Method for calculating geometric dimension of integral node of steel truss girder

Abstract

The invention discloses a steel truss girder overall node geometric dimension calculation method which comprises the following steps: reading rod system finite element model data, naming node names, calculating an included angle between a chord member and each web member at a node and an included angle between the chord member and a longitudinal x axis, and obtaining section numbers of each chord member and each web member at the node; according to the number of piers of the full bridge, the position of the node and the connection form of the rod pieces, the connection form of node chord member ends is judged; setting node geometric dimension calculation initial parameters; the height H of the end of each chord member in the node on one side of the axis of the chord member is obtained; and calculating the sizes of other parts of the node. Aiming at the problems that the number of steel truss girder nodes is large, the number of size parameters is large, and the design efficiency is low, the invention provides a universal steel truss girder overall node geometric dimension calculation method, and the design efficiency and the design quality are improved. According to the method, fine design of the gusset plate is achieved, the design scheme that the node design result is always the most steel-saving design scheme under the set initial parameter framework is adopted, and the design economy can be guaranteed.

Description

Technical Field

[0001] The invention belongs to the field of bridge engineering design, and in particular relates to a method for calculating geometric dimensions of integral nodes of a steel truss beam. Background Art

[0002] The integral node of steel truss is developed on the basis of scattered nodes. It has significant practical economic benefits for factory and construction site installation and has been adopted by the vast majority of steel trusses.

[0003] The steel truss is simulated in the finite element program with a bar system finite element model, and the cross-sectional dimensions of the steel truss members are determined through finite element analysis. The bar system finite element model cannot simulate the overall node where the chord and web of the steel truss meet. The shape of the node plate is usually drawn manually in CAD according to the dimensions of each member at the intersection and in combination with various structural detail requirements, resulting in a variety of node plate shapes for the entire bridge, huge drawing workload, and low design efficiency.

[0004] Therefore, when faced with the design of large quantities of steel truss nodes, a method for calculating the geometric dimensions of the overall nodes of steel trusses is urgently needed to improve the design efficiency. Summary of the invention

[0005] The present invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a method for calculating the geometric dimensions of the integral nodes of a steel truss.

[0006] The technical solution of the present invention is: a method for calculating the geometric dimensions of the integral node of a steel truss, comprising the following steps: A. Read the bar system finite element model data, name the node, calculate the angle between the chord and each web member at the node, and the angle between the chord and the longitudinal x-axis, obtain the section number of each chord and web member at the node, use the web member section number as the index keyword to search the section database and bolt database, and obtain the web member section type, the section width B on both sides of the web member axis, and the distance from the web member joint plate to the joint joint plate L; B. Determine the connection form of the node chord ends based on the number of bridge piers, node locations and rod connection forms; C. Set the initial parameters for node geometry calculation, including the radius of the node plate inverted arc R, the minimum distance from the end of the arc to the joint distToGap, the minimum distance from the end of the arc to the node plate weld distToSeam, the minimum distance from the joint plate at the web splice to the corner of the node plate distToCorner, the dovetail length of the web joint plate tailLength, the distance from the top of the dovetail arc of the web joint plate to the splicing plate distToArc, the minimum clear distance between the web joint plate and other plates tailDist, and whether the ends of the inclined web members at the front and rear sides of the node are the same length isSame; D. Obtain the height H of each chord end in the node on one side of the chord axis, use the chord section number as the index keyword to search the section database, obtain the vertical distance of the section riser below the chord axis and the vertical distance of the section riser above the chord axis, and use them as the height of the node chord end below the chord axis and the height of the node chord end above the chord axis respectively; E. Calculate the size of other parts of the node.

