A method for calculating the geometric size of a steel truss beam integral joint

Abstract

The application discloses a kind of steel truss whole node geometric size evolution method, comprising the following steps: reading bar finite element model data, naming node name, the angle between chord and each web between node, the angle between chord and longitudinal x axis is calculated, the section number of each chord and web at node is obtained;According to the number of whole bridge pier, the position of node and the connection form of bar, the connection form of node chord end is judged;Set node geometric size evolution initial parameter;The height H of each chord end in node on the side of chord axis is obtained;The size of other parts of node is calculated.The application provides a kind of general steel truss whole node geometric size evolution method for the problems of many steel truss nodes, many size parameters, low design efficiency and the like, improves design efficiency and design quality.The application realizes the fine design of node plate, and the design result of node is always the most economical design scheme of steel under the framework of set initial parameter, which can guarantee the economy of design.

Description

Technical Field

[0001] This invention belongs to the field of bridge engineering design, and specifically relates to a method for calculating the geometric dimensions of integral nodes of steel truss girders. Background Technology

[0002] The integral steel truss girder node evolved from the piece-together node and offers significant practical economic benefits for both factory and on-site installation. It is now used by the vast majority of steel truss girders.

[0003] In finite element analysis programs, steel trusses are simulated using a truss finite element model, and the cross-sectional dimensions of the steel truss members are determined through finite element analysis. However, the truss finite element model cannot simulate the overall nodes where the chords and web members of the steel truss meet. The shapes of the gusset plates are usually drawn manually in CAD based on the dimensions of each member at the intersection and various structural detail requirements. This results in a wide variety of gusset plate shapes across the entire bridge, a huge workload for drawing, and low design efficiency.

[0004] Therefore, when faced with the design of a large number of steel truss girder nodes, there is an urgent need for a method to calculate the overall geometric dimensions of steel truss girder nodes in order to improve design efficiency. Summary of the Invention

[0005] This 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 overall nodes of a steel truss beam.

[0006] The technical solution of this invention is: a method for calculating the geometric dimensions of integral nodes of steel truss beams, comprising the following steps:

[0007] A. Read the finite element model data of the pole system, name the nodes, calculate the angle between the chord and each web member at the node, the angle between the chord and the longitudinal x-axis, obtain the section number of each chord and web member at the node, and search the section database and bolt database with the web member section number as the index key to 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 splice plate to the joint L;

[0008] B. Determine the connection form of the chord end of the node based on the total number of bridge piers, the location of the node, and the connection form of the members;

[0009] C. Set initial parameters for node geometry calculation, including the radius R of the node plate rounded arc, the minimum distance from the end of the arc to the joint distToGap, the minimum distance from the end of the arc to the weld of the node plate distToSeam, the minimum distance from the joint plate at the splice of the web member to the corner of the node plate distToCorner, the dovetail length of the web member joint plate tailLength, the distance from the top of the dovetail arc of the web member joint plate to the splice plate distToArc, the minimum clear distance between the web member joint plate and other plates tailDist, and whether the ends of the diagonal web members on the front and rear sides of the node are of equal length isSame;

[0010] D. Obtain the height H of each chord end on one side of the chord axis within the node. Retrieve the section database using the chord section number as the index key to obtain the vertical distance of the section vertical plate below the chord axis and the vertical distance of the section vertical plate 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.

[0011] E. Calculate the dimensions of other parts of the node.

[0012] Furthermore, step E calculates the dimensions of other parts of the node, as follows:

[0013] E1. If the rod connection is a high-strength bolt connection, proceed to steps E2 to E8; if the rod connection is a welded connection, proceed to steps E9 to E11.

[0014] E2. The radius R1 of the rounded arc between the chord and the web member is assigned according to the radius R of the rounded arc of the node plate. The free edge of the node between the chord and the web member is designed vertically. The radius R2 of the rounded arc between the web members is taken as positive infinity.

