Self-balanced arch foot joint and design method of circular steel pipe concrete arch and prestressed concrete beam

Abstract

The present application relates to the technical field of building construction, and discloses a self-balancing arch foot joint of a circular steel pipe concrete arch and a prestressed steel concrete beam and a design method, which comprises a circular steel pipe concrete arch, a lower chord steel beam, a pressure bearing ring plate, a prestressed cable, an overhead arch supporting column and a concrete block, the end of the lower chord steel beam is connected with the middle part of the overhead arch supporting column, the pressure bearing ring plate is connected with the end of the circular steel pipe concrete arch, the end of the circular steel pipe concrete arch is arranged to be inclined relative to the circular steel pipe concrete arch and the overhead arch supporting column, the pressure bearing ring plate is installed at the connection of the lower chord steel beam and the overhead arch supporting column, and the prestressed cable penetrates through the lower chord steel beam and is connected with the overhead arch supporting column. The present application has no influence on the buildings on both sides, can provide greater bearing capacity, is suitable for large-span overhead arches, can make the stress be uniformly transmitted, the prestressed cable penetrates through the connection, and the force transmission is direct.

Description

Self-balancing arch foot joints and design methods for circular steel-concrete composite arches and prestressed reinforced concrete beams Technical Field

[0001] This invention relates to the technical field of building construction, and in particular to self-balancing arch foot nodes and design methods for circular steel tube concrete arches and prestressed steel-concrete beams. Background Technology

[0002] Arch structures have the advantages of reasonable stress distribution and beautiful shape, and can achieve large-span spatial crossing. The most common type is the large-span arch bridge in bridge engineering, and it is also widely used in stadiums, building corridors and other architectural engineering fields.

[0003] The force transmission path of an arch is that the vertical load is converted into the axial pressure of the arch, thereby making full use of the bearing capacity of the arch section. The axial force is eventually transmitted to the arch foot to form an outward thrust. A strong thrust balancing structure is needed to prevent the arch foot from sliding and to constrain the displacement of the arch foot. Once the arch foot undergoes horizontal displacement, the force state of the arch will change from axial compression to curved beam, and the internal force will change from axial pressure to bending moment. The structural system will no longer be valid.

[0004] Arch foot nodes are the intersection points of the arch and the thrust-balanced structure, bearing significant internal forces. Existing arch foot node forms include: 1) Ground-supported arches with concrete foundations at the arch foot. A typical ground-supported arch is an arch bridge, where the arch foot rests on the ground, and the arch foot is an embedded concrete foundation; 2) A steel-structured elevated arch where the arch foot is the buildings at both ends. A typical elevated arch is a steel-structured arched corridor between concrete buildings, suitable for situations where the buildings on both sides can withstand the arch thrust. The construction involves embedding steel frames within the building's walls and columns, with the arch foot being the intersection of the steel arch and the embedded steel frames, and the node type being a steel node; 3) A steel-structured elevated arch employing a self-balancing system, typically a steel-structured arched corridor between buildings. When the arch thrust has a significant impact on the buildings on both sides, a self-balancing system is formed between the lower chord steel beam and the arch, thus preventing thrust on the buildings. The arch foot is the intersection of the steel arch and the lower chord steel beam, and the node type is a steel node.

[0005] Ground-supported arches are primarily used in bridges, but are less common in building construction due to the requirement that the arch feet must be grounded. Arches with the arch feet supported by two adjacent buildings have two limitations: the arch section is made of steel, resulting in relatively low cross-sectional load-bearing capacity; and the adjacent buildings must be sufficiently rigid to provide thrust. Therefore, this type is suitable for small-span, lightweight arches. Ground-supported arches using a lower chord steel beam to balance the arch thrust have the advantage of self-balancing and not generating thrust on the buildings. However, they are limited by: the arch section is made of steel, resulting in relatively low cross-sectional load-bearing capacity; and the lower chord is a steel beam, which has relatively low material strength, limiting the thrust provided by the lower chord. Therefore, this type is also suitable for small-span, lightweight arches. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and to provide a self-balancing arch foot node for circular steel tube concrete arches and prestressed steel-concrete beams.

[0007] Another objective of this invention is to provide a design method for self-balancing arch foot nodes of circular steel tube concrete arches and prestressed steel-concrete beams.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] The self-balancing arch foot node of the circular steel tube concrete arch and prestressed steel-concrete beam includes a circular steel tube concrete arch, a lower chord steel beam, a pressure-bearing ring plate, prestressing cables, an elevated arch support column, and concrete blocks. The end of the lower chord steel beam is connected to the middle of the elevated arch support column, the pressure-bearing ring plate is connected to the end of the circular steel tube concrete arch, the end of the circular steel tube concrete arch is inclined relative to the circular steel tube concrete arch and the elevated arch support column, the pressure-bearing ring plate is installed at the connection between the lower chord steel beam and the elevated arch support column, and the prestressing cables pass through the lower chord steel beam and are connected to the elevated arch support column.

[0010] A better option is that the inner cavity of the overhead arch support column is provided with a support column web, and the steel beam web of the lower chord steel beam is located on top of the support column web.

[0011] A better option is that the lower chord steel beam includes a steel beam end plate and a steel beam web. The steel beam web is connected to the support column of the overhead arch. The steel beam webs are connected to each other through the steel beam end plate. The prestressed cable passes through the steel beam end plate. The prestressed cable is located between two adjacent steel beam webs. The circular steel tube concrete arch is inclinedly connected to the steel beam web.

