A construction method for in-situ repair and reinforcement of supporting steel pipe columns

Abstract

The present invention belongs to the technical field of bridge engineering construction, and in particular relates to a method for in-situ repair and reinforcement of supporting steel pipe columns. By pouring plain concrete inside the steel pipe columns, the compressive bearing capacity of the original structure of the steel pipe columns is increased, and by pouring a reinforced concrete coating on the outer wall of the steel pipe columns, the tensile bearing capacity of the original structure of the steel pipe columns is increased, thereby achieving the repair and reinforcement of steel pipe columns that have been subjected to impact and yield deformation. The beneficial effect of the present invention is that it can complete the secondary reinforcement of damaged steel pipe columns without dismantling the supporting steel pipe columns and the structure above the column top, achieving in-situ repair and reinforcement of damaged steel pipe columns. For urban cross-road doorway steel pipe column supports, it can greatly reduce the construction period and alleviate municipal traffic pressure.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge engineering construction, and in particular relates to an in-situ repair and reinforcement construction method for a supporting steel pipe column. Background Art

[0002] With the large-scale construction of urban viaducts, more and more bridges crossing roads are being constructed in cities. Cross-line bridges are mostly constructed using the portal steel pipe support method, which can reduce traffic pressure as much as possible. Due to the continuous construction, the portal steel pipe support has the risk of being damaged by collisions with social vehicles and construction vehicles. For the portal support that has been erected, if the steel pipe column undergoes large plastic deformation after being hit by external force, the structural bearing capacity will be greatly reduced. The commonly used reinforcement methods currently include increasing the cross-section method, external steel reinforcement method, and external FRP reinforcement method. Sometimes it is necessary to dismantle the supporting steel pipe column and the structure above the column top. The construction process is complicated and the construction period is long. It cannot achieve the purpose of rapid repair, and the municipal traffic pressure is high.

[0003] Chinese patent CN 106593004 A provides a method for reinforcing steel pipe columns with a reinforced square steel tube and concrete-reinforced fiber composite. The method involves placing a square steel tube around the existing steel pipe column, encasing the column. A fiber-reinforced composite is wrapped around the outer square steel tube. After the adhesive of the fiber-reinforced composite cures, a filler is poured between the existing steel pipe column and the outer square steel tube. The filler is a self-stressing, self-compacting concrete (SSC) with a formula of cement: water: sand: stone (1:0.23-0.33:0.85-1.08:0.92-1.09), with 0.8-2.5% by weight of a water reducer. This technology combines the techniques of self-stressing and self-compacting concrete, applying SSC structures to steel pipe column reinforcement projects. The SSC-encased SSC is used to partially or completely reinforce damaged steel pipe columns, achieving a strong ferrule effect on the existing steel pipe column without increasing steel usage, thereby improving its bearing capacity and ductility.

[0004] However, this technology uses self-stressed concrete to bear the load. The self-stress created by the concrete improves mechanical properties such as elastic modulus, bond strength, impact modulus, and fatigue resistance, making the concrete more effective in bearing loads. Using other fillers can easily lead to stress concentration, affecting the strength of the steel column.

[0005] Therefore, achieving rapid in-situ repair of steel pipe columns is of great significance to ensuring the normal traffic and construction progress of municipal roads. Summary of the Invention

[0006] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a construction method for in-situ repair and reinforcement of supporting steel pipe columns, which realizes the in-situ repair and reinforcement of damaged steel pipe columns, can greatly reduce the construction period of urban cross-road portal type steel pipe column supports and alleviate municipal traffic pressure.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for in-situ repair and reinforcement of a supporting steel pipe column is provided, wherein plain concrete is poured inside the steel pipe column and a reinforced concrete coating is poured on the outer wall of the steel pipe column, thereby performing an inner and outer double-layer in-situ repair and reinforcement of the supporting steel pipe column. The method specifically comprises the following steps:

[0009] (1) Temporarily reinforce the damaged steel pipe column by evenly adding stiffening steel plates around the outer wall of the damaged steel pipe column. The length of the stiffening steel plates is required to cover the damaged area of ​​the steel pipe column.

