Low pier column steel-concrete combined gate pier structure

Abstract

The utility model provides a kind of low pier column steel mixed combined portal pier structure, belong to bridge engineering technical field.It is composed of reinforced concrete pier column, pier top steel mixed structure combination section and prestressed concrete bent cap three parts, first construction reinforced concrete pier column when construction, and embed finish rolling screw thread steel in pier top;After reinforced concrete pier column concrete reaches design strength, install steel shell, and with the bolt connection of cover beam inner embedded steel plate;After that, cast-in-place prestressed concrete bent cap and tension prestressed steel bundle;Finally, press-in steel shell inner micro-expansion concrete, and in prestressed concrete bent cap top give finish rolling screw thread steel certain initial force, and the pipe and reserved round hole are carried out pressure grouting treatment.Set up steel mixed structure combination section between pier column top and prestressed concrete bent cap, realize load transmission path optimization, eliminate pier column secondary bending moment generated in cover beam prestressed tension stage thoroughly, significantly reduce the adverse effect of secondary bending moment to low pier column.

Description

Technical Field

[0001] This utility model belongs to the field of bridge engineering technology and relates to a low-profile steel-concrete composite portal pier structure. Background Technology

[0002] Portal piers are widely used in bridge engineering in my country due to their advantages such as high lateral stiffness, convenient construction, strong obstacle-crossing ability, and good seismic performance. A typical portal pier structure mainly consists of reinforced concrete pier columns and prestressed concrete cap beams. The conventional construction procedure is to first pour the pier columns, and then construct the prestressed concrete cap beams using the cast-in-place method with scaffolding. Stress analysis of this structural system shows that under the action of prestressed steel strand tension in the cap beams and overall temperature changes, the cap beams will generate transverse shear forces and significant secondary bending moments on the pier columns. It is worth noting that the magnitude of these loads (especially secondary bending moments) is closely related to the stiffness of the pier columns: the greater the stiffness of the pier columns, the greater the loads they bear, especially the secondary bending moments.

[0003] Due to limitations imposed by the track elevation and the structures that need to be crossed, engineering designs often require the use of portal piers consisting of short columns and large-span prestressed concrete cap beams. For short columns, due to their low height and high stiffness, secondary bending moments often become the key factor controlling their stress.

[0004] To eliminate or reduce the adverse effects of secondary bending moments on short piers, two measures are typically adopted in engineering: one is to strengthen the reinforcement of the pier, and the other is to install supports at the top of the pier. Strengthening the reinforcement of the pier leads to dense reinforcement, significantly increasing construction difficulty and making it difficult to guarantee the quality of pouring, thus increasing construction risks. In addition, for some short piers with extremely high stiffness, even with strengthened reinforcement, their stress may still be insufficient to meet the code requirements. Although the support scheme can effectively eliminate the secondary bending moments generated on the pier, the supports themselves require regular maintenance and replacement after damage. Especially for portal piers with limited space under the cap beam (such as "station-bridge integrated" rail transit stations, or situations where maintenance rooms are located under the cap beam), the later maintenance and replacement of the support scheme are significantly difficult, greatly limiting its application. Utility Model Content

[0005] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a steel-concrete composite portal pier structure for short piers that can eliminate the adverse effects of secondary bending moments of steel strands on short piers.

[0006] The objective of this utility model can be achieved through the following technical solutions:

[0007] The low-profile steel-concrete composite portal pier structure includes a reinforced concrete pier column, a steel-concrete composite structure section at the top of the pier, and a prestressed concrete cap beam. The steel-concrete composite structure section at the top of the pier is located at the upper end of the reinforced concrete pier column, and the prestressed concrete cap beam is located above the steel-concrete composite structure section at the top of the pier. An initial positioning component is provided between the prestressed concrete cap beam and the steel-concrete composite structure section at the top of the pier, and a fixing component is provided between the reinforced concrete pier column, the steel-concrete composite structure section at the top of the pier, and the prestressed concrete cap beam.

[0008] The initial positioning component is used to initially position the prestressed concrete cap beam. When the prestressed steel strands inside the prestressed concrete cap beam are tensioned, the prestressed concrete cap beam can be moved laterally to release the additional bending moment. The fixing component is used to fix the reinforced concrete pier, the steel-concrete structure joint section at the top of the pier, and the prestressed concrete cap beam together after the prestressed steel strands are tensioned.

[0009] In the aforementioned low-profile steel-concrete composite portal pier structure, the initial positioning component includes a connecting steel plate located at the top of the steel-concrete composite section at the pier top and an embedded steel plate located at the bottom of the prestressed concrete cap beam. The connecting steel plate has several connecting holes, and connecting bolts connected to the embedded steel plate at their upper ends pass through the connecting holes. When the prestressed steel strands in the prestressed concrete cap beam are tensioned, the connecting bolts can slide horizontally within the connecting holes.

