CN116289518A - High-strength steel pipe ultra-high-performance concrete simple support, continuous truss girder and construction method thereof - Google Patents

High-strength steel pipe ultra-high-performance concrete simple support, continuous truss girder and construction method thereof Download PDF

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Publication number
CN116289518A
CN116289518A CN202310470378.7A CN202310470378A CN116289518A CN 116289518 A CN116289518 A CN 116289518A CN 202310470378 A CN202310470378 A CN 202310470378A CN 116289518 A CN116289518 A CN 116289518A
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steel pipe
chord member
uhpc
truss girder
strength steel
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黄文金
陈逸君
翁逸寒
柯荔微
林本清
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Fujian Agriculture and Forestry University
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Fujian Agriculture and Forestry University
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    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D19/00—Structural or constructional details of bridges
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D21/00—Methods or apparatus specially adapted for erecting or assembling bridges
    • E01D21/06—Methods or apparatus specially adapted for erecting or assembling bridges by translational movement of the bridge or bridge sections
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D21/00—Methods or apparatus specially adapted for erecting or assembling bridges
    • E01D21/10—Cantilevered erection
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
    • E01D2101/00—Material constitution of bridges
    • E01D2101/20—Concrete, stone or stone-like material
    • E01D2101/24—Concrete
    • E01D2101/26—Concrete reinforced
    • E01D2101/28—Concrete reinforced prestressed
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/91—Use of waste materials as fillers for mortars or concrete

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  • Civil Engineering (AREA)
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Abstract

The invention relates to a high-strength steel pipe ultra-high performance concrete simply supported continuous truss, which comprises a high-strength steel pipe truss formed by fixing a pressed chord member, a web member and a tension chord member, wherein the pressed chord member and the tension chord member are filled with UHPC with different performances, the interior of the tension chord member is filled with UHPC doped with steel fibers, and the interior of the pressed chord member is filled with UHPC doped with coarse aggregate; the continuous truss beam adopts a novel welding seam arrangement mode at the butt joint position of the chords. The material strength is higher, the section combination effect is good, and the truss girder has stronger crossing capacity; the material performance of the chord member is fully exerted; the dead weight of the structure is small, and the effective bearing capacity is large; the damage to the concrete in the pipe is small; the construction is convenient, the quality is controllable, and the safety is high.

Description

High-strength steel pipe ultra-high-performance concrete simple support, continuous truss girder and construction method thereof
Technical Field
The invention relates to a high-strength steel pipe ultra-high performance concrete simply supported and continuous truss girder and a construction method thereof, and relates to the technical field of bridge engineering.
Background
Concrete filled steel tube truss (concrete-filled steel tubular truss girder, CFST truss girder for short) is evolved from steel tube trusses in which both the chord members and web members are steel tubes. Compared with a steel pipe truss, the chord member in-pipe concrete of the steel pipe concrete truss can obviously improve the rigidity and bearing capacity of the chord member and the intersecting point, so that the chord member is stressed like a continuous beam elastically supported on a steel pipe web member, therefore, the steel pipe concrete truss has larger overall bending bearing capacity and bending rigidity than the steel pipe truss and is often used as a girder of a girder bridge, a rigid frame bridge or a cable-stayed bridge, a stiffening girder of a suspension bridge and a arch rib of the arch bridge, thereby reducing the dead weight of the structure and improving the spanning capacity of the bridge.
