CN113174828A - Bridge tower upper cross beam and design method thereof - Google Patents

Bridge tower upper cross beam and design method thereof Download PDF

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CN113174828A
CN113174828A CN202110475735.XA CN202110475735A CN113174828A CN 113174828 A CN113174828 A CN 113174828A CN 202110475735 A CN202110475735 A CN 202110475735A CN 113174828 A CN113174828 A CN 113174828A
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top plate
tower
upper cross
upper beam
bridge tower
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CN113174828B (en
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肖海珠
邱峰
周伟平
谢兰博
黄玲
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China Railway Major Bridge Reconnaissance and Design Institute Co Ltd
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China Railway Major Bridge Reconnaissance and Design Institute Co Ltd
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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
    • E01D11/00—Suspension or cable-stayed bridges
    • 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
    • E01D19/00—Structural or constructional details of bridges
    • E01D19/14—Towers; Anchors ; Connection of cables to bridge parts; Saddle supports
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/10—Geometric CAD
    • G06F30/17—Mechanical parametric or variational design
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces

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Abstract

The application relates to a bridge tower upper beam and a design method thereof, which comprises the following steps: the two ends of the top plate are used for being connected to the tower column; the two webs are used for being connected to the tower column, arranged below the top plate and connected with the top plate, and integrally surround to form a groove-shaped concrete member; and the plurality of prestressed tendons are used for being connected to the tower column, one part of the prestressed tendons penetrate through the top plate, the other part of the prestressed tendons penetrate through the web plate, and the plurality of prestressed tendons and the groove-shaped concrete member form a groove-shaped prestressed concrete structure. Under the condition of meeting the design requirement of the upper cross beam, a bottom plate in the traditional box-type concrete is cancelled, and the structure of a horizontal clapboard is cancelled at the joint of the upper cross beam and the tower column, so that the situation that the horizontal clapboard divides the space in the tower column is avoided, and the arrangement positions of the stay cables and the steel anchor beams conflict with the horizontal clapboard; the design method firstly preliminarily determines the section parameters and the prestress configuration, can avoid repeated trial calculation of large-scale finite element analysis, and improves the efficiency.

Description

Bridge tower upper cross beam and design method thereof
Technical Field
The application relates to the field of bridge engineering, in particular to an upper beam of a bridge tower and a design method thereof.
Background
At present, an upper cross beam of a concrete tower column of a cable-stayed bridge or a suspension bridge generally adopts a box-shaped section, and the upper cross beam of the box-shaped section comprises a top plate, a top plate and a web plate. The upper beam of the tower column is connected with the tower column, and besides the alignment of the web plate of the upper beam and the tower wall, a horizontal clapboard is arranged at the joint of the tower column and the upper beam and positioned in the tower column to meet the requirements of transverse force transfer and rigidity transition.
In some related technologies, for cable-stayed bridges, horizontal partition plates are correspondingly arranged at the top plate of an upper cross beam to divide the space in a tower column, so that difficulty is brought to arrangement of a stay cable anchoring structural steel anchor beam in a large-span cable-stayed bridge, and the arrangement space is limited. The solutions commonly used are:
(1) moving the upper beam upwards or downwards to avoid the stay cable anchoring area; however, in this method, the cross beam may not be in the optimal stress position in the height direction due to the movement of the cross beam, and the transverse stress performance of the tower column is affected.
(2) Adjusting the vertical spacing of the stay cables and increasing the vertical height of the tower column so as to meet the space requirement of steel anchor beam arrangement; however, this method results in uneven cable surface arrangement, and increases the size and cost of the tower.
(3) Locally adjusting the steel anchor beam into a form of anchoring a concrete tooth block; however, the method sacrifices the uniformity of the stay cable anchoring form on the tower column, the construction is inconvenient due to the addition of one anchoring type, and the stress of the tower wall of the tooth block anchor is more unfavorable compared with a steel anchor beam.