[0012] A better option is that the wall thickness of the circular steel tube in the circular steel tube concrete arch is in the range of [20, 50], in mm.

[0013] Another objective of this invention is achieved through the following technical solution:

[0014] The design method for self-balancing arch foot nodes of circular steel-concrete composite arches and prestressed steel-concrete composite beams includes the following steps:

[0015] S1. The self-balancing arch foot nodes of the circular steel tube concrete arch and prestressed steel-concrete beam include the circular steel tube concrete arch, the lower chord steel beam, the pressure ring plate, the prestressed cable, the overhead arch support column and the concrete block.

[0016] Axial force on a circular steel-concrete composite arch The structure is broken down into the axial force borne by the circular steel tubes of the circular steel tube concrete arch. The axial force borne by the concrete inside the circular steel tube of the circular steel tube concrete arch. The axial force borne by the circular steel tubes of the circular steel tube concrete arch. The axial force transmitted through the web of the steel beam in the circular steel-concrete composite arch via the lower chord steel beam is divided into two parts. The axial force transmitted from the circular steel tube concrete arch to the concrete block through the bearing ring plate. Based on the compressive strength of the concrete inside the circular steel tube concrete arch. The diameter of the circular steel pipe in the circular steel pipe concrete arch The axial force transmitted from the circular steel tube concrete arch to the concrete block through the bearing ring plate The width of the bearing ring plate is obtained. The axial force borne by the concrete inside the circular steel tube of the circular steel tube concrete arch. The normal stress of the concrete inside the circular steel tube concrete arch was obtained. This causes the normal stress in the concrete inside the circular steel tube concrete arch to increase. Less than or equal to the compressive strength of the concrete inside the circular steel tube concrete arch ;

[0017] S2, based on the tensile force borne by the lower chord steel beam. Horizontal force at arch foot node and the tension of the prestressed cable The number of prestressed cables was obtained. Based on the tensile force borne by the lower chord steel beam With the number of prestressed cables The bearing capacity of the web of the lower chord steel beam within the support column of the arch is verified to determine the steel beam web that meets the standard.

[0018] S3, based on the width of the bearing ring plate Normal stress in concrete within a circular steel tube concrete arch Number of prestressed cables The steel beam web conforms to the standard, and the arch foot joints are constructed according to the construction method, including addressing the horizontal compressive stress in the concrete of the arch foot joints in the construction method. Calculations were performed to obtain the self-balancing arch foot nodes of the circular steel tube concrete arch and the prestressed steel concrete beam;

[0019] S4. Perform three-dimensional compression verification on the self-balancing arch foot joints of the circular steel tube concrete arch and prestressed steel-concrete beam: based on the compressive stress of the concrete inside the circular steel tube of the circular steel tube concrete arch. Horizontal compressive stress in concrete at arch foot joints during construction The maximum compressive principal stress value of the arch foot node was obtained. When the maximum compressive principal stress value of the arch foot node Less than or equal to the compressive strength of the concrete inside the circular steel tube concrete arch At that time, the design of the self-balancing arch foot nodes of the circular steel tube concrete arch and the prestressed steel concrete beam was completed.

[0020] A better option is that, in step S1, the width of the pressure ring plate... The calculation formula is:

[0021] ;

[0022]

[0023] ;

[0024] ;

[0025] in, This refers to the compressive strength of the concrete inside the circular steel-tube concrete arch. The axial force of the circular steel tube concrete arch is transmitted to the concrete block through the bearing ring plate. Let be the diameter of the circular steel tube in the circular steel tube concrete arch. The axial force borne by the circular steel tube in the circular steel tube concrete arch. This refers to the axial force transmitted through the web of the lower chord steel beam in a circular steel-concrete composite arch. The horizontal force borne by the web of the lower chord steel beam through the weld seam. The angle between the circular steel-concrete arch and the horizontal plane. The length of the circular steel-concrete arch extending into the arch foot node. For the shear strength of the steel in a circular steel-concrete composite arch, The thickness of the web of the lower chord steel beam is given.

[0026] A better option is that, in step S1, the normal stress of the concrete inside the circular steel tube concrete arch... The calculation formula is:

[0027]

[0028] in, This refers to the axial force borne by the concrete inside the circular steel tube of a circular steel-concrete composite arch. Let be the diameter of the circular steel tube in the circular steel tube concrete arch. The thickness of the circular steel tube in the circular steel tube concrete arch. This refers to the compressive strength of the concrete inside the circular steel tube concrete arch.

[0029] A better option is the number of prestressed cables in step S2. The calculation formula is:

[0030] ;

[0031] ;

[0032] ;

[0033] ;

[0034] in, For the tension of the prestressed cable, This represents the cross-sectional area of ​​a single prestressed cable. The tension control stress of the prestressed cable, For the axial force of the circular steel-concrete composite arch, The angle between the circular steel-concrete arch and the horizontal plane. The tensile force borne by the lower chord steel beam. This represents the steel area of ​​the web plate in the lower chord steel beam. To control the stress level of steel design, The strength of the steel used in the circular steel-concrete arch.