[0010] (2) cutting a circular hole above the damaged area of ​​the steel pipe column;

[0011] (3) Pour concrete into the steel pipe column through the circular hole to near the height of the opening, completing the initial transformation of the steel pipe column's load-bearing system from the steel pipe column being loaded on a single column to the steel pipe column and the plain concrete inside the column being loaded on a combined basis;

[0012] (4) Tie the steel frame around the outer wall of the steel pipe column and install the side formwork around the outer periphery of the steel frame;

[0013] (5) Pour concrete around the outer wall of the steel pipe column until the pouring height exceeds the opening of the steel pipe column, so that the concrete fills the space inside and outside the steel pipe column through the circular hole;

[0014] (6) After the poured concrete is cured to the design strength, the side formwork is removed to complete the secondary conversion of the steel pipe column's load-bearing system from the steel pipe column and the plain concrete inside the column to the steel pipe column and the reinforced concrete wrapped outside the column, thus completing the in-situ repair and reinforcement of the steel pipe column.

[0015] Preferably, in the step (1), the stiffening steel plates are evenly distributed at 45° on the cross section of the steel pipe column, and the thickness of the stiffening steel plates is not less than 12 mm and the width is not less than 20 cm, so as to increase the cross-sectional area and stiffness of the damaged steel pipe column; the length of the stiffening steel plates can cover the damaged area of ​​the steel pipe column, and the two ends of the stiffening steel plates have a certain connection length with the intact area of ​​the steel pipe column, wherein the bottom connection length is not less than 50 cm, so as to ensure the effective connection between the stiffening steel plates and the steel pipe column; the top connection length is not less than 200 cm, so as to reserve an effective reinforcement distance for pouring concrete above the damaged area of ​​the steel pipe column, so that the effective reinforcement distance of the reinforced area above the damaged area of ​​the concrete-poured steel pipe column is not less than 150 cm, and at the same time, a stiffness increasing distance from the steel pipe column to the concrete pouring area is reserved, that is, the length of the stiffening steel plate that exceeds the reinforced area above the damaged area of ​​the steel pipe column and is not poured with concrete, which is not less than 50 cm.

[0016] Preferably, in step (2), the circular hole is located between two adjacent stiffening steel plates, and the diameter of the circular hole should not be too large, preferably 150 mm, so that the concrete pump pipe can be inserted; the circular hole is located at a height of not less than 100 cm above the damaged area of ​​the steel pipe column to prevent secondary damage to the adjacent area of ​​the damaged area when pouring concrete into the interior of the steel pipe column.

[0017] Preferably, the step (3) is specifically as follows: passing the concrete pump pipe through the reserved circular hole, pouring concrete into the steel pipe column, and stopping pouring until the height of the concrete pouring surface in the steel pipe column is close to the position of the circular hole. After the concrete in the steel pipe column is cured to the design strength, the compressive bearing capacity of the section of the damaged area of ​​the steel pipe column is effectively increased, and the initial conversion of the steel pipe column force system from the steel pipe column single column force to the steel pipe column and the plain concrete in the column joint force is realized.

[0018] Preferably, in step (4), the steel skeleton and the side formwork are based on the bottom foundation block of the steel pipe column; the steel skeleton surface area covers the steel pipe column and the outer wall reinforcing steel plate surface area; the main reinforcement of the steel skeleton on one side of the damaged area of ​​the steel pipe column is encrypted to improve the structural safety factor.

[0019] Preferably, the step (5) is specifically as follows: a concrete pump pipe is extended from the top of the steel pipe column side formwork into between the outer wall of the steel pipe column and the side formwork, concrete is poured and an inserted vibrator is used to vibrate as the concrete is poured until the top surface of the poured concrete exceeds the height of the circular hole reserved on the steel pipe column.

[0020] Preferably, the step (6) is specifically as follows: covering the top surface of the concrete poured on the outside of the steel pipe column with a geomembrane and sprinkling water for curing; after the concrete strength reaches the design strength, removing the geomembrane and the side formwork, thereby effectively increasing the tensile bearing capacity of the damaged area of ​​the steel pipe column, and realizing a secondary conversion of the steel pipe column force system from the steel pipe column and the plain concrete inside the column being jointly stressed to the steel pipe column and the reinforced concrete wrapped outside the column being jointly stressed, thereby completing the in-situ repair and reinforcement of the steel pipe column.

