CN110004832B - Large-span cantilever truss type bent cap bracket system and construction method - Google Patents
Large-span cantilever truss type bent cap bracket system and construction method Download PDFInfo
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- CN110004832B CN110004832B CN201910281143.7A CN201910281143A CN110004832B CN 110004832 B CN110004832 B CN 110004832B CN 201910281143 A CN201910281143 A CN 201910281143A CN 110004832 B CN110004832 B CN 110004832B
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- 238000010276 construction Methods 0.000 title claims abstract description 36
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 76
- 239000010959 steel Substances 0.000 claims abstract description 76
- 230000007246 mechanism Effects 0.000 claims abstract description 54
- 230000000712 assembly Effects 0.000 claims abstract description 13
- 238000000429 assembly Methods 0.000 claims abstract description 13
- 239000004576 sand Substances 0.000 claims description 14
- 238000003466 welding Methods 0.000 claims description 13
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 238000001514 detection method Methods 0.000 claims description 6
- 239000004575 stone Substances 0.000 claims description 5
- 230000007423 decrease Effects 0.000 claims description 4
- 230000000903 blocking effect Effects 0.000 claims description 2
- 238000009432 framing Methods 0.000 description 6
- 239000010410 layer Substances 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 230000007704 transition Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000002457 bidirectional effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
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- 230000007547 defect Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 230000007306 turnover Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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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
- E01D21/00—Methods or apparatus specially adapted for erecting or assembling bridges
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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
- E01D21/00—Methods or apparatus specially adapted for erecting or assembling bridges
- E01D21/10—Cantilevered erection
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Abstract
The invention discloses a long-span cantilever truss type bent cap support system which sequentially comprises a supporting device, an elevation adjusting device, a truss mechanism and an operation platform from bottom to top; the truss mechanism comprises two truss main bodies, each truss main body comprises two truss assemblies, each truss assembly comprises an upper chord member and a lower chord member, a plurality of upper nodes are arranged on each upper chord member, a plurality of lower nodes are arranged on each lower chord member, and a straight web member is arranged between each upper node and each corresponding lower node; the middle point of each two adjacent upper nodes is provided with a central node, and an inclined web member distributed in an eight shape is arranged between each central node and two adjacent lower nodes. The invention also discloses a construction method of the long-span cantilever truss type bent cap bracket system. The large-span cantilever truss type bent cap bracket system and the construction method disclosed by the invention are convenient to assemble, disassemble and construct, small in steel consumption and adjustable in height of the integral truss structure; and the normal running of the vehicle is not affected in the working state.
Description
Technical Field
The invention relates to the technical field of engineering construction, in particular to a long-span cantilever truss type bent cap bracket system and a construction method.
Background
With the increasing promotion of urban mass production in China, urban population scale is steadily increased, and urban expressways become an important means for solving urban traffic jams. The common urban expressway in China adopts a ground road and a main line overhead, namely a bearing platform of the main line overhead is positioned in a central separation zone of the ground road, and a cantilever type bent cap is adopted as an overhead supporting structure to realize double-layer traffic of the road.
As a cast-in-place concrete structure, the traditional bowl-buckle type full framing process is subject to more and more constraints and challenges:
1. when the full framing system is constructed, the whole projection range of the bent cap does not allow vehicles to pass: 1) For the existing road reconstruction engineering, the technology increases the difficulty of temporary conservation (the more intense the surrounding land resources are, the greater the limited degree is); 2) For new construction, the technology requires additional construction temporary channels, the area is often the arrangement range of the rain sewage pipeline, and the area is required to be abandoned in the later period, so that the construction cost is increased, the stone and machinery investment is large, and the technology does not meet the requirements of energy conservation, environmental protection and green construction;
2. the full framing system needs reliable foundation treatment, for soft soil areas, the depth of foundation treatment is often 1.5-2.0 times of the height of a newly built road cushion layer, and a 20cm concrete cushion layer needs to be poured on the surface layer, the cushion layer is all chiseled after construction is completed, temporary consumption of concrete and extra investment of stone are increased, and a large amount of precious social resources are consumed at the same time of increasing construction cost;
3. the whole stability of the full framing system is subject to the periphery, when heavy vehicles frequently pass around the framing system, the newly poured bent cap is extremely easy to be disturbed to generate cracks, and a large hidden trouble is formed for later overhead operation.
In summary, in order to solve the problems of large resource consumption, high construction cost, hidden danger of a main structure and the like in the traditional bowl-buckle type full framing process, a novel capping beam bracket system is developed.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: the large-span cantilever truss type bent cap bracket system is convenient to assemble, disassemble and construct, small in steel consumption and adjustable in height of the integral truss structure; and the normal running of the vehicle in the projection range of the bent cap is not influenced under the working state.