[0035] A better option is that, in step S2, the formula for verifying the bearing capacity of the web of the lower chord steel beam within the support column of the arch is:

[0036] ;

[0037] in, The tensile force borne by the lower chord steel beam. The number of prestressed cables, The height of the web of the steel beam. The thickness of the web of the steel beam. The steel strength of the circular steel-concrete composite arch;

[0038] When the web thickness of the steel beam is greater than the steel strength of the circular steel tube concrete arch, reduce the tensile force borne by the lower chord steel beam. And increase the number of prestressed cables .

[0039] A better option, in step S3, is the construction method as follows:

[0040] S41. Hoist the circular steel pipe concrete arch into place, insert the web of the lower chord steel beam, and weld the circular steel pipe concrete arch, the web of the lower chord steel beam, and the support column of the arch into a whole.

[0041] S42. Pour concrete into the lower chord steel beam in step S41 and leave holes for prestressed cables, then pass the prestressed cables through the holes.

[0042] S43. After the concrete in the lower chord steel beam reaches the required strength, the prestressed tendons are tensioned, and concrete is filled into the joint area and solidified into concrete blocks. After completion, the arch foot joint is formed.

[0043] S44. Install the arch components section by section into the arch foot nodes in step S43, and close them to form an arch frame;

[0044] S45. Construction is carried out on each floor slab on the arch frame in step S44, and the arch frame bears the load of each floor slab.

[0045] A better option is to reduce the horizontal compressive stress in the concrete at the arch foot joint in step S43. The calculation formula is:

[0046] ;

[0047] in, The cross-sectional area of ​​the three webs extending into the node region; This represents the concrete area of ​​the node region. For the tension of the prestressed cable, The height of the lower chord steel beam. The thickness of the web of the lower chord steel beam is given. The flange thickness of the lower chord steel beam is given. The width of the lower chord steel beam. This refers to the elastic modulus of concrete. This is the elastic modulus of steel.

[0048] A better option is, in step S4, the maximum compressive principal stress value of the arch foot node. The calculation method is as follows:

[0049] ;

[0050] ;

[0051] ;

[0052] in, This refers to the horizontal compressive stress in the concrete at the arch foot joint. The angle between the circular steel-concrete arch and the horizontal plane. This refers to the compressive strength of the concrete inside the circular steel-tube concrete arch. This refers to the compressive stress in the concrete inside the circular steel tube of a circular steel-concrete composite arch. This refers to the compressive stress in the steel material of a circular steel-concrete composite arch. This represents the normal stress in the concrete inside the circular steel-tube concrete arch. The term "compressive stress" refers to the compressive stress in the steel and the normal stress in the concrete within a circular steel-concrete composite arch under ideal conditions. The design should aim to achieve this ideal state. , , All three are equal.

[0053] The present invention has the following advantages and beneficial effects compared with the prior art:

[0054] This invention utilizes a self-balancing arch foot node and design method for circular steel tube concrete arches and prestressed steel-concrete beams, which has no impact on the buildings on both sides, provides greater load-bearing capacity, is suitable for large-span elevated arches, ensures uniform force transmission, and features through-connection of prestressed concrete beams for direct force transmission. Attached Figure Description

[0055] Figure 1 is a cross-sectional view of the self-balancing arch foot node of the circular steel tube concrete arch and prestressed steel concrete beam of the present invention.

[0056] Figure 2 is a schematic diagram of the self-balancing arch foot node of the circular steel tube concrete arch and the prestressed steel concrete beam of the present invention.

[0057] Figure 3 is a front view of the self-balancing arch foot node of the circular steel tube concrete arch and prestressed steel concrete beam of the present invention.

[0058] Figure 4 is a cross-sectional view of Figure 3 along the AA direction;

[0059] Figure 5 is a cross-sectional view of Figure 3 in the BB direction;

[0060] Figure 6 is a cross-sectional view of Figure 3 in the CC direction;

[0061] Figure 7 is a cross-sectional view of Figure 3 in the DD direction;

[0062] The components in the attached diagram are labeled as follows: 1-Circular steel tube concrete arch; 2-Lower chord steel beam; 201-Steel beam end plate; 202-Steel beam web plate; 3-Bearing ring plate; 4-Prestressed cable; 5-Aerial arch support column; 501-Support column wall plate; 502-Support column bearing plate; 503-Support column stiffening plate; 504-Hole; 6-Concrete block. Detailed Implementation

[0063] The invention's objective will be further described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described in detail here, but the implementation of the invention is not limited to the following embodiments.

[0064] As shown in Figure 1-6, the self-balancing arch foot node of the circular steel tube concrete arch and prestressed reinforced concrete beam includes a circular steel tube concrete arch 1, a lower chord steel beam 2, a bearing ring plate 3, six prestressing cables 4, an elevated arch support column 5, and a concrete block 6. An opening 504 is provided on the right side of the elevated arch support column 5. The left end of the lower chord steel beam 2 is inserted into the elevated arch support column 5 through the opening 504, and the opening 504 is fully penetrated welded. The end of the circular steel tube concrete arch 1 is welded to the bearing ring plate 3. The bearing ring plate 3 is installed at the connection between the lower chord steel beam 2 and the elevated arch support column 5. The end of the circular steel tube concrete arch 1 intersects at an incline relative to both the lower chord steel beam 2 and the elevated arch support column 5. The prestressing cables 4 pass through the lower chord steel beam 2 and the connection between the circular steel tube concrete arch 1 and the elevated arch support column 5. The end of the prestressing cables 4 is fixedly connected to the outside of the elevated arch support column 5. The circular steel tube concrete arch 1, the lower chord steel beam 2, the bearing ring plate 3, the prestressed cable 4, and the overhead arch support column 5 form a node area. Concrete is poured into the node area to form concrete blocks 6, so that the circular steel tube concrete arch 1 is subjected to triaxial compression.

