CN101122118B - Method for reinforcing and modifying through steel truss bridge - Google Patents

Abstract

A lower supported type steel truss bridge reinforcing and reconstructing method. The technical proposal lies in that plane supports (2) of steel structure are fixed and connected to both sides at the bottom of the trusses (1) with rectangular cross sections through welding or thread connection; the bottoms of the connected plane supports (2) and the trusses (1) are on the same plane. The method can add the transverse rigidity of the steel truss bridge, and reduce the transverse vibration; the materials are saved, the construction and maintenance are simple and convenient, and the cost is low.

Description

Reinforcement and Retrofit Methods of Downward Steel Truss Bridges

technical field

The invention relates to a method for strengthening and reforming an under-supported steel truss bridge.

Background technique

Under-supported steel truss is used as the load-bearing structure of the bridge. The cross section of the steel truss is rectangular, and the bridge deck is located at the bottom of the steel truss, so the bottom of the truss is the main force-bearing member. The lateral vibration amplitude of long-span, express or high-speed line bridges (that is, the left and right swings of the bridge) is relatively large, especially for some old bridges, due to the low design standards at the beginning or the long service life, the lateral stiffness of the bridge is obviously low, and the bridge The lateral amplitude is too large to meet the needs of traffic development. In order to increase the lateral stiffness of the truss and reduce the lateral vibration amplitude of the bridge, the existing method of reinforcement and reconstruction is: to connect multiple angle steels or channel steels with bolts to most members of the steel truss to increase the cross-section of the members. The disadvantages of this method are: material consumption is large, a large number of bolt holes cause great damage to the original structure, the construction is cumbersome and difficult, and the maintenance and repair in the later stage are difficult.

Contents of the invention

The purpose of the present invention is to provide a method for strengthening and reforming the under-supported steel truss bridge, which can increase the lateral stiffness of the steel truss bridge and reduce the lateral amplitude; the materials used are few, the construction and maintenance are simple and convenient, and the required cost Low.

The present invention solves the technical problem, and the adopted technical scheme is: a method for strengthening and reforming a down-supported steel truss bridge, which is as follows: on both sides of the bottom of the truss (1) with a rectangular cross-section, welding or bolts are used to The way of connection is to fix the plane bracket connected to the steel structure, and the plane bracket connected is on the same plane as the bottom of the truss.

Compared with the prior art, the beneficial effect of the present invention is that the planar brackets connected to the steel structure are fixed on both lateral sides of the bottom of the rectangular cross-section steel truss, so that the lateral width of the steel truss bottom that is mainly stressed will be directly increased, and the cost will be reduced. With less material, the transverse rigidity of the bottom of the steel truss can be significantly increased, thereby significantly reducing the transverse amplitude of the bridge; the steel structures extending from both sides of the bottom of the steel truss can be directly connected with the plane bracket, which is not only for the original Some truss structures are not damaged, and the method of the invention also simplifies the steps of reinforcement and transformation, and the construction is simple and convenient, which not only shortens the construction period, reduces costs and expenses, but also facilitates later maintenance and repair. In addition, the planar bracket can also be used as a supporting structure for sidewalks, driveways, pipe network lines or billboards as required, effectively utilizing the space of the bracket.

The specific method of fixedly connecting the plane brackets above is as follows: the end of the beam at the bottom of the truss extends out to connect several cross braces; The diagonal braces are connected obliquely in the rectangular internodes; the chords, cross braces and diagonal braces together form a plane bracket.

The specific method of obliquely connecting diagonal braces in the above-mentioned rectangular internodes is as follows: connect more than one diagonal braces in the rectangular internodes, and at least one end of one diagonal brace is connected to the corner of the rectangular internodes.

The bracket constructed by the above method can well form an integral structure with the original truss structure, especially its bottom support, which is not only convenient for construction, but also has good mechanical properties and large bearing capacity.