The technical scheme adopted by the invention is as follows: the utility model provides a large-span cantilever truss-type bent cap bracket system, which comprises a supporting device vertically connected to a foundation bearing platform, wherein a truss mechanism of a cantilever structure is arranged at the top of the supporting device, an elevation adjusting device for adjusting the height of the truss mechanism is arranged between the supporting device and the truss mechanism, and an operation platform for constructing the bent cap is arranged at the top of the truss mechanism;
the truss mechanism comprises two integral truss bodies with the same structure, the two truss bodies are symmetrically arranged along the extending direction of the capping beam, and the heights of the truss bodies linearly decrease along the extending direction from one end close to the upright post to the outer end; the truss main body comprises two truss assemblies which are symmetrically arranged, and the two truss assemblies are connected into an integrated structure through a parallel support;
the truss assembly comprises an upper chord member and a lower chord member, wherein a plurality of upper nodes are uniformly arranged on the upper chord member, a plurality of lower nodes which are in one-to-one correspondence with the upper nodes are arranged on the lower chord member, and a straight web member is arranged between each upper node and the corresponding lower node; the central position of every two adjacent upper nodes is provided with a central node, and an inclined web member distributed in an eight shape is arranged between each central node and two adjacent lower nodes.
As an improvement, the upper chord member, the lower chord member, the straight web member and the inclined web member all comprise double-layer channel steel, and the double-layer channel steel is connected through a lacing plate.
The parallel connection support comprises at least two X-shaped pull rods, wherein the two X-shaped pull rods are arranged at two ends of the truss main body in the length direction, so that the end faces of the upper chord member and the lower chord member are connected; a plurality of upper straight pull rods are arranged between the upper chords of the two symmetrically arranged truss assemblies along the length direction, a plurality of lower straight pull rods are arranged between the lower chords, and diagonal pull rods are arranged between the adjacent lower straight pull rods along diagonal angles.
As an improvement, the elevation adjusting device comprises an upper pipe fitting and a lower pipe fitting, wherein fine stone concrete is poured into the upper pipe fitting, and the upper pipe fitting is sealed by adopting a steel plate; the upper pipe fitting is inserted and assembled in the inner cavity of the lower pipe fitting, and machine-made sand is poured between the bottom of the upper pipe fitting and the bottom of the inner cavity of the lower pipe fitting; the side wall of the lower pipe fitting is provided with a sand outlet, and a blocking bolt is connected in the sand outlet.
Preferably, the difference between the diameter of the inner hole of the lower pipe fitting and the outer diameter of the upper pipe fitting is 5-10mm.
As an improvement, a plurality of connecting screws are uniformly arranged between the upper pipe fitting and the lower pipe fitting along the circumferential direction, and two ends of the connecting screws are respectively and correspondingly connected to an upper mounting plate of the upper pipe fitting and a lower mounting plate of the lower pipe fitting; the upper pipe fitting is connected with the truss main body through bolts, and the lower pipe fitting is connected with the supporting device through bolts.
And the bottom of the inner cavity of the lower pipe fitting is connected with an I-shaped stiffening plate.
Further, the operation platform comprises a plurality of I-steel, and the I-steel is arranged at the position corresponding to the upper node on the upper chord; one of the I-beams corresponding to the upright post is interrupted, a fixed block is arranged between one end of the interrupted I-beam close to the upright post and the upper chord, and an inclined strut is arranged between the end of the interrupted I-beam, which is away from the upright post, and the lower chord; square timber is arranged between the lower chord member and the upright post.
Still further, the supporting device comprises four supporting columns, the upper ends of the four supporting columns are connected with the elevation adjusting device, the lower ends of the supporting columns are connected with a foundation bearing platform through steel pipe supports with the diameter smaller than that of the supporting columns, and a plurality of stiffening plates are arranged on the outer side walls of the steel pipe supports along the circumferential direction; a scissor brace is arranged between two support columns arranged along the length direction of the truss mechanism.