In some related technologies, for a suspension bridge, a main cable saddle is arranged on the tower top, an upper beam is usually arranged close to the tower top, a stay cable is not arranged in a tower column for anchoring, and the arrangement of an upper beam top plate corresponding to a horizontal partition plate in the tower column does not have the problem of limited arrangement space of the stay cable, but the existence of the partition plate also increases the complexity of construction.
In some related technologies, a cable-stayed bridge and a suspension bridge are combined for a cable-stayed-suspension cooperative system bridge, an upper cross beam is arranged close to the tower top, a main saddle is arranged on the tower top of a tower column, and a stay cable is anchored in the tower column. Meanwhile, the defects caused by the arrangement of the partition plates in the cable-stayed bridge and the suspension bridge exist.
In some related technologies, verification calculation is often performed in a finite element analysis manner in the design of the upper cross beam, but a problem of repeated trial calculation of large-scale finite element analysis exists, and efficiency is low.
Disclosure of Invention
The embodiment of the application provides an upper cross beam of a bridge tower and a design method thereof, which aim to solve the problem that in the related art, a horizontal partition plate partitions the space in a tower column, so that the arrangement positions of a stay cable and a steel anchor beam conflict with the horizontal partition plate.
In a first aspect, there is provided a bridge tower upper beam comprising:
the two ends of the top plate are used for being connected to the tower column;
the two webs are used for being connected to a tower column, the two webs are arranged below the top plate, and the two webs are connected with the top plate and integrally surround to form a groove-shaped concrete member;
and the prestressed tendons are used for being connected to the tower column, one part of the prestressed tendons penetrates through the top plate, the other part of the prestressed tendons penetrates through the web plate, and the plurality of prestressed tendons and the groove-shaped concrete member form a groove-shaped prestressed concrete structure.
In some embodiments, both ends of the top plate are provided with first structures for reducing stress concentration;
a second structure for reducing stress concentration is arranged at the joint of the top plate and the web plate;
and the two ends of the web plate are respectively provided with a third structure for reducing stress concentration, one part of the first structure is close to the second structure, and the second structure and the third structure are connected through the part.
In some embodiments, the first structure comprises:
a first chamfered connecting portion provided on a groove wall of the groove-shaped concrete member in a width direction of the top plate and connected to the top plate;
a second chamfer connection part located above the top plate and connected with the top plate; the elevation of the top of the second chamfer connecting part is equal to the elevation of the top of the tower column; the second chamfer connecting parts in the two first structures form a channel with the top plate.
In some embodiments, the third structure comprises:
the third chamfer connecting part is arranged at the bottom of the web plate and is used for being connected with a tower column;
and the fourth chamfer connecting part is positioned on one surface opposite to the two webs, one end of the fourth chamfer connecting part is connected with the third chamfer connecting part, and the other end of the fourth chamfer connecting part vertically extends upwards and is connected with the first chamfer connecting part.
In some embodiments, the second structure includes a fifth chamfered connection on a groove wall of the groove-shaped concrete member, and both ends of the fifth chamfered connection extend along a length direction of the top plate and are connected to the first chamfered connection.
In a second aspect, there is provided a bridge tower comprising:
two towers; and the number of the first and second groups,
a pylon upper cross beam as claimed in any one of claims mounted between two of the pylons.
In a third aspect, a design method for an upper beam of a bridge tower is provided, which comprises the following steps:
acquiring calculation parameters, wherein the calculation parameters comprise the thicknesses of the top plate and the web plate which are determined preliminarily, the width of the top plate, the number of prestressed beams and the diameter of the prestressed beams;
obtaining the beam height according to the calculation parameters, and forming the structural parameters of the upper cross beam with the calculation parameters;
establishing a finite element analysis model of the upper bridge tower beam according to the structural parameters and analyzing whether the upper bridge tower beam meets the design requirements under different working conditions;
if the structural parameters meet the design requirements, taking the structural parameters as design parameters of the upper beam of the bridge tower; otherwise, the calculation parameters are obtained again.