[0007] Furthermore, step E calculates the size of other parts of the node, and the specific process is as follows: E1. If the rod connection is a high-strength bolt connection, execute steps E2 to E8; if the rod connection is a welding connection, execute steps E9 to E11; E2. The radius of the inverted arc R1 between the chord and the web is assigned according to the inverted arc radius R of the node plate. The free edge of the node between the chord and the web is designed to be vertical, and the radius of the inverted arc R2 between the webs is taken to be positive infinity. E3. The total length of the web bar joint plate webPlateL is the sum of the dovetail length of the web bar joint plate tailLength, the distance from the top of the dovetail arc of the web bar joint plate to the splicing plate distToArc, and the distance from the web splicing plate to the seam jointPlateL; E4. When the web section is box-shaped, the half width B1 of the node web end is the sum of the cross-sectional width B on both sides of the web axis and the minimum distance distToCorner between the joint plate and the corner of the node plate at the web joint; when the web section is H-shaped or W-shaped, the half width B1 of the node web end is set according to the cross-sectional width B on both sides of the web axis; E5. Calculate the comparison length L1 and the comparison length L2. The initial length L0 from the node center to the end of the web joint is selected according to the maximum value between the comparison length L1 and the comparison length L2; E6. Check whether the net distance between each web member joint plate and other plates is greater than the minimum net distance tailDist. If the judgment result is true, the node web member end length Lweb is the initial length L0; if the judgment result is false, iterate on the basis of the initial length L0 with a positive length δL1 as the incremental step, Lweb=L0+n*δL1, n is the number of iterations, until the judgment result is true, and record the node web member end length Lweb at this time; E7. All the ends of the web members in the node are calculated according to steps E3 to E6. When isSame is true, the length of all the ends of the web members in the node is the maximum length of the ends of the web members in the front and rear sides of the node; skip this step when isSame is false; E8. Calculate the length of the chord ends of all nodes in the node Lchord; E9. The radius of the inverted arc R1 between the chord and the web is assigned according to the inverted arc radius R of the node plate. The free edge of the node between the chord and the web is designed to be parallel to the axis of the web. The radius of the inverted arc R2 between the webs is assigned according to the inverted arc radius R of the node plate minus 100mm. E10. The half width B1 of all web member ends in the node is set according to the cross-sectional width B on both sides of the web member axis; E11. Calculate the length of the web ends of all nodes in the node, Lweb, and the length of the chord ends of all nodes in the node, Lchord.

[0008] Furthermore, the calculation method of the comparison length L1 in step E5 is specifically as follows: E51. Calculate the projection length La of the sum of the radius R1 of the inverted arc between the chord and the web, the minimum distance distToGap from the end of the arc to the joint, and the height H of the chord end on one side of the chord axis (close to the web side). The projection line is parallel to the chord axis. E52. Calculate the projection length Lb of the half-width B1 of the node web end on the web axis, and the projection line is parallel to the chord axis; E53. The selected length L1 is the sum of the projection length La and the projection length Lb.

[0009] Furthermore, the calculation method of the selected length L2 in step E5 is specifically as follows: E54. Calculate the projection length Ld of the minimum clear distance tailDist between the web joint plate and other plates on the web axis, and the projection line is parallel to the chord axis; E55. Calculate the projection length Le of the cross-section width B on both sides of the web axis on the web axis, with the projection line parallel to the chord axis; E56. The selected length L2 is the sum of the total length of the web plate webPlateL, the projected length Ld and the projected length Le.

[0010] Furthermore, the calculation method of the length Lchord of a node chord end in step E8 is as follows: E81. Calculate the projection length Lg of the node web end length Lweb (the node web end adjacent to the node chord end) on the chord axis, with the projection line perpendicular to the chord axis; E82. Calculate the projection length Lh of the half-width B1 of the node web member end (the node web member end adjacent to the node chord member end) on the chord axis, with the projection line perpendicular to the chord axis; E83. When the connection form of the node chord end is welding connection, the length of the node chord end Lchord is the sum of the projection length Lg, the projection length Lh, the radius of the inverted arc between the chord and the web R1, and the minimum distance distToSeam from the end of the arc to the node plate weld; E84. When the connection form of the node chord end is high-strength bolt connection, the length of the node chord end Lchord is the sum of the projection length Lg, the projection length Lh, the inverted arc radius R1 between the chord and the web, and the minimum distance distToGap from the end of the arc to the joint.