[0065] The outer frame of the circular steel tube concrete arch 1 is a circular steel tube, into which high-grade concrete is poured to form the structure, serving as the load-bearing structure for the floor slab. The circular steel tube concrete arch 1 has a composite section, in which the concrete blocks 6 are circumferentially constrained by the circular steel tubes, exhibiting good ductility and contributing to the axial load-bearing capacity through joint stress. The diameter of the circular steel tube in the circular steel tube concrete arch 1 is D, the wall thickness of the steel plate of the bearing ring plate 3 is t, and it is filled with high-grade plain concrete. The axial force that the circular steel tube concrete arch 1 can withstand is... The lower chord steel beam 2 has a cross-sectional dimension of H×B×tw×tf (i.e., height H×width B×web thickness tw×flange thickness tf). Three steel beam webs 202 divide the beam into two cavities; these cavities are filled with concrete, forming a steel-concrete composite beam. One side of the bearing ring plate 3 is welded to the circular steel tube of the circular steel-concrete arch 1, while the other side of the bearing ring plate 3 has a large contact surface with the concrete block 6. This reduces the concentrated compressive stress on the circular steel tube wall to a value that the concrete block 6 can withstand, achieving smooth stress distribution. The function of the bearing ring plate 3 is to increase the contact surface between the circular steel tube of the circular steel-concrete arch 1 and the concrete block 6, thereby reducing the local pressure to the compressive bearing capacity of the concrete block 6. The width of the pressure ring plate 3 is The thickness of the pressure ring plate 3 is The cross-sectional area of ​​prestressed cable 4 is... The prestress applied to prestressed cable 4 is The supporting column 5 of the elevated arch serves a supporting function.

[0066] The lower chord steel beam 2 comprises two steel beam end plates 201 and three steel beam web plates 202. The ends of the three steel beam web plates 202 are inserted into the inner cavity of the supporting column 5 of the elevated arch and welded to the inner wall. The three steel beam web plates 202 are connected by the two steel beam end plates 201, forming two cavities. Concrete is filled between these cavities, and holes for prestressed cables 4 are pre-drilled. Six prestressed cables 4 are arranged in two rows of three columns, passing through the steel beam end plates 201 and the pre-drilled holes for the prestressed cables 4. The ends of the circular steel tube concrete arch 1 are provided with grooves for inclined connection to the steel beam web plates 202. The upper and lower flanges of the lower chord steel beam 2 do not extend into the node area, maintaining the node area connection. The three steel beam web plates 202 are welded to the holes 504 of the supporting column 5 of the elevated arch, with weld lengths of [missing information]. , , .

[0067] As shown in Figure 2-6, the supporting column 5 of the elevated arch includes four supporting column wall panels 501, three supporting column bearing plates 502, and one supporting column stiffening plate 503. The four supporting column wall panels 501 form the outer frame of the elevated arch supporting column 5. The supporting column stiffening plate 503 is welded to the turning point of the outer frame, and the three supporting column bearing plates 502 are welded to the inner cavity of the outer frame. The three supporting column bearing plates 502 are arranged in parallel, and the web plates 202 of the three steel beams of the lower chord steel beam 2 are welded to the three supporting column bearing plates 502 respectively.

[0068] The design method for the self-balancing arch foot joint of the circular steel-concrete composite arch and the prestressed steel-concrete composite beam includes the following steps:

[0069] S1, the self-balancing arch foot node of the circular steel tube concrete arch 1 and the prestressed steel-concrete beam includes the circular steel tube concrete arch 1, the lower chord steel beam 2, the pressure ring plate 3, the prestressed cable 4, the overhead arch support column 5, and the concrete block 6.

[0070] Axial force on the circular steel tube concrete arch 1 The structure is broken down into the axial force borne by the circular steel pipe of the circular steel pipe concrete arch 1. The axial force borne by the concrete inside the circular steel tube of the circular steel tube concrete arch 1 The axial force borne by the circular steel pipe of the circular steel pipe concrete arch 1. The axial force transmitted by the steel beam web 202 through the lower chord steel beam 2 of the circular steel tube concrete arch 1 is divided into two parts. The axial force transmitted from the circular steel tube concrete arch 1 to the concrete block 6 through the bearing ring plate 3 Based on the compressive strength of the concrete inside the circular steel tube concrete arch 1 The diameter of the circular steel pipe in the circular steel pipe concrete arch 1 The axial force transmitted from the circular steel tube concrete arch 1 to the concrete block 6 through the bearing ring plate 3 The width of the bearing ring plate 3 is obtained. The axial force borne by the concrete inside the circular steel tube of the circular steel tube concrete arch 1 The normal stress of the concrete inside the circular steel tube concrete arch 1 was obtained. This causes the normal stress in the concrete within the circular steel tube concrete arch 1 to... Less than or equal to the compressive strength of the concrete inside the circular steel tube concrete arch 1 ;

[0071] S2, based on the tensile force borne by the lower chord steel beam 2 Horizontal force at arch foot node and the tension of prestressed cable 4 The number of prestressed cables 4 was obtained. According to the tensile force borne by the lower chord steel beam 2 With the number of prestressed cables 4 The bearing capacity of the web 202 of the lower chord steel beam 2 within the support column 5 of the overhead arch is verified to determine the standard-compliant web 202 of the steel beam.