The material of the above-mentioned cross brace is I-shaped or box-section steel; the material of the chord and the diagonal brace is angle steel, channel steel or I-shaped steel. In this way, while ensuring the transverse rigidity of the bridge, the vertical rigidity of the cross brace is large, and the vertical vibration amplitude of the bracket can be effectively reduced; the chords and diagonal braces are light-weight rods, which can save costs.

After the above-mentioned plane brackets are fixedly connected, steel plates, wooden boards or concrete slabs are laid on the plane brackets to form driveways, sidewalks or inspection roads. In this way, the use value of the bridge is also increased while being reinforced.

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Fig. 1 is a schematic diagram of the three-dimensional structure of the truss of the under-supported steel truss bridge reinforced by the method of the embodiment of the present invention.

FIG. 2 is an end view of FIG. 1 .

Detailed ways

Example

Figures 1 and 2 show that a specific embodiment of the present invention is: a method for strengthening and reforming a down-supported steel truss bridge, which is as follows: on both sides of the bottom of the truss 1 with a rectangular cross-section, welding or The way of threaded connection is fixedly connecting the plane bracket 2 of the steel structure, and the connected plane bracket 2 is on the same plane as the bottom of the truss 1 .

Wherein, the specific method of fixedly connecting the plane bracket 2 is: the end of the beam 12 at the bottom of the truss 1 protrudes and connects the cross brace 22; The diagonal braces 23 are obliquely connected in several rectangular internodes formed with the cross braces 22 ;

The specific method of obliquely connecting the diagonal braces 23 in the rectangular internodes is: connect one or more than one diagonal braces 23 in the rectangular internodes, and at least one end of one diagonal brace 23 is connected to the corner of the rectangular internodes.

The material of the cross brace 22 in this example is I-shaped or box-section steel; the material of the chord 21 and the diagonal brace 23 is angle steel, channel steel or I-shaped steel.

After the plane bracket 2 is fixedly connected, steel plates, planks or concrete bridge slabs are laid on the plane bracket 2 to form a driveway, sidewalk or inspection road.

When the present invention is implemented, the height of bracket 2 cross brace 22 should generally be higher than the height of diagonal brace 23 and chord 21. Determined to ensure that the entire steel truss can bear sufficient load without producing a large local vertical amplitude.

Claims (4)

1. A method for strengthening and reforming an under-supported steel truss bridge, the method is: at the bottom both sides of the truss (1) of rectangular cross-section, adopt the mode of welding or bolt connection to fix the plane bracket connected to the steel structure (2), the connected plane bracket (2) is on the same plane as the bottom of the truss (1); The concrete way of described fixedly connecting plane bracket (2) is: the end of truss (1) bottom cross beam (12) stretches out and connects cross brace (22); The other end of cross brace (22) is parallel to longitudinal beam The chords (21) of (11) are connected, and obliquely connect the diagonal braces (23) in several rectangular sections formed by the chords (21) and the cross braces (22); the chords (21), the cross braces (22 ) and diagonal brace (23) constitute plane bracket (2) together. 2. The reinforcement and reconstruction method of a kind of under-supported steel truss bridge according to claim 1, characterized in that: the specific method of obliquely connecting diagonal braces (23) in the described rectangular internodes is as follows: More than one diagonal brace (23) is connected in the space, and one end of at least one diagonal brace (23) is connected on the corner of the rectangular internode. 3. The reinforcement and transformation method of a kind of under-supported steel truss bridge according to claim 2, characterized in that: the material of the cross brace (22) adopts I-shaped or box-section steel; the chord (21) And diagonal brace (23) material adopts angle steel, channel steel or I-beam. 4. The method for strengthening and reforming a bottom-loaded steel truss bridge according to claim 2, characterized in that: after the plane bracket (2) is fixedly connected, laying on the plane bracket (2) Steel, wooden or concrete slabs that form driveways, sidewalks or access roads.

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