[0011] Furthermore, the calculation method of the length Lchord of a node chord end and the calculation method of the length Lweb of a node web end in step E11 are specifically as follows: E111. The angle between the chord and the web is α, the length L3 is the radius R1 of the rounded arc between the chord and the web divided by the tangent of the angle α / 2, the length L4 is the half-width B1 of the node web end divided by the sine of the angle α, the length L5 is the height H of the chord end on one side of the chord axis (close to the web side) divided by the tangent of the angle α, the length L6 is the half-width B1 of the node web end divided by the tangent of the angle α, and the length L7 is the height H of the chord end on one side of the chord axis (close to the web side) divided by the sine of the angle α; E112. The length of the node chord end Lchord is the sum of the length L3, length L4, length L5, and the minimum distance distToSeam from the end of the arc to the node plate weld; E113. The length of the node web end Lweb is the sum of the length L3, the length L6, the length L7, and the minimum distance distToSeam from the end of the arc to the node plate weld.

[0012] Furthermore, when there are more than one node web member ends, after the current node web member end and the adjacent web member end are inverted according to R2, it is determined whether the distance between the end of the arc and the web member end is greater than the minimum distance distToSeam between the end of the arc and the node plate weld. If the judgment result is true, the node web member end length Lweb is not adjusted; if the judgment result is false, the node web member end length Lweb is iterated with a positive length δL2 as the incremental step, Lnew=Lweb+n*δL2, n is the number of iterations, until the judgment result is true, and the node web member end length Lweb at this time is recorded as Lnew.

[0013] Furthermore, the bar system finite element model data in step A includes unit coordinates, unit sections, unit groups, and pier node groups.

[0014] Furthermore, the rod connection forms in step B include the following two forms: welding connection and high-strength bolt connection.

[0015] Furthermore, in step E, the node web member end length refers to the length from the node center to the end of the web member joint, and the node chord member end length refers to the length from the node center to the end of the chord member joint.

[0016] The beneficial effects of the present invention are as follows: The steel truss integral node targeted by the present invention is the most common node form, and a parametric solution method for each size of the node plate is provided, which is easy to realize the digital design of the node through programming, has strong versatility, high solution efficiency, and can ensure design efficiency.

[0017] The present invention realizes the refined design of the node plate, and the node design result is always the design scheme that saves the most steel within the set initial parameter framework, which can ensure the economy of the design.

[0018] The present invention lays a foundation for node parameterized modeling and helps to efficiently realize the forward design of steel trusses. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a flow chart of the method of the present invention; Figure 2 is a schematic diagram of a node in a bar system finite element model according to an embodiment of the present invention; Figure 3 It is an embodiment of the present invention and a node design result based on the present invention. DETAILED DESCRIPTION

[0020] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and embodiments: like Figures 1 to 3 As shown, a method for calculating the geometric dimensions of the integral node of a steel truss beam comprises the following steps: A. Read the bar system finite element model data, name the node, calculate the angle between the chord and each web member at the node, and the angle between the chord and the longitudinal x-axis, obtain the section number of each chord and web member at the node, use the web member section number as the index keyword to search the section database and bolt database, and obtain the web member section type, the section width B on both sides of the web member axis, and the distance from the web member joint plate to the joint joint plate L; B. Determine the connection form of the node chord ends based on the number of bridge piers, node locations and rod connection forms; C. Set the initial parameters for node geometry calculation, including the radius of the node plate inverted arc R, the minimum distance from the end of the arc to the joint distToGap, the minimum distance from the end of the arc to the node plate weld distToSeam, the minimum distance from the joint plate at the web splice to the corner of the node plate distToCorner, the dovetail length of the web joint plate tailLength, the distance from the top of the dovetail arc of the web joint plate to the splicing plate distToArc, the minimum clear distance between the web joint plate and other plates tailDist, and whether the ends of the inclined web members at the front and rear sides of the node are the same length isSame; D. Obtain the height H of each chord end in the node on one side of the chord axis, use the chord section number as the index keyword to search the section database, obtain the vertical distance of the section riser below the chord axis and the vertical distance of the section riser above the chord axis, and use them as the height of the node chord end below the chord axis and the height of the node chord end above the chord axis respectively; E. Calculate the size of other parts of the node.