[0015] E3. The total length of the web member joint plate, webPlateL, is the sum of the dovetail length of the web member joint plate, the distance from the top of the dovetail arc of the web member joint plate to the splicing plate, distToArc, and the distance from the web member splicing plate to the joint, jointPlateL.

[0016] E4. When the cross-section of the web member is box-shaped, the half-width B1 of the end of the web member at the node is the sum of the cross-section width B on both sides of the web member axis and the minimum distance distToCorner from the corner of the node plate at the splice of the web member; when the cross-section of the web member is H-shaped or king-shaped, the half-width B1 of the end of the web member at the node is set according to the cross-section width B on both sides of the web member axis.

[0017] E5. Calculate the selection length L1 and selection length L2. The initial length L0 from the node center to the end of the web member joint is selected according to the maximum value between the selection length L1 and selection length L2.

[0018] E6. Check whether the net distance between each joint plate of the web member and other plates is greater than the minimum net distance tailDist. If the judgment result is true, the length Lweb of the web member end of the node is the initial length L0. If the judgment result is false, iterate on the initial length L0 with a positive length δL1 as the increment step, Lweb=L0+n*δL1, where n is the number of iterations, until the judgment result is true, and record the length Lweb of the web member end of the node at this time.

[0019] E7. All web member ends within the node are calculated according to steps E3 to E6. When the isSame condition (whether the front and rear diagonal web member ends are equal) is true, the length of all diagonal web member ends within the node is the maximum value between the lengths of the front and rear diagonal web member ends of the node; skip this step when the isSame condition (whether the front and rear diagonal web member ends are equal) is false.

[0020] E8. Calculate the length Lchord of the end of the chord at all nodes within the node;

[0021] E9. The radius of the rounded arc between the chord and the web member, R1, is assigned according to the radius of the rounded arc of the node plate, R2, is assigned according to the radius of the rounded arc of the node plate, R2, is assigned according to the radius of the rounded arc of the node plate minus 100mm.

[0022] E10. The half-width B1 of all web members within the node is set according to the cross-sectional width B on both sides of the web member axis;

[0023] E11. Calculate the length of the web member end Lweb and the length of the chord member end Lchord of all nodes within the node.

[0024] Furthermore, the calculation method for the comparison length L1 in step E5 is as follows:

[0025] E51. The radius of the rounded arc between the chord and the web member, R1, the minimum distance from the end of the arc to the joint, distToGap, and the height H of the end of the chord on one side of the chord axis (closer to the web member), calculate the projection length La of the sum of the above three on the web member axis, and the projection line is parallel to the chord axis.

[0026] E52. Calculate the projection length Lb of the half-width B1 of the end of the web member on the axis of the web member, with the projection line parallel to the axis of the chord member;

[0027] E53. The selection length L1 is the sum of the projected length La and the projected length Lb.

[0028] Furthermore, the calculation method for the comparison length L2 in step E5 is as follows:

[0029] E54. Calculate the projection length Ld of the minimum clear distance tailDist between the web member joint plate and other plates on the web member axis, with the projection line parallel to the chord member axis.

[0030] E55. Calculate the projection length Le of the section width B on both sides of the web member axis onto the web member axis, with the projection line parallel to the chord member axis;

[0031] E56. The selection length L2 is the sum of the total length webPlateL of the web joint plate, the projected length Ld, and the projected length Le.

[0032] Furthermore, the calculation method for the length Lchord at the end of a chord node in step E8 is as follows:

[0033] E81. Calculate the projection length Lg of the node web member end length Lweb (the node web member end adjacent to the node chord member end) on the chord member axis, with the projection line perpendicular to the chord member axis;

[0034] 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 member axis, with the projection line perpendicular to the chord member axis;

[0035] E83. When the connection form of the node chord end is a welded connection, the node chord end length Lchord is the sum of the projected length Lg, the projected length Lh, the radius of the rounded arc between the chord and the web member R1, and the minimum distance from the end of the arc to the weld of the node plate distToSeam.