Steel pipe concrete truss girder: the CFST truss beam adopts steel pipe concrete for chord members, and steel pipes for web members, as shown in figure 1. The CFST truss chord steel tube is a seamed tube formed by welding Q235 or Q345 steel coils, and the chord steel tube is filled with common concrete with C30-C60. With the increase of bridge span, when adopting the CFST truss girder structure, in order to improve the truss girder bearing capacity, the cross-sectional dimension of the rod piece such as the chord member pipe diameter can be increased or the strength grade of the concrete can be improved. The defects are as follows: 1. affecting the under-bridge clearance. For a large-span bridge, the structural stress requirement can be met by adopting a larger section height and rod piece size in actual engineering, so that the clearance under the bridge is compressed or the bridge deck elevation is improved. 2. The structural gravity effect is relatively high. When the span is increased, the cross section size of the truss girder is increased sharply, so that the effect of the truss girder on constant load is obviously increased, and the effective bearing capacity of the structure is reduced. 3. The ultimate bearing capacity of the truss girder is low. Firstly, in the construction stage, particularly in the process of pouring concrete in pipes, the chord members and the web member steel pipes bear larger load, so that the chord members and the web member steel pipes are overstressed and even locally approach yield; secondly, the tensile strength of concrete in the tension chord (the lower chord in the positive bending moment area or the upper chord in the negative bending moment area) is lower, and meanwhile, the compressive strength of concrete in the compression chord (the upper chord in the positive bending moment area or the lower chord in the negative bending moment area) is limited, so that the ultimate bending resistance bearing capacity of the truss girder is not high. 4. The bending rigidity of the truss girder is not high after cracking. The tensile limit strain of the common concrete is low, and under the effect of design load, the concrete in the chord member pipe can be pulled to crack, so that the rigidity of the combined section is reduced, and the truss beam generates larger deflection.
A prestressed concrete filled steel tube composite truss and a construction method thereof are provided: the prestressed steel pipe concrete combined truss beam and the construction method thereof are shown in application number 2013100356187, and mainly comprise two parallel upper chords, a lower chord and a plurality of steel pipe web members symmetrically connected with the upper chord steel pipe and the lower chord steel pipe, as shown in figure 2. The upper chord steel pipe is filled with concrete, the web member is an empty steel pipe or a steel pipe filled with concrete, the lower chord steel pipe is filled with concrete, and the post-tensioning prestressed tendons are arranged in the lower chord steel pipe. The steel pipes of the chord members and the web members are made of common steel, and the concrete filled in the pipes is common concrete. The structure is used for applying prestress to the lower chord steel pipe, and is mainly used for improving bending bearing capacity and bending rigidity and reducing dead weight of the structure.
The construction steps are as follows: (1) Welding a lower chord steel pipe, placing and fixing a prestressed tendon in the lower chord steel pipe according to the designed position, filling concrete in the lower chord steel pipe, and tensioning the prestressed tendon after the concrete strength reaches 75%; (2) welding the steel web member on the lower chord steel pipe; and (3) welding the upper chord steel pipe with the steel web member to form the truss girder.
The defects are as follows: 1. the prestress construction cost is higher and the construction period is longer. The tensioning prestressing process is complex, the construction is complicated, special tensioning equipment and construction teams are needed, and the mechanical equipment cost and the labor cost are increased. 2. The prestressed reinforcement sleeve influences the construction quality of concrete in the chord member tube. The prestressed rib corrugated pipe shuttled inside the chord steel pipe occupies the effective space inside the steel pipe, influences the concrete pouring speed and the compact forming, and reduces the quality of concrete. 3. Post-tensioning construction results in damage to the intersecting nodes. Because post-tensioning is adopted to apply the prestress in the chord member pipe, the concrete in the pipe is poured first, and then the web member steel pipe is welded on the lower chord member steel pipe, so that the concrete near a welding heat affected zone is damaged by high welding temperature, and the stress performance of the intersecting joint of the chord member and the web member is reduced. 4. The durability of the prestressed structure is a problem. The prestressed anchor head is arranged at the end part of the chord steel pipe, and is required to be designed specifically for durability, so that the corrosion resistance difficulty and maintenance cost are increased.
Disclosure of Invention
In view of the defects of the prior art, the technical problem to be solved by the invention is to provide a high-strength steel pipe ultra-high performance concrete simply support, a continuous truss and a construction method thereof.
In order to solve the technical problems, the technical scheme of the invention is as follows:
a high-strength steel pipe ultra-high performance concrete simple truss girder comprises a high-strength steel pipe truss girder formed by fixing a pressed chord member, a web member and a tension chord member, wherein the pressed chord member and the tension chord member are respectively filled with UHPC with different performances, the interior of the tension chord member is filled with UHPC doped with steel fibers, and the interior of the pressed chord member is filled with UHPC doped with coarse aggregate.
