A cable-stayed bridge rigid frame system structure

Abstract

The present invention belongs to the technical field of cable-stayed bridges, and specifically relates to a rigid frame system structure of a cable-stayed bridge, including a tower-beam combination structure and a stiffening structure. The tower-beam combination structure includes a steel main beam passing through a bridge tower body, and first shear nails arranged at intervals are welded on the web of the steel main beam; the stiffening structure includes a vertical stiffening steel plate arranged adjacent to the outer side of the bridge tower body, and second shear nails arranged at intervals are welded on the inner side of the vertical stiffening steel plate; the rigid frame system structure of the cable-stayed bridge provided by the present invention is a supplement to the existing rigid frame system structure of the cable-stayed bridge. Combined with calculation and analysis, the rigid frame system structure provided by the present invention can make full use of the excellent tensile properties of steel and the excellent compressive properties of concrete, improve the local stress performance of the steel main beam, and the combination of the steel main beam and the concrete bridge tower can be guaranteed, the stress is clear, and the construction is convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of cable-stayed bridges, and in particular relates to a rigid frame system structure of a cable-stayed bridge. Background Art

[0002] With the country's policy requirements of promoting green highways and developing "four transportations", bridge industrialization, namely structural standardization, factory prefabrication and mechanized construction, has been put on the agenda. Due to the geographical location, topography and landforms of mountain bridges, their industrialization often requires lightweight structures for easy transportation and installation. The steel-concrete composite beam + prefabricated bridge deck structure is increasingly being adopted in actual projects due to its reasonable acceptance, light weight of the steel main beam and high degree of factory production. For bridges with large spans or when the surrounding environment has high requirements for the landscape of the structure itself, the steel-concrete composite beam cable-stayed bridge type is often adopted.

[0003] The rigid frame system has become a common constraint system for mountain bridges, especially cable-stayed bridges with high piers in valley terrain, due to its high rigidity, good structural stability under daily loads and wind and vehicle vibrations, and strong bearing capacity. In the design of cable-stayed bridges with rigid frame systems, the pier-tower-beam connection area is one of the key design parts. The main tower at this location needs to withstand the vertical force transmitted by the cable and the bending moment caused by the unbalanced horizontal force. The main beam needs to withstand huge axial force and bending moment, and at the same time bear the torque caused by the vehicle eccentric load.

[0004] In existing concrete cable-stayed bridges, the rigid frame system is usually designed in coordination with the tower cross beam and the main beam block 0. The tower cross beam is prestressed in the transverse direction and anchored on the concrete bridge tower. The rigid frame system of steel-concrete composite beam cable-stayed bridges is rarely used in China. The effective combination of steel main beams and concrete bridge towers has a great impact on the local stress of the structure within this range, the transmission of force to the lower tower column, and even the stress of the entire bridge. Summary of the invention

[0005] The object of the present invention is to provide a cable-stayed bridge rigid frame system structure, which has the advantages of facilitating the combination of a steel main beam and a concrete bridge tower, improving the local stress of the main beam and making the stress clear.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A cable-stayed bridge rigid frame system structure, comprising:

[0008] A tower-beam combination structure, comprising a steel main beam passing through a tower body of a bridge tower, wherein first shear studs arranged at intervals are welded on the web of the steel main beam;

[0009] The reinforcing structure comprises a vertical reinforcing steel plate arranged close to the outer side of the bridge tower body, and second shear studs arranged at intervals are welded to the inner side of the vertical reinforcing steel plate.

[0010] Under preferred conditions, the first shear studs are arranged at intervals along the longitudinal direction of the bridge and the vertical direction of the bridge, and the adjacent spacings are 200 mm.

[0011] Under preferred conditions, the second shear studs are arranged at intervals along the transverse direction and the vertical direction of the bridge, and the adjacent spacings are all 400 mm.

[0012] Under preferred conditions, the stiffening structure further comprises:

[0013] A plurality of prestressed high-strength precision-rolled threaded coarse steel bars are provided and arranged at intervals along the transverse and vertical directions of the bridge.

[0014] Under preferred conditions, the adjacent spacing of the prestressed high-strength precision-rolled threaded coarse steel bars along the transverse direction of the bridge is 800 mm, and the adjacent spacing along the vertical direction of the bridge is 600 mm.