[0021] Step E calculates the size of other parts of the node. The specific process is as follows: E1. If the rod connection is a high-strength bolt connection, execute steps E2 to E8; if the rod connection is a welding connection, execute steps E9 to E11; E2. The radius of the inverted arc R1 between the chord and the web is assigned according to the inverted arc radius R of the node plate. The free edge of the node between the chord and the web is designed to be vertical, and the radius of the inverted arc R2 between the webs is taken to be positive infinity. E3. The total length of the web bar joint plate webPlateL is the sum of the dovetail length of the web bar joint plate tailLength, the distance from the top of the dovetail arc of the web bar joint plate to the splicing plate distToArc, and the distance from the web splicing plate to the seam jointPlateL; E4. When the web section is box-shaped, the half width B1 of the node web end is the sum of the cross-sectional width B on both sides of the web axis and the minimum distance distToCorner between the joint plate and the corner of the node plate at the web joint; when the web section is H-shaped or W-shaped, the half width B1 of the node web end is set according to the cross-sectional width B on both sides of the web axis; E5. Calculate the comparison length L1 and the comparison length L2. The initial length L0 from the node center to the end of the web joint is selected according to the maximum value between the comparison length L1 and the comparison length L2; E6. Check whether the net distance between each web member joint plate and other plates is greater than the minimum net distance tailDist. If the judgment result is true, the node web member end length Lweb is the initial length L0; if the judgment result is false, iterate on the basis of the initial length L0 with a positive length δL1 as the incremental step, Lweb=L0+n*δL1, n is the number of iterations, until the judgment result is true, and record the node web member end length Lweb at this time; E7. All the ends of the web members in the node are calculated according to steps E3 to E6. When isSame is true, the length of all the ends of the web members in the node is the maximum length of the ends of the web members in the front and rear sides of the node; skip this step when isSame is false; E8. Calculate the length of the chord ends of all nodes in the node Lchord; E9. The radius of the inverted arc R1 between the chord and the web is assigned according to the inverted arc radius R of the node plate. The free edge of the node between the chord and the web is designed to be parallel to the axis of the web. The radius of the inverted arc R2 between the webs is assigned according to the inverted arc radius R of the node plate minus 100mm. E10. The half width B1 of all web member ends in the node is set according to the cross-sectional width B on both sides of the web member axis; E11. Calculate the length of the web ends of all nodes in the node, Lweb, and the length of the chord ends of all nodes in the node, Lchord.

[0022] The specific process of the calculation method of the comparison length L1 in step E5 is as follows: E51. Calculate the projection length La of the sum of the radius R1 of the inverted arc between the chord and the web, the minimum distance distToGap from the end of the arc to the joint, and the height H of the chord end on one side of the chord axis (close to the web side). The projection line is parallel to the chord axis. E52. Calculate the projection length Lb of the half-width B1 of the node web end on the web axis, and the projection line is parallel to the chord axis; E53. The selected length L1 is the sum of the projection length La and the projection length Lb.

[0023] The specific process of the calculation method of the comparison length L2 in step E5 is as follows: E54. Calculate the projection length Ld of the minimum clear distance tailDist between the web joint plate and other plates on the web axis, and the projection line is parallel to the chord axis; E55. Calculate the projection length Le of the cross-section width B on both sides of the web axis on the web axis, with the projection line parallel to the chord axis; E56. The selected length L2 is the sum of the total length of the web plate webPlateL, the projected length Ld and the projected length Le.

[0024] The calculation method of the end length Lchord of a node chord in step E8 is as follows: E81. Calculate the projection length Lg of the node web end length Lweb (the node web end adjacent to the node chord end) on the chord axis, with the projection line perpendicular to the chord axis; E82. Calculate the projection length Lh of the half-width B1 of the node web member end (the node web member end adjacent to the node chord member end) on the chord axis, with the projection line perpendicular to the chord axis; E83. When the connection form of the node chord end is welding connection, the length of the node chord end Lchord is the sum of the projection length Lg, the projection length Lh, the radius of the inverted arc between the chord and the web R1, and the minimum distance distToSeam from the end of the arc to the node plate weld; E84. When the connection form of the node chord end is high-strength bolt connection, the length of the node chord end Lchord is the sum of the projection length Lg, the projection length Lh, the inverted arc radius R1 between the chord and the web, and the minimum distance distToGap from the end of the arc to the joint.