In some embodiments, the design requirements for beam height include bending and torsion resistance requirements, characterized by:
the calculation formula of the beam height size meeting the bending resistance requirement is as follows:
Figure BDA0003047331760000041
the calculation formula of the beam height size meeting the torsion resistance requirement is as follows:
Figure BDA0003047331760000042
wherein N is the axial force to which the upper cross beam is subjected, NpThe additional axial force caused by the prestressing tendons, b the width of the top plate, t1Is the thickness of the top plate, t2Is the thickness of the web, [ sigma ]]Is the allowable stress of the upper beam, T is the torque applied to the upper beam, TmaxTo design the wall thickness at the control points, b is the roof width, [ tau ]]Allowable shear stress of the upper beam, h1Upper beam height h to meet the bending resistance requirement2The upper beam height for meeting the torsion-resistant requirement.
In some embodiments, forming the structural parameters comprises:
optimizing the beam height according to the size of the beam height meeting the bending resistance and torsion resistance;
and optimizing the number and the diameter of the prestressed tendons in the calculation parameters according to the optimized beam height.
In some embodiments, the design requirements include stress of the upper beam, wherein:
the stress expression of the upper beam is as follows:
Figure BDA0003047331760000043
in the formula: n is the axial force of the upper cross beam caused by external force, NpFor additional axial forces caused by the prestressing tendons, M being the bending moment of the upper cross-beam, MpAn additional bending moment induced for the prestressing tendons; [ sigma ]]To accommodate the stress, σ is the stress of the upper beam, WmaxThe bending section modulus is defined as b is the width of the top plate, h is the height of the upper beam, t1Is the thickness of the top plate, t2Is the thickness of the web.
The beneficial effect that technical scheme that this application provided brought includes:
the embodiment of the application provides an upper crossbeam of a bridge tower, two webs are arranged at the bottom of a top plate and are arranged at intervals, the extending direction of the two webs is the same as the length direction of the top plate, the top plate and the two webs surround to form a groove-shaped concrete member, and prestressed bundles are arranged in the top plate and the two webs to form a groove-shaped prestressed concrete structure; under the condition that the stress requirement of an upper cross beam structure is met, a bottom plate in traditional box type concrete is eliminated by the aid of the groove type prestressed concrete structure, and a horizontal partition plate structure is eliminated at the joint of the groove type prestressed concrete structure and a tower column.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is an overall structural schematic diagram of a connection between an upper cross beam and a tower column provided in an embodiment of the present application;
FIG. 2 is a schematic cross-sectional view of an upper cross-beam at A-A according to an embodiment of the present disclosure;
fig. 3 is a schematic cross-sectional view at B-B provided in an embodiment of the present application.
In the figure: 1. a top plate; 2. a web; 3. a second chamfered connecting portion; 4. a fifth chamfered connecting portion; 5. a fourth chamfered connecting portion; 6. a first chamfered connecting portion; 7. a third chamfered connecting portion; 8. a tower column; 9. pre-stressing tendons; 10. the space in the column; 11. a channel.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The embodiment of the application provides an upper cross beam of a bridge tower and a design method thereof, which can solve the problem that the arrangement positions of a stay cable and a steel anchor beam conflict with a horizontal clapboard caused by the division of the space in the tower column by the horizontal clapboard in the related technology.
Referring to fig. 1-3, an upper cross beam of a bridge tower includes a top plate 1, two webs 2 and a plurality of prestressed tendons 9;
the two ends of the top plate 1 are used for being connected to a tower column 8, the two webs 2 are used for being connected to the tower column 8 and arranged below the top plate 1, the two webs 2 are arranged at intervals and are the same as the extending direction of the top plate 1, and the two webs 2 are connected with the top plate 1 and integrally surround to form a groove-shaped concrete member;
the plurality of prestressed tendons 9 are used for being connected to the tower column 8, wherein a part of the prestressed tendons 9 penetrate through the top plate 1 and penetrate along the length direction of the top plate 1; the other part of the prestressed tendons 9 penetrates through the web 2 and penetrates along the extending direction of the web 2, and the top plate 1, the web 2 and the plurality of prestressed tendons 9 penetrating through the web 2 form a groove-shaped prestressed concrete structure.