[0015] Under preferred conditions, the stiffening structure further comprises:

[0016] A plurality of stiffening ribs are provided, which are arranged at intervals on the inner side of the vertical stiffening steel plate and are arranged vertically along the entire length of the vertical stiffening steel plate.

[0017] Under preferred conditions, the stiffening ribs are divided into two groups, both of which are spaced apart in the transverse direction of the bridge, wherein the adjacent spacing of the first group of stiffening ribs adjacent to the web of the steel main beam is 400 mm, and the adjacent spacing of the second group of stiffening ribs located in the mid-span range of the vertical stiffening steel plates is 2400 mm.

[0018] Under preferred conditions, only the web of the steel main beam passes through the tower body.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] The cable-stayed bridge rigid frame system structure provided by the present invention is a supplement to the existing cable-stayed bridge rigid frame system structure. Combined with calculation and analysis, the rigid frame system structure provided by the present invention can make full use of the excellent tensile performance of steel and the excellent compressive performance of concrete, improve the local stress performance of the steel main beam, and the combination of the steel main beam and the concrete bridge tower can be guaranteed, the stress is clear, and the construction is convenient.

[0021] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic elevation diagram of a rigid frame system structure of a cable-stayed bridge provided according to an embodiment of the present invention is shown;

[0023] Figure 2A schematic plan view of a rigid frame system structure of a cable-stayed bridge provided according to an embodiment of the present invention is shown;

[0024] Figure 3 A cross-sectional schematic diagram showing a rigid frame system structure of a cable-stayed bridge provided according to an embodiment of the present invention;

[0025] Figure 4 A schematic diagram of an analysis model for a specific calculation example in the present invention is shown;

[0026] Figure 5 It is shown as a schematic diagram of the model boundary in the calculation example;

[0027] Figure 6 The figure shows the longitudinal stress diagram of the concrete bridge deck and the upper edge of the bridge tower in the calculation example;

[0028] Figure 7 The figure shows the longitudinal stress diagram of the concrete bridge deck and the lower edge of the bridge tower in the calculation example;

[0029] Figure 8 The figure shows the transverse stress diagram of the concrete bridge deck and the upper edge of the bridge tower in the calculation example;

[0030] Fig. 9 The figure shows the transverse stress diagram of the concrete bridge deck and the lower edge of the bridge tower in the calculation example;

[0031] Fig.10 The figure shows the schematic diagram of equivalent stress on the upper edge of the steel beam in the calculation example;

[0032] Fig.11 The figure shows the schematic diagram of equivalent stress at the lower edge of the steel beam in the calculation example;

[0033] Explanation of numbers in the figure: 10-bridge tower body, 20-steel main beam, 21-first shear nail, 30-vertical stiffening steel plate, 31-second shear nail, 32-prestressed high-strength precision-rolled threaded coarse steel bar, 33-stiffening rib plate, 331-first group of stiffening rib plates, 332-second group of stiffening rib plates. DETAILED DESCRIPTION

[0034] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0035] It should be noted that, in the present invention, when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0037] like Figure 1 , 2 As shown in Figure 3, the present invention provides a cable-stayed bridge rigid frame system structure, including a tower-beam combination structure and a stiffening structure thereof, wherein the tower-beam combination structure includes a steel main beam 20 passing through a bridge tower body 10, and first shear studs 21 arranged at intervals are welded on the web of the steel main beam 20, and the first shear studs 21 are arranged at intervals along the longitudinal direction of the bridge and the vertical direction of the bridge, and the adjacent spacings are all 200 mm.

[0038] The reinforcing structure comprises a vertical reinforcing steel plate 30 arranged close to the outside of the tower body 10, and the inner side of the vertical reinforcing steel plate 30 is welded with a second shearing nail 31 arranged at intervals. The second shearing nails 31 are arranged at intervals along the transverse bridge direction and the vertical bridge direction, and the adjacent spacing is 400mm.

[0039] In the present invention, in order to further improve the stress conditions at the consolidation point of the pier tower beam, the reinforcing structure also includes prestressed high-strength precision-rolled threaded coarse steel bars 32 and stiffening ribs 33. A plurality of prestressed high-strength precision-rolled threaded coarse steel bars 32 are provided, and are arranged at intervals along the transverse and vertical directions of the bridge. The adjacent spacing of the prestressed high-strength precision-rolled threaded coarse steel bars 32 along the transverse direction of the bridge is 800 mm, and the adjacent spacing along the vertical direction of the bridge is 600 mm.