[0036] E84. When the connection form of the node chord end is a high-strength bolt connection, the node chord end length Lchord is the sum of the projected length Lg, the projected length Lh, the radius of the rounded arc between the chord and the web member R1, and the minimum distance from the end of the arc to the joint distToGap.

[0037] Furthermore, the calculation methods for the length Lchord of a chord member end and the length Lweb of a web member end in step E11 are as follows:

[0038] E111. The angle between the chord and the web member is denoted as α. The length L3 is the tangent of the radius R1 of the rounded arc between the chord and the web member divided by the angle α / 2. The length L4 is the sine of the half-width B1 of the web member end divided by the angle α. The length L5 is the tangent of the height H of the chord member end on one side of the chord axis (near the web member) divided by the angle α. The length L6 is the tangent of the half-width B1 of the web member end divided by the angle α. The length L7 is the sine of the height H of the chord member end on one side of the chord axis (near the web member) divided by the angle α.

[0039] E112. The length Lchord at the end of the node chord is the sum of length L3, length L4, length L5, and the minimum distance distToSeam from the end of the arc to the weld of the node plate.

[0040] E113. The length Lweb of the node web member end is the sum of length L3, length L6, length L7, and the minimum distance distToSeam from the end of the arc to the weld of the node plate.

[0041] Furthermore, when there are more than one node web member end, after the current node web member end and the adjacent web member end are rounded by R2, it is determined whether the distance from the end of the rounded arc to the web member end is greater than the minimum distance from the end of the rounded arc to the weld seam of the node plate, distToSeam. If the determination result is true, the node web member end length Lweb is not adjusted; if the determination result is false, it is iterated based on the node web member end length Lweb with a positive increment step of δL2, Lnew=Lweb+n*δL2, where n is the number of iterations, until the determination result is true, and the node web member end length Lweb at this time is recorded as Lnew.

[0042] Furthermore, the finite element model data of the truss system in step A includes element coordinates, element sections, element groups, and pier node groups.

[0043] Furthermore, the connection methods for the rods in step B include the following two forms: welded connection and high-strength bolt connection.

[0044] Furthermore, in step E, the length of the node web member end refers to the length from the node center to the end of the web member joint, and the length of the node chord member end refers to the length from the node center to the end of the chord member joint.

[0045] The beneficial effects of this invention are as follows:

[0046] The present invention addresses the most common type of integral steel truss node, and provides a parametric solution method for each dimension of the node plate. It is easy to implement digital node design through programming, has strong versatility, high solution efficiency, and can ensure design efficiency.

[0047] This invention enables refined design of node plates. The node design results are always the most economical design scheme in terms of steel consumption within the set initial parameter framework, which can ensure the economic efficiency of the design.

[0048] This invention lays the foundation for parametric modeling of nodes, which helps to achieve efficient forward design of steel trusses. Attached Figure Description

[0049] Figure 1 This is a flowchart of the method of the present invention;

[0050] Figure 2 This is a schematic diagram of a node in a finite element model of a rod system according to an embodiment of the present invention;

[0051] Figure 3 This is a node design result based on the present invention, according to an embodiment of the present invention. Detailed Implementation

[0052] The present invention will now be described in detail with reference to the accompanying drawings and embodiments:

[0053] like Figures 1 to 3 As shown, a method for calculating the geometric dimensions of integral nodes of a steel truss girder includes the following steps:

[0054] A. Read the finite element model data of the pole system, name the nodes, calculate the angle between the chord and each web member at the node, the angle between the chord and the longitudinal x-axis, obtain the section number of each chord and web member at the node, and search the section database and bolt database with the web member section number as the index key to 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 splice plate to the joint L;

[0055] B. Determine the connection form of the chord end of the node based on the total number of bridge piers, the location of the node, and the connection form of the members;