[0021] The beneficial effects of the present invention are:

[0022] (1) The present invention can achieve in-situ repair and reinforcement of damaged steel pipe columns without dismantling the supporting steel pipe columns and the structure above the column tops. For urban cross-road doorway steel pipe column supports, it can greatly reduce the construction period and alleviate municipal traffic pressure.

[0023] (2) In the present invention, the compressive bearing capacity of the original structure of the steel pipe column is increased by pouring plain concrete inside the steel pipe column, and the tensile bearing capacity of the original structure of the steel pipe column is increased by pouring a reinforced concrete coating layer on the outer wall of the steel pipe column, thereby realizing the repair and reinforcement of the steel pipe column that has yielded and deformed due to impact. The construction process is simple and the construction convenience is good, and it can be completed without the need for large-scale special equipment.

[0024] (3) The multiple reinforcing steel plates around the outer wall of the steel pipe column in the present invention can not only play a temporary reinforcement role for the steel pipe column, but the reinforcing steel plates at the top exceeding the reinforcement area can also ensure that the stiffness of the repaired and reinforced steel pipe column gradually increases from top to bottom, thereby eliminating the possibility of structural stress concentration from a structural perspective and increasing the stress safety of the repaired and reinforced steel pipe column.

[0025] (4) In the present invention, a circular hole is opened in a certain area above the damaged steel pipe column, and there is no need to use steel plate welding to reinforce it later. It can be filled with concrete poured inside and outside the steel pipe column.

[0026] (5) In the present invention, the main reinforcement of the steel skeleton on one side of the damaged area of ​​the steel pipe column is densified, which further increases the structural safety factor and improves the structural safety reserve while ensuring the tensile bearing capacity of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of step 2 of the in-situ repair and reinforcement construction method for supporting steel pipe columns of the present invention;

[0028] Figure 2 Schematic diagram of the AA section of step 2 of the in-situ repair and reinforcement construction method for the supporting steel pipe column of the present invention;

[0029] Figure 3 Schematic diagram of step 4 of the in-situ repair and reinforcement construction method for supporting steel pipe columns of the present invention;

[0030] Figure 4 Schematic diagram of section BB of step four of the in-situ repair and reinforcement construction method for supporting steel pipe columns of the present invention;

[0031] Figure 5 Schematic diagram of step seven of the in-situ repair and reinforcement construction method for supporting steel pipe columns of the present invention;

[0032] Figure 6 This is a schematic diagram of the CC section of step seven of the in-situ repair and reinforcement construction method for supporting steel pipe columns of the present invention.

[0033] In the figure, 1-steel pipe column; 2-reinforcing steel plate; 3-damaged area of ​​steel pipe column; 4-circular hole; 5-concrete; 6-steel pipe column foundation; 7-reinforcement skeleton; 7-1-main reinforcement of the reinforcement skeleton; 8-side formwork; 9-reinforcement area above the damaged area of ​​the steel pipe column. DETAILED DESCRIPTION

[0034] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0035] To make the objectives, technical solutions, and advantages of the present invention more apparent, the present invention will be further described in detail below with reference to the accompanying drawings. It is apparent that the embodiments described are only some, not all, of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0036] The in-situ repair and reinforcement construction method of the supporting steel pipe column provided by the present invention is as follows: Figure 1-6 As shown, the following steps are included:

[0037] (1) Eight reinforcing steel plates 2 with a thickness of not less than 12 mm and a width of not less than 20 cm are uniformly welded around the outer wall of the damaged steel pipe column 1, and the reinforcing steel plates 2 are distributed at 45° on the cross section of the steel pipe column 1. Figure 1 、 2 As shown; the length of the stiffening steel plate 2 covers the damaged area 3 of the steel pipe column, and the two ends of the stiffening steel plate 2 have a certain connection length with the intact area of ​​the steel pipe column 1, wherein the bottom connection length is not less than 50 cm to ensure the effective connection between the stiffening steel plate 2 and the steel pipe column 1, and the top connection length is not less than 200 cm to reserve an effective reinforcement distance for pouring concrete 5 above the damaged area 3 of the steel pipe column, so that the effective reinforcement distance (length) of the reinforced area 9 above the damaged area of ​​the steel pipe column poured with concrete 5 is not less than 150 cm, as shown Figure 5 As shown, a stiffness increasing distance from the steel pipe column 1 to the concrete 5 pouring area is reserved, that is, the length of the stiffening steel plate 2 exceeding the reinforced area 9 above the damaged area of ​​the steel pipe column and the part where the concrete 5 is not poured is not less than 50 cm.