[0010] The diameter of the connecting hole is larger than the outer diameter of the connecting bolt. When tensioning the prestressed steel strands, the prestressed concrete cap beam is allowed to freely expand and contract along the axial direction of the connecting bolt (expansion / contraction ≥ design displacement value + 10mm), while also serving a limiting function. The connecting bolt is a high-strength bolt.

[0011] In the aforementioned low-profile steel-concrete composite portal pier structure, the connecting hole is a horizontally elongated oval hole, the length of which is perpendicular to the direction of tensioning the prestressed steel strands. During the tensioning of the prestressed steel strands, the prestressed concrete cap beam is lowered along the length of the horizontally elongated oval hole, thereby causing the connecting bolts to slide within the hole.

[0012] In the aforementioned low-profile steel-concrete composite portal pier structure, the steel-concrete structure section at the pier top comprises a steel shell and micro-expansion concrete within the steel shell. The connecting steel plate is the top plate of the steel shell, and its side has an extension. The connecting hole is located on the extension. The extension extends horizontally outward, creating a clearance space below it to facilitate the connection of the connecting bolts.

[0013] In the above-mentioned low-profile steel-concrete composite portal pier structure, stiffening ribs are provided between the extension and the outer wall of the steel shell to improve the structural strength of the extension.

[0014] In the above-mentioned low-profile steel-concrete composite portal pier structure, the fixing component includes a finely rolled threaded steel bar fixed at its lower end within the reinforced concrete pier column, a through hole corresponding to the finely rolled threaded steel bar in the steel-concrete composite section at the top of the pier, and a steel pipe corresponding to the finely rolled threaded steel bar in the prestressed concrete cap beam. The finely rolled threaded steel bar passes through the through hole and the steel pipe sequentially from bottom to top and is fixed inside the steel pipe by grouting.

[0015] The diameter of the through hole in the steel-concrete structure joint section at the pier top is slightly larger than the diameter of the fine-rolled threaded steel bar (through hole diameter > fine-rolled threaded steel bar diameter + design displacement value + 10mm), which facilitates the insertion of the fine-rolled threaded steel bar. The steel pipe in the cap beam forms an unbonded channel, and the movement of the steel-concrete structure joint section at the pier top during the tensioning of the prestressed steel strands will not affect the fine-rolled threaded steel bar.

[0016] In the aforementioned low-profile steel-concrete composite portal pier structure, the steel pipe is a galvanized steel pipe.

[0017] The construction method for a low-profile steel-concrete composite portal pier structure includes the following steps:

[0018] Step 1: Construct reinforced concrete piers and pre-embed precision-rolled threaded steel bars at the top of the piers;

[0019] Step 2: After the concrete inside the reinforced concrete pier reaches the design strength, install the steel shell;

[0020] Step 3: Install the pre-embedded steel plate on the top of the steel shell and connect it with connecting bolts;

[0021] Step 4: Cast-in-place prestressed concrete cap beam and tension the prestressed steel strands;

[0022] Step 5: Press-cast the micro-expansion concrete inside the steel shell;

[0023] Step 6: Apply a certain initial force to the prestressed concrete cap beam with fine-rolled threaded steel, and perform grouting treatment on the steel pipe and through hole to form a grouting body.

[0024] In the above-mentioned construction method of the steel-concrete composite portal pier structure, before the cast-in-place prestressed concrete cap beam in step four, the cap beam formwork and prestressed steel strands are installed first.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] The traditional low-profile portal pier structure with reinforced concrete section at the top is replaced with a steel-concrete composite section at the top. This eliminates the need for high reinforcement in the pier column or supports, significantly reducing the adverse effects of secondary bending moments on the low-profile pier column and effectively avoiding the difficulties of support maintenance. Attached Figure Description

[0027] Figure 1 This is the overall layout diagram of the low-profile steel-concrete composite portal pier structure.

[0028] Figure 2 This is the front view of the steel-concrete structure section at the top of the pier.

[0029] Figure 3 This is a side view of the steel-concrete structure section at the top of the pier.

[0030] Figure 4 yes Figure 2 Sectional view at point AA.

[0031] Figure 5 yes Figure 2 Sectional view at point BB.

