CN101397854A - Enveloping prestressing force fastening type steel tube concrete column and reinforcement method - Google Patents

Abstract

The invention discloses a fastened steel pipe concrete column confined by pre-stress and a reinforcement method thereof. The column is mainly applied to the reinforcement of a monolayer, multilayer or high-rise frame column which exceeds the limit value of the strength, rigidity or axial compression ratio. The basic principle of the invention is as follows: transverse pre-tensioning of a steel plate which is added to the surface of a rectangular or round reinforced concrete column is built up by screwing down a shear high strength bolt and the resultant force thereof acts on the surface of the reinforced concrete column; in accordance with the principle that acting force equals to counter acting force, the surface of the reinforced concrete column generates a counter acting force (positive pressure) towards the inner wall of the steel plate; in such way, friction force, which is corresponding to the positive pressure and is the so-called shear resistant bearing capacity in a project, is generated between the concrete surface and the inner wall of the steel plate, thereby achieving the loaded effect of the current steel pipe concrete column that is manufactured by casting concrete on the prepared steel pipe. Due to the existence of the transverse pre-stress, the mechanical effect of the steel pipe concrete column in the invention is better than the current one.

Description

Outsourcing Prestressed Fastening Concrete Steel Tube Column and Its Reinforcement Method

technical field

The invention relates to a concrete column structure and a reinforcement method, in particular to an outsourcing prestressed fastening type steel pipe concrete column and a reinforcement method, belonging to the technical field of building structures.

Background technique

At present, when making concrete-filled steel pipe columns in high-rise buildings, steel pipes are usually made first, and then concrete is poured into the steel pipes. The problem with this kind of columns is that the concrete will shrink when it is set at high temperature, so that there is a gap between the concrete and the steel pipes, making it difficult to melt. as one. For the addition of floors to existing buildings, in order to increase the strength and rigidity of the columns, it is often necessary to reinforce the columns. At present, it is usually reinforced by wrapping angle steel outside the existing columns and adding panels. This method is difficult to ensure that the steel plate and the original concrete Transmit shear force to work together, but can only consider the strength and stiffness of the steel frame and the original concrete structure separately. The main reason is that there is no positive pressure between the steel plate surface and the concrete surface, that is, the shear force cannot be transmitted, and there is no basic premise for joint work. . Another method is to pour reinforced concrete directly around the existing concrete column to increase the cross section of the column. If no methods such as planting bars are used, the two cannot be guaranteed to work together. Time-consuming, difficult construction, high cost.

Contents of the invention

The technical problem to be solved by the present invention is to provide a reinforcement method for outsourcing prestressed fastening type concrete-filled steel pipe columns, and at the same time provide a structural form of outsourced prestressed fastening type steel pipe concrete columns. The reinforcement method and structure can make the reinforced concrete column and the outsourcing steel plate close together through prestressing, so as to work together to improve the rigidity and strength of the concrete column and meet the use requirements.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical scheme: the method for reinforcing the outsourcing prestressed fastening type concrete filled steel tube column comprises the following steps:

(1) Check and repair the original reinforced concrete columns, polish and clean the surface;

(2) Drill holes on the reinforced concrete column and implant steel bars; the diameter of the implanted steel bars is 16-25mm, and the implantation depth is 160-250mm;

(3) Brush high-temperature-resistant structural glue on the surface of the reinforced concrete column, and then cover the surface of the reinforced concrete column with steel plates that have been opened in sections. The hole diameter of the steel plate is larger than the diameter of the planting bar, and the planting bar is exposed to the surface of the steel plate by 20-40mm.

(4) Insert torsional shear type high-strength bolts on the bolt support bracket of the steel plate, tighten the high-strength bolts, so that the steel plate can establish a pre-tension force laterally, and use the principle of equal force and reaction force to generate positive pressure between the high-strength bolts and the steel plate, Therefore, it has the friction force of shear resistance, so that the steel plate is close to the surface of the reinforced concrete column;

(5) All the seams of the steel plates are welded by grooves, so that all the steel plates are connected as a closed whole;

(6) Weld and weld the steel bars of the planting bar head and the steel plate firmly; then outsource the steel mesh cement mortar with high grade and mixed with fireproof powder.

Outsourced prestressed fastening concrete-filled rectangular columns. Including rectangular reinforced concrete columns, there are 4 angle steel-shaped steel plates wrapped around the four corners of each section of the rectangular reinforced concrete columns, and rectangular steel plates with the same height as the angle steel-shaped steel plates are installed between the angle steel-shaped steel plates; each section of the reinforced concrete column There are two vertical seams on each surface, between the vertical seams is a torsional shear type high-strength bolt support bracket, and a torsional shear type high-strength bolt is worn on the torsional shear type high-strength bolt support bracket, and the angle steel shape of each section The steel plate and the rectangular steel plate are provided with holes according to the position of the reinforced concrete column, and are hung on the surface of the rectangular reinforced concrete column through the hole.

The angle-steel-shaped steel plate is an L-shaped equal-leg angle-steel cross-section, and the rectangular steel plate is a straight cross-section.