[0038] (2) A circular hole 4 with a diameter of 150 mm is cut by electric welding 100 cm above the damaged area 3 of the steel pipe column. The circular hole 4 is located between two adjacent stiffening steel plates 2. Figure 1 、 2 shown.

[0039] (3) The concrete pump pipe is passed through the reserved circular hole 4, and concrete 5 is poured into the steel pipe column 1 until the height of the concrete 5 pouring surface in the steel pipe column 1 is close to the position of the circular hole 4. After the concrete in the steel pipe column 1 is cured to the design strength, the compressive bearing capacity of the damaged area 3 of the steel pipe column is effectively increased, and the initial conversion of the force system of the steel pipe column 1 from the force of the steel pipe column 1 alone to the force of the steel pipe column 1 and the plain concrete 5 in the column is realized.

[0040] (4) With the steel pipe column foundation 6 as support, a circle of steel frame 7 is tied around the outer wall of the steel pipe column 1. The surface area of ​​the steel frame 7 covers the surface area of ​​the steel pipe column 1 and the outer wall stiffening steel plate 2. Figure 3 、 4 As shown; the main reinforcement 7-1 of the steel frame on one side of the damaged area 3 of the steel pipe column is densified; the concrete protective layer pad is tied on the outside of the steel frame 7 (located between the steel frame 7 and the side formwork 8, not marked in the figure). After the steel frame 7 and the concrete protective layer pad are tied, the side formwork 8 is installed and tightened. The effective reinforcement distance from the top of the steel frame 7 to the damaged area 3 of the steel pipe column is not less than 150cm, so that after pouring concrete 5, the reinforced area 9 above the damaged area of ​​the steel pipe column can effectively improve the tensile bearing capacity of the original structure of the steel pipe column 1. The distance from the top of the steel frame 7 to the top of the stiffening steel plate 2 (the part where the concrete 5 is not poured) is not less than 50cm, so that the stiffening steel plate 2 beyond the reinforced area 9 above the damaged area of ​​the steel pipe column can ensure that the stiffness of the repaired and reinforced steel pipe column 1 gradually increases from top to bottom, thereby eliminating structural stress concentration from a structural perspective.

[0041] (5) The concrete pump pipe extends from the top of the side formwork 8 into the space between the outer wall of the steel pipe column 1 and the side formwork 8, and the concrete 5 is poured and vibrated with an inserted vibrator until the top surface of the poured concrete 5 exceeds the height of the circular hole 4 reserved on the steel pipe column 1.

[0042] (6) Continue pouring concrete 5, and fill the space inside and outside the steel pipe column 1 through the circular hole 4 communication channel until the pouring surface height exceeds a certain height of the circular hole 4, which can be 10-15 cm higher than the height of the circular hole 4, and fully vibrate.

[0043] (7) Cover the top surface of the concrete 5 poured outside the steel pipe column 1 with a geomembrane and sprinkle water for maintenance. After the strength of the concrete 5 reaches the designed strength, remove the geomembrane and the side formwork 8. Figure 5 、 6, effectively increasing the tensile bearing capacity of the damaged area 3 of the steel pipe column, realizing the secondary conversion of the force system of the steel pipe column 1 from the joint force of the steel pipe column 1 and the plain concrete 5 inside the column to the joint force of the steel pipe column 1 and the reinforced concrete 5 wrapped outside the column, completing the in-situ repair and reinforcement of the steel pipe column 1.

