Design method for cast-in-place beam support based on Midas civil and non-orthogonal to existing road

Abstract

The invention discloses a cast-in-place beam support design method based on Midas civil and non-orthogonal to an existing road, and relates to the field of bridge construction and building. The method comprises the steps that firstly, a cast-in-place beam support structure space model is established in AutoCAD, a plurality of truss beams are utilized to span an existing road, each structure in the cast-in-place beam support structure space model established in AutoCAD needs to occupy a layer independently, and a file is stored as a dxf file; a Midas ciil calculation model is established, a dxf file is imported into midas, the steel pipe pier and the longitudinal distribution beam are selected and moved by a proper distance in the-Z direction, and the longitudinal distribution beam is elastically connected with the truss beam; and loading is carried out, and the small distribution beams are loaded in different areas according to a cast-in-place beam structure plane projection drawing. And respectively calculating dead loads Gi and Qi borne by each area, simultaneously calculating the length and li of the small distribution beams in each area, further calculating dead loads and live loads borne by the small distribution beams in each area, and applying line loads to the small distribution beams in the corresponding areas. And running a program to calculate and analyze the strength and the rigidity. And carrying out linear elastic buckling stability analysis on the overall structure.

Description

Technical Field

[0001] The invention relates to the field of bridge construction, and in particular to a design method for a cast-in-place beam support that is non-orthogonal to an existing road based on Midas civil. Background Art

[0002] With the continuous development of bridge construction, it is common for newly built cast-in-place box girders to cross existing roads. When the two are orthogonal or the intersection angle is large, truss girders can be arranged along the bridge and door openings can be set up to meet the traffic requirements of the existing road. When the intersection angle between the newly built cast-in-place box girder and the existing road is small, when the truss girders are arranged along the bridge, a large number of steel pipe piers must be set up within the projection range of the newly built bridge, which will affect traffic and even bring danger to the support structure when vehicles pass.

[0003] The existing patent document with the document number CN118014120A discloses a method for optimizing the construction of cast-in-place beam supports across rivers, wading water, and complex geological conditions. The method includes the following steps: survey the current status of cast-in-place bridge beam supports to determine the influencing factors of cast-in-place beam supports across roads, the requirements of water-wading cast-in-place beam supports for the support foundation, and the detailed technical parameters for the erection of complex geological beam supports. This existing technology can better improve the speed of cast-in-place beams and speed up the construction progress; obtain the relevant technical parameters of the comprehensive technology of water-wading cast-in-place beam supports, adopt targeted measures to meet the requirements of the support foundation, reduce safety risks, and improve the construction quality of cast-in-place beams; through comparative analysis of the comprehensive technology of complex geological cast-in-place beam supports, obtain detailed technical parameters for the erection of supports under complex geological conditions, which is more referenceable and practical than traditional technologies; through optimization of the support, the number of Bailey beams used can be reduced while ensuring the safety and effectiveness of the overall structure of the support, meeting the green, civilized, and safe construction standards.

[0004] However, the prior art does not take into special consideration the situation where a newly built cast-in-situ box girder crosses an existing road, and does not provide a corresponding solution.

[0005] Therefore, it is particularly important to study a support layout type that can meet the safe passage of the existing road when the newly built cast-in-place box girder crosses the existing road with a small intersection angle, and to use the Midas civil finite element program to perform rapid finite element modeling and calculation analysis on the support. Summary of the invention

[0006] The technical problems to be solved by the present invention are:

[0007] The present invention aims to solve the above-mentioned deficiencies in the prior art and proposes a truss beam arrangement type that crosses an existing road horizontally. At the same time, the plane projection diagram of the cast-in-place beam structure is used to cross-divide the nodes with small distribution beams, and then the loading is carried out in different areas, which overcomes the difficulty of oblique loading and improves the modeling efficiency.