[0025] The specific process of the calculation method of the end length Lchord of a node chord member and the calculation method of the end length Lweb of a node web member in step E11 is as follows: E111. The angle between the chord and the web is α, the length L3 is the radius R1 of the rounded arc between the chord and the web divided by the tangent of the angle α / 2, the length L4 is the half-width B1 of the node web end divided by the sine of the angle α, the length L5 is the height H of the chord end on one side of the chord axis (close to the web side) divided by the tangent of the angle α, the length L6 is the half-width B1 of the node web end divided by the tangent of the angle α, and the length L7 is the height H of the chord end on one side of the chord axis (close to the web side) divided by the sine of the angle α; E112. The length of the node chord end Lchord is the sum of the length L3, length L4, length L5, and the minimum distance distToSeam from the end of the arc to the node plate weld; E113. The length of the node web end Lweb is the sum of the length L3, the length L6, the length L7, and the minimum distance distToSeam from the end of the arc to the node plate weld.

[0026] When there are more than one node web member ends, after the current node web member end and the adjacent web member end are rounded according to R2, it is determined whether the distance between the end of the arc and the web member end is greater than the minimum distance distToSeam between the end of the arc and the node plate weld. If the judgment result is true, the node web member end length Lweb is not adjusted; if the judgment result is false, it is iterated based on the node web member end length Lweb with a positive length δL2 as the incremental step, Lnew=Lweb+n*δL2, n is the number of iterations, until the judgment result is true, and the node web member end length Lweb at this time is recorded as Lnew.

[0027] The bar system finite element model data in step A includes unit coordinates, unit sections, unit groups, and pier node groups.

[0028] Specifically, the unit grouping includes a chord member group and the unit numbers contained therein, and a web member group and the unit numbers contained therein.

[0029] The rod connection forms in step B include the following two forms: welding connection and high-strength bolt connection.

[0030] In step E, the node web member end length refers to the length from the node center to the end of the web member joint, and the node chord member end length refers to the length from the node center to the end of the chord member joint.

[0031] More specifically, the node center is the intersection of the chord axis and the web axis.

[0032] Specifically, in step E, the angle between the chord and the web is no greater than 90°. Example

[0033] A node in the finite element model of a steel truss beam system is shown as follows: Figure 2 The bridge is a simply supported steel truss with two piers. The rods are connected by welding. This node is the third node behind the symmetry axis.

[0034] Step A: Read the bar system finite element model data and name the node E2 according to its position in the model.

[0035] After calculation, the angle between chord 1 and web 1 is 64°, the angle between web 1 and web 2 is 52°, the angle between web 2 and chord 2 is 64°, the section numbers of chord 1 and chord 2 are both 1, and the section numbers of web 1 and web 2 are both 21. Using the web section number 21 as the index keyword to search the section database and bolt database, it is found that the web section type is box-shaped, the section width B on both sides of the web axis is 300mm, and the distance from the web joint plate to the joint joint is jointPlateL=0.

[0036] Step B: Determine the connection form of the node chord end according to the following principles.

[0037] The side along the bridge with a larger mileage is called the front side, and the side along the bridge with a smaller mileage is called the rear side.

[0038] Step B1. When the rod connection form is welding connection, the end of the node chord is welding connection.

[0039] Step B2. The rod connection form is high-strength bolt connection. When the number of piers in the whole bridge is greater than 2, the node chord ends at the middle pier support points are all connected by high-strength bolts, and the node chord ends at the side pier support points are all connected by welding; the rear chord ends of all nodes of the rear side span except those located at the side pier support points are connected by high-strength bolts, and the front chord ends are connected by welding; the rear chord ends of all nodes of the front side span except those located at the side pier support points are connected by welding, and the front chord ends are connected by high-strength bolts; the rear chord ends of all nodes on the rear side of the middle span are connected by welding, and the front chord ends of all nodes are connected by high-strength bolts; the rear chord ends of all nodes in the middle span and in front of it are connected by high-strength bolts, and the front chord ends of all nodes are connected by welding.