Through the structure setting above, the cell type structure that two webs 2 and roof 1 formed, in addition set up many prestressing tendons 9 in web 2 and roof 1, make the cell type prestressed concrete structure of entablature for whole formation, the structural force of entablature can satisfy under the king-post 8 to its operation requirement, bottom plate in the traditional box concrete has been cancelled, and also cancel the horizontal baffle that will strengthen traditional box concrete and king-post 8 and be connected, avoid appearing horizontal baffle and cut apart the king-post inner space 10 of king-post 8, and then influence arranging of stayed cable anchor structure steel anchor beam in the large-span cable-stay bridge.
When the upper crossbeam is used, only the prestressed tendons 9 are connected with the tower column 8, then the top plate 1 and the web plate 2 are poured, so that the upper crossbeam and the tower column 8 are integrally formed, the upper crossbeam does not need to move up or down, and the crossbeam is ensured to be at the optimal stress position in the height direction; the vertical distance of the stay cables does not need to be adjusted, the vertical height of the tower column 8 does not need to be increased, and the cable surface arrangement is ensured to be uniform and smooth; and the steel anchor beam does not need to be locally adjusted into a concrete tooth block anchoring mode.
The structural form of the upper cross beam does not influence the arrangement of the steel anchor beam, the reasonability of the arrangement of the stay cables and the uniformity of the anchoring form are guaranteed, the height of the tower column is not additionally increased, and the construction difficulty is reduced.
In addition, the bottom plate is removed, so that the concrete consumption and the tower column scale are reduced, the construction difficulty is reduced, and the construction cost and the construction period are saved.
In some preferred embodiments, to ensure that the stress concentration is reduced and the force is transferred uniformly, the following settings are performed, specifically:
two ends of the top plate 1, which are used for being connected with the tower column 8, are respectively provided with a first structure, and the first structures are connected with the top plate 1 and the tower column 8, so that the stress concentration between the top plate 1 and the tower column 8 is reduced; a second structure is arranged at the joint of the top plate 1 and the web plate 2, and the second structure reduces stress concentration between the top plate 1 and the web plate 2; the both ends that are used for the column 8 to connect on the web 2 are equipped with the third structure respectively, and the third structure is connected with web 2 and column 8, reduces the stress concentration of web 2 and column 8 junction, and partly second structure is close to of first structure to second structure and third structure pass through this part and connect, form complete structure.
As shown in fig. 1 and 2, further, the first structure includes a first chamfered connection 6 and a second chamfered connection 3; the first chamfered connecting portions 6 are provided along the width direction of the top plate 1 and on the groove walls of the groove-shaped concrete members, reinforce the connection of the top plate 1 and the tower column 8, and reduce stress concentration.
Second chamfer connecting portion 3 is located the top of roof 1 to be connected with roof 1, set up along the width direction of roof 1, the chamfer angle of second chamfer connecting portion 3 is greater than the chamfer angle of first chamfer connecting portion 6, and first chamfer connecting portion 6 strengthens roof 1 and column 8's connection from top to bottom with second chamfer connecting portion 3, and reduces stress concentration.
Further, in order to ensure that a main cable saddle steel grid arrangement area of a suspension cable system does not conflict with the prestressed tendons of the top plate of the upper crossbeam and adapt to the height difference between the top plate 1 and the top of the tower column 8 caused by the arrangement of the prestressed tendons, the following settings are carried out:
roof 1 aligns with the wallboard of column 8, and the elevation at the top of second chamfer connecting portion 3 equals with the elevation at the top of column 8 tower, and second chamfer connecting portion 3 in two first structures and roof 1 form passageway 11, and the detectable of each component of fortune dimension stage of being convenient for can be repaiied, makes cable-stay system steel anchor beam arrange not receive the space restriction, does not need the conversion sawtooth piece anchor, and it is clear and definite to pass power, the construction of being convenient for.