[0008] The technical solution adopted by the present invention to solve the above technical problems is: a truss beam spans across an existing road, based on a calculation method of a cast-in-place beam support that is non-orthogonal to the existing road in Midas civil, wherein the method is performed in sequence according to the following steps:

[0009] The cast-in-place beam support comprises a steel pipe pier (1), a longitudinal distribution beam (2), a truss beam (3), a small distribution beam (4) and a thin steel plate (5), wherein the longitudinal distribution beam (2) has a height of h2, the upper and lower chords of the truss beam (3) have a height of h3, and the small distribution beam (4) has a height of h4.

[0010] First, a cast-in-place beam support structure spatial model is established in AutoCAD. The spatial model is the centroid connection line of each main structure. To ensure that the existing road is unobstructed, a number of truss beams (3) are used to cross the existing road. The number of truss beams (3) on each span is called a group of truss pieces. The center of the lower chord of the truss beam (3) is taken as the coordinate origin, the span direction of the truss beam (3) is the X axis, the direction of the existing road is the Y axis, and a plurality of groups of truss beams (3) are arranged along the Y axis; the lower end points of the vertical bars at both ends of each group of truss pieces (3) are connected along the Y axis to form a longitudinal distribution beam (2); the longitudinal distribution beam (2) is drawn along the -Z direction at a certain interval to form a steel pipe pier (1); the upper chord of the left end of each group of truss pieces (3) is connected along the Y axis to form a small distribution beam (4), and a plurality of small distribution beams (4) are arranged at a certain interval in the +X direction, and the small distribution beams (4) on the plane are grouped as 1; the small distribution beam (4) is copied along the +Z direction, the copy distance is (h3+h4) / 2, and the copied small distribution beams (4) are grouped as 2, and at the same time, a plane projection diagram (6) of the cast-in-place beam structure is placed on the plane, and the plane projection diagram contains the plane projection diagrams of the flange plate, the web plate, the top and bottom plates, and the cross beam. The thin steel plate (5) laid on the small distribution beam (4) of the second marshaling is irrelevant to the calculation and is not considered in the model.

[0011] Each structure in the above-mentioned cast-in-place beam support structure spatial model established in AutoCAD needs to occupy a separate layer, and the file is saved as a dxf file.

[0012] Secondly, the calculation model of Midas civil was established. The dxf file was imported into midas, and the steel pipe pier (1) and the longitudinal distribution beam (2) were selected, and moved in the -Z direction by (h2+h3) / 2, and the longitudinal distribution beam (2) and the truss beam (3) were elastically connected; the steel pipe pier (1) was moved in the -Z direction by h2 / 2, and the top of the steel pipe pier (1) was elastically connected to the corresponding point of the longitudinal distribution beam (2); the small distribution beam (4) of group 1 was deleted, and the small distribution beam (4) of group 2 was elastically connected to the corresponding point of the upper chord of the truss beam (3). The material and section properties of each unit were given, and the bottom of the steel pipe pier (1) was constrained.

[0013] Next, load. The cast-in-place beam structure plane projection diagram (6) loads the small distribution beam (4) in different areas. Calculate the constant load Gi and Qi borne by each area respectively, and at the same time calculate the length li of the small distribution beam (4) in each area, and then calculate the constant load (Gi / li) and live load (Qi / li) borne by the small distribution beam (4) in each area, and apply the line load to the small distribution beam (4) in the corresponding area. Run the program to calculate and analyze the strength and stiffness.

[0014] Finally, the linear elastic buckling stability analysis of the overall structure is carried out.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] The present invention studies a support arrangement type that satisfies the safe passage of existing roads when a newly built cast-in-place box girder crosses an existing road and the intersection angle between the two is small, and uses the Midas civil finite element program to perform rapid finite element modeling calculation and analysis on the support, and provides a corresponding new solution for the situation where a newly built cast-in-place box girder crosses an existing road. The present invention realizes the arrangement and rapid modeling calculation of cast-in-place beam supports in the case of non-orthogonality with the existing road, and solves the actual technical problems in the construction process.