[0032] In the diagram, 1. Reinforced concrete pier; 2. Steel-concrete composite section at the pier top; 21. Steel shell; 22. Micro-expansion concrete; 23. Through hole; 3. Prestressed concrete cap beam; 31. Steel pipe; 41. Connecting steel plate; 411. Connecting hole; 412. Extension; 413. Stiffening rib; 42. Embedded steel plate; 43. Connecting bolt; 5. Precision rolled threaded steel. Detailed Implementation

[0033] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0034] like Figure 1 The illustrated low-profile steel-concrete composite portal pier structure includes reinforced concrete pier columns 1, a steel-concrete composite structure section 2 at the top of the pier, and a prestressed concrete cap beam 3. Reinforced concrete pier columns 1 are installed on the lower sides of both ends of the prestressed concrete cap beam 3. A steel-concrete composite structure section 2 is located at the upper end of each reinforced concrete pier column 1, and the prestressed concrete cap beam 3 is positioned above the steel-concrete composite structure section 2. An initial positioning component is provided between the prestressed concrete cap beam 3 and the steel-concrete composite structure section 2, and a fixing component is provided between the reinforced concrete pier columns 1, the steel-concrete composite structure section 2, and the prestressed concrete cap beam 3.

[0035] The initial positioning component is used to initially position the prestressed concrete cap beam 3. When the prestressed steel strands inside the prestressed concrete cap beam 3 are tensioned, the prestressed concrete cap beam 3 can be moved laterally to release the additional bending moment. The fixing component is used to fix the reinforced concrete pier column 1, the steel-concrete structure joint section 2 at the top of the pier and the prestressed concrete cap beam 3 together after the prestressed steel strands are tensioned.

[0036] like Figure 2 and Figure 3As shown, the initial positioning assembly includes a connecting steel plate 41 located at the top of the steel-concrete composite section 2 at the pier top and an embedded steel plate 42 located at the bottom of the prestressed concrete cap beam 3. The connecting steel plate 41 has several connecting holes 411, and connecting bolts 43, whose upper ends are connected to the embedded steel plate 42, pass through the connecting holes 411. The connecting bolts 43 are high-strength bolts, allowing them to slide horizontally within the connecting holes 411 during the tensioning of the prestressed steel strands in the prestressed concrete cap beam 3. During the tensioning of the prestressed steel strands, the prestressed concrete cap beam 3 is allowed to freely expand and contract along the axial direction of the connecting bolts 43 (expansion / contraction ≥ design displacement value + 10mm), while also serving a limiting function.

[0037] like Figure 4 As shown, the connecting hole 411 is a horizontally elongated oval hole, and the length direction of the horizontally elongated oval hole is perpendicular to the direction of tensioning the prestressed steel strand. When tensioning the prestressed steel strand, it will cause the prestressed concrete cap beam 3 to move down along the length of the horizontally elongated oval hole, thereby causing the connecting bolt 43 to slide within the horizontally elongated oval hole.

[0038] like Figure 2 and Figure 3 As shown, the steel-concrete composite structure section 2 at the top of the pier includes a steel shell 21 and micro-expansion concrete 22 disposed inside the steel shell 21. The connecting steel plate 41 is the top plate of the steel shell 21. The side of the connecting steel plate 41 has an extension 412. The connecting hole 411 is disposed on the extension 412. The extension 412 extends horizontally outward, and a clearance space is formed below the extension 412 to facilitate the connection of the connecting bolt 43.

[0039] like Figure 2 and Figure 4 As shown, several stiffening ribs 413 are provided between the extension 412 and the outer wall of the steel shell 21 to improve the structural strength of the extension 412.

[0040] like Figure 2 and Figure 3 As shown, the fixing component includes a finely rolled threaded steel bar 5 fixedly connected to the lower end of the reinforced concrete pier column 1. The finely rolled threaded steel bars 5 can be evenly distributed in rows or arrays as needed. The steel-concrete structure joint section 2 at the top of the pier has through holes 23 corresponding to the finely rolled threaded steel bars 5. Figure 5 As shown, the prestressed concrete cap beam 3 has galvanized steel pipes 31 corresponding to the threaded steel bars 5. The threaded steel bars 5 pass through the through holes 23 from bottom to top and extend into the steel pipes 31, and are then fixed inside the steel pipes 31 by grouting. The diameter of the through holes 23 in the steel-concrete structure joint section 2 at the pier top is slightly larger than the diameter of the threaded steel bars 5 (through hole diameter 23 > diameter of threaded steel bars 5 + design displacement value + 10mm), which facilitates the insertion of the threaded steel bars 5. The inside of the steel pipes 31 is an unbonded channel, so the movement of the steel-concrete structure joint section 2 at the pier top during the tensioning of the prestressed steel strands will not affect the threaded steel bars 5.

