the truss so that in the nodes the parts of the belts and braces are layered in different planes bolted directly without fasonok; at least two cross-links connecting multi-diagonal main trusses; load-bearing elements of the bridge web, supported by multi-span main trusses and consisting of longitudinal ribbed panels fastened to each other and transverse beams located at the bottom of the structure and made of composite materials, and longitudinal ribbed panels are attached to the lower belts of multi-span main trusses.

Features of a technical solution, which are its distinguishing features, give the following technical effect. The location of the supporting elements of the bridge at the bottom of the span allows to reduce the construction height of the span to the size that is comfortable in pedestrian bridges. The use of composite materials for load-bearing elements of the bridge bed reduces the forces in the elements of multi-span main trusses, reduces the total weight of the span and accelerates construction work. Joining the longitudinal ribbed panels of the bridge to the lower belts of the multi-span main trusses enables them to work together and further reduces the efforts in the elements of the multi-span main trusses, deflections and the total consumption of materials.

The construction of the invention is illustrated by drawings, where in FIG. Fig. 1 shows a fragment of the span facade, Fig. 2 shows a cross section of the span, where 1 is a multi-diagonal main truss, 2 is the lower belt of a multi-diagonal main truss, 3 is a transverse beam, 4 is a longitudinal ribbed flooring panel, 5 is a connection between multi-diagonal main farms.

The use of the invention is implemented by the contracting construction organization on the basis of the corresponding project. The span is being assembled at a construction site near the bridge. Multi-span main trusses 1 are made in a horizontal position on an assembly table in sections comprising, for example, half of their full length. The finished sections of the main trusses are raised to a vertical position and installed in a slipway, connected to each other by overlays and transverse beams 3. The longitudinal ribbed panels of the flooring 4 of the bridge web are combined with each other into mounting blocks with a length of, for example, half the span and, after installation in place, they are attached to the transverse beams 3 and to the lower belts of the multi-diagonal main trusses 2. After that, the connections between the multi-diagonal main trusses 5 are mounted and a protective polymer coating is applied to the footpath Ie. The finished span is installed on the supports with one or two truck cranes. With significant dimensions of the span, installation can be done by pre-assembling, for example, two volumetric mounting elements and installing them in the span using a temporary intermediate support.

Claims (1)

A pedestrian bridge span with multi-span main trusses made of composite materials, including: at least two multi-span main trusses, the belts of which are made of corners and stripes of rectangular section, and braces are made of one or more stripes of rectangular cross section, located with their wide sides in vertical planes parallel to the general plane of the truss so that in the nodes the details of the belts and braces are layered in different planes and are bolted directly, without 3 gussets; at least two cross-links connecting multi-diagonal main trusses; load-bearing elements of the bridge web, supported by multi-diagonal main trusses and consisting of longitudinal ribbed panels fastened to each other, and transverse beams, characterized in that the load-bearing elements of the bridge web are located at the bottom of the structure, made of composite materials, and the longitudinal ribbed panels are attached to the lower belts of multi-railing main trusses and transverse beams.

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