The utility model provides a continuous truss girder of high-strength steel pipe ultra-high performance concrete, includes the positive moment section of side span, hogging moment section, mid-span positive moment section, hogging moment section, the positive moment section of side span that connect gradually, and every section comprises the fixed high-strength steel pipe truss girder that constitutes of pressurized chord member, web member and tension chord member, the UHPC that mixes steel fiber has all been poured into in the tension chord member, the UHPC that mixes thick aggregate has all been poured into in the pressurized chord member inside, butt joint through the internal flange between the corresponding chord member of adjacent section, and the butt joint steel pipe seam welding of chord member.
Preferably, the sections are cut according to positive and negative bending moment areas, wherein the pressed chords and the tension chords of the adjacent sections are distributed in an up-and-down staggered mode, the cutting positions are located between the nodes, and the web members at the cutting positions are welded after being welded.
Preferably, the inner flanges are coaxially fixed at the connecting ends of the corresponding chords, and the adjacent inner flanges are fixedly connected through high-strength bolts.
The construction method of the high-strength steel pipe ultra-high performance concrete simply supported truss girder comprises the following steps: (1) WeldingManufacturing a pressed chord member and a tension chord member, welding a web member between the pressed steel pipe and the tension steel pipe, and forming a high-strength steel pipe truss beam serving as a framework by the pressed chord member, the web member and the tension chord member; (2) Hoisting the high-strength steel pipe truss to a designated position by a mobile crane; (3) Filling concrete in the chord member pipe, filling UHPC doped with steel fibers into the tension chord member, and filling UHPC doped with coarse aggregate into the compression chord member to form C u FS h T simple support truss girder.
The construction method of the high-strength steel pipe ultra-high performance concrete continuous truss girder comprises the following steps: (1) Prefabricating high-strength steel pipe truss girder segments of positive and negative bending moment sections respectively, and pouring UHPC in chord members of the high-strength steel pipe truss girder segments of the negative bending moment sections to form C u FS h T truss sections; (2) C for hoisting hogging moment section u FS h T truss sections; (3) Hoisting the high-strength steel pipe truss girder segment of the side span positive bending moment section and adopting the inner flange and C of the negative bending moment section u FS h The T truss girder sections are butted; (4) Hoisting the high-strength steel pipe truss girder segment of the mid-span positive bending moment section and adopting the inner flange and C of the negative bending moment section u FS h The T truss girder sections are butted; (5) Welding a rear welding web member at the cut-off position, and connecting two adjacent truss girder sections; (6) Welding a first arc section and a second arc section of the chord butt joint steel pipe; (7) Filling UHPC in chord members of the high-strength steel pipe truss girder sections in the side span positive bending moment areas; (8) Filling UHPC in chord members of the high-strength steel pipe truss girder sections in the mid-span positive bending moment area; (9) UHPC doped with coarse aggregate is poured into the pipes at the butt joint positions of the tension and compression chords, and a third arc section of the butt joint steel pipe is welded to form C u FS h T continuous truss girder.
Preferably, the first arc section of the welding chord butt-joint steel pipe is positioned on the lower semicircular arc section, the second arc section is positioned on the opposite side of the upper semicircular arc section, and the third arc section is positioned between the second arc sections of the upper semicircular arc section.
Compared with the prior art, the invention has the following beneficial effects:
1. the material strength is higher, the sectional combination effect is good, and the girder has stronger crossing capacity
(1) The high-strength steel pipe and UHPC with the strength matched with the steel pipe are adopted, so that the material strength of the steel pipe and the UHPC is fully exerted, and the ultimate bearing capacity and the rigidity of the combined section are further improved;
(2) The UHPC doped with the steel fibers is filled in the tension chord tube, so that the effects of inhibiting, delaying and bridging concrete cracks by the steel fibers can be exerted, and the initial cracking strength and the ultimate tensile strength of the UHPC are improved, thereby improving the ultimate bearing capacity and the bending rigidity of the truss girder. Meanwhile, compared with the common concrete, the UHPC has larger initial cracking strength and larger anchoring effect on the steel fibers, so that the ultimate tensile strength of the UHPC doped with the steel fibers is larger than that of the common concrete doped with the steel fibers.