[0072] S3, based on the width of the bearing ring plate 3 Normal stress of concrete within the circular steel tube concrete arch 1 4. Number of prestressed cables The standard steel beam web 202 and the arch foot joints are constructed according to the construction method, and the horizontal compressive stress of the concrete in the arch foot joints in the construction method is addressed. Calculations were performed to obtain the self-balancing arch foot nodes of the circular steel tube concrete arch 1 and the prestressed steel concrete beam;

[0073] S4. Perform three-dimensional compression verification on the self-balancing arch foot joints of the circular steel tube concrete arch 1 and the prestressed steel-concrete beam: based on the compressive stress of the concrete inside the circular steel tube of the circular steel tube concrete arch 1. Horizontal compressive stress in concrete at arch foot joints during construction The maximum compressive principal stress value of the arch foot node was obtained. When the maximum compressive principal stress value of the arch foot node Less than or equal to the compressive strength of the concrete inside the circular steel tube concrete arch 1 At that time, the design of the self-balancing arch foot nodes of the circular steel tube concrete arch 1 and the prestressed steel concrete beam was completed.

[0074] Axial force of the circular steel tube concrete arch 1 The allocation is analyzed as follows:

[0075] Axial force in the circular steel tube concrete arch 1 The axial force is transmitted to the arch foot node. It is divided into two parts, one part being the axial force. The other part of the axial force is transmitted along the circular steel pipe inside the circular steel pipe concrete arch 1. The force is transmitted along the concrete within the circular steel-tube concrete arch 1. Among these forces, the axial force... It is divided into two parts, one part being the axial force. A portion of the axial force is transmitted through the web 202 of the steel beam welded to the circular steel tube of the circular steel tube concrete arch 1. The pressure is transferred to the concrete block 6 through the bearing ring plate 3 connected to the end of the circular steel tube concrete arch 1.

[0076] 1. Axial force transmitted to the web 202 of the steel beam The shear strength of the weld can be calculated using the following formula:

[0077]

[0078]

[0079] The horizontal force borne by the web 202 of the lower chord steel beam 2 through the weld is... The angle between the circular steel-concrete arch 1 and the horizontal plane is [angle]. The length of the circular steel-concrete arch 1 extending into the arch foot node. The shear strength of the steel in the circular steel-concrete arch 1 is given. The thickness of the web 202 of the lower chord steel beam 2 is given.

[0080] 2. Axial force The pressure is transferred to the concrete block 6 through the bearing ring plate 3 connected to the end of the circular steel tube concrete arch 1. The wall thickness t of the circular steel tube of the circular steel tube concrete arch 1 is usually between 20 and 50 mm. If the circular steel tube is in direct contact with the concrete block 6, localized high stress will be generated. This localized high stress exceeds the local bearing capacity of the concrete block 6, resulting in localized splitting and crushing of the concrete block 6. The width of the bearing ring plate 3... The calculation formula is:

[0081]

[0082]

[0083] in, The compressive strength of the concrete inside the circular steel-tube concrete arch 1. The axial force of the circular steel tube concrete arch 1 is transmitted to the concrete block 6 through the bearing ring plate 3. Let be the diameter of the circular steel pipe in the circular steel pipe concrete arch 1. The axial force borne by the circular steel tube of the circular steel tube concrete arch 1. The axial force transmitted by the circular steel tube concrete arch 1 through the web 202 of the lower chord steel beam 2.

[0084] 3. Axial force in the last part Concrete transfer along the inside of the circular steel tube concrete arch 1 Normal stress of concrete inside the circular steel tube concrete arch 1 The calculation formula is:

[0085]

[0086] in, The axial force borne by the concrete inside the circular steel tube of the circular steel tube concrete arch 1. Let be the diameter of the circular steel pipe in the circular steel pipe concrete arch 1. The wall thickness of the circular steel tube in the circular steel tube concrete arch 1 is [missing information]. The compressive strength of the concrete inside the circular steel-tube concrete arch 1. The axial force of the circular steel-concrete arch 1 is... Axial force and axial force sum.

[0087] For the number of prestressed cables 4 The analysis of the web 202 of the lower chord steel beam 2 within the support column 5 of the overhead arch is as follows:

[0088] 1. Number of prestressed cables (4) The calculation formula is:

[0089] ;

[0090] ;

[0091] ;

[0092] ;

[0093] in, For the tension of prestressed cable 4, This is the cross-sectional area of ​​a single prestressed cable 4. The tension control stress for prestressed cable 4, The axial force of the circular steel-concrete arch 1 is... The angle between the circular steel-concrete arch 1 and the horizontal plane is [angle]. The tensile force borne by the lower chord steel beam 2 This refers to the steel area of ​​the web plate 202 in the lower chord steel beam 2. To control the stress level of steel design, The strength of the steel in the circular steel tube concrete arch 1.

[0094] 2. The formula for verifying the bearing capacity of the web 202 of the lower chord steel beam 2 within the support column 5 of the arch is as follows:

[0095] ;

[0096] in, The tensile force borne by the lower chord steel beam 2 The number of prestressed cables 4, The height of the web of the steel beam is 202. The thickness of the web of the steel beam is 202. The steel strength of the circular steel tube concrete arch 1;

[0097] When the thickness of the web 202 of the steel beam is greater than the steel strength of the circular steel tube concrete arch 1, the tensile force borne by the lower chord steel beam 2 should be reduced. And increase the number of prestressed cables 4 .

