Cable-stayed bridge steel arch tower steel-concrete combined section connecting structure and construction method

Abstract

The invention belongs to the field of cable-stayed bridges in bridge engineering, and particularly relates to a cable-stayed bridge steel arch tower steel-concrete combined section connecting structure which is characterized in that tower columns of a plurality of arch-shaped steel bridge towers are intersected on an integral steel tower base, and the middle lower part of the integral steel tower base is connected with a concrete tower base in a concrete pouring manner; a steel lattice is designed at the root of the integral steel tower base, a pressure-bearing steel bottom plate is arranged at the lower end of the steel lattice, perforated steel plates are arranged on the bottom face of the pressure-bearing steel bottom plate and comprise a plurality of perforated steel plates in the bridge direction and a plurality of perforated steel plates in the transverse bridge direction, and through steel bars are arranged in round holes corresponding to the perforated steel plates. A traditional pressure-bearing shear transmission type steel-concrete combined section connecting structure is locally optimized and improved, the perforated steel plate is arranged at the bottom of the pressure-bearing steel bottom plate, the problem that concrete pouring construction in a steel lattice is difficult is solved, positioning construction and installation of the whole steel tower base are facilitated, the shear resistance is improved, force transmission is clear, the structure is simple, and construction is convenient.

Description

Technical Field

[0001] The invention belongs to the field of cable-stayed bridges in bridge engineering, and in particular relates to a steel-concrete combined section connection structure of a steel arch tower of a cable-stayed bridge and a construction method. Background Art

[0002] In recent years, with the strengthening of domestic economic strength, the construction of bridges not only considers functional requirements, but also the requirements for urban landscape are getting higher and higher. Bridges are also designed as landscape buildings. Steel arch tower cable-stayed bridges have become a new form. Its characteristics are novel and unique structure and beautiful shape. It is a bold innovation of urban cable-stayed bridges. Combined with the development of domestic steel structure technology, its scope of use is becoming wider and wider.

[0003] At present, the steel-concrete combined section of the bridge tower is mainly in the full pressure-bearing type and the pressure-bearing shear-transfer type. The full pressure-bearing method is to anchor the steel tower in the concrete tower base by combining the pressure-bearing steel bottom plate and prestressed fine-rolled threaded steel bars at the interface between the root of the steel tower and the concrete tower base. The axial force of the bridge tower is transmitted in the form of pressure through the pressure-bearing steel bottom plate, the bending moment is borne by the prestressed fine-rolled threaded steel bars, and the shear force is transmitted through the friction force of the contact surface; the pressure-bearing shear-transfer method is to design the root of the steel tower into a formatted form. The steel format is composed of an outer steel wall plate and an intermediate longitudinal and transverse partition. Shear nails or perforated steel plate shear keys are set in the steel format, and a pressure-bearing steel bottom plate is set at the bottom end. Concrete is poured in the steel format. For the connection section with a large bending moment, prestressed fine-rolled threaded steel bars are also required to ensure that the structure does not produce tensile stress.

[0004] The main problems of the above-mentioned conventional pressure-bearing shear-transmitting steel-concrete combined section are as follows: the structure inside the steel grid is quite complicated. A single steel tower base is divided into 16 grids by the outer steel tower wall plate and the middle longitudinal and transverse partitions. Perforated steel bottom plate connectors are arranged in the grid, and steel bars and prestressed precision-rolled threaded steel bars are arranged. The working space is small, the environment is poor, and the operation is inconvenient. It is impossible to ensure that the steel bars are accurately positioned and smoothly inserted into the middle hole of the perforated steel plate. It is difficult to pour concrete in the steel grid and the quality is not easy to guarantee. The design and installation of the positioning support are subject to many conditions. Therefore, it is necessary to locally optimize the traditional pressure-bearing shear-transmitting steel-concrete combined section. Summary of the invention

[0005] The problem to be solved by the present invention is to overcome the shortcomings of the background technology and provide a steel-concrete combined section connection structure and a construction method for a cable-stayed bridge steel arch tower.