The invention also provides a construction method of the long-span cantilever truss type bent cap bracket system, which comprises the following steps:
a. truss manufacturing, namely blanking according to a design drawing, and welding to manufacture a truss assembly with a double-spliced structure; welding the two truss assemblies through parallel brackets to form a truss main body;
b. after the truss main body is manufactured, flaw detection is carried out on the welding quality of the truss main body so as to determine whether the truss main body meets the design requirement;
c. symmetrically assembling the two truss main bodies which are qualified in detection through connecting bolts to form a complete truss mechanism;
d. the supporting device is installed, a steel pipe support, a supporting column and an elevation adjusting device are installed from bottom to top on the basis of a foundation bearing platform, and all the components are connected through flanges; the corresponding support columns are connected and fixed by adopting a scissor brace;
e. hoisting the assembled integral truss mechanism to the top of the supporting device, connecting the truss mechanism with the elevation adjusting device, adding square timber between the lower chords of the truss mechanism and the upright posts, and simultaneously arranging temporary opposite-pulling screws between the two lower chords so as to keep the truss mechanism stable;
f. i-steel is arranged at each connecting node position on the top of the truss main body and the upper chord, and a plurality of I-steel are sequentially arranged to form an operation platform;
g. after construction is completed, the whole truss mechanism is controlled to descend by a certain height by utilizing the elevation adjusting device, so that the truss mechanism is separated from a cover beam after construction is completed, split bolts between a split screw and two truss main bodies are sequentially detached, and then the two truss main bodies are sequentially hoisted and evacuated; and finally, removing the supporting device.
Compared with the prior art, the technical scheme of the invention has the following technical advantages:
in the supporting system, the supporting device is arranged on the foundation pile cap at the bottom of the upright post, and the truss mechanism with the cantilever structure is arranged on the supporting device, so that the normal passing of vehicles in the projection range of the bent cap is not influenced in the construction process. And moreover, the whole truss system adopts a lattice type splicing structure, the height of the truss main body linearly decreases along the direction from one end close to the upright post to the extension of the outer end, namely, the whole truss main body is of a trapezoid structure, and the self weight of the supporting system is furthest reduced on the premise of meeting the requirement of supporting force, so that the supporting system is convenient to detach.
In addition, the conventional truss system in the prior art is assembled and disassembled by parts during assembly and disassembly, so that the whole mechanism is heavy, the assembly and disassembly process is complex, and the safety performance is insufficient. When the cantilever truss mechanism is installed, the cantilever truss mechanism can be hoisted from top to bottom, and the assembled truss mechanism can be integrally installed; during dismantling, under the influence of the cover beam after pouring, the cantilever truss is dismantled by selecting a part (the parts are spliced into a whole later) or is dismantled by selecting a left-right integral type, so that the labor and the machinery for construction are less, the construction period is short, and the cost is low. In addition, because the dead weight of the cantilever truss system is relatively small (the total weight is not more than 20 tons and the single piece is not more than 10 tons), the invention adopts an integral dismantling scheme, and the whole system is only provided with field assembly nodes in the central area of the structure. In addition, the cantilever truss system is not provided with a parallel system in the range of the spliced nodes and the upright posts, so that the influence of the upright posts on the dismantling of the cantilever truss is avoided.
At present, common urban express ways in China are designed according to two-way six lanes, the length of a cantilever of a bent cap is usually not less than 8m, the distance between supporting points is usually not more than 7m, and under the span arrangement, the overall steel consumption of the truss system of the invention can be reduced to 150kg/m 2 About 40% to 50% of the conventional solid web system.
Drawings
FIG. 1 is a schematic structural view of a large span cantilever truss cap bracket system of the present invention.
Fig. 2 is a schematic structural view of the truss body of the present invention.
Fig. 3 is a front view of the truss assembly of the present invention.
Fig. 4 is an enlarged schematic view of the structure at X in fig. 1.
Fig. 5 is a transverse cross-sectional view of the long span cantilever truss cap bracket system of the present invention taken along the upright post location.
Fig. 6 is a cross-sectional view of the "X" shaped pull rod of fig. 1.
Fig. 7 is a construction state diagram of the long span cantilever truss type bent cap bracket system of the present invention.
Wherein, 100-upright post, 110-wedge steel module, 101-truss main body, 1-truss component, 1.1-upper chord, 1.2-lower chord, 1.3-upper node, 1.4-lower node, 1.5-straight web member, 1.6-center node, 1.7-diagonal web member, 2-parallel support, 2.1- "X" -shaped pull rod, 2.2-upper straight pull rod, 2.3-lower straight pull rod, 2.4-diagonal pull rod, 3-upper pipe fitting, 4-lower pipe fitting, 5-connecting screw, 6- "I" -shaped steel, 7-triangular steel plate, 8-diagonal pull rod, 9-square timber, 10-supporting column, 11-steel pipe support, 12-scissor support, 13-horizontal connecting rod, 14-lacing plate, 15-opposite-pulling screw rod
Detailed Description
The invention is further described below with reference to the drawings and the detailed description.
In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "top", "upper", "lower", "center position", "side wall", "upper", "lower", etc. are directions or positional relationships based on the drawings are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or element to be referred to must have a specific direction, be constructed and operated in the specific direction, and thus should not be construed as limiting the present invention.