As shown in fig. 1 and 2, the second structure further includes a fifth chamfered connecting portion 4 on a groove wall of the groove-type concrete member, and both end top plates of the fifth chamfered connecting portion 4 extend in a length direction and are connected to the first chamfered connecting portion 6.
As shown in fig. 1-3, further, the third structure comprises a third chamfered connecting part 7 and a fourth chamfered connecting part 5, wherein the third chamfered connecting part 7 is horizontally arranged at the bottom of the web 2, is perpendicular to the extending direction of the top plate 1, and is used for connecting with the tower column 8; the fourth chamfered connecting portion 5 is located on the opposite side of the two webs 2, i.e. on the opposite groove wall of the groove-shaped concrete element, one end of which is connected to the third chamfered connecting portion 7 and the other end of which extends vertically upwards to be connected to the first chamfered connecting portion 6.
Through above setting, carry out holistic connection with roof 1 and web 2, roof 1 and column 8, web 2 and column 8, the structure between, better reduction stress concentration.
There is provided a bridge tower comprising: two towers 8, and the above-mentioned upper bridge beam, which is installed between the two towers 8 to integrally form the bridge tower.
When the bridge tower is adopted, the force transmission horizontal partition plate at the bottom of the upper beam is prevented from being arranged in the tower column 8, the reasonability of the arrangement of the stay cables and the uniformity of the anchoring form are ensured, and the height of the tower column cannot be additionally increased; the elimination of the bottom plate reduces the consumption of concrete and the scale of the tower column, reduces the construction difficulty, and saves the construction cost and the construction period.
The upper cross beam meets the use requirement and has certain requirements on the size, so the application also provides a design method of the bridge tower upper cross beam, the size obtained by the groove type prestressed concrete structure meets the use requirement, and the method specifically comprises the following steps:
s1, obtaining calculation parameters, wherein the calculation parameters comprise the thicknesses of the top plate 1 and the web plate 2 which are preliminarily determined, the width of the top plate 1, and the number and the diameter of the prestressed tendons 9; the thickness of the top plate 1 and the web 2 and the width of the top plate 1 are selected according to empirical values, and the reason for the selection according to the empirical values is that in the field, the thickness of the top plate 1 and the web 2 and the width of the top plate 1 are fixed in several types of sizes, and when the roof is used, the roof is only selected from the several types of sizes; drawing up the number and diameter of the prestressed beams 9 to form calculation parameters; wherein;
s2, obtaining the beam height according to the calculation parameters, and forming the structural parameters of the upper cross beam with the calculation parameters;
s3, establishing a finite element analysis model of the upper bridge tower beam according to the structural parameters and analyzing whether the upper bridge tower beam meets the design requirements under different working conditions;
s4, if the structural parameters meet the design requirements, taking the structural parameters as design parameters of the upper beam of the bridge tower, wherein the design parameters are the size actually applied to the bridge tower when the upper beam is poured and constructed, and constructing the bridge tower according to the design parameters; otherwise, the calculation parameters are obtained again.
In the above steps, in step S2, the beam height is obtained according to the calculation parameters, the design requirements that the beam height needs to meet are the bending resistance and the torsion resistance, and the specific expression is obtained through the data in step S1 as follows:
the calculation formula of the beam height size meeting the bending resistance requirement is as follows:
Figure BDA0003047331760000091
the torsion state of the upper cross beam in the working conditions of cross wind, lane unbalance loading and asymmetric cable force on the upstream and downstream sides is deduced from the general theory of the open thin-wall rod piece, and the beam height size calculation formula meeting the torsion resistance requirement is as follows:
Figure BDA0003047331760000092
wherein N is the axial force to which the upper cross beam is subjected, NpThe additional axial force caused by the prestressing tendons 9, b the width of the top plate 1, t1Is the thickness of the top plate 1, t2Is the thickness of the web 2, [ sigma ]]For allowable stress, T is the torque experienced by the upper beam, TmaxTo design the wall thickness at the control point, b is the width of the top plate 1, [ tau ]]Allowable shear stress of the upper beam, h1Upper beam height h to meet the bending resistance requirement2The upper beam height for meeting the torsion-resistant requirement.