[0017] When the intersection angle between the newly built cast-in-place box girder and the existing road is small, when the truss beam is arranged along the bridge direction, a large number of steel pipe piers are set within the projection range of the newly built bridge, which will not affect traffic and will not bring danger to the support structure when vehicles pass. Compared with the traditional support arrangement type, the present invention creatively uses truss beams to cross existing roads to meet the needs of vehicle traffic; fully utilizes the interaction between AutoCAD and Midas civil, draws the support structure and the plane projection diagram of the cast-in-place beam structure in AutoCAD, and loads the small distribution beams in different areas in the structural plane projection diagram. This modeling and calculation method is convenient and efficient, avoiding the processing of numerous units in civil and finding loading positions.

[0018] The invention adopts the bracket arrangement type to ensure the safe passage of vehicles, and adopts the calculation method to improve the modeling efficiency. The invention has a reference and guiding role for similar situations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the spatial analysis of the support structure of the present invention.

[0020] Figure 2 It is the plane projection of the cast-in-place beam structure and the plane position diagram of the small distribution beam described in the present invention.

[0021] Figure 3 It is a schematic cross-sectional view of the bracket of the present invention.

[0022] In the figure: steel pipe pier 1, longitudinal distribution beam 2, truss beam 3, small distribution beam 4, thin steel plate 5, cast-in-place beam structure plane 6.

[0023] The following will be combined with the attached Figure 1-3 The specific implementation of the present invention is described as follows: Figures 1 to 3 As shown, the method described is carried out in the following steps in sequence:

[0024] The cast-in-place beam support comprises a steel pipe pier (1), a longitudinal distribution beam (2), a truss beam (3), a small distribution beam (4) and a thin steel plate (5), wherein the longitudinal distribution beam (2) has a height of h2, the upper and lower chords of the truss beam (3) have a height of h3, and the small distribution beam (4) has a height of h4.

[0025] First, a cast-in-place beam support structure spatial model is established in AutoCAD. The spatial model is the centroid connection line of each main structure. To ensure that the existing road is unobstructed, a number of truss beams (3) are used to cross the existing road. The number of truss beams (3) on each span is called a group of truss pieces. The center of the lower chord of the truss beam (3) is taken as the coordinate origin, the span direction of the truss beam (3) is the X axis, the direction of the existing road is the Y axis, and a plurality of groups of truss beams (3) are arranged along the Y axis; the lower end points of the vertical bars at both ends of each group of truss pieces (3) are connected along the Y axis to form a longitudinal distribution beam (2); the longitudinal distribution beam (2) is drawn along the -Z direction at a certain interval to form a steel pipe pier (1); the upper chord of the left end of each group of truss pieces (3) is connected along the Y axis to form a small distribution beam (4), and a plurality of small distribution beams (4) are arranged at a certain interval in the +X direction, and the small distribution beams (4) on the plane are grouped as 1; the small distribution beam (4) is copied along the +Z direction, the copy distance is (h3+h4) / 2, and the copied small distribution beams (4) are grouped as 2, and at the same time, a plane projection diagram (6) of the cast-in-place beam structure is placed on the plane, and the plane projection diagram contains the plane projection diagrams of the flange plate, the web plate, the top and bottom plates, and the cross beam. The thin steel plate (5) laid on the small distribution beam (4) of the second marshaling is irrelevant to the calculation and is not considered in the model.

[0026] Each structure in the above-mentioned cast-in-place beam support structure spatial model established in AutoCAD needs to occupy a separate layer, and the file is saved as a dxf file.