(3) UHPC mixed with a proper amount of coarse aggregate with small particle size is filled in the pressed chord member tube, so that the shrinkage of concrete in the tube can be reduced, the combined effect of the high-strength steel tube and UHPC is enhanced, and the material cost is reduced.
2. Fully exert the material property of the chord member
UHPC with different performances is respectively filled in the tensile chord steel pipe and the compressive chord steel pipe according to the stress requirements of the chord, so that the stress performance of the material can be fully exerted. Specifically, the primary characteristic requirement for compressed chord-filled UHPC is compressive strength, while the primary characteristic requirement for tension chord-filled UHPC is tensile strength. Meanwhile, the girder is cut off by utilizing the characteristics of a construction method, so that different filling modes can be adopted for different sections of girder chords according to stress conditions, and the mechanical properties of UHPC are fully exerted.
3. The dead weight of the structure is small and the effective bearing capacity is large
The high-strength steel pipe and UHPC are adopted to replace the common steel pipe and the common concrete of the CFST truss girder, so that the section height of the truss girder and the size of a rod piece can be obviously reduced under the condition of the same span, the self weight of the structure is effectively reduced, the effective bearing capacity of the structure is improved, and the clearance under a bridge is further increased or the elevation of the bridge deck is reduced.
4. The damage of the concrete in the welded geminate transistors is small
(1) A small section of steel pipe is reserved at two ends of the chord members of the truss girder segment respectively and is used for butt welding, so that the damage of high temperature welding to concrete in the pipe can be avoided.
(2) The novel arrangement mode is adopted for the steel pipe welding seams at the butt joint positions of the chords, compared with the traditional welding seam arrangement mode, the grouting phenomenon in the process of pouring concrete in the pipes is reduced, the positions of the welding seams are limited in the neutralization shaft and the compression area, the welding seams are not located at the maximum tensile stress positions of the sections, and the influence of welding defects on the stress performance of the components is reduced.
5. Convenient construction, controllable quality and high safety
(1) The adoption of the high-strength and ultra-high-performance material can reduce the structural dead weight, facilitate construction and hoisting and reduce the use of the node structure and the prestressed ribs in the tension chord tube on the basis of ensuring the spanning capability of the truss girder, thereby reducing the cost of manual and mechanical equipment and shortening the construction period.
(2) Hogging moment area C prefabricated in factory in hoisting position u FS h After the T truss girder segments, the inner flange is adopted to butt-joint the high-strength steel pipe truss girder segments in the positive bending moment zone, thereby realizing the closure of the steel structure, refilling UHPC in chord members of the segments in the positive bending moment zone, and completing C u FS h And (5) constructing the T truss girder. The construction method can reduce the workload of on-site welding and concrete pouring, quicken closure progress, reduce construction control difficulty by utilizing the favorable condition of mutual abutment of construction shearing force of the span, and improve construction quality of spliced parts and cantilever construction safety.
The mode of butt joint upper chord member at cut department and then whole root welding web member compares traditional butt joint web member or adds the connected mode of reinforcement web member, and the web member installation location of being convenient for reduces construction error, improves construction quality.
The invention will be described in further detail with reference to the drawings and the detailed description.
Drawings
Fig. 1 is a cross-sectional view of a concrete filled steel tube truss.
Fig. 2 is a cross-sectional view of a prestressed concrete filled steel tube truss.
FIG. 3 is a diagram of an embodiment C of the present invention u FS h T simple support truss structure pattern diagram.
FIG. 4 is C u FS h Four cross sectional configurations of the T-truss (with the hogging moment section as an example).
FIG. 5 is C u FS h And (3) a section division diagram of positive and negative bending moment areas of the T-shaped continuous truss girder.