[0098] The construction method for the self-balancing arch foot joint of the circular steel-concrete composite arch 1 and the prestressed steel-concrete composite beam includes the following steps:

[0099] S41. Hoist the circular steel pipe concrete arch 1 into place, insert the web 202 of the lower chord steel beam 2 into the support column 5 of the arch, and then weld the circular steel pipe concrete arch 1, the web 202 of the lower chord steel beam 2 and the support column 5 of the arch into a whole. There is no stress in the joint area during this step.

[0100] S42. Pour concrete into the lower chord steel beam 2 in step S41 and leave a hole for the prestressed cable 4. Pass the prestressed cable 4 through the hole. There is no stress in the node area in this step.

[0101] S43. After the concrete in the lower chord steel beam 2 reaches the required strength, the prestressed cable 4 is tensioned, and concrete is filled into the joint area and solidified into concrete blocks 6, forming the arch foot joint. The tension applied to the prestressed cable 4... This stress is transformed into horizontal pressure on the arch foot node, which is jointly borne by the web 202 of the lower chord steel beam 2 extending into the node area and the concrete block 6 within the node area. The horizontal compressive stress of the concrete in the arch foot node is... The calculation formula is:

[0102] ;

[0103] in, The cross-sectional area of ​​the web 202 of the three steel beams extending into the node area; This represents the concrete area of ​​the node region. For the tension of prestressed cable 4, The height of the lower chord steel beam 2 is... The thickness of the web 202 of the lower chord steel beam 2 is given. The flange thickness of the lower chord steel beam 2 is... The width of the lower chord steel beam 2 is... This refers to the elastic modulus of concrete. This is the elastic modulus of steel.

[0104] The axial compressive deformation of the lower chord steel beam 2 at this time causes relative displacement between the arch feet. This relative displacement can be used as a monitoring reference. The calculation formula is:

[0105] ;

[0106] in, L represents the tension in the prestressed cable 4, and L is the span of the lower chord steel beam 2. The strain of the lower chord steel beam 2 is... This refers to the elastic modulus of concrete. This is the elastic modulus of steel.

[0107] S44. Install the arch components section by section into the arch foot nodes in step S43, and then close them to form an integral arch frame.

[0108] S45. Construction proceeds on the floor slabs of each level on the integral arch frame from step S44, with the arch frame bearing the load of each floor slab. After the integral arch frame is installed and formed, it possesses overall rigidity and gradually bears the load in step S5, until the axial force at the arch foot reaches the design value. At this point, the axial forces of the circular steel-concrete arch 1, the prestressed cable 4, and the lower chord steel beam 2 are balanced at the arch foot node, meaning the arch foot is in equilibrium. The axial force borne by the arch foot on the circular steel-concrete arch 1... The angle with the horizontal ground is The tension of prestressed cable 4 Along the horizontal ground direction. During the loading process of the arch frame, the axial force of the circular steel tube concrete arch 1 gradually increases, and the resulting horizontal thrust is balanced by the prestress in the lower chord steel beam 2. The critical equilibrium point is when the two cancel each other out.

[0109] ;

[0110] At this time, the tension in prestressed cable 4 remains... constant.

[0111] When the arch foot thrust continues to increase and exceeds the applied prestress, the lower chord steel beam 2 begins to be under tension, and the equilibrium state is as follows:

[0112] ;

[0113] in, The tension in the lower chord steel beam 2 is the tensile force.

[0114] Based on the above construction completion, a three-dimensional compressive stress verification was performed on the self-balancing arch foot joints of the circular steel-concrete arch 1 and the prestressed steel-concrete beam. The stress was found to be no greater than the strength design value. The maximum compressive principal stress value of the arch foot joint was determined. The calculation method is as follows:

[0115] ;

[0116] ;

[0117] ;

[0118] in, This refers to the horizontal compressive stress in the concrete at the arch foot joint. The angle between the circular steel-concrete arch 1 and the horizontal plane is [angle]. The compressive strength of the concrete inside the circular steel-tube concrete arch 1. The compressive stress in the concrete inside the circular steel tube of the circular steel tube concrete arch 1 is given. The compressive stress of the steel in the circular steel-concrete arch 1. The normal stress is the concrete inside the circular steel-tube concrete arch 1. The term "compressive stress" refers to the combined compressive stress in the steel and the normal stress in the concrete within the circular steel-concrete composite arch 1 under ideal conditions. The design should aim to achieve this ideal state. , , All three are equal.

[0119] The corresponding maximum force direction angle is:

[0120] ;

[0121] When the maximum compressive principal stress value of the arch foot node Less than or equal to the compressive bearing capacity of the concrete inside the circular steel tube concrete arch 1 At that time, the design of the self-balancing arch foot nodes of the circular steel tube concrete arch 1 and the prestressed steel concrete beam was completed.

[0122] The beneficial effects of the arch foot node in this embodiment are as follows: the prestressed cable 4 and the lower chord steel beam 2 are used to balance the arch thrust, so there is no impact on the buildings on both sides. The arch section of the circular steel tube concrete arch 1 can provide greater load-bearing capacity and is suitable for large-span overhead arches; the end of the circular steel tube concrete arch 1 is equipped with a bearing ring plate 3 to realize the force transition between the circular steel tube and the concrete block 6, so that the force is evenly transmitted; the circular steel tube of the circular steel tube concrete arch 1, the steel beam web 202 of the lower chord steel beam 2, and the prestressed cable 4 are connected through the node area, and the force is transmitted directly.