[0044] The above examples of the present invention are described in detail, but the content is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for in-situ repair and reinforcement of a supporting steel pipe column, characterized in that: The damaged area of ​​the supporting steel pipe column is repaired and reinforced in situ by pouring plain concrete inside the steel pipe column and pouring a reinforced concrete covering layer on the outer wall of the steel pipe column. The following steps are included: (1) Temporarily reinforce the damaged steel pipe column by evenly adding stiffening steel plates along the outer wall of the damaged steel pipe column. The length of the stiffening steel plates is required to cover the damaged area of ​​the steel pipe column. There is a certain connection length between the two ends of the stiffening steel plates and the undamaged area of ​​the steel pipe column, of which the bottom connection length is not less than 50 cm to ensure the effective connection between the stiffening steel plates and the steel pipe column. The top connection length is not less than 200 cm to reserve an effective reinforcement distance for pouring concrete above the damaged area of ​​the steel pipe column, so that the effective reinforcement distance of the reinforced area above the damaged area of ​​the concrete poured steel pipe column is not less than 150 cm. At the same time, a stiffness increasing distance from the steel pipe column to the concrete pouring area is reserved, that is, the length of the stiffening steel plate that exceeds the reinforced area above the damaged area of ​​the steel pipe column and is not poured with concrete, which is not less than 50 cm. (2) Cutting a circular hole above the damaged area of ​​the steel pipe column; (3) Pour concrete into the steel pipe column through the circular hole to near the height of the opening, completing the initial transformation from the force of the steel pipe column alone to the force of the steel pipe column and the plain concrete inside the column; (4) Tie the steel frame around the outer wall of the steel pipe column and install the side formwork around the outer periphery of the steel frame; (5) Pour concrete around the outer wall of the steel pipe column until the pouring height exceeds the opening of the steel pipe column, so that the concrete fills the space inside and outside the steel pipe column through the circular hole; (6) After the poured concrete is cured to the design strength, the side formwork is removed to complete the secondary conversion of the steel pipe column's load-bearing system from the steel pipe column and the plain concrete inside the column to the steel pipe column and the reinforced concrete wrapped outside the column, thus completing the in-situ repair and reinforcement of the steel pipe column.

2. The in-situ repair and reinforcement construction method for supporting steel pipe columns according to claim 1 is characterized in that: In the step (1), the stiffening steel plates are evenly distributed at 45° on the cross section of the steel pipe column, and the thickness of the stiffening steel plates is not less than 12 mm and the width is not less than 20 cm.

3. The in-situ repair and reinforcement construction method for supporting steel pipe columns according to claim 1 is characterized in that: In the step (2), the circular hole is located between two adjacent stiffening steel plates and is located at a height of not less than 100 cm above the damaged area of ​​the steel pipe column.

4. The in-situ repair and reinforcement construction method for supporting steel pipe columns according to claim 1 is characterized in that: In the step (4), the steel skeleton and the side formwork are based on the bottom foundation block of the steel pipe column, and the steel skeleton surface area covers the steel pipe column and the outer wall reinforcing steel plate surface area; when tying the steel skeleton, the main reinforcement of the steel skeleton on the side of the damaged area of ​​the steel pipe column is densified.

5. The in-situ repair and reinforcement construction method for supporting steel pipe columns according to claim 1 is characterized in that: The step (3) is specifically as follows: passing the concrete pump pipe through the reserved circular hole, pouring concrete into the steel pipe column, and stopping pouring until the height of the concrete pouring surface in the steel pipe column is close to the position of the circular hole, and curing the concrete in the steel pipe column to the design strength.

6. The in-situ repair and reinforcement construction method for supporting steel pipe columns according to claim 1 is characterized in that: The step (5) is specifically as follows: a concrete pump pipe is extended from the top of the side formwork into the space between the outer wall of the steel pipe column and the side formwork, concrete is poured and vibrated with an inserted vibrating rod as the concrete is poured until the top surface of the poured concrete exceeds the height of the circular hole reserved on the steel pipe column.

7. The in-situ repair and reinforcement construction method for supporting steel pipe columns according to claim 1 is characterized in that: The step (6) is specifically as follows: covering the top surface of the concrete poured outside the steel pipe column with a geomembrane and sprinkling water for curing; after the concrete strength reaches the designed strength, removing the geomembrane and the side formwork to complete the in-situ repair and reinforcement of the steel pipe column.

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