[0006] The present invention is achieved through the following technical solutions: A steel-concrete combined section connection structure of a cable-stayed bridge steel arch tower comprises three arched steel bridge towers, the tower columns of the three arched steel bridge towers intersect at an integral steel tower base, the middle and lower parts of the integral steel tower base are connected to the concrete tower base by concrete pouring; an anchoring steel plate is arranged at the middle and lower parts of the integral steel tower base, prestressed precision-rolled threaded steel bars are anchored on the anchoring steel plate, and the lower ends of the prestressed precision-rolled threaded steel bars are pre-buried in the concrete tower base; a steel grid is designed at the root of the integral steel tower base, the steel grid comprises an outer steel wall plate and middle longitudinal and transverse partitions, and the lower end of the steel grid is arranged A pressure-bearing steel bottom plate is arranged, and a perforated steel plate is arranged on the bottom surface of the pressure-bearing steel bottom plate. A plurality of circular holes are evenly arranged on the perforated steel plate from top to bottom. The perforated steel plate comprises a plurality of perforated steel plates along the bridge direction and a plurality of perforated steel plates in the transverse direction of the bridge. The perforated steel plates along the bridge direction and the perforated steel plates in the transverse direction of the bridge are perpendicular to each other, wherein the perforated steel plates along the bridge direction correspond one-to-one to the Y-direction stiffening ribs in the tower column, and the perforated steel plates in the transverse direction of the bridge correspond one-to-one to the X-direction stiffening ribs in the tower column, and through steel bars are arranged in the circular holes corresponding to the perforated steel plates along the bridge direction and the circular holes corresponding to the perforated steel plates in the transverse direction of the bridge.

[0007] Furthermore, reinforcing steel bars are provided at the anchorage points at the lower ends of the prestressed precision-rolled threaded steel bars.

[0008] The present invention also includes a construction method for a steel-concrete combined section connection structure of a cable-stayed bridge steel arch tower, comprising the following steps: Step 1: Process the integral steel tower base; construct the cap pile foundation; embed the concrete tower base steel bars; Step 2: Install the positioning bracket in the tower base on the top of the cap; pour the concrete at the bottom of the concrete tower base. When the concrete at the bottom of the concrete tower base reaches the design strength, hoist the integral steel tower base onto the positioning bracket, adjust the position and elevation of the integral steel tower base by the jack, and after accurate positioning, weld the pressure-bearing steel bottom plate and the perforated steel plate below to the positioning bracket, tie the through steel bars in the perforated steel plate, install the prestressed precision-rolled threaded steel bar channel, and embed the prestressed precision-rolled threaded steel bar; Step 3: Pour the upper concrete of the concrete tower base. After the concrete reaches the designed strength, tension the prestressed precision-rolled threaded steel bars. After tensioning, perform grouting and anchor sealing to complete the steel-concrete joint section connection of the cable-stayed bridge steel arch tower.

[0009] The present invention partially optimizes and improves the traditional pressure-bearing shear-transmitting steel-concrete combined section connection structure, separates the perforated steel plate connector from the steel grid, and sets the perforated steel plate at the bottom of the pressure-bearing steel bottom plate. The external placement of the perforated steel plate connector solves the problem of the difficulty in pouring concrete in the steel grid. The connection structure is easy and quick to install. After positioning and installation, concrete is directly poured, and prestressed precision-rolled threaded steel bars are tensioned, which shortens the construction period and facilitates construction. The reinforced concrete set in the hole is easier to pour densely. At the same time, the design structure of the present invention ensures the shear force transmission of the integral steel tower base in the longitudinal and transverse directions of the bridge, which facilitates the positioning, construction and installation of the integral steel tower base. The perforated steel plate shear connector added below the pressure-bearing steel bottom plate improves the shear resistance, achieving the purpose of clear force transmission, simple structure and convenient construction. It is not only safe and reliable, but also saves construction costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is an external cross-sectional view of the connection between the integral steel tower base and the concrete tower base of the present invention; Figure 2 It is a cross-sectional view of the connection between the integral steel tower base and the concrete tower base of the present invention; Figure 3 for Figure 1 The top section plan view of Figure 4 for Figure 2 The mid-section plan view of Figure 5 This is a large-scale drawing of the perforated steel plate of the present invention; Figure 6 It is a schematic diagram of a partial three-dimensional structure of the integral steel tower base of the present invention; Figure 7 It is a schematic diagram of the partial three-dimensional structure of the integral steel tower base of the present invention from another angle.

[0011] In the figure, 1 is the integral steel tower base, 2 is the outer steel wall plate, 3 is the X-direction stiffening rib, 4 is the Y-direction stiffening rib, 5 is the partition, 6 is the anchor steel plate, 7 is the pressure-bearing steel bottom plate, 8 is the prestressed precision-rolled threaded steel bar, 9 is the reinforcing steel bar, 10 is the fixed end, 11 is the tensioning end, 12 is the perforated steel plate, 13 is the concrete tower base, 14 is the circular hole, and 15 is the through steel bar. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0013] The bridge tower of this embodiment is an arched steel bridge tower, including three arched steel bridge towers, including two main and one auxiliary tower columns, the tower columns are connected by space cable surface cables, and the central axis of the bridge tower is an ellipse. Considering that the steel-concrete combination section is set on each tower column, six positions need to be set, and the forces at different positions are different, and the construction is inconvenient, etc., therefore, this embodiment proposes that the three arched steel bridge towers are intersected at the integral steel tower base 1 and then connected with the concrete tower base 13. The bidirectional transverse bending moment at the bottom of a single arched steel bridge tower and the bidirectional longitudinal bending moment of the two main arched steel bridge towers are balanced at the integral steel tower base 1, avoiding the situation that the steel-concrete combination section of a single tower column is subjected to excessive force, the structural force is reasonable, the integral steel tower base 1 can be prefabricated and installed as a whole, and at the same time, the traditional pressure-bearing shear-transmitting connection structure is partially optimized and improved, and two-way perforated steel plates 12 shear connectors are added at the bottom of the pressure-bearing steel bottom plate 7 to improve the shear resistance, so as to achieve the purpose of clear force transmission, simple structure and convenient construction. The steel-concrete combined section connection structure of this embodiment is described in detail below.