In the description of the present invention, it should be noted that, unless explicitly stated and limited otherwise, the terms "connected," "mounted," and "mounted" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
As shown in fig. 1, the invention provides a long-span cantilever truss type bent cap bracket system, which comprises a supporting device vertically connected to a foundation bearing platform, wherein a truss mechanism with a cantilever structure is arranged at the top of the supporting device, and the truss mechanism is particularly fastened through bolt connection, so that the later disassembly is convenient.
An elevation adjusting device for adjusting the height of the truss mechanism is arranged between the supporting device and the truss mechanism. As shown in fig. 5, the elevation adjusting device comprises an upper pipe fitting 3 and a lower pipe fitting 4, wherein fine stone concrete is poured into the upper pipe fitting 3, and the upper pipe fitting is sealed by adopting a steel plate; the upper pipe fitting 3 is inserted and assembled in the inner cavity of the lower pipe fitting 4, and machine-made sand is poured between the bottom of the upper pipe fitting 3 and the bottom of the inner cavity of the lower pipe fitting 4. And be equipped with the play sand hole that the diameter is not less than 30mm on the lateral wall of lower pipe fitting 4, under the operation state, go out sand hole internal connection and be connected with the shutoff bolt, when the capping beam construction is accomplished the back, need demolish truss mechanism, at first open the shutoff bolt on the lower pipe fitting 4, discharge mechanism sand, truss mechanism wholly descends certain height to make truss mechanism and capping beam separation.
The device realizes the function of elevation adjustment by adjusting the quantity of machine-made sand. Typically, the machine-made sand is adjusted to a height of no more than 30cm. The height is overlarge, and the stability of the elevation adjusting device is poor; if the height adjustment is too small, a plurality of kinds of fixed adjusting blocks are required to be arranged. When the timing is performed according to 30cm, the specification of the regulating block is only required to be configured with two types of 0.3m and 0.6 m.
Since the inner cavity of the lower pipe fitting 4 is filled with machine-made sand, the control of the gap between the outer side wall of the upper pipe fitting 3 and the inner side wall of the lower pipe fitting 4 is very critical. The gap is too large, machine-made sand can overflow upwards, the stability of the whole truss mechanism is affected, the gap is too small, and the phenomenon of clamping between the side walls of the upper pipe fitting 3 and the lower pipe fitting 4 is easy to occur. In this embodiment, the difference between the diameter of the inner bore of the lower tubular member 4 and the outer diameter of the upper tubular member 3 is preferably 5-10mm. And most preferably 10mm.
In the structure, the upper pipe fitting 3 and the lower pipe fitting 4 are made of seamless steel pipes, and the wall thickness of the seamless steel pipes is determined according to the design, but is not smaller than 12mm. Specifically, the upper end of the upper pipe fitting 3, the lower end of the lower pipe fitting 4 is provided with a flange steel plate serving as a supporting structure, the steel plate at the bottom of the lower pipe fitting 4 is equivalent to a plate for bearing uniformly distributed loads, and if a stiffening structure is not provided, the possibility of hidden danger of bearing capacity and deformation loss exists. Therefore, in this embodiment, an i-shaped stiffening plate is connected to the bottom of the inner cavity of the lower pipe fitting 4.
A plurality of connecting screws 5 are uniformly arranged between the upper pipe fitting 3 and the lower pipe fitting 4 along the circumferential direction, and two ends of the connecting screws 5 are correspondingly connected to the upper mounting plate 3.1 of the upper pipe fitting 3 and the lower mounting plate 4.1 of the lower pipe fitting 4 respectively. Four connecting screws 5 are arranged in the structure, and the four connecting screws 5 are arranged to resist the overturning effect of the cantilever truss cabinet under the uneven effect. In addition, the upper pipe fitting 3 is connected with the truss main body 101 through bolts, the lower pipe fitting 4 is connected with the supporting device through bolts, and the bolt connection structure is convenient to assemble and disassemble.
The truss mechanism comprises two integral truss main bodies 101 with the same structure, the two truss main bodies 101 are symmetrically arranged along the extending direction of the capping beam, and the height of the truss main bodies 101 linearly decreases along the extending direction from one end close to the upright post 100 to the outer end. Specifically, the two truss bodies 101 are fastened together by a connecting plate and a connecting bolt.
The truss body 101 has an outermost end height of 40% ± 10% of the bearing point area near the column 100. That is, the truss main body 101 has a trapezoid shape in its entire outer shape, and the height of one end thereof near the column 100 is highest, and the height of the truss main body 101 is smaller and smaller in the outward extending direction. Specifically, a section of the truss body 101 near the upright post has a rectangular structure.