[0056] C. Set initial parameters for node geometry calculation, including the radius R of the node plate rounded arc, the minimum distance from the end of the arc to the joint distToGap, the minimum distance from the end of the arc to the weld of the node plate distToSeam, the minimum distance from the joint plate at the splice of the web member to the corner of the node plate distToCorner, the dovetail length of the web member joint plate tailLength, the distance from the top of the dovetail arc of the web member joint plate to the splice plate distToArc, the minimum clear distance between the web member joint plate and other plates tailDist, and whether the ends of the diagonal web members on the front and rear sides of the node are of equal length isSame;

[0057] D. Obtain the height H of each chord end on one side of the chord axis within the node. Retrieve the section database using the chord section number as the index key to obtain the vertical distance of the section vertical plate below the chord axis and the vertical distance of the section vertical plate 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.

[0058] E. Calculate the dimensions of other parts of the node.

[0059] Step E calculates the dimensions of the other parts of the node. The specific process is as follows:

[0060] E1. For members connected by high-strength bolts, proceed to steps E2 to E8; for members connected by welded connections, proceed to steps E9 to E11.

[0061] E2. The radius R1 of the rounded arc between the chord and the web member is assigned according to the radius R of the rounded arc of the node plate. The free edge of the node between the chord and the web member is designed vertically. The radius R2 of the rounded arc between the web members is taken as positive infinity.

[0062] E3. The total length of the web member joint plate, webPlateL, is the sum of the dovetail length of the web member joint plate, the distance from the top of the dovetail arc of the web member joint plate to the splicing plate, distToArc, and the distance from the web member splicing plate to the joint, jointPlateL.

[0063] E4. When the cross-section of the web member is box-shaped, the half-width B1 of the end of the web member at the node is the sum of the cross-section width B on both sides of the web member axis and the minimum distance distToCorner from the corner of the node plate at the splice of the web member; when the cross-section of the web member is H-shaped or king-shaped, the half-width B1 of the end of the web member at the node is set according to the cross-section width B on both sides of the web member axis.

[0064] E5. Calculate the selection length L1 and selection length L2. The initial length L0 from the node center to the end of the web member joint is selected according to the maximum value between the selection length L1 and selection length L2.

[0065] E6. Check whether the net distance between each joint plate of the web member and other plates is greater than the minimum net distance tailDist. If the judgment result is true, the length Lweb of the web member end of the node is the initial length L0. If the judgment result is false, iterate on the initial length L0 with a positive length δL1 as the increment step, Lweb=L0+n*δL1, where n is the number of iterations, until the judgment result is true, and record the length Lweb of the web member end of the node at this time.

[0066] E7. All web member ends within the node are calculated according to steps E3 to E6. When the isSame condition (whether the front and rear diagonal web member ends are equal) is true, the length of all diagonal web member ends within the node is the maximum value between the lengths of the front and rear diagonal web member ends of the node; skip this step when the isSame condition (whether the front and rear diagonal web member ends are equal) is false.

[0067] E8. Calculate the length Lchord of the end of the chord at all nodes within the node;

[0068] E9. The radius of the rounded arc between the chord and the web member, R1, is assigned according to the radius of the rounded arc of the node plate, R2, is assigned according to the radius of the rounded arc of the node plate, R2, is assigned according to the radius of the rounded arc of the node plate minus 100mm.

[0069] E10. The half-width B1 of all web members within the node is set according to the cross-sectional width B on both sides of the web member axis;

[0070] E11. Calculate the length of the web member end Lweb and the length of the chord member end Lchord of all nodes within the node.

[0071] The calculation method for the comparison length L1 in step E5 is as follows:

[0072] E51. The radius of the rounded arc between the chord and the web member, R1, the minimum distance from the end of the arc to the joint, distToGap, and the height H of the end of the chord on one side of the chord axis (closer to the web member), calculate the projection length La of the sum of the above three on the web member axis, and the projection line is parallel to the chord axis.