[0040] The stiffening ribs 33 are provided in plurality and are arranged at intervals on the inner side of the vertical stiffening steel plate 30 and arranged vertically along the entire length of the vertical stiffening steel plate 30 .

[0041] Furthermore, according to the present invention, the stiffening ribs 33 are divided into two groups, both of which are arranged at intervals along the transverse direction of the bridge, wherein the adjacent spacing of the first group of stiffening ribs 331 adjacent to the web of the steel main beam 20 is 400 mm, and the adjacent spacing of the second group of stiffening ribs 332 located in the mid-span range of the vertical stiffening steel plate 30 is 2400 mm.

[0042] In the present invention, only the web of the steel main beam 20 passes through the bridge tower body 10 , that is, the wing plate of the steel main beam 20 does not pass through the bridge tower body 10 .

[0043] In the present invention, the first shear stud 21 and the second shear stud 31 are both cylindrical head welding studs with a diameter of 22 mm, and the material of the cylindrical head welding studs is ML15 or ML15AL.

[0044] The following further analyzes and explains the rigid frame system structure of the cable-stayed bridge provided by the present invention through a specific calculation example.

[0045] 1. Finite element analysis model

[0046] In the calculation and analysis, three main beam sections 0#, 1# and 2# were selected, with a total length of 39m, among which the range of section 0# corresponds to the consolidation area of ​​pier tower beam.

[0047] 1.1 Finite element discretization

[0048] The finite element calculation adopts the large-scale general finite element calculation software Ansys R15.0; among them, the concrete bridge deck and bridge tower adopt SOLID45 units, and the steel main beam and steel cross beam adopt SHELL63 units. The steel main beam and the concrete bridge deck are connected by a common node. The prestressed steel strands in the cross beam on the tower column are simulated by the solid force reinforcement method. The prestressed tendon unit is LINK8 unit, which is coupled with the concrete unit through the constraint equation method, and the prestressed load is applied by the cooling method. The cable unit is not established in this calculation model. The cable force applied to the analysis model is simulated by extracting the internal force of the cable of the corresponding load condition in the overall calculation model and applying it to the corresponding node. The local analysis model is as follows Figure 4 shown.

[0049] 1.2 Boundary conditions

[0050] In this calculation, in order to simulate the boundary conditions at the ends of the model, virtual beam units with a length of 10 cm were established at the top and bottom of the bridge tower column and the left and right ends of the model. The virtual beam unit was established using the BEAM4 unit, and its elastic modulus was enlarged 10 times to simulate the effect of the rigid arm. The virtual beam unit is connected to the top and bottom of the tower column and the nodes at the ends of the model by establishing constraint equations to generate rigid zones. The bottom of the bridge tower is treated as consolidated, and the force boundaries of the corresponding working conditions are applied to the remaining rigid arms (the top of the bridge tower, the left and right ends of the main beam) according to the corresponding cross-sectional internal forces extracted from the MidasCivil overall model. The model boundary conditions are as follows: Figure 5 shown.

[0051] 1.3 Calculation of loads

[0052] This calculation takes into account the effects of structural deadweight, bridge deck pavement and vehicle loads.

[0053] (1) The deadweight of the structure is loaded in the form of inertial load, and the acceleration is taken as 10m / s 2 .

[0054] (2) The second phase of the dead load is mainly considered to be the effect of the bridge deck pavement, according to 3.5kN / m 2 Consider, as a surface load applied to the bridge deck.

[0055] (3) The automobile load is applied as highway-Ⅰ lane load in accordance with the General Specification for Design of Highway Bridges and Culverts (JTG D60-2015). In order to consider the most unfavorable automobile load distribution mode for the pier-to-beam fixed connection area, the mobile load tracker function is used in the MidasCivil overall calculation model to track the layout of the automobile load when the maximum negative bending moment is generated in the steel main beam unit at the root of the bridge tower, and the load is applied in the Ansys local analysis model accordingly.

[0056] 1.4 Load combinations

[0057] The crack resistance verification for the normal use limit state adopts the frequently encountered combination: 1.0 dead load + 0.7 vehicle load (excluding vehicle impact force).