The truss main body 101 comprises two truss assemblies 1 which are symmetrically arranged, and the two truss assemblies 1 are connected into an integral structure through a parallel support 2. As shown in fig. 6, specifically, the parallel connection bracket 2 includes at least two "X" type pull rods 2.1, where the two "X" type pull rods 2.1 are disposed at two ends of the truss main body 101 in the length direction, so as to implement end connection between the upper chord member 1.1 and the lower chord member 1.2; a plurality of upper straight pull rods 2.2 are arranged between the upper chords 1.1 of the two symmetrically arranged truss assemblies 1 along the length direction, a plurality of lower straight pull rods 2.3 are arranged between the lower chords 1.2, and diagonal pull rods 2.4 are arranged between the adjacent lower straight pull rods 2.3 along diagonal angles.
The spacing between the two truss assemblies 1 is determined by the specification of the upright posts 100, the net spacing is generally not more than the width of the upright posts plus 20cm, the width is overlarge, the span of an operation platform is increased, and the economy is lower; too small a width, the inclination caused by the construction error of the column 100 causes difficulty in installing the truss.
As shown in fig. 4, specifically, the truss assembly 1 includes an upper chord member 1.1 and a lower chord member 1.2, a plurality of upper nodes 1.3 are uniformly arranged on the upper chord member 1.1, a plurality of lower nodes 1.4 corresponding to the upper nodes 1.3 one by one are arranged on the lower chord member 1.2, and a straight web member 1.5 is arranged between each upper node 1.3 and the corresponding lower node 1.4. The center of each two adjacent upper nodes 1.3 is provided with a center node 1.6, i.e. the pitch of the connecting nodes on the upper chord 1.1 is half that of the connecting nodes on the lower chord 1.2, so as to reduce the bending action of the upper chord 1.1.
A diagonal web member 1.7 distributed in an eight shape is arranged between each central node 1.6 and two adjacent lower nodes 1.4, specifically, the upper end of each diagonal web member 1.7 is connected at the middle node 1.6 of the upper chord member 1.1, the lower end of each diagonal web member 1.7 is connected at the position of the lower node 1.4 corresponding to the middle node 1.6, the correspondence here means that two lower nodes 1.4 are correspondingly arranged under each middle node 1.6, and the two lower nodes 1.4 are located at two sides of the projection position of the middle node 1.6 on the lower chord member 1.2, namely, the middle node 1.6 and the two lower nodes 1.4 form a triangle structure.
The upper chord member 1.1 and the lower chord member 1.2 adopt a lattice system formed by double-groove steel, the supporting range is increased due to the effect, and a reinforced steel plate is welded into a box section; the web members are connected with the chord members by node plates; the straight web member 1.5 and the inclined web member 1.7 also adopt double-groove steel sections. The sections of the double channel steels are arranged oppositely according to the limbs and the backs, and the lacing plates 14 are arranged between the double channel steels to reduce the slenderness ratio of the separated limbs and ensure the stability of the components.
The bearing capacity of the truss system rod pieces is stably controlled. On the one hand, the calculated out-of-plane length of the rod is usually 2 times the calculated in-plane length, so the rod is unsuitable for box section steel (the unit price is higher than that of channel steel); on the other hand, the construction unit usually stores a large number of 10# channels (loss residual values of the temporary construction structure) having a length of about 2 to 3 m. The lattice type rod piece not only can utilize the residual value of the turnover waste material, but also can realize the bidirectional stability requirement of the design requirement, and really realizes energy-saving and green construction.
The overall length of the truss main body 101 is not smaller than "capping beam length+construction work width" and the height is about 2.4m to 3.2m. This value is the economic height, i.e., within this range, the cantilever truss body 101 has the lowest steel usage. When the height is too small, the chord lever arm is reduced, the chord lever axial force is increased, and the steel consumption is increased; when the height is too large, the chord members are limited by the structural requirement, the slenderness ratio is not too low, the nominal stress is small, the number of the web members is increased sharply after the height is increased, and the steel consumption rises immediately.
The top of truss mechanism is equipped with the operation platform that is used for the construction bent cap. The working platform comprises a plurality of I-steel 6, and the I-steel 6 is arranged at a position corresponding to the upper node 1.3 on the upper chord 1.1. Specifically, in this embodiment, each i-steel 6 is connected and fixed with the upper chord member 1.1 by bolts, so that the lifting and the dismounting are convenient. Of course, in other embodiments, direct welding may be used for fixation.