[0027] Secondly, the calculation model of Midas civil was established. The dxf file was imported into midas, and the steel pipe pier (1) and the longitudinal distribution beam (2) were selected, and moved in the -Z direction by (h2+h3) / 2, and the longitudinal distribution beam (2) and the truss beam (3) were elastically connected; the steel pipe pier (1) was moved in the -Z direction by h2 / 2, and the top of the steel pipe pier (1) was elastically connected to the corresponding point of the longitudinal distribution beam (2); the small distribution beam (4) of group 1 was deleted, and the small distribution beam (4) of group 2 was elastically connected to the corresponding point of the upper chord of the truss beam (3). The material and section properties of each unit were given, and the bottom of the steel pipe pier (1) was constrained.

[0028] Next, load. The plan projection diagram (6) of the cast-in-place beam structure loads the small distribution beam (4) in different areas. Calculate the constant load Gi and Qi borne by each area respectively, and at the same time calculate the length and li of the small distribution beam (4) in each area, and then calculate the constant load (Gi / li) and live load (Qi / li) borne by the small distribution beam (4) in each area, and apply the line load to the small distribution beam (4) in the corresponding area. Run the program to calculate and analyze the strength and stiffness.

[0029] Finally, the linear elastic buckling stability analysis of the overall structure is carried out.

[0030] Midas civil software is within the scope of prior art. Example

[0031] First, a spatial model of the cast-in-place beam support structure is established in AutoCAD. Several truss beams are used to span the existing road. The several truss beams on each span are called a group of truss beams. The center of the lower chord of the truss beam is taken as the coordinate origin, the span direction of the truss beam is the X-axis, and the direction of the existing road is the Y-axis. Several groups of truss beams are set along the Y-axis; the lower end points of the vertical bars at both ends of each group of truss pieces are connected along the Y-axis to form a longitudinal distribution beam; the longitudinal distribution beams are drawn along the -Z direction at a certain interval to form a steel pipe pier; the upper chord of the left end of each group of truss pieces is connected along the Y-axis to form a small distribution beam, and several small distribution beams are arranged at a certain interval in the +X direction. The small distribution beams on this plane are grouped as 1; the small distribution beams are copied along the +Z direction, and the copied small distribution beams are grouped as 2. At the same time, the plane projection diagram of the cast-in-place beam structure is placed on this plane. Thin steel plates are laid on the small distribution beams of group 2. In the above-mentioned cast-in-place beam support structure spatial model established in AutoCAD, each structure needs to occupy a separate layer, and the file is saved as a dxf file. Secondly, the Midas civil calculation model is established. Import the dxf file in midas, select the steel pipe pier and the longitudinal distribution beam, and move them to the -Z direction for an appropriate distance. The longitudinal distribution beam is elastically connected to the truss beam; the steel pipe pier is moved to the -Z direction for a certain distance, and the top of the steel pipe pier is elastically connected to the corresponding point of the longitudinal distribution beam; delete the small distribution beam 1 of group 1, and the small distribution beam of group 2 is elastically connected to the corresponding point of the upper chord of the truss beam. Assign each unit material and section properties, and constrain the bottom of the steel pipe pier. Thirdly, load. The plane projection diagram of the cast-in-place beam structure loads the small distribution beam in different regions. Calculate the constant load Gi and Qi borne by each region respectively, and at the same time calculate the length and li of the small distribution beam in each region, and then calculate the constant load (Gi / li) and live load (Qi / li) borne by the small distribution beam in each region, and apply the line load to the small distribution beam in the corresponding region. Run the program to calculate and analyze the strength and stiffness. Finally, perform linear elastic buckling stability analysis on the overall structure.

[0032] The method of the present invention has been verified to effectively solve the actual technical problems in the construction process and realize the arrangement and rapid modeling calculation of cast-in-place beam supports in the case of non-orthogonality with the existing road.