[0058] The strength verification of the ultimate bearing capacity state adopts the basic combination: 1.1×[1.2 dead load + 1.4 vehicle load (including vehicle impact force)].

[0059] 2. Main verification results

[0060] 2.1 Cracking resistance calculation of normal serviceability limit state

[0061] Under the frequently encountered combination, the longitudinal stress of the concrete bridge deck and bridge tower is as follows Figure 6 , Figure 7As shown. It can be seen that except for the cable action point and some stress concentration areas at the boundary, the overall longitudinal stress level is between -5.89MPa and 3.0MPa. At the connection between the bridge deck and the upper crossbeam of the bridge tower, a tensile stress of about 3MPa appears on the upper edge of the bridge deck and a compressive stress of about -5.89MPa appears on the lower edge, which is caused by the sudden change of stiffness here.

[0062] Under the frequently encountered combination, the lateral stress of the concrete bridge deck and bridge tower is as follows Figure 8 , Fig. 9 It can be seen that except for the compressive stress exceeding -10MPa at the junction of the tower column and the bridge deck, the overall transverse stress level is between -7.33MPa and 0.67MPa, and there is basically no tensile stress except at the cable action point.

[0063] 2.2 Strength verification of steel main beam under basic combination under ultimate bearing capacity state

[0064] Under the basic combination, the equivalent stress of the steel main beam is as follows: Fig.10 , Fig.11 As shown in the figure, it can be seen that the upper flange of the steel beam has a relatively low stress level due to the common node connection with the bridge deck. Stress concentration occurs at the junction of the steel main beam and the upper cross beam of the bridge tower. Except for the stress concentration point, the stress level of the steel main beam is basically below 154MPa. The stress of the vertical stiffener is relatively small, ranging from 31.5MPa to 62.2MPa.

[0065] 3. Calculation conclusion

[0066] (1) Judging from the tensile stress levels of the concrete bridge deck and bridge towers under frequently encountered combinations, their crack resistance can meet the requirements.

[0067] (2) The stress of the steel main beam does not exceed the design strength of the material.

[0068] It can be seen from the above calculation and analysis that the rigid frame system structure provided by the present invention can make full use of the excellent tensile properties of steel and the excellent compressive properties of concrete, improve the local stress performance of the steel main beam, and the combination of the steel main beam and the concrete bridge tower can be guaranteed, and the stress is clear.

[0069] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0070] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0071] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A cable-stayed bridge rigid frame system structure, characterized in that: include: A tower-beam combination structure, comprising a steel main beam (20) passing through a tower body (10), wherein first shear studs (21) arranged at intervals are welded on the web of the steel main beam (20); the first shear studs (21) are arranged at intervals along the longitudinal direction of the bridge and the vertical direction of the bridge, and the adjacent spacings are all 200 mm; The reinforcing structure comprises a vertical reinforcing steel plate (30) arranged adjacent to the outside of the bridge tower body (10), and second shear studs (31) arranged at intervals are welded to the inside of the vertical reinforcing steel plate (30); the second shear studs (31) are arranged at intervals along the transverse bridge direction and the vertical bridge direction, and the adjacent spacings are all 400 mm; The reinforcement structure further comprises: Prestressed high-strength precision-rolled threaded thick steel bars (32), a plurality of which are provided and arranged at intervals in the transverse and vertical directions of the bridge; A plurality of stiffening ribs (33) are provided, which are arranged at intervals on the inner side of the vertical stiffening steel plate (30) and are arranged vertically along the entire length of the vertical stiffening steel plate (30); The stiffening ribs (33) are divided into two groups, both of which are spaced apart in the transverse direction of the bridge, wherein the adjacent spacing of the first group of stiffening ribs (331) adjacent to the web of the steel main beam (20) is 400 mm, and the adjacent spacing of the second group of stiffening ribs (332) located in the mid-span range of the vertical stiffening steel plate (30) is 2400 mm.

2. The cable-stayed bridge rigid frame system structure according to claim 1 is characterized in that: The adjacent spacing of the prestressed high-strength precision-rolled threaded coarse steel bars (32) along the transverse direction of the bridge is 800 mm, and the adjacent spacing along the vertical direction of the bridge is 600 mm.

3. The cable-stayed bridge rigid frame system structure according to claim 1 is characterized in that: Only the web of the steel main beam (20) passes through the bridge tower body (10).

Images