One I-steel 6 in the positions corresponding to the upright post 100 in the plurality of I-steels 6 is interrupted, a fixed block 7 is arranged between one end of the interrupted I-steel 6 close to the upright post 100 and the upper chord member 1.1, the fixed block 7 is specifically a triangular steel plate, and an inclined strut 8 is arranged between the end part of the interrupted I-steel 6, which is away from the upright post 100, and the lower chord member 1.2.
Square timber 9 is arranged between the lower chord member 1.2 and the upright post 100, meanwhile, a temporary split screw 15 is arranged between the two lower chord members 1.2, a double-spliced groove steel loading member is arranged on the lower chord member 1.2, and the split screw 15 is matched between the double-spliced groove steel members and fastened at two ends of the split screw through nuts.
So that a stable spacing is maintained between the bottom chord 1.2 and the column 100 to ensure stability of the overall truss mechanism.
In general, the height of the cover beam is larger and is not smaller than 2.0m, so that the problem of high-altitude operation enclosure during the cover beam reinforcement and the template support is solved, the width of the operation platforms at two sides is not smaller than 1.5m, and otherwise, the heights of the two side enclosures are required to be heightened. Not only is a temporary construction facility increased, but also the construction of the main body structure of the bent cap is not facilitated.
The supporting device comprises four supporting columns 10, the upper ends of the four supporting columns 10 are connected with the elevation adjusting device, the lower ends of the supporting columns 10 are connected with a foundation bearing platform through steel pipe supports 11 with the diameter smaller than that of the supporting columns 10, and a plurality of stiffening plates are arranged on the outer side walls of the steel pipe supports 11 along the circumferential direction; a scissor brace 12 and a horizontal connecting rod 13 are arranged between two support columns 10 arranged along the length direction of the truss mechanism.
The supporting device is positioned at the edge of the foundation platform to reduce the cantilever length of the bracket system and ensure the supporting foundation to be a permanent structure. The supporting device adopts an assembled steel pipe, the steel pipe is connected with the steel pipe by adopting a flange, and the length of a single section of steel pipe is determined according to the actual condition of engineering; the specification of the supporting steel pipe is determined according to the calculation design, the diameter is not smaller than 530mm, and the wall thickness is not smaller than 10mm. The steel pipe support 11 is arranged at the bottom of the supporting device and serves as a transition joint so as to adapt to the defect that the flange part of the supporting steel pipe is positioned outside the range of the bearing platform. Because the distance between the edge of the city expressway Gao Jiali column and the edge of the foundation pile cap is too small, the arrangement of the supporting upright column 100 along the bridge to the inter-column support is considered, the center line of the steel pipe needs to be out of the range of the edge of the upright column, and when the distance between the upright column 100 and the edge of the pile cap is smaller than the radius of the flange of the steel pipe, part of the flange is in a suspended state out of the foundation pile cap. The transition joint adopts a steel pipe with smaller specification (ensuring that the whole body of the transition joint is positioned in the foundation pile cap), and a stiffening steel plate is arranged in the region of the transition joint and the flange plate. The bottom of the supporting device is connected with the embedded steel plate of the foundation pile cap by adopting a welding seam.
As shown in fig. 7, a construction state diagram of the present invention is shown, wherein a template mechanism and a wedge-shaped steel module 110 are further arranged above the working platform, and are used for constructing a wedge-shaped surface of the lower end surface of the capping beam.
The invention also provides a construction method of the long-span cantilever truss type bent cap bracket system, which specifically comprises the following steps:
a. truss manufacturing, namely, blanking according to a design drawing, and welding to manufacture a truss assembly 1.1 with a double-spliced structure; welding the two truss assemblies 1.1 through parallel brackets 2 to form a truss main body 101;
b. after the truss main body 101 is manufactured, flaw detection is carried out on welding quality of the truss main body 101 so as to determine whether the truss main body 101 meets design requirements;
c. symmetrically assembling the two truss main bodies 101 which are qualified in detection through connecting bolts to form a complete truss mechanism;
d. the supporting device is installed, a steel pipe support 11, a support column 10 and an elevation adjusting device are installed from bottom to top on the basis of a foundation bearing platform, and all the components are connected through flanges; the corresponding support columns 10 are fixedly connected by using a scissor support 12;
e. hoisting the assembled integral truss mechanism to the top of a supporting device, connecting the truss mechanism with an elevation adjusting device, adding square timber 9 between a lower chord member 1.2 of the truss mechanism and a stand column 100, and simultaneously arranging temporary counter-pulling screws 15 between the two lower chord members 1.2, wherein the counter-pulling screws 15 and the lower chord members 1.2 are provided with double-spelling steel as loading fastening members so as to keep the truss mechanism stable;
f. i-steel 6 is arranged at each connecting node position on the top of the truss main body 101 and the upper chord 1.1, and a plurality of I-steel 6 are sequentially arranged to form an operation platform; the I-steel 6 is in threaded connection with the truss main body 11; the distribution beam of the operation platform is not suitable for welding with the cantilever truss, on one hand, the single hoisting weight of the upper bracket system is increased, and on the other hand, the operation radius of the crane is increased by the cantilevers at the two ends of the distribution beam; in addition, if field welding is adopted, repeated mounting and dismounting work amounts are too large, so that the distributing beam and the cantilever truss are connected through bolts;
g. after the construction is completed, the whole truss mechanism is controlled to descend by a certain height by utilizing the elevation adjusting device, so that the truss mechanism is separated from a cover beam after the construction is completed, the split bolts between the split screws 15 and the two truss main bodies 101 are disassembled, and then the two truss main bodies 101 are hoisted and evacuated in sequence; and finally, removing the supporting device. The two truss main bodies 101 are separated and lifted, so that the lifting weight is reduced by half, and the working platform can not be dismounted during the dismounting process.