The outer layer of the rectangular steel plate is spot-welded with steel wire mesh, and brushed with high-grade cement fireproof mortar with fireproof powder, and its thickness is determined according to the fireproof grade.

Outsourced prestressed fastened steel tube concrete cylinder. Including circular reinforced concrete columns, on the surface of the circular reinforced concrete columns, there are 4 to 8 arc-shaped cross-section steel plates according to the size of the column diameter. The arc-shaped cross-section steel plates are divided into several sections according to the column height. There is a torsional shear type high-strength bolt support bracket at the end, and a torsional shear type high-strength bolt is threaded on the torsional shear type high-strength bolt support bracket. The arc-shaped cross-section steel plate of each section is cut according to the planting position of the reinforced concrete column. hole, and hang on the surface of the reinforced concrete column through the hole, and the arc-shaped cross-section steel plates are fixed and connected as a whole by torsional shear type high-strength bolts.

The arc-shaped section steel plate is a 1/4 arc-shaped or 1/8 arc-shaped section.

Steel wire mesh is spot-welded on the outer layer of the arc-shaped steel plate, and it is brushed with high-grade cement fireproof mortar with fireproof powder, and its thickness is determined according to the fireproof level.

Compared with the prior art, the present invention uses fastening steel plates to wrap the surface of the concrete column, and uses high-strength torsional-shear bolts for fastening and connection. The prestressing value is controlled by the section at the head cutout, and the prestressing of this bolt is simple and accurate. The torsional shear type high-strength bolts generate extrusion force and pre-tightening force from the periphery to the middle, so that the surface of the reinforced concrete column and the outer fastening steel plate are closely connected together, and a positive pressure is generated, and the shear load of the contact surface is passed. Force, so that the two work together, not only the reinforcement effect is good, the construction difficulty is small, time-saving, labor-saving, and low cost. Its basic principle is to make the fastening steel plate added to the surface of the rectangular or circular reinforced concrete column, and then establish a transverse pretension force after being tightened by torsional shear type high-strength bolts, and its resultant force acts on the surface of the reinforced concrete column. , the surface of the reinforced concrete column also produces a reaction force (positive pressure) on the inner wall of the fastening steel plate, so that the concrete surface and the inner surface of the fastening steel plate have a friction force corresponding to the positive pressure, that is, the shear bearing capacity in the project, reaching the current advanced Mechanics of CFST columns with recast concrete from steel pipes. Due to the existence of transverse prestress, its mechanical effect is better than the former. On the outer side of the outsourcing steel plate, use the planting head and torsional shear type high-strength bolt bracket as the fixing point. After spot welding the steel wire mesh, brush the refractory mortar mixed with fireproof powder. The thickness is determined according to the fireproof level. The invention is mainly applied to the reinforcement of single-layer, multi-layer and high-rise frame columns after the limit value of strength, stiffness or axial compression ratio exceeds the limit.

Description of drawings

Fig. 1 is the side structure schematic diagram of outsourcing prestressed fastening type concrete filled steel pipe rectangular column of the present invention;

Fig. 2 is the schematic cross-sectional structure schematic diagram of the outsourcing prestressed fastening type concrete filled steel pipe rectangular column of the present invention;

Fig. 3 is a self-balancing system in which the surface force (transverse prestress) and reaction force (the reaction force of the column to the steel plate) are equal to form a force on the surface of the outsourcing prestressed fastening type concrete filled steel pipe rectangular column of the present invention;

Fig. 4 is a schematic diagram of the cross-sectional structure of the outsourcing prestressed fastening type circular steel pipe concrete column of the present invention;

Fig. 5 is a self-balancing system in which the section action force (circumferential pretension) and reaction force (the radial reaction force of the column to the steel plate) of the outsourcing prestressed fastening circular steel pipe concrete column section of the present invention are equal to form a force.