Under the action of a certain load working condition, the axial force borne by the upper cross beam is relatively a fixed value N, the borne bending moment M is influenced by the tower column frame effect and has direct influence on the bending rigidity EI of the upper cross beam, and in addition, the configuration of the prestressed beam 9 can cause axial compressive stress N to the upper cross beampAnd an additional bending moment Mp(ii) a And N ispRelated to the distribution area of the prestressed beams 9 and the tension control stress, M is determined by the beam height and section parameters of the upper cross beam, MpAn additional bending moment induced to the tendon 9, which value is related to the tendon-distribution eccentricity e of the tendon 9, i.e. Mp＝NpAnd (x e). When the prestress is configured, M is taken preliminarilyp＝NpAnd x e is-M, and the number and the diameter of the prestressed tendons 9 can be preliminarily determined.
Therefore, when the beam height is calculated by using the formula, each quantity is a known value, and random selection in a large range is not needed to be carried out indiscriminately, so that repeated calculation and calculation quantity are reduced.
In addition, after the beam height is obtained in step S2 and before the structural parameters of the upper cross member are formed, the following steps are performed:
and (3) taking a beam height value which meets torsion resistance and bending resistance, optimizing the obtained beam height to obtain an optimized value, correspondingly optimizing the value of the prestressed beam 9 in the calculation parameters according to the optimized value of the beam height, and then forming the optimized value of the prestressed beam 9 in the calculation parameters, the thicknesses of the top plate 1 and the web plate 2 and the width of the top plate 1 into structural parameters of the upper cross beam according to the optimized value of the beam height.
Step S3, specifically, establishing a full-bridge finite element analysis model according to the proposed upper crossbeam structure size and the configuration of the prestressed beams 9, considering the actual boundary conditions, and applying various load working conditions; and (4) considering various working condition combinations specified by the design specifications, and checking the design requirements of the prestressed concrete of the upper beam under the action of controlling the working condition combinations.
Wherein the design requirements include stress requirements imposed on the upper beam, and the stress expression of the upper beam can be analyzed according to the above:
Figure BDA0003047331760000101
in the formula: n is the axial force of the upper cross beam caused by external force, NpFor the additional axial force caused by the prestressing tendons 9, M is the bending moment of the upper cross-beam, MpAn additional bending moment induced for the prestressing tendons 9; [ sigma ]]To accommodate the stress, σ is the stress of the upper beam, WmaxB is the width of the top plate 1, and h is the flexural section modulusUpper beam height, t1Is the thickness of the top plate 1, t2Is the thickness of the web 2; n is a radical ofpRelated to the distribution area of the prestressed beams 9 and the tension control stress, M is determined by the beam height and section parameters of the upper cross beam, MpAn additional bending moment is induced to the tendon 9, which value is related to the tendon eccentricity e of the tendon 9.
In conclusion, when the design method of the upper cross beam is designed through the steps, the beam height can be calculated by utilizing the principle that the axial force N borne by the upper cross beam is relatively a fixed value under the action of a certain load working condition and an empirical value, and further the section parameter of the upper cross beam can be determined; the pre-calculation is performed on the structure dimensions, thereby reducing the calculation for subsequent finite element analysis.
In the process, the prestressed tendons 9 need to be configured, and only when the number and the diameter of the prestressed tendons 9 are uncertain, the range of value checking is large, but compared with the mode of carrying out finite element checking analysis under the conditions that the thickness, the width and the beam height of the top plate 1 and the web plate 2 are uncertain, the design method utilizes the principle that the axial force N borne by the upper cross beam is relatively a fixed value under the action of a certain load working condition, so that the beam height is determined, the cross section product of the upper cross beam is further determined, the value range of the value checking is reduced, the calculated amount of the checking calculation is reduced, and the calculated amount in the process of carrying out the finite element analysis later is obviously reduced.
The process of determining the section parameters and the prestress configuration is clear, the problem of repeated trial calculation of large-scale finite element analysis can be solved, and the efficiency is improved.