[0033] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A cast-in-place beam support design method based on Midas civil that is non-orthogonal to existing roads, characterized by: The method described is carried out in the following steps: The cast-in-place beam support comprises a steel pipe pier (1), a longitudinal distribution beam (2), a truss beam (3), a small distribution beam (4) and a thin steel plate (5), wherein the height of the longitudinal distribution beam (2) is h2, the height of the upper and lower chords of the truss beam (3) is h3, and the height of the small distribution beam (4) is h4; First, a cast-in-place beam support structure spatial model is established in AutoCAD. The spatial model is the centroid connection line of each main structure. In order to ensure the smooth flow of the existing road, several truss beams (3) are used to cross the existing road. In the above-mentioned cast-in-place beam support structure spatial model established in AutoCAD, each structure needs to occupy a separate layer, and the file is saved as a dxf file; Secondly, using the Midas civil calculation model, the dxf file is imported into midas, the steel pipe pier (1) and the longitudinal distribution beam (2) are selected, and they are moved in the -Z direction by (h2+h3) / 2, and the longitudinal distribution beam (2) is elastically connected to the truss beam (3); the steel pipe pier (1) is moved in the -Z direction by h2 / 2, and the top of the steel pipe pier (1) is elastically connected to the corresponding point of the longitudinal distribution beam (2); Next, load the small distribution beam (4) in different regions according to the plane projection diagram (6) of the cast-in-place beam structure, and calculate the dead load Gi and Qi borne by each region respectively, and calculate the length li of the small distribution beam (4) in each region, and then calculate the dead load (Gi / li) and live load (Qi / li) borne by the small distribution beam (4) in each region, and apply the line load to the small distribution beam (4) in the corresponding region; Finally, the linear elastic buckling stability analysis of the overall structure is carried out.

2. The method for designing a cast-in-place beam support based on Midas civil and non-orthogonal to an existing road according to claim 1, characterized in that: In the process of using a plurality of truss beams (3) to cross an existing road, the plurality of truss beams (3) on each span are called a group of truss beams; the center of the lower chord of the truss beam (3) is taken as the coordinate origin, the span direction of the truss beam (3) is taken as the X-axis, the direction of the existing road is taken as the Y-axis, and a plurality of groups of truss beams (3) are arranged along the Y-axis; the lower end points of the vertical bars at both ends of each group of truss beams (3) are connected along the Y-axis to form a longitudinal distribution beam (2); the longitudinal distribution beams (2) are drawn at a certain interval in the -Z direction to form a steel pipe pier (1); each 1 The upper chord at the left end of the group truss piece (3) is connected along the Y axis to form a small distribution beam (4), and a plurality of small distribution beams (4) are arranged at a certain interval in the +X direction, and the small distribution beams (4) on the plane are grouped as 1; the small distribution beams (4) are copied along the +Z direction, and the copy distance is (h3+h4) / 2, and the copied small distribution beams (4) are grouped as 2. At the same time, a plane projection diagram (6) of the cast-in-place beam structure is placed on the plane, and the plane projection diagram contains the plane projection diagrams of the flange plate, the web plate, the top and bottom plates, and the cross beam.

3. The method for designing a cast-in-place beam support based on Midas civil and non-orthogonal to an existing road according to claim 2, characterized in that: In the calculation model using Midas civil, the elastic connection between the small distribution beam (4) of group 1 and the small distribution beam (4) of group 2 and the corresponding points of the upper chord of the truss beam (3) is deleted, and the material and section characteristics of each unit are given, and the bottom of the steel pipe pier (1) is constrained.

4. The method for designing a cast-in-place beam support based on Midas civil and non-orthogonal to an existing road according to claim 3 is characterized in that: During the loading process, the program is run to calculate and analyze the strength and stiffness.

5. The method for designing a cast-in-place beam support based on Midas civil and non-orthogonal to an existing road according to claim 3, characterized in that: In the process of using the Midas civil calculation model, before assigning the material and section properties of each unit and the bottom constraint of the steel pipe pier (1), the small distribution beam (4) of group 1 is deleted, and the small distribution beam (4) of group 2 is elastically connected to the corresponding point of the upper chord of the truss beam (3).

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