Detailed ways

的合力P₂＝2×2.828P＝5.656P反作用于紧固钢板内侧面，亦钢筋混凝土柱1表面与紧固钢板内表面之间产生正压力，这是确保紧固钢板与钢筋混凝土柱1共同工作的剪力(N_v＝α_RημP)来源，然后将钢板的所有接缝采用坡口对焊，使所有钢板连为封闭整体，分别将植筋头钢筋与钢板围焊焊牢；然后在矩形钢板3的外表层点焊钢丝网片，并刷加防火粉的高标号水泥防火砂浆即可，防火砂浆的厚度按防火等级确定。Embodiment 1 of the present invention: outsourcing prestressed fastening type steel tube concrete rectangular column. As shown in accompanying drawings 1 and 2, at first the outer surface of the rectangular reinforced concrete column 1 is inspected and repaired, the surface is polished, cleaned and leveled, and holes are drilled and steel bars are planted on the reinforced concrete column 1 according to the design requirements; the implanted steel bars The diameter is 16-25mm, the implantation depth is 160-250mm, the steel bar head is exposed to the surface of the reinforced concrete column 1 by 30-40mm, and 8 fastening steel plates are respectively opened for the positions of the planted bars. Adjust the position of the steel plate. 8 fastening steel plates (four angle steel plates 2 at the four corners of the reinforced concrete column 1 and four rectangular steel plates 3 in the middle, the angle steel plates 2 are L-shaped equal-leg angle steel sections, and the rectangular steel plates 3 are straight-shaped cross sections) Along the height direction of the reinforced concrete column 1, it is divided into several sections, each section is 1-2m, and there are two vertical joints on each surface of each section, and torsional shear type high-strength bolt brackets 4 are arranged between the vertical joints. The torsional shear type high strength bolt support bracket 4 is worn with the torsional shear type high strength bolt 5 . Apply high-temperature-resistant structural adhesive to the surface of reinforced concrete column 1 in sections, and hang 8 fastening steel plates corresponding to the positions of the planting bars. Tighten the torsion-shear type high-strength bolts 5 on the torsion-shear type high-strength bolt support bracket 4 (the torx head is cut and tightened), so that the eight fastening steel plates generate a pre-tension force P horizontally (as shown in Figure 3), and the pre-tension force P The resultant force P ₁ =2×1.414P=2.828P acts on the original reinforced concrete column 1 from the four corners of the column, according to the principle that the action force is equal to the reaction force (as shown in Figure 3, ${\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="A200810300187E00081.png,A200810300187E00091.png"\; state="\{\{state\}\}">P</figure-callout>}}_1={\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="A200810300187E00081.png,A200810300187E00091.png"\; state="\{\{state\}\}">P</figure-callout>}}_1^{\&prime;}$ ),but

The resulting force P ₂ =2×2.828P=5.656P reacts on the inner surface of the fastening steel plate, and produces a positive pressure between the surface of the reinforced concrete column 1 and the inner surface of the fastening steel plate, which is to ensure that the fastening steel plate and the reinforced concrete column 1 work together Work shear force (N _v = α _R ημP) source, and then all the seams of the steel plates are welded by grooves, so that all the steel plates are connected as a closed whole, and the steel bars of the planting head and the steel plates are welded firmly; then The outer layer of the rectangular steel plate 3 is spot-welded with steel wire mesh, and brushed with high-grade cement fireproof mortar with fireproof powder. The thickness of the fireproof mortar is determined according to the fireproof grade.

，预拉

使圆弧状截面钢板6对钢筋混凝土柱1表面产生预压力，如图5所示，即钢筋混凝土柱1表面与圆弧状截面钢板6之间产生正压应力，从而保证圆弧状截面钢板6与钢筋混凝土柱1表面传递剪应力而共同工作。当扭剪型高强螺栓5达到设计要求的紧固力时，梅花头处被剪断，亦达到紧固产生的横向预拉力，整个圆周长在预拉力作用下对圆形的钢筋混凝土柱1表面产生反作用力，根据作用力等于反作用力原理，则钢筋混凝土柱1表面对圆弧状截面钢板6内侧产生反作用应

，如图5所示，从而形成自平衡结构体系。分段将植筋头钢筋与圆弧状截面钢板6塞焊焊牢，然后将圆弧状截面钢板6的所有接缝采用坡口对焊，使所有圆弧状截面钢板6连为封闭整体，在植筋头和扭剪型高强螺栓支托架4上固定钢丝网片，将掺有防火粉的高标号水泥防火砂浆分层抹上，防火砂浆厚度由结构防火等级确定。Embodiment 2 of the present invention: outsourcing prestressed fastening type steel tube concrete cylinder. As shown in accompanying drawing 4, 5, at first the outer surface of circular reinforced concrete column 1 is checked and repaired, and the surface is polished and cleaned up; drill holes and plant steel bars on reinforced concrete column 1 according to the design requirements; implanted The diameter of the steel bar is 16-25mm, the implantation depth is 160-250mm, the steel bar head is exposed to the surface of the reinforced concrete column 1 by 30-40mm, and 4 pieces (D≤800mm) or 8 pieces (D>800mm) are given for the position of the reinforcement respectively. Arc-shaped cross-section steel plate 6 (the steel plate 6 of arc-shaped cross-section is 1/4 arc-shaped or 1/8 arc-shaped cross-section) is perforated, and the aperture should be greater than the planting bar diameter, in order to adjust the position of the steel plate. 4 or 8 arc-shaped cross-section steel plates 6 are divided into several sections along the height direction of the reinforced concrete column 1, each section is 1-2m. After the surface of the reinforced concrete column 1 is coated with high-temperature-resistant structural glue, the arc-shaped cross-section steel plate 6 is hung up in sections immediately, and the high-strength bolt 5 of the torsional shear type is worn on the support bracket 4 of the high-strength bolt of the torsional shear type. Tighten the high-strength torsional shear bolt 5 to make the arc-shaped cross-section steel plate 6 circumferentially produce pre-tension

, pre-pull

Make the arc-shaped cross-section steel plate 6 generate pre-pressure on the surface of the reinforced concrete column 1