The design of a groove-shaped upper beam of a bridge tower column of a certain cable-stayed suspension cable cooperation system is taken as an example below. With C60 concrete, the requirements for the allowable stress of the header and the allowable shear stress of the header when the header is used with the tower 8 are as follows:
the allowable stress [ σ ] of the upper beam is 20MPa, and the allowable shear stress [ τ ] of the upper beam is 1.75 MPa.
And then according to the allowable stress of the upper cross beam and the required value of the allowable shear stress of the upper cross beam, preliminarily analyzing to obtain a fixed value N-597436 kN, M-720307.06 kN-M and T-16183.97 kN-M of the axial force N exerted on the upper cross beam under the control working condition.
The specification of the primary arrangement 34 beams is 19 phis15.2 of the tendons 9.
Taking t according to the structural requirement1＝1.5m，t2When b is 1.5m and 8m, the result is obtained by substituting the above calculation formula:
beam height meeting bending resistance requirements:
Figure BDA0003047331760000121
beam height to meet torsion resistance requirements:
Figure BDA0003047331760000122
according to the result, the height of the beam is 10m, and the prestressed tendon 9 is optimized to be 40-19 phis15.2; obtaining specific values of the structural parameters: the thickness of the top plate 1 is 1.5m, the width is 8m, the thickness of the web plate 2 is 1.5m, the height of the beam is 10m, the number of the prestressed beams 9 is 40, and the specification is 19 phis15.2。
Establishing a full-bridge structure finite element analysis model according to the obtained structural parameters, considering actual boundary conditions, and applying various load working conditions; considering various working condition combinations specified by design specifications, checking and calculating the design requirement of the prestressed concrete of the upper beam under the action of controlling the working condition combinations to check and calculate the stress of the upper beam, and pressing the whole section of the upper beam;
the minimum value of the compressive stress is 3.01MPa, the maximum value is 18.6MPa and is less than 20MPa, and the strength of the upper cross beam with the size meets the requirement.
In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience in describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present application. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
It is noted that, in the present application, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A bridge tower upper beam, comprising:
the two ends of the top plate (1) are connected to the tower column (8);
two webs (2) for connecting to a tower column (8), wherein the two webs (2) are arranged below the top plate (1), and the two webs (2) are connected with the top plate (1) and integrally surround to form a trough-shaped concrete member;
a plurality of prestressed tendons (9) for connecting to the tower column (8), wherein a part of the prestressed tendons (9) are arranged in the top plate (1) in a penetrating way, another part of the prestressed tendons (9) are arranged in the web plate (2) in a penetrating way, and the plurality of prestressed tendons (9) and the groove-shaped concrete member form a groove-shaped prestressed concrete structure.
2. The upper cross beam of a bridge tower of claim 1, wherein:
two ends of the top plate (1) are provided with first structures for reducing stress concentration;
a second structure for reducing stress concentration is arranged at the joint of the top plate (1) and the web plate (2);
and both ends of the web plate (2) are provided with third structures for reducing stress concentration, one part of the first structure is close to the second structure, and the second structure and the third structure are connected through the part.
3. The bridge tower upper beam of claim 2, wherein the first structure comprises:
a first chamfered connecting portion (6) provided on a groove wall of the groove-shaped concrete member in a width direction of the top plate (1) and connected to the top plate (1);
a second chamfer connection part (3) which is positioned above the top plate (1) and is connected with the top plate (1); the elevation of the top of the second chamfer connecting part (3) is equal to the elevation of the top of the tower column (8); the second chamfer connecting parts (3) in the two first structures form a channel (11) with the top plate (1).
4. The bridge tower upper beam of claim 3, wherein the third structure comprises:
a third chamfered connection (7) provided at the bottom of the web (2) and adapted to be connected to a tower (8);
and the fourth chamfer connecting part (5) is positioned on one surface opposite to the two webs (2), one end of the fourth chamfer connecting part is connected with the third chamfer connecting part (7), and the other end of the fourth chamfer connecting part vertically extends upwards and is connected with the first chamfer connecting part (6).