FIG. 6 is C u FS h And C, constructing a first inner flange at the chord member splicing position of the T truss girder.
FIG. 7 is C u FS h And C, constructing a second graph by an inner flange at the chord member splicing position of the T truss girder.
FIG. 8 is C u FS h And (3) a steel pipe weld joint layout diagram at the chord member butt joint of the T truss girder.
In the figure: 1-a pressed chord; 2-web members; 3-tension chords; 4-parallel connection; 5-UHPC doped with coarse aggregate; 6-UHPC doped with steel fibers; 7-an inner flange; 8-stiffening rib plates; 9-bolt holes; 10-lining tube; 11-high-strength bolts; 12-post welding web members; 13-butt-joint steel pipes, 13-1 first arc sections, 13-2 second arc sections, 13-3 third arc sections and delta-welding seams.
Detailed Description
The invention will be further described with reference to the accompanying drawings and examples.
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.
As shown in fig. 1 to 8, the present embodiment can solve the following technical problems in the above-mentioned background art:
(1) Aiming at the problems of smaller under-bridge clearance and higher structural gravity occupation, the method adopts high-strength steel pipes and ultra-high-performance concrete (ultra-high performance concrete, UHPC for short) to replace common steel pipes and concrete, and can obviously reduce the section height of the truss girder and the size of a rod piece under the condition of the same span or bearing capacity, thereby effectively reducing the structural dead weight and further solving the clearance problem;
(2) Aiming at the problems of lower bearing capacity and low bending rigidity after cracking, a high-strength steel pipe and UHPC with strength matched with the steel pipe are adopted to fully exert the strength of the material and the combined effect of the material and the UHPC, so that the strength of the combined section and the rigidity after cracking are improved;
(3) Aiming at the problems of construction cost, construction period, concrete quality, durability, damaged node area and the like caused by the arrangement of the prestressed tendons, the UHPC doped with steel fibers is adopted to improve the tensile strength of the combined section, so that the scheme of tensioning the prestressed tendons is replaced, and adverse effects caused by the arrangement of the prestressed tendons are avoided.
The application of the high-strength steel pipe ultra-high performance concrete (C for short) u FS h T) truss girder can be used for girder of simple or continuous bridge, and its main member includes tension chord member (lower chord member of positive bending moment district and upper chord member of hogging moment district), pressurized chord member (upper chord member of positive bending moment district and lower chord member of hogging moment district) and web member, and the welded node of web member and chord member is the K shape node mainly. The chord members and the web members are connected into a plane truss girder through intersecting welding seams, and a plurality of plane truss girders can be welded into a space truss girder by adopting parallel connection.
The steel pipes of the chord members and the web members are high-strength steel pipes, UHPC doped with steel fibers is filled in the tension chord members, UHPC doped with a proper amount of coarse aggregate with small particle size is filled in the pressed chord members, and the parallel steel pipes can be made of common steel. The intersecting welds of the chord and web members or parallel connection are typically of the fillet type. Chord steel pipe lengthening is achieved through inner flange connection and butt joint steel pipe welding.
The embodiment provides a high-strength steel pipe ultra-high performance concrete simple girder, which comprises a high-strength steel pipe girder formed by fixing a pressed chord member, a web member and a tension chord member, wherein the pressed chord member and the tension chord member are respectively filled with UHPC with different performances, the interior of the tension chord member is filled with UHPC doped with steel fibers, and the interior of the pressed chord member is filled with UHPC doped with coarse aggregate.
The utility model provides a continuous truss girder of high-strength steel pipe ultra-high performance concrete, includes the positive moment section of side span, hogging moment section, mid-span positive moment section, hogging moment section, the positive moment section of side span that connect gradually, and every section comprises the fixed high-strength steel pipe truss girder that constitutes of pressurized chord member, web member and tension chord member, the UHPC that mixes steel fiber has all been poured into in the tension chord member, the UHPC that mixes thick aggregate has all been poured into in the pressurized chord member inside, butt joint through the internal flange between the corresponding chord member of adjacent section, and the butt joint steel pipe seam welding of chord member.