[0123] The above-described specific embodiments are preferred embodiments of the present invention and are not intended to limit the present invention. Any other changes or equivalent substitutions made without departing from the technical solution of the present invention are included within the protection scope of the present invention.

Claims

1. A self-balancing arch foot joint for a circular steel-concrete composite arch and a prestressed steel-concrete composite beam, characterized in that: The system comprises a circular steel tube concrete arch, a lower chord steel beam, a pressure-bearing ring plate, prestressed cables, an elevated arch support column, and concrete blocks. The end of the lower chord steel beam is connected to the middle of the elevated arch support column. The pressure-bearing ring plate is connected to the end of the circular steel tube concrete arch. The end of the circular steel tube concrete arch is inclined relative to the circular steel tube concrete arch and the elevated arch support column. The pressure-bearing ring plate is installed at the connection between the lower chord steel beam and the elevated arch support column. The prestressed cables pass through the lower chord steel beam and are connected to the elevated arch support column. The concrete blocks are formed by pouring concrete into the joint area composed of the circular steel tube concrete arch, lower chord steel beam, pressure-bearing ring plate, prestressed cables, and elevated arch support column. The elevated arch support column has a support column web inside its cavity. The lower chord steel beam includes a steel beam end plate and a steel beam web, with the steel beam web of the lower chord steel beam located at the top of the support column web. The axial force on the circular steel tube concrete arch... The structure is broken down into the axial force borne by the circular steel tubes of the circular steel tube concrete arch. The axial force borne by the concrete inside the circular steel tube of the circular steel tube concrete arch. The axial force borne by the circular steel tubes of the circular steel tube concrete arch. The axial force transmitted through the web of the steel beam in the circular steel-concrete composite arch via the lower chord steel beam is divided into two parts. The axial force transmitted from the circular steel tube concrete arch to the concrete block through the bearing ring plate. 。 2. The self-balancing arch foot node of the circular steel tube concrete arch and prestressed steel-concrete beam according to claim 1, characterized in that: The lower chord steel beam includes a steel beam end plate and a steel beam web. The steel beam web is connected to the support column of the overhead arch. The steel beam webs are connected to each other through the steel beam end plate. The prestressed cable passes through the steel beam end plate and is located between two adjacent steel beam webs. The circular steel tube concrete arch is inclinedly connected to the steel beam web.

3. The self-balancing arch foot node of the circular steel tube concrete arch and prestressed steel-concrete beam according to claim 1, characterized in that: The wall thickness of the circular steel tube in the circular steel tube concrete arch ranges from [20, 50], in mm.

4. A design method for self-balancing arch foot nodes of circular steel-concrete composite arches and prestressed reinforced concrete beams, characterized in that, The self-balancing arch foot node for the circular steel tube concrete arch and prestressed steel-concrete beam as described in claim 1 includes the following steps: S1. The self-balancing arch foot node for the circular steel tube concrete arch and prestressed steel-concrete beam includes a circular steel tube concrete arch, a lower chord steel beam, a bearing ring plate, prestressing cables, an overhead arch support column, and concrete blocks; the axial force on the circular steel tube concrete arch... The structure is broken down into the axial force borne by the circular steel tubes of the circular steel tube concrete arch. The axial force borne by the concrete inside the circular steel tube of the circular steel tube concrete arch. The axial force borne by the circular steel tubes of the circular steel tube concrete arch. The axial force transmitted through the web of the steel beam in the circular steel-concrete composite arch via the lower chord steel beam is divided into two parts. The axial force transmitted from the circular steel tube concrete arch to the concrete block through the bearing ring plate. Based on the compressive strength of the concrete inside the circular steel tube concrete arch. The diameter of the circular steel pipe in the circular steel pipe concrete arch The axial force transmitted from the circular steel tube concrete arch to the concrete block through the bearing ring plate The width of the bearing ring plate is obtained. The axial force borne by the concrete inside the circular steel tube of the circular steel tube concrete arch. The normal stress of the concrete inside the circular steel tube concrete arch was obtained. This causes the normal stress in the concrete inside the circular steel tube concrete arch to increase. Less than or equal to the compressive strength of the concrete inside the circular steel tube concrete arch S2, based on the tensile force borne by the lower chord steel beam. Horizontal force at arch foot node and the tension of the prestressed cable The number of prestressed cables was obtained. Based on the tensile force borne by the lower chord steel beam With the number of prestressed cables The bearing capacity of the web of the lower chord steel beam within the support column of the arch is verified to determine the steel beam web that meets the standard; S3, based on the width of the bearing ring plate. Normal stress in concrete within a circular steel tube concrete arch Number of prestressed cables The steel beam web conforms to the standard, and the arch foot joints are constructed according to the construction method, including addressing the horizontal compressive stress in the concrete of the arch foot joints in the construction method. Calculations were performed to obtain the self-balancing arch foot nodes of the circular steel-concrete composite arch and the prestressed steel-concrete composite beam; the horizontal compressive stress of the concrete in the arch foot nodes was also calculated. The calculation formula is: ;in, The cross-sectional area of ​​the three webs extending into the node region; This represents the concrete area of ​​the node region. For the tension of the prestressed cable, The height of the lower chord steel beam. The thickness of the web of the lower chord steel beam is given. The flange thickness of the lower chord steel beam is given. The width of the lower chord steel beam. This refers to the elastic modulus of concrete. S4. Three-dimensional compressive stress calculation of the self-balancing arch foot joints of the circular steel tube concrete arch and prestressed steel-concrete composite beam: based on the compressive stress of the concrete inside the circular steel tube of the circular steel tube concrete arch. Horizontal compressive stress in concrete at arch foot joints during construction The maximum compressive principal stress value of the arch foot node was obtained. When the maximum compressive principal stress value of the arch foot node Less than or equal to the compressive strength of the concrete inside the circular steel tube concrete arch At that time, the design of the self-balancing arch foot nodes of the circular steel-concrete composite arch and the prestressed steel-concrete composite beam was completed; the maximum compressive principal stress value of the arch foot node was determined. The calculation method is as follows: ； ； ;in, This refers to the horizontal compressive stress in the concrete at the arch foot joint. The angle between the circular steel-concrete arch and the horizontal plane. This refers to the compressive strength of the concrete inside the circular steel-tube concrete arch. This refers to the compressive stress in the concrete inside the circular steel tube of a circular steel-concrete composite arch. This refers to the compressive stress in the steel material of a circular steel-concrete composite arch. This represents the normal stress in the concrete inside the circular steel-tube concrete arch. The term "compressive stress" refers to the compressive stress in the steel and the normal stress in the concrete within a circular steel-concrete composite arch under ideal conditions. The design should aim to achieve this ideal state. 、 、 All three are equal.