[0040] Step B3. The rod connection form is high-strength bolt connection. When the number of bridge piers is 2, the chord ends of the node closest to the symmetry axis along the bridge direction are all connected by high-strength bolts; for all nodes behind this node, the chord ends behind the node are connected by high-strength bolts, and the chord ends in front of the node are connected by welding; for all nodes in front of this node, the chord ends behind the node are connected by welding, and the chord ends in front of the node are connected by high-strength bolts.

[0041] According to the number of bridge piers, the location of the nodes and the connection form of the rods, step B1 is executed to determine whether the end of the node chord is welded.

[0042] Step C. Set the initial parameters for node geometry calculation, the radius of the node plate inverted arc R=300mm, the minimum distance from the end of the arc to the joint distToGap=0, the minimum distance from the end of the arc to the node plate weld distToSeam=300mm, the minimum distance from the joint plate at the web splice to the corner of the node plate distToCorner=0, the dovetail length of the web joint plate tailLength=0, the distance from the top of the dovetail arc of the web joint plate to the splicing plate distToArc=0, the minimum clear distance between the web joint plate and other plates tailDist=0, whether the ends of the diagonal web members on the front and rear sides of the node are the same length isSame=false.

[0043] Step D. Search the section database with the chord section number 1 as the index keyword, and it can be known that the height of the node chord end below the chord axis is 420 mm, and the height of the node chord end above the chord axis is 420 mm.

[0044] Step E. Calculate the size of other parts of the node.

[0045] Step E1. If the rod connection is a high-strength bolt connection, execute steps E2 to E8; if the rod connection is a welding connection, execute steps E9 to E11. For this embodiment, if the rod connection is a welding connection, execute steps E9 to E11.

[0046] Step E9. The inverted arc radius R1 between the chord and the web is assigned according to the inverted arc radius R of the node plate, that is, R1=300mm. The free edge of the node between the chord and the web is designed to be parallel to the axis of the web. The inverted arc radius R2 between the webs is assigned according to the inverted arc radius R of the node plate minus 100mm, that is, R2=200mm.

[0047] Step E10. The half-width B1 of all web member ends in the node is set according to the cross-sectional width B on both sides of the web member axis, that is, the half-width B1 of the web member 1 end is 300mm, and the half-width B1 of the web member 2 end is 300mm.

[0048] Step E11. Calculate the length Lweb of the ends of all the web members in the node and the length Lchord of the ends of all the chord members in the node.

[0049] Calculate the length of the chord 1 end Lchord and the length of the web 1 end Lweb: E111. The angle between chord 1 and web 1 is α. The length L3 is the radius R1 of the rounded arc between chord 1 and web 1 divided by the tangent of angle α / 2. In this example, L3=480.1mm. The length L4 is the half-width B1 of the end of node web 1 divided by the sine of angle α. In this example, L4=333.78mm. The length L5 is the height H of the end of chord 1 on the side of the chord axis (close to the web side) divided by the tangent of angle α. In this example, L5=204.85mm. The length L6 is the half-width B1 of the end of node web 1 divided by the tangent of angle α. In this example, L6=146.32mm. The length L7 is the height H of the end of chord 1 on the side of the chord axis (close to the web side) divided by the sine of angle α. In this example, L7=467.29mm.

[0050] E112. The length of the end of node chord 1, Lchord, is the sum of length L3, length L4, length L5, and the minimum distance distToSeam from the end of the arc to the node plate weld, that is, Lchord = 1318.73mm.

[0051] E113. The length Lweb of the end of the node web member 1 is the sum of the length L3, the length L6, the length L7, and the minimum distance distToSeam from the end of the arc to the node plate weld, that is, Lweb = 1393.71mm.

[0052] In this example, there is more than one node web member end. After the node web member 1 end and the node web member 2 end are chamfered according to R2, the distance between the end of the arc and the end of the web member 1 is 365mm, which is greater than the minimum distance of 300mm between the end of the arc and the node plate weld. The judgment result is true and no further iteration is required. The length Lweb of the node web member 1 end is not adjusted and is 1393.71mm.

[0053] Repeat step E11 for the ends of chord member 2 and web member 2 to obtain the node design result. Figure 3 .