[0014] In this embodiment, the columns of the three arched steel bridge towers meet at an integral steel tower base 1, specifically, three elliptical steel box towers meet at a pressure-bearing steel bottom plate 7. The elliptical steel box tower includes an outer steel wall plate 2, X-direction stiffening ribs 3 and Y-direction stiffening ribs 4. The X-direction stiffening ribs 3 and Y-direction stiffening ribs 4 in the outer steel wall plate 2 are connected downwardly to the partition plate 5 to ensure that the downward force transmission of the elliptical steel box tower is clear. The pressure-bearing steel bottom plate 7 is buried in the concrete tower base 13 to transmit the axial forces of the three elliptical steel box towers under different working conditions to the concrete tower base 13. The lower and middle parts of the integral steel tower base 1 are connected to the concrete tower base 13 by concrete pouring, and the lower parts of the anchoring steel plates 6 of the integral steel tower base 1 are connected to the concrete tower base 13 by concrete pouring.

[0015] An anchoring steel plate 6 is provided in the middle and lower part of the integral steel tower base 1. The anchoring steel plate 6 is used for anchoring the prestressed precision-rolled threaded steel bar 8. The anchoring steel plate 6 is the tensioning end 11 of the prestressed precision-rolled threaded steel bar 8. The lower end of the prestressed precision-rolled threaded steel bar 8 is pre-buried in the concrete tower base 13. The lower end of the prestressed precision-rolled threaded steel bar 8 is the fixed end 10, i.e., the anchoring end. The prestressed precision-rolled threaded steel bar 8 mainly bears the bending moment of the integral steel tower base 1. It is preferred to provide reinforcing steel bars 9 near the anchoring point of the lower end of the prestressed precision-rolled threaded steel bar 8.

[0016] A steel grid is designed at the root of the integral steel tower base 1. The steel grid includes an outer steel wall plate 2 and a longitudinal and transverse partition 5 in the middle. The steel grid is an existing well-known structure and will not be introduced here. A pressure-bearing steel bottom plate 7 is arranged at the lower end of the steel grid. The pressure-bearing steel bottom plate 7 is buried inside the concrete tower base 13. A shear key of a perforated steel plate 12 is arranged on the bottom surface of the pressure-bearing steel bottom plate 7, which mainly bears the shear force received by the integral steel tower base 1. A plurality of circular holes 14 are evenly arranged on the perforated steel plate 12 of this embodiment from top to bottom. The perforated steel plate 12 is arranged in two directions, including a plurality of perforated steel plates 12 in the longitudinal direction and a plurality of perforated steel plates 12 in the transverse direction. The perforated steel plates 12 in the longitudinal direction and the perforated steel plates 12 in the transverse direction are perpendicular to each other, wherein the perforated steel plates 12 in the longitudinal direction correspond one-to-one with the Y-direction stiffening ribs 4 in the tower column, and the perforated steel plates 12 in the transverse direction correspond one-to-one with the X-direction stiffening ribs 3 in the tower column. Through steel bars 15 are arranged in the circular holes 14 corresponding to the perforated steel plates 12 along the bridge direction and in the circular holes 14 corresponding to the perforated steel plates 12 across the bridge direction.

[0017] The construction method of the above-mentioned connection structure comprises the following steps: Step 1: Process the prefabricated integral steel tower base 1 in the factory, and simultaneously tie the steel bars of the pre-embedded concrete tower base 13; construct the cap pile foundation.

[0018] Step 2: Install the positioning bracket (formed by welding of steel sections) in the tower base at the top of the cap. Set up some formwork to cast the lower concrete of the concrete tower base 13. When the lower concrete of the concrete tower base 13 reaches the design strength, use a crane to hoist the integral steel tower base 1 onto the positioning bracket. Use a jack to adjust the position and elevation of the integral steel tower base 1. After accurate positioning, weld the pressure-bearing steel bottom plate 7 and the perforated steel plate 12 below to the positioning bracket, then tie the through steel bars 15 in the perforated steel plate 12, install the prestressed fine-rolled threaded steel bar 8 channel, and pre-embed the prestressed fine-rolled threaded steel bar 8.