[0073] E52. Calculate the projection length Lb of the half-width B1 of the end of the web member on the axis of the web member, with the projection line parallel to the axis of the chord member;

[0074] E53. The selection length L1 is the sum of the projected length La and the projected length Lb.

[0075] The calculation method for the comparison length L2 in step E5 is as follows:

[0076] E54. Calculate the projection length Ld of the minimum clear distance tailDist between the web member joint plate and other plates on the web member axis, with the projection line parallel to the chord member axis.

[0077] E55. Calculate the projection length Le of the section width B on both sides of the web member axis onto the web member axis, with the projection line parallel to the chord member axis;

[0078] E56. The selection length L2 is the sum of the total length webPlateL of the web joint plate, the projected length Ld, and the projected length Le.

[0079] The calculation method for the length Lchord at the end of a chord node in step E8 is as follows:

[0080] E81. Calculate the projection length Lg of the node web member end length Lweb (the node web member end adjacent to the node chord member end) on the chord member axis, with the projection line perpendicular to the chord member axis;

[0081] 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 member axis, with the projection line perpendicular to the chord member axis;

[0082] E83. When the connection form of the node chord end is a welded connection, the node chord end length Lchord is the sum of the projected length Lg, the projected length Lh, the radius of the rounded arc between the chord and the web member R1, and the minimum distance from the end of the arc to the weld of the node plate distToSeam.

[0083] E84. When the connection form of the node chord end is a high-strength bolt connection, the node chord end length Lchord is the sum of the projected length Lg, the projected length Lh, the radius of the rounded arc between the chord and the web member R1, and the minimum distance from the end of the arc to the joint distToGap.

[0084] The calculation methods for the length Lchord of a chord member end and the length Lweb of a web member end in step E11 are as follows:

[0085] E111. The angle between the chord and the web member is denoted as α. The length L3 is the tangent of the radius R1 of the rounded arc between the chord and the web member divided by the angle α / 2. The length L4 is the sine of the half-width B1 of the web member end divided by the angle α. The length L5 is the tangent of the height H of the chord member end on one side of the chord axis (near the web member) divided by the angle α. The length L6 is the tangent of the half-width B1 of the web member end divided by the angle α. The length L7 is the sine of the height H of the chord member end on one side of the chord axis (near the web member) divided by the angle α.

[0086] E112. The length Lchord at the end of the node chord is the sum of length L3, length L4, length L5, and the minimum distance distToSeam from the end of the arc to the weld of the node plate.

[0087] E113. The length Lweb of the node web member end is the sum of length L3, length L6, length L7, and the minimum distance distToSeam from the end of the arc to the weld of the node plate.

[0088] When there is more than one node web member end, after the current node web member end and the adjacent web member end are rounded by R2, it is determined whether the distance from the end of the rounded arc to the web member end is greater than the minimum distance from the end of the rounded arc to the weld seam of the node plate, distToSeam. If the determination result is true, the node web member end length Lweb is not adjusted; if the determination result is false, it is iterated based on the node web member end length Lweb with a positive increment step of δL2, Lnew=Lweb+n*δL2, where n is the number of iterations, until the determination result is true, and the node web member end length Lweb at this time is recorded as Lnew.

[0089] The finite element model data of the truss system in step A includes element coordinates, element sections, element groups, and pier node groups.

[0090] Specifically, the unit grouping includes the chord group and its constituent unit numbers, and the web group and its constituent unit numbers.

[0091] In step B, the connection methods for the rods include the following two types: welded connection and high-strength bolt connection.

[0092] In step E, the length of the node web member end refers to the length from the node center to the end of the web member joint, and the length of the node chord member end refers to the length from the node center to the end of the chord member joint.

[0093] More specifically, the center of the aforementioned node is the intersection of the chord axis and the web axis.