The foregoing description of the preferred embodiments of the present invention is provided for illustration and is not to be construed as limiting the claims. The present invention is not limited to the above embodiments, and the specific structure thereof is allowed to be changed, and all changes made within the scope of the invention as independently claimed are within the scope of the invention.
Claims (8)
1. The utility model provides a large span cantilever truss-like bent cap support system which characterized in that: the device comprises a supporting device vertically connected to a foundation pile cap, wherein a truss mechanism of a cantilever structure is arranged at the top of the supporting device, an elevation adjusting device for adjusting the height of the truss mechanism is arranged between the supporting device and the truss mechanism, and an operation platform for constructing a capping beam is arranged at the top of the truss mechanism;
the truss mechanism comprises two integral truss main bodies (101) with the same structure, the two truss main bodies (101) are symmetrically arranged along the extending direction of the capping beam, and the heights of the truss main bodies (101) linearly decrease along the extending direction from one end close to the upright post (100) to the outer end; the truss main body (101) comprises two truss assemblies (1) which are symmetrically arranged, and the two truss assemblies (1) are connected into an integral structure through a parallel support (2);
the truss assembly (1) comprises an upper chord member (1.1) and a lower chord member (1.2), wherein a plurality of upper nodes (1.3) are uniformly arranged on the upper chord member (1.1), a plurality of lower nodes (1.4) which are in one-to-one correspondence with the upper nodes (1.3) are arranged on the lower chord member (1.2), and a straight web member (1.5) is arranged between each upper node (1.3) and the corresponding lower node (1.4); the central position of each two adjacent upper nodes (1.3) is provided with a central node (1.6), and an inclined web member (1.7) distributed in an eight shape is arranged between each central node (1.6) and two adjacent lower nodes (1.4);
the parallel connection bracket (2) comprises at least two X-shaped pull rods (2.1), wherein the two X-shaped pull rods (2.1) are arranged at two ends of the truss main body (101) in the length direction, so that the end faces of the upper chord member (1.1) and the lower chord member (1.2) are connected; a plurality of upper straight pull rods (2.2) are arranged between the upper chords (1.1) of the two symmetrically arranged truss assemblies (1) along the length direction, a plurality of lower straight pull rods (2.3) are arranged between the lower chords (1.2), and diagonal pull rods (2.4) are arranged between the adjacent lower straight pull rods (2.3) along diagonal angles; the working platform comprises a plurality of I-steel (6), and the I-steel (6) is arranged at the position corresponding to the upper node (1.3) on the upper chord member (1.1); one I-steel (6) of the I-steel (6) at the position corresponding to the upright post (100) is interrupted, a fixed block (7) is arranged between one end of the interrupted I-steel (6) close to the upright post (100) and the upper chord (1.1), and an inclined strut (8) is arranged between the end part of the interrupted I-steel (6) deviating from the upright post (100) and the lower chord (1.2); square timber (9) is arranged between the lower chord member (1.2) and the upright post (100).
2. The large span cantilever truss type bent cap bracket system according to claim 1, wherein: the upper chord member (1.1), the lower chord member (1.2), the straight web members (1.5) and the inclined web members (1.7) comprise double-layer channel steel, and the double-layer channel steel is connected through a lacing plate (14).
3. The large span cantilever truss type bent cap bracket system according to claim 1, wherein: the elevation adjusting device comprises an upper pipe fitting (3) and a lower pipe fitting (4), wherein fine stone concrete is poured into the upper pipe fitting (3) and is sealed by adopting a steel plate; the upper pipe fitting (3) is inserted and assembled in the inner cavity of the lower pipe fitting (4), and machine-made sand is poured between the bottom of the upper pipe fitting (3) and the bottom of the inner cavity of the lower pipe fitting (4); the side wall of the lower pipe fitting (4) is provided with a sand outlet, and a blocking bolt is connected in the sand outlet.