[0041] The construction method for this low-profile steel-concrete composite portal pier structure includes the following steps:

[0042] Step 1: Construct reinforced concrete pier 1 and pre-embed precision rolled threaded steel bar 5 on the top of the pier.

[0043] Step 2: After the concrete inside the reinforced concrete pier 1 reaches the design strength, install the steel shell 21; at this time, put the steel shell 21 in from top to bottom, and align the precision rolled threaded steel bar 5 with the corresponding through hole 23, until the steel shell 21 is stably placed on the reinforced concrete pier 1.

[0044] Step 3: Install the embedded steel plate 42 on the top of the steel shell 21, and connect the embedded steel plate 42 to the connecting steel plate 41 using connecting bolts 43. The embedded steel plate 42 has through holes corresponding to the connecting holes 411. The connecting bolts 43 pass through the through holes and are then fixed by locking nuts.

[0045] Step 4: Install the cap beam formwork, galvanized steel pipe 31 and prestressed steel strands, ensure the position of the embedded steel plate 42, cast the prestressed concrete cap beam 3 in place, and tension the prestressed steel strands.

[0046] Step 5: Press and pour the micro-expansion concrete 22 inside the steel shell 21.

[0047] Step 6: Apply a certain initial force to the prestressed concrete cap beam 3 and apply grouting treatment to the steel pipe 31 and through hole 23 to form a grouting body.

[0048] By setting a steel-concrete structure joint section between the top of the pier and the prestressed concrete cap beam, the load transfer path is optimized, the secondary bending moment of the pier generated during the prestressing tensioning stage of the cap beam is completely eliminated, and a maintenance-free rigid structural system for the low pier is formed. This significantly reduces the adverse effects of the secondary bending moment on the low pier and effectively avoids the problem of support maintenance.

[0049] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A low-profile steel-concrete composite portal pier structure, characterized in that, It includes a reinforced concrete pier (1), a steel-concrete structure joint section (2) at the top of the pier, and a prestressed concrete cap beam (3). The steel-concrete structure joint section (2) at the top of the pier is located at the upper end of the reinforced concrete pier (1), and the prestressed concrete cap beam (3) is located above the steel-concrete structure joint section (2) at the top of the pier. An initial positioning component is provided between the prestressed concrete cap beam (3) and the steel-concrete structure joint section (2) at the top of the pier, and a fixing component is provided between the reinforced concrete pier (1), the steel-concrete structure joint section (2) at the top of the pier, and the prestressed concrete cap beam (3).

2. The short-pier column steel-concrete composite portal pier structure according to claim 1, characterized in that, The initial positioning component includes a connecting steel plate (41) at the top of the steel-concrete structure joint section (2) at the pier top and an embedded steel plate (42) at the bottom of the prestressed concrete cap beam (3). The connecting steel plate (41) is provided with a plurality of connecting holes (411). A connecting bolt (43) with its upper end connected to the embedded steel plate (42) is inserted into the connecting hole (411). When the prestressed steel strands in the prestressed concrete cap beam (3) are tensioned, the connecting bolt (43) can slide horizontally in the connecting hole (411).

3. The short-pier column steel-concrete composite portal pier structure according to claim 2, characterized in that, The connecting hole (411) is a horizontally elongated oval hole, and the length direction of the horizontally elongated oval hole is perpendicular to the direction of tensioning the prestressed steel strand.

4. The short-pier column steel-concrete composite portal pier structure according to claim 2, characterized in that, The steel-concrete composite structure section (2) at the top of the pier includes a steel shell (21) and micro-expansion concrete (22) inside the steel shell (21). The connecting steel plate (41) is the top plate of the steel shell (21). The side of the connecting steel plate (41) has an extension (412), and the connecting hole (411) is provided on the extension (412).

5. The short-pier column steel-concrete composite portal pier structure according to claim 4, characterized in that, A stiffening rib (413) is provided between the extension (412) and the outer wall of the steel shell (21).

6. The short-pier column steel-concrete composite portal pier structure according to claim 1, characterized in that, The fixing component includes a fine-rolled threaded steel bar (5) whose lower end is fixed in the reinforced concrete pier column (1). The steel-concrete structure joint section (2) at the top of the pier has a through hole (23) corresponding to the fine-rolled threaded steel bar (5). The prestressed concrete cap beam (3) has a steel pipe (31) corresponding to the fine-rolled threaded steel bar (5). The fine-rolled threaded steel bar (5) passes through the through hole (23) and the steel pipe (31) from bottom to top and is fixed in the steel pipe (31) by grouting.

7. The short-pier column steel-concrete composite portal pier structure according to claim 6, characterized in that, The steel pipe (31) is a galvanized steel pipe (31).

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