[0094] Specifically, in step E, the angle between the chord and the web member is no greater than 90°. Example

[0095] A schematic diagram of a node in the finite element model of a steel truss beam system is shown below. Figure 2 As shown. The bridge is a simply supported steel truss bridge with two piers. The members are connected by welding. This node is the third node behind the axis of symmetry.

[0096] Step A. Read the finite element model data of the rod system and name the node E2 according to its position in the model.

[0097] Calculations show that the angle between chord member 1 and web member 1 is 64°, the angle between web member 1 and web member 2 is 52°, and the angle between web member 2 and chord member 2 is 64°. Both chord member 1 and chord member 2 have section numbers of 1, and both web member 1 and web member 2 have section numbers of 21. Searching the section database and bolt database using web member section number 21 as the index keyword reveals that the web member section type is box-shaped, the section width B on both sides of the web member axis is 300mm, and the distance from the web member splice plate to the joint L is 0.

[0098] Step B: Determine the connection form of the node chord end according to the following principles.

[0099] The side of the bridge towards the greater mileage is called the front side, and the side of the bridge towards the lesser mileage is called the rear side.

[0100] Step B1. When the member connection is a welded connection, the end of the node chord is a welded connection.

[0101] Step B2. The member connection method is high-strength bolt connection. When the number of piers in the whole bridge is greater than 2, the ends of the chord members at the support of the intermediate pier are all connected with high-strength bolts, and the ends of the chord members at the support of the side pier are all connected with welds. In the rear side span, except for the nodes at the support of the side pier, the ends of the rear chord members are connected with high-strength bolts, and the ends of the front chord members are connected with welds. In the front side span, except for the nodes at the support of the side pier, the ends of the rear chord members are connected with welds, and the ends of the front chord members are connected with high-strength bolts. In the middle span, the ends of the rear chord members at the mid-span are connected with welds, and the ends of the front chord members at all nodes are connected with high-strength bolts. In the middle span and its front side, the ends of the rear chord members at all nodes are connected with high-strength bolts, and the ends of the front chord members at all nodes are connected with welds.

[0102] Step B3. The member connection method is high-strength bolt connection. When the number of piers in the whole bridge is 2, the chord end of the node closest to the longitudinal axis of symmetry is connected with high-strength bolts. For all nodes behind this node, the chord end of the node behind the node is connected with high-strength bolts, and the chord end of the node in front of the node is connected by welding. For all nodes in front of this node, the chord end of the node behind the node is connected by welding, and the chord end of the node in front of the node is connected with high-strength bolts.

[0103] Based on the total number of bridge piers, the location of nodes, and the connection method of members, step B1 is executed to determine that the end of the node chord is a welded connection.

[0104] Step C. Set the initial parameters for node geometry calculation: node plate rounded radius R = 300mm, minimum distance from the end of the rounded arc to the joint distToGap = 0, minimum distance from the end of the rounded arc to the weld of the node plate distToSeam = 300mm, minimum distance from the joint plate at the splice of the web member to the corner of the node plate distToCorner = 0, dovetail length of the web member joint plate tailLength = 0, distance from the top of the dovetail arc of the web member joint plate to the splice plate distToArc = 0, minimum clear distance between the web member joint plate and other plates tailDist = 0, and whether the ends of the diagonal web members on the front and rear sides of the node are of equal length isSame = false.

[0105] Step D. Using section number 1 as the index key, the section database is searched. It can be found that the height of the end of the node chord below the chord axis is 420mm, and the height of the end of the node chord above the chord axis is 420mm.

[0106] Step E. Calculate the dimensions of the other parts of the node.

[0107] Step E1. If the rod connection is a high-strength bolt connection, proceed to steps E2 to E8; if the rod connection is a welded connection, proceed to steps E9 to E11. In this embodiment, the rod connection is a welded connection, so proceed to steps E9 to E11.