4. A long span cantilever truss type bent cap frame system according to claim 3, wherein: the difference value between the diameter of the inner hole of the lower pipe fitting (4) and the outer diameter of the upper pipe fitting (3) is 5-10mm.
5. The large span cantilever truss type bent cap bracket system according to claim 4, wherein: a plurality of connecting screws (5) are uniformly arranged between the upper pipe fitting (3) and the lower pipe fitting (4) along the circumferential direction, and two ends of the connecting screws (5) are correspondingly connected to an upper mounting plate (3.1) of the upper pipe fitting (3) and a lower mounting plate (4.1) of the lower pipe fitting (4) respectively; the upper pipe fitting (3) is connected with the truss main body (101) through bolts, and the lower pipe fitting (4) is connected with the supporting device through bolts.
6. The long span cantilever truss type bent cap frame system according to any one of claims 3 to 5, wherein: the bottom of the inner cavity of the lower pipe fitting (4) is connected with an I-shaped stiffening plate.
7. The large span cantilever truss type bent cap bracket system according to claim 1, wherein: the supporting device comprises four supporting columns (10), the upper ends of the four supporting columns (10) are connected with the elevation adjusting device, the lower ends of the supporting columns (10) are connected with a foundation bearing platform through steel pipe supports (11) with diameters smaller than those of the supporting columns (10), and a plurality of stiffening plates are arranged on the outer side walls of the steel pipe supports (11) along the circumferential direction; a scissor brace (12) is arranged between two support columns (10) arranged along the length direction of the truss mechanism.
8. A construction method based on the long-span cantilever truss type bent cap bracket system of claim 7, which is characterized by comprising the following steps:
a. truss manufacturing, namely manufacturing a truss assembly (1) with a double-spliced structure by welding according to a design drawing and blanking; welding the two truss components to form a truss main body (101) through a parallel support (2);
b. after the truss main body (101) is manufactured, flaw detection is carried out on welding quality of the truss main body (101) so as to determine whether the truss main body (101) meets design requirements;
c. symmetrically assembling the two truss main bodies (101) which are qualified in detection through connecting bolts to form a complete truss mechanism;
d. the supporting device is installed, a steel pipe support (11), a support column (10) and an elevation adjusting device are installed from bottom to top on the basis of a foundation bearing platform, and all the components are connected through flanges; the corresponding support columns (10) are fixedly connected by using a scissor brace (12);
e. hoisting the assembled integral truss mechanism to the top of the supporting device, connecting the truss mechanism with the elevation adjusting device, adding square timber (9) between a lower chord (1.2) of the truss mechanism and the upright post (100), and simultaneously arranging temporary opposite-pulling screws (15) between the two lower chords (1.2) so as to keep the truss mechanism stable;
f. i-steel (6) is arranged at each connecting node position on the top of the truss main body (101) and the upper chord (1.1), and a plurality of I-steel (6) are sequentially arranged to form an operation platform;
g. after construction is completed, the whole truss mechanism is controlled to descend by a certain height by utilizing the elevation adjusting device, so that the truss mechanism is separated from a cover beam after construction is completed, splicing bolts between a counter-pulling screw rod (15) and two truss main bodies (101) are sequentially detached, and then the two truss main bodies (101) are sequentially lifted and evacuated; and finally, removing the supporting device.
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| CN110735478B (en) * | 2019-10-28 | 2021-04-30 | 盐城工学院 | Assembled concrete truss building structure |
| CN111620244B (en) * | 2020-06-05 | 2021-08-10 | 招商局重庆交通科研设计院有限公司 | Bridge floor crane |
| CN113235450B (en) * | 2021-06-10 | 2022-05-10 | 天津城建大学 | Support for quickly and accurately positioning truss nodes of truss bridge |
| CN114108825B (en) * | 2021-11-30 | 2023-06-30 | 中建钢构工程有限公司 | Large-span single-span conversion truss installation method |
| CN114922095B (en) * | 2022-03-18 | 2024-02-13 | 中国人民解放军陆军工程大学 | Assembled light high-strength fiber composite construction support |
| CN115418951B (en) * | 2022-05-31 | 2024-06-04 | 宁波市政工程建设集团股份有限公司 | Assembled cantilever bent cap bracket and construction method thereof |
| CN116219892B (en) * | 2022-12-31 | 2024-01-12 | 兰州交通大学 | Intelligent adjustable assembled high-speed railway mound top support construction hydraulic support platform |
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