In the embodiment of the invention, the sections are cut according to positive and negative bending moment areas, wherein the pressed chords and the tension chords of the adjacent sections are distributed in a staggered way up and down, the cutting positions are positioned between the nodes, and the web members at the cutting positions are welded after being whole.
In the embodiment of the invention, the inner flanges are coaxially fixed at the connecting ends of the corresponding chords, and the adjacent inner flanges are fixedly connected through high-strength bolts.
The construction method of the high-strength steel pipe ultra-high performance concrete simply supported truss girder comprises the following steps: (1) Welding a pressed chord member and a tension chord member, and welding a web member between the pressed steel pipe and the tension steel pipe, wherein the pressed chord member, the web member and the tension chord member form a high-strength steel pipe truss beam serving as a framework; (2) Hoisting the high-strength steel pipe truss to a designated position by a mobile crane; (3) Filling concrete in the chord member pipe, filling UHPC doped with steel fibers into the tension chord member, and filling UHPC doped with coarse aggregate into the compression chord member to form C u FS h T simple support truss girder.
The C is u FS h The T simple truss girder is stressed clearly, and the web member shaft force is larger as the web member shaft force is closer to the fulcrum, so that different wall thicknesses can be adopted under the condition that the web member diameter is unchanged according to actual needs. In this embodiment, the pressed chord and the tension chord may have different diameters and wall thicknesses of steel pipe, i.e., D 1 ≠D 2 And t 1 ≠t 2 。
The construction method of the high-strength steel pipe ultra-high performance concrete continuous truss girder comprises the following steps: (1) Prefabricating high-strength steel pipe truss girder segments of positive and negative bending moment sections respectively, and pouring UHPC in chord members of the high-strength steel pipe truss girder segments of the negative bending moment sections to form C u FS h T truss sections; (2) Hoisting hogging moment sectionC of (2) u FS h T truss sections; (3) Hoisting the high-strength steel pipe truss girder segment of the side span positive bending moment section and adopting the inner flange and C of the negative bending moment section u FS h The T truss girder sections are butted; (4) Hoisting the high-strength steel pipe truss girder segment of the mid-span positive bending moment section and adopting the inner flange and C of the negative bending moment section u FS h The T truss girder sections are butted; (5) Welding a rear welding web member at the cut-off position, and connecting two adjacent truss girder sections; (6) Welding a first arc section and a second arc section of the chord butt joint steel pipe; (7) Filling UHPC in chord members of the high-strength steel pipe truss girder sections in the side span positive bending moment areas; (8) Filling UHPC in chord members of the high-strength steel pipe truss girder sections in the mid-span positive bending moment area; (9) UHPC doped with coarse aggregate is poured into the pipes at the butt joint positions of the tension and compression chords, and a third arc section of the butt joint steel pipe is welded to form C u FS h T continuous truss girder.
In the embodiment of the invention, the first arc section of the welding chord butt joint steel pipe is positioned on the lower semicircular arc section, the second arc section is positioned on the opposite side of the upper semicircular arc section, and the third arc section is positioned between the second arc sections of the upper semicircular arc section.
In the embodiment of the invention, a small section of steel pipe is reserved at two ends of the chord members of the truss girder segment respectively for butt welding, so that the damage of high-temperature welding to concrete in the pipe can be avoided.
In the embodiment of the invention, in the step (1), when the truss girder segments are divided, the positive and negative bending moment areas of the bending moment diagram are cut off, and the post-welding web members are subjected to subsequent repair welding. The chord member cut-off position is positioned between two nodes, so that the node domain is avoided, and the arc starting and arc falling points of the chord member butt welding seam are avoided from the upper edge and the lower edge of the chord member steel pipe, so that the cross or structural conflict with the welding seam of the web member and the parallel connection is avoided.