[0108] Step E9. The radius R1 of the rounded arc between the chord and the web member is assigned according to the radius R of the rounded arc of the node plate, that is, R1=300mm. The free edge of the node between the chord and the web member is designed to be parallel to the axis of the web member. The radius R2 of the rounded arc between the web members is assigned according to the radius R of the rounded arc of the node plate minus 100mm, that is, R2=200mm.

[0109] Step E10. The half-width B1 of all web members within 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 web member 1 is 300mm, and the half-width B1 of web member 2 is 300mm.

[0110] Step E11. Calculate the length of the web member end Lweb and the length of the chord member end Lchord of all nodes within the node.

[0111] Calculate the length of the end of chord 1, Lchord, and the length of the end of web member 1, Lweb:

[0112] E111. The angle between chord member 1 and web member 1 is denoted as α. Length L3 is the tangent of the radius R1 of the rounded arc between chord member 1 and web member 1 divided by angle α / 2. In this example, L3 = 480.1 mm. Length L4 is the sine of the half-width B1 at the end of web member 1 divided by angle α. In this example, L4 = 333.78 mm. Length L5 is the tangent of the height H (closer to web member) of the end of chord member 1 on one side of the chord axis divided by angle α. In this example, L5 = 204.85 mm. Length L6 is the tangent of the half-width B1 at the end of web member 1 divided by angle α. In this example, L6 = 146.32 mm. Length L7 is the sine of the height H (closer to web member) of the end of chord member 1 on one side of the chord axis divided by angle α. In this example, L7 = 467.29 mm.

[0113] E112. The length Lchord at the end of node chord 1 is the sum of lengths L3, L4, L5, and the minimum distance distToSeam from the end of the arc to the weld of the node plate, i.e., Lchord = 1318.73 mm.

[0114] E113. The length Lweb of the end of node web member 1 is the sum of length L3, length L6, length L7, and the minimum distance distToSeam from the end of the arc to the weld of the node plate, i.e., Lweb = 1393.71 mm.

[0115] In this example, there is more than one node web member end. After the nodes of web member 1 and web member 2 are rounded by R2, the distance from the end of the rounded arc to the end of web member 1 is 365mm, which is greater than the minimum distance of 300mm from the end of the rounded arc to the weld of the node plate. The judgment result is true and no further iteration is needed. The length Lweb of the node web member 1 end is not adjusted and is 1393.71mm.

[0116] Repeat step E11 for both the second end of the chord member and the second end of the web member to obtain the node design results. See Figure 3 .

[0117] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A method for calculating the geometric dimensions of integral nodes of a steel truss girder, characterized in that: Includes the following steps: A. Read the finite element model data of the pole system, name the nodes, calculate the angle between the chord and each web member at the node, the angle between the chord and the longitudinal x-axis, obtain the section number of each chord and web member at the node, and search the section database and bolt database with the web member section number as the index key to 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 splice plate to the joint L; B. Determine the connection form of the chord end of the node based on the total number of bridge piers, the location of the node, and the connection form of the members; C. Set initial parameters for node geometry calculation, including the radius R of the node plate rounded arc, the minimum distance from the end of the arc to the joint distToGap, the minimum distance from the end of the arc to the weld of the node plate distToSeam, the minimum distance from the joint plate at the splice of the web member to the corner of the node plate distToCorner, the dovetail length of the web member joint plate tailLength, the distance from the top of the dovetail arc of the web member joint plate to the splice plate distToArc, the minimum clear distance between the web member joint plate and other plates tailDist, and whether the ends of the diagonal web members on the front and rear sides of the node are of equal length isSame; D. Obtain the height H of each chord end on one side of the chord axis within the node. Retrieve the section database using the chord section number as the index key to obtain the vertical distance of the section vertical plate below the chord axis and the vertical distance of the section vertical plate 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 dimensions of other parts of the node.