5. The upper cross beam of a bridge tower of claim 3, wherein: the second structure comprises a fifth chamfer connecting part (4) positioned on the groove wall of the groove-shaped concrete member, wherein two ends of the fifth chamfer connecting part (4) extend along the length direction of the top plate (1) and are connected with the first chamfer connecting part (6).
6. A bridge tower, comprising:
two towers (8); and the number of the first and second groups,
the bridge girder according to any of claims 1 to 5, which is mounted between two of the towers (8).
7. A method of designing an upper beam of a bridge tower as claimed in claim 1, comprising the steps of:
obtaining calculation parameters, wherein the calculation parameters comprise the thicknesses of the top plate (1) and the web plate (2) which are determined preliminarily, the width of the top plate (1), the number of the prestressed tendons (9) and the diameter of the prestressed tendons;
obtaining the beam height according to the calculation parameters, and forming the structural parameters of the upper cross beam with the calculation parameters;
establishing a finite element analysis model of the upper bridge tower beam according to the structural parameters and analyzing whether the upper bridge tower beam meets the design requirements under different working conditions;
if the structural parameters meet the design requirements, taking the structural parameters as design parameters of the upper beam of the bridge tower; otherwise, the calculation parameters are obtained again.
8. The method of claim 7, wherein the design requirements for beam height include bending and torsion resistance requirements, and wherein the method further comprises the steps of:
the calculation formula of the beam height size meeting the bending resistance requirement is as follows:
Figure FDA0003047331750000031
the calculation formula of the beam height size meeting the torsion resistance requirement is as follows:
Figure FDA0003047331750000032
wherein N is the axial force to which the upper cross beam is subjected, NpThe additional axial force caused by the prestressing tendons (9), b the width of the top plate (1), t1Is the thickness, t, of the top plate (1)2Is the thickness of the web (2) [ sigma ]]Is the allowable stress of the upper beam, T is the torque applied to the upper beam, TmaxTo design the wall thickness at the control point, b is the width of the top plate (1) [ τ [)]Allowable shear stress of the upper beam, h1Upper beam height h to meet the bending resistance requirement2The upper beam height for meeting the torsion-resistant requirement.
9. The method of designing an upper beam of a bridge tower of claim 7, wherein forming said structural parameters comprises the steps of:
optimizing the beam height according to the size of the beam height meeting the bending resistance and torsion resistance;
and optimizing the number and the diameter of the prestressed tendons (9) in the calculation parameters according to the optimized beam height.
10. The method of claim 7, wherein the design requirements include upper beam stress, and wherein the method further comprises:
the stress expression of the upper beam is as follows:
Figure FDA0003047331750000033
in the formula: n is the axial force of the upper cross beam caused by external force, NpAdditional axial force caused by the prestressing tendons (9), M being the bending moment of the upper cross-beam, MpAn additional bending moment induced for the prestressing tendons (9); [ sigma ]]To accommodate the stress, σ is the stress of the upper beam, WmaxB is the width of the top plate (1), h is the height of the upper beam, t1Is the thickness, t, of the top plate (1)2Is the thickness of the web (2).
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20090058069A (en) * 2007-12-04 2009-06-09 한양대학교 산학협력단 Bridge supported by a plurality of cable
CN109898423A (en) * 2019-03-22 2019-06-18 中铁大桥勘测设计院集团有限公司 A kind of king-tower lower beam pre-stress stretching method and structure
CN211815595U (en) * 2019-04-03 2020-10-30 中交二公局第一工程有限公司 Lower tower column tension and compression structure for cable tower

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20090058069A (en) * 2007-12-04 2009-06-09 한양대학교 산학협력단 Bridge supported by a plurality of cable
CN109898423A (en) * 2019-03-22 2019-06-18 中铁大桥勘测设计院集团有限公司 A kind of king-tower lower beam pre-stress stretching method and structure
CN211815595U (en) * 2019-04-03 2020-10-30 中交二公局第一工程有限公司 Lower tower column tension and compression structure for cable tower

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