[0054] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A method for calculating the geometric dimensions of the integral nodes of a steel truss beam, characterized in that: The following steps are involved: A. Read the bar system finite element model data, name the node, calculate the angle between the chord and each web member at the node, and the angle between the chord and the longitudinal x-axis, obtain the section number of each chord and web member at the node, use the web member section number as the index keyword to search the section database and bolt database, and obtain the web member section type, the section width B on both sides of the web member axis, and the distance from the web member joint plate to the joint joint plate L; B. Determine the connection form of the node chord ends according to the number of bridge piers, node locations and rod connection forms; C. Set the initial parameters for node geometry calculation, including the radius of the node plate inverted arc R, the minimum distance from the end of the arc to the joint distToGap, the minimum distance from the end of the arc to the node plate weld distToSeam, the minimum distance from the joint plate at the web splice to the corner of the node plate distToCorner, the dovetail length of the web joint plate tailLength, the distance from the top of the dovetail arc of the web joint plate to the splicing plate distToArc, the minimum clear distance between the web joint plate and other plates tailDist, and whether the ends of the inclined web members at the front and rear sides of the node are the same length isSame; D. Obtain the height H of each chord end in the node on one side of the chord axis, use the chord section number as the index keyword to search the section database, obtain the vertical distance of the section riser below the chord axis and the vertical distance of the section riser above the chord axis, and use them as the height of the node chord end below the chord axis and the height of the node chord end above the chord axis respectively; E. Calculate the size of other parts of the node.

2. A method for calculating geometric dimensions of an integral node of a steel truss according to claim 1, characterized in that: Step E calculates the size of other parts of the node. The specific process is as follows: E1. If the rod connection is a high-strength bolt connection, execute steps E2 to E8; if the rod connection is a welding connection, execute steps E9 to E11; E2. The radius of the inverted arc R1 between the chord and the web is assigned according to the inverted arc radius R of the node plate. The free edge of the node between the chord and the web is designed to be vertical, and the radius of the inverted arc R2 between the webs is taken to be positive infinity. E3. The total length of the web bar joint plate webPlateL is the sum of the dovetail length of the web bar joint plate tailLength, the distance from the top of the dovetail arc of the web bar joint plate to the splicing plate distToArc, and the distance from the web splicing plate to the seam jointPlateL; E4. When the web section is box-shaped, the half width B1 of the node web end is the sum of the cross-sectional width B on both sides of the web axis and the minimum distance distToCorner between the joint plate and the corner of the node plate at the web joint; when the web section is H-shaped or W-shaped, the half width B1 of the node web end is set according to the cross-sectional width B on both sides of the web axis; E5. Calculate the comparison length L1 and the comparison length L2. The initial length L0 from the node center to the end of the web joint is selected according to the maximum value between the comparison length L1 and the comparison length L2; E6. Check whether the net distance between each web member joint plate and other plates is greater than the minimum net distance tailDist. If the judgment result is true, the node web member end length Lweb is the initial length L0; If the judgment result is false, then iterate based on the initial length L0 with a positive length δL1 as the incremental step, Lweb=L0+n*δL1, n is the number of iterations, until the judgment result is true, and record the node web end length Lweb at this time; E7. All the ends of the web members in the node are calculated according to steps E3 to E6. When isSame is true, the length of all the ends of the web members in the node is the maximum length of the ends of the web members in the front and rear sides of the node; skip this step when isSame is false; E8. Calculate the length of the chord ends of all nodes in the node Lchord; E9. The radius of the inverted arc R1 between the chord and the web is assigned according to the inverted arc radius R of the node plate. The free edge of the node between the chord and the web is designed to be parallel to the axis of the web. The radius of the inverted arc R2 between the webs is assigned according to the inverted arc radius R of the node plate minus 100mm. E10. The half width B1 of all web member ends in the node is set according to the cross-sectional width B on both sides of the web member axis; E11. Calculate the length of the web ends of all nodes in the node, Lweb, and the length of the chord ends of all nodes in the node, Lchord.

3. A method for calculating geometric dimensions of an integral node of a steel truss according to claim 2, characterized in that: The specific process of the calculation method of the comparison length L1 in step E5 is as follows: E51. Calculate the projection length La of the sum of the radius R1 of the inverted arc between the chord and the web, the minimum distance distToGap from the end of the arc to the joint, and the height H of the chord end on one side of the chord axis (close to the web side). The projection line is parallel to the chord axis. E52. Calculate the projection length Lb of the half-width B1 of the node web end on the web axis, and the projection line is parallel to the chord axis; E53. The selected length L1 is the sum of the projection length La and the projection length Lb.