5. The design method for the self-balancing arch foot node of the circular steel tube concrete arch and prestressed steel concrete beam according to claim 4, characterized in that, In step S1, the width of the pressure-bearing ring plate The calculation formula is: ； ； ； ;in, This refers to the compressive strength of the concrete inside the circular steel-tube concrete arch. The axial force of the circular steel tube concrete arch is transmitted to the concrete block through the bearing ring plate. Let be the diameter of the circular steel tube in the circular steel tube concrete arch. The axial force borne by the circular steel tube in the circular steel tube concrete arch. This refers to the axial force transmitted through the web of the lower chord steel beam in a circular steel-concrete composite arch. The horizontal force borne by the web of the lower chord steel beam through the weld seam. The angle between the circular steel-concrete arch and the horizontal plane. The length of the circular steel-concrete arch extending into the arch foot node. For the shear strength of the steel in a circular steel-concrete composite arch, The thickness of the web of the lower chord steel beam is given.

6. The design method for the self-balancing arch foot node of the circular steel tube concrete arch and prestressed steel-concrete beam according to claim 4, characterized in that, In step S1, the normal stress of the concrete inside the circular steel tube concrete arch... The calculation formula is: ;in, This refers to the axial force borne by the concrete inside the circular steel tube of a circular steel-concrete composite arch. Let be the diameter of the circular steel tube in the circular steel tube concrete arch. The thickness of the circular steel tube in the circular steel tube concrete arch. This refers to the compressive strength of the concrete inside the circular steel tube concrete arch.

7. The design method for the self-balancing arch foot node of the circular steel tube concrete arch and prestressed steel concrete beam according to claim 4, characterized in that, In step S2, the number of prestressed cables The calculation formula is: ； ； ； ;in, For the tension of the prestressed cable, This represents the cross-sectional area of ​​a single prestressed cable. The tension control stress of the prestressed cable, For the axial force of the circular steel-concrete composite arch, The angle between the circular steel-concrete arch and the horizontal plane. The tensile force borne by the lower chord steel beam. This represents the steel area of ​​the web plate in the lower chord steel beam. To control the stress level of steel design, The strength of the steel used in the circular steel-concrete arch.

8. The design method for the self-balancing arch foot node of the circular steel tube concrete arch and prestressed steel concrete beam according to claim 4, characterized in that, In step S2, the formula for verifying the bearing capacity of the web of the lower chord steel beam within the support column of the arch is as follows: ;in, The tensile force borne by the lower chord steel beam. The number of prestressed cables, The height of the web of the steel beam. The thickness of the web of the steel beam. The steel strength of the circular steel-concrete composite arch is considered; when the web thickness of the steel beam is greater than the steel strength of the circular steel-concrete composite arch, the tensile force borne by the lower chord steel beam is reduced. And increase the number of prestressed cables 。 9. The design method for the self-balancing arch foot node of the circular steel tube concrete arch and prestressed steel concrete beam according to claim 4, characterized in that, In step S3, the construction method is as follows: S41, hoist the circular steel pipe concrete arch into place, insert the web of the lower chord steel beam, and weld the circular steel pipe concrete arch, the web of the lower chord steel beam, and the support column of the arch into a whole; S42, pour concrete into the lower chord steel beam in step S41 and leave holes for prestressed tendons, and pass the prestressed tendons through the holes; S43. After the concrete in the lower chord steel beam reaches the required strength, the prestressed tendons are tensioned, and concrete is filled into the joint area and solidified into concrete blocks, forming an arch foot joint. S44. The arch members are installed section by section into the arch foot joint in step S43 and then closed to form an arch frame. S45. The floor slabs on the arch frame in step S44 are constructed, and the arch frame bears the load of each floor slab.

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