In the embodiment of the invention, in the step (1), UHPC is poured into chord members of high-strength steel pipe truss girder segments (two ends of each segment are left with a small section) of a hogging moment section, and then an inner flange is welded. When the UHPC in the chord member pipe of the high-strength steel pipe truss girder segment of the hogging moment section is poured, a small section is reserved at two ends of the segment respectively, and the length of the reserved section is slightly longer than that of the inner flange, so that the concrete can be prevented from being damaged by welding heat.
For the weld arrangement of steel pipes at the chord butt joint,in order to reduce the influence of welding on the stress performance of the material, the disconnection position of the arc sections is positioned near the neutralization shaft and the compression zone, wherein the disconnection position of the first arc section and the second arc section is near the neutralization shaft; the position of the disconnection position of the second arc section and the third arc section is shown in fig. 8 of the specification, wherein alpha=arccosr i /r o ，r i Is the inner radius of the steel pipe, r o Is the outer radius of the steel pipe. The delta is 2 The beveled butt weld (i.e., beveled in the second arc segment) has a beveled shape that aids in retaining the melted welding material.
In the actual use process, the sizes of the steel pipes of the pressed chords, the web members and the tension chords and the cross section construction form of the truss girder can be adjusted according to the requirements of structural stress, bridge deck arrangement and the like.
For UHPC doped with steel fibers, the volume doping amount of the steel fibers can be adjusted according to actual needs, and the doping amount range is 1.0% -3.0%. The doping amount of the steel fiber is determined by considering the sum of positive and negative effects, engineering cost and construction difficulty. The length of the steel fiber is 12-20 mm, the steel fiber is adjusted according to actual needs, and long fibers (the optimal length-diameter ratio of 90) can be used when the reinforcing effects of the UHPC tensile strength, the ultimate strain and the elastic modulus are required to be improved under the condition of the same doping amount; short fibers (with an optimal aspect ratio of 65) may be used if desired to enhance the strength of the UHPC initial burst.
For UHPC doped with coarse aggregate, the mixing amount of the coarse aggregate can be 22% under the premise of keeping the total aggregate amount unchanged, and the maximum particle size is 8-12 mm; in the actual mix ratio design, the design principle of close packing is required to be followed, and good grading is ensured.
The application adopts the high-strength steel pipe and UHPC to replace the common steel pipe and the common concrete of the CFST truss girder respectively, the material strength is higher, the structure is lighter, and the structure crossing capacity is improved. UHPC with different performances is filled in the compressed and tension chords so as to adapt to different stress requirements of the tension and the compressed chords, and the stress performance of the material is fully exerted. The steel pipe welding seam at the butt joint of the chord members adopts a novel arrangement mode, which is beneficial to reducing slurry overflow, ensures that the welding seam is positioned near the neutral shaft and the compression area, and reduces the damage of the welding to the concrete in the pipe. The chord steel pipes of the full bridge are firstly butted, then concrete in the chord steel pipes of the positive bending moment sections of the adjacent side spans and the middle spans is poured successively, so that the safety of cantilever construction can be improved, the advantage condition that shearing forces of construction of the side spans are mutually butted can be fully utilized, the construction control precision of the spliced position is improved, and the closure progress is accelerated. For the continuous structure, the connection part of the positive bending moment and the negative bending moment is cut off, so that the stress performance of truss girder segments in different filling modes can be fully exerted, the weight and the length of the segments can be reduced, and the cantilever assembly construction is facilitated. The chord member cut-off position is positioned between two nodes to avoid the node domain, and meanwhile, the arc starting and arc falling points of the chord member butt welding seam are avoided from the upper edge and the lower edge of the chord member steel pipe to avoid the crossing or the structural conflict of the welding seam with the web member and the parallel connection.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the invention in any way, and any person skilled in the art may make modifications or alterations to the disclosed technical content to the equivalent embodiments. However, any simple modification, equivalent variation and variation of the above embodiments according to the technical substance of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims (7)

1. The utility model provides a steel pipe ultra-high performance concrete simple girder of exceling in, includes the steel pipe truss of exceling in that comprises compressed chord member, web member and tension chord member are fixed, its characterized in that: the pressed chord member and the tension chord member are respectively filled with UHPC with different performances, wherein the tension chord member is internally filled with UHPC doped with steel fibers, and the pressed chord member is internally filled with UHPC doped with coarse aggregate.