4. A method for calculating geometric dimensions of an integral node of a steel truss according to claim 2, characterized in that: The specific process of the calculation method of the comparison length L2 in step E5 is as follows: E54. Calculate the projection length Ld of the minimum clear distance tailDist between the web joint plate and other plates on the web axis, and the projection line is parallel to the chord axis; E55. Calculate the projection length Le of the cross-section width B on both sides of the web axis on the web axis, with the projection line parallel to the chord axis; E56. The selected length L2 is the sum of the total length of the web plate webPlateL, the projected length Ld and the projected length Le.

5. The method for calculating geometric dimensions of an integral node of a steel truss according to claim 2, characterized in that: The calculation method of the end length Lchord of a node chord in step E8 is as follows: E81. Calculate the projection length Lg of the node web end length Lweb (the node web end adjacent to the node chord end) on the chord axis, with the projection line perpendicular to the chord axis; E82. Calculate the projection length Lh of the half-width B1 of the node web member end (the node web member end adjacent to the node chord member end) on the chord axis, with the projection line perpendicular to the chord axis; E83. When the connection form of the node chord end is welding connection, the length of the node chord end Lchord is the sum of the projection length Lg, the projection length Lh, the radius of the inverted arc between the chord and the web R1, and the minimum distance distToSeam from the end of the arc to the node plate weld; E84. When the connection form of the node chord end is high-strength bolt connection, the length of the node chord end Lchord is the sum of the projection length Lg, the projection length Lh, the inverted arc radius R1 between the chord and the web, and the minimum distance distToGap from the end of the arc to the joint.

6. A method for calculating geometric dimensions of an integral node of a steel truss according to claim 2, characterized in that: The specific process of the calculation method of the end length Lchord of a node chord member and the calculation method of the end length Lweb of a node web member in step E11 is as follows: E111. The angle between the chord and the web is α, the length L3 is the radius R1 of the rounded arc between the chord and the web divided by the tangent of the angle α / 2, the length L4 is the half-width B1 of the node web end divided by the sine of the angle α, the length L5 is the height H of the chord end on one side of the chord axis (close to the web side) divided by the tangent of the angle α, the length L6 is the half-width B1 of the node web end divided by the tangent of the angle α, and the length L7 is the height H of the chord end on one side of the chord axis (close to the web side) divided by the sine of the angle α; E112. The length of the node chord end Lchord is the sum of the length L3, the length L4, the length L5, and the minimum distance distToSeam from the end of the arc to the node plate weld; E113. The length of the node web end Lweb is the sum of the length L3, the length L6, the length L7, and the minimum distance distToSeam from the end of the arc to the node plate weld.

7. A method for calculating geometric dimensions of an integral node of a steel truss according to claim 6, characterized in that: When there are more than one node web member ends, after the current node web member end and the adjacent web member end are rounded according to R2, it is determined whether the distance between the end of the arc and the web member end is greater than the minimum distance distToSeam between the end of the arc and the node plate weld. If the judgment result is true, the node web member end length Lweb is not adjusted; if the judgment result is false, it is iterated based on the node web member end length Lweb with a positive length δL2 as the incremental step, Lnew=Lweb+n*δL2, n is the number of iterations, until the judgment result is true, and the node web member end length Lweb at this time is recorded as Lnew.

8. The method for calculating geometric dimensions of an integral node of a steel truss according to claim 1, characterized in that: The bar system finite element model data in step A includes unit coordinates, unit sections, unit groups, and pier node groups.

9. The method for calculating geometric dimensions of an integral node of a steel truss according to claim 1, characterized in that: The rod connection forms in step B include the following two forms: welding connection and high-strength bolt connection.

10. The method for calculating geometric dimensions of an integral node of a steel truss beam according to claim 2, characterized in that: In step E, the node web member end length refers to the length from the node center to the end of the web member joint, and the node chord member end length refers to the length from the node center to the end of the chord member joint.

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