2. The method for calculating the geometric dimensions of integral nodes of a steel truss girder according to claim 1, characterized in that: Step E calculates the dimensions of the other parts of the node. The specific process is as follows: E1. For members connected by high-strength bolts, proceed to steps E2 to E8; for members connected by welded connections, proceed to steps E9 to E11. E2. The radius R1 of the rounded arc between the chord and the web member is assigned according to the radius R of the rounded arc of the node plate. The free edge of the node between the chord and the web member is designed vertically. The radius R2 of the rounded arc between the web members is taken as positive infinity. E3. The total length of the web member joint plate, webPlateL, is the sum of the dovetail length of the web member joint plate, the distance from the top of the dovetail arc of the web member joint plate to the splicing plate, distToArc, and the distance from the web member splicing plate to the joint, jointPlateL. E4. When the cross-section of the web member is box-shaped, the half-width B1 of the end of the web member at the node is the sum of the cross-section width B on both sides of the web member axis and the minimum distance distToCorner from the corner of the node plate at the splice of the web member; when the cross-section of the web member is H-shaped or king-shaped, the half-width B1 of the end of the web member at the node is set according to the cross-section width B on both sides of the web member axis. E5. Calculate the selection length L1 and selection length L2. The initial length L0 from the node center to the end of the web member joint is selected according to the maximum value between the selection length L1 and selection length L2. E6. Check whether the clear distance between each joint plate of the web member and other plates is greater than the minimum clear distance tailDist. If the judgment result is true, the length Lweb of the end of the web member of the node is the initial length L0. If the judgment result is false, then iterate with a positive value length δL1 as the increment step based on the initial length L0, Lweb=L0+n*δL1, where n is the number of iterations, until the judgment result is true, and record the length Lweb of the node web end at this time. E7. All web member ends within the node are calculated according to steps E3 to E6. When the isSame condition (whether the front and rear diagonal web member ends are equal) is true, the length of all diagonal web member ends within the node is the maximum value between the lengths of the front and rear diagonal web member ends of the node; skip this step when the isSame condition (whether the front and rear diagonal web member ends are equal) is false. E8. Calculate the length Lchord of the end of the chord at all nodes within the node; E9. The radius of the rounded arc between the chord and the web member, R1, is assigned according to the radius of the rounded arc of the node plate, R2, is assigned according to the radius of the rounded arc of the node plate, R2, is assigned according to the radius of the rounded arc of the node plate minus 100mm. E10. The half-width B1 of all web members within 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 member end Lweb and the length of the chord member end Lchord of all nodes within the node.

3. The method for calculating the geometric dimensions of an integral node of a steel truss girder according to claim 2, characterized in that: The calculation method for the comparison length L1 in step E5 is as follows: E51. Calculate the projection length La of the sum of the following three values ​​on the axis of the web member: radius R1 of the rounded arc between the chord member and the web member, minimum distance distToGap from the end of the arc to the joint, and height H of the end of the chord member on the side of the chord member axis closer to the web member. The projection line is parallel to the axis of the chord member. E52. Calculate the projection length Lb of the half-width B1 of the end of the web member on the axis of the web member, with the projection line parallel to the axis of the chord member; E53. The selection length L1 is the sum of the projected length La and the projected length Lb.

4. The method for calculating the geometric dimensions of an integral node of a steel truss girder according to claim 2, characterized in that: The calculation method for 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 member joint plate and other plates on the web member axis, with the projection line parallel to the chord member axis. E55. Calculate the projection length Le of the section width B on both sides of the web member axis onto the web member axis, with the projection line parallel to the chord member axis; E56. The selection length L2 is the sum of the total length webPlateL of the web joint plate, the projected length Ld, and the projected length Le.

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

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

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

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

9. The method for calculating the geometric dimensions of integral nodes of a steel truss girder according to claim 1, characterized in that: In step B, the connection methods for the rods include the following two types: welded connection and high-strength bolt connection.

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

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