2. The utility model provides a continuous truss girder of high-strength steel pipe ultra-high performance concrete, includes that side span positive moment section, hogging moment section, mid-span positive moment section, hogging moment section, side span positive moment section that connect gradually set up, its characterized in that: each section is composed of a high-strength steel pipe truss beam formed by fixing pressed chords, web members and tension chords, UHPC doped with steel fibers is poured into the tension chords, UHPC doped with coarse aggregate is poured into the pressed chords, the corresponding chords of adjacent sections are in butt joint through inner flanges, and butt joint steel pipes of the chords are in seam welding.
3. The high strength steel pipe ultra-high performance concrete continuous truss girder according to claim 2, wherein: cutting according to positive and negative bending moment areas, wherein pressed chords and tension chords of adjacent sections are distributed in an up-and-down staggered mode, cutting positions are located between nodes, and the web members at cutting positions are welded after being whole.
4. The high strength steel pipe ultra-high performance concrete continuous truss girder according to claim 2, wherein: the inner flanges are coaxially fixed at the connecting ends of the corresponding chords, and the adjacent inner flanges are fixedly connected through high-strength bolts.
5. The construction method of the high-strength steel pipe ultra-high-performance concrete simply supported truss girder as claimed in claim 1, which is characterized by comprising the following steps: (1) Welding a pressed chord member and a tension chord member, and welding a web member between the pressed steel pipe and the tension steel pipe, wherein the pressed chord member, the web member and the tension chord member form a high-strength steel pipe truss beam serving as a framework; (2) Hoisting the high-strength steel pipe truss to a designated position by a mobile crane; (3) Filling concrete in the chord member pipe, filling UHPC doped with steel fibers into the tension chord member, and filling UHPC doped with coarse aggregate into the compression chord member to form C u FS h T simple support truss girder.
6. A method for constructing a high-strength steel pipe ultra-high performance concrete continuous truss girder according to any one of claims 2 to 4, comprising the following steps: (1) Prefabricating high-strength steel pipe truss girder segments of positive and negative bending moment sections respectively, and pouring UHPC in chord members of the high-strength steel pipe truss girder segments of the negative bending moment sections to form C u FS h T truss sections; (2) C for hoisting hogging moment section u FS h T truss sections; (3) Hoisting the high-strength steel pipe truss girder segment of the side span positive bending moment section and adopting the inner flange and C of the negative bending moment section u FS h The T truss girder sections are butted; (4) High-strength steel for hoisting midspan positive bending moment sectionTube truss segment and C adopting inner flange and hogging moment section u FS h The T truss girder sections are butted; (5) Welding a rear welding web member at the cut-off position, and connecting two adjacent truss girder sections; (6) Welding a first arc section and a second arc section of the chord butt joint steel pipe; (7) Filling UHPC in chord members of the high-strength steel pipe truss girder sections in the side span positive bending moment areas; (8) Filling UHPC in chord members of the high-strength steel pipe truss girder sections in the mid-span positive bending moment area; (9) UHPC doped with coarse aggregate is poured into the pipes at the butt joint positions of the tension and compression chords, and a third arc section of the butt joint steel pipe is welded to form C u FS h T continuous truss girder.
7. The construction method of the high-strength steel pipe ultra-high performance concrete continuous truss girder according to claim 6, wherein the construction method comprises the following steps: the first arc section of the welding chord member butt joint steel pipe is located the lower semicircle arc section, the second arc section is located the opposite side of the upper semicircle arc section, and the third arc section is located between the second arc section of the upper semicircle arc section.
CN202310470378.7A 2023-04-27 2023-04-27 High-strength steel pipe ultra-high-performance concrete simple support, continuous truss girder and construction method thereof Pending CN116289518A (en)

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CN202310470378.7A CN116289518A (en) 2023-04-27 2023-04-27 High-strength steel pipe ultra-high-performance concrete simple support, continuous truss girder and construction method thereof

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