[0019] Step three: Set up the formwork for the rest of the concrete tower base 13, pour the upper concrete of the concrete tower base 13, and vibrate it in layers. For some areas where the space is small and the vibrating rod cannot vibrate, it is necessary to insert the steel bars manually and hit the formwork with a wooden hammer to vibrate to ensure the density of the concrete. During the pouring process, check the stability of the embedded prestressed fine-rolled threaded steel bars 8, the prestressed fine-rolled threaded steel bar channels and other embedded parts, and reset and fix them in time for loosening, deformation, displacement, etc. After the concrete reaches the designed strength, tension the prestressed fine-rolled threaded steel bars 8, and anchor the upper end of the prestressed fine-rolled threaded steel bars 8 to the anchor steel plate 6. After tensioning is completed, grouting and anchor sealing are carried out to complete the connection of the steel-concrete joint section of the steel arch tower of the cable-stayed bridge. The next step is to support the construction of the bridge tower segment.

[0020] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A steel-concrete combined section connection structure of a cable-stayed bridge steel arch tower, comprising three arched steel bridge towers, characterized in that: The columns of the three arched steel bridge towers meet at an integral steel tower base (1), and the middle and lower parts of the integral steel tower base (1) are connected to a concrete tower base (13) by concrete pouring; an anchoring steel plate (6) is arranged at the middle and lower parts of the integral steel tower base (1), and prestressed fine-rolled threaded steel bars (8) are anchored on the anchoring steel plate (6), and the lower ends of the prestressed fine-rolled threaded steel bars (8) are pre-buried in the concrete tower base (13); a steel grid is designed at the root of the integral steel tower base (1), and the steel grid includes an outer steel wall plate (2) and middle longitudinal and transverse partitions (5); a pressure-bearing steel bottom plate (7) is arranged at the lower end of the steel grid, and a perforated steel plate (12) is arranged on the bottom surface of the pressure-bearing steel bottom plate (7) A plurality of circular holes (14) are evenly arranged on the perforated steel plate (12) from top to bottom, the perforated steel plate (12) includes a plurality of perforated steel plates (12) in the longitudinal direction of the bridge and a plurality of perforated steel plates (12) in the transverse direction of the bridge, the perforated steel plates (12) in the longitudinal direction of the bridge and the perforated steel plates (12) in the transverse direction of the bridge are perpendicular to each other, wherein the perforated steel plates (12) in the longitudinal direction of the bridge correspond one-to-one with the Y-direction stiffening ribs (4) in the tower column, and the perforated steel plates (12) in the transverse direction of the bridge correspond one-to-one with the X-direction stiffening ribs (3) in the tower column, and through steel bars (15) are arranged in the circular holes (14) corresponding to the perforated steel plates (12) in the longitudinal direction of the bridge and the circular holes (14) corresponding to the perforated steel plates (12) in the transverse direction of the bridge.

2. The steel-concrete combined section connection structure of the steel arch tower of the cable-stayed bridge according to claim 1 is characterized in that: A reinforcing steel bar (9) is provided at the anchor point at the lower end of the prestressed precision-rolled threaded steel bar (8).

3. According to the cable-stayed bridge steel arch tower steel-concrete combined section connection structure of claim 1, a cable-stayed bridge steel arch tower steel-concrete combined section connection structure construction method comprises the following steps: Step 1: Processing the integral steel tower base (1); constructing the cap pile foundation; pre-embedding the steel bars of the concrete tower base (13); Step 2: Install a positioning bracket in the tower base at the top of the cap; pour concrete at the bottom of the concrete tower base (13); when the concrete at the bottom of the concrete tower base (13) reaches the designed strength, hoist the integral steel tower base (1) onto the positioning bracket, adjust the position and elevation of the integral steel tower base (1) by a jack, and after accurate positioning, weld the pressure-bearing steel bottom plate (7) and the perforated steel plate (12) below to the positioning bracket, tie the through steel bars (15) in the perforated steel plate (12), install the prestressed precision-rolled threaded steel bar channel, and embed the prestressed precision-rolled threaded steel bar (8); Step 3: pouring concrete on the upper part of the concrete tower base (13), and after the concrete reaches the designed strength, tensioning the prestressed fine-rolled threaded steel bars (8), and after the tensioning is completed, grouting and anchoring are performed to complete the connection of the steel-concrete joint section of the steel arch tower of the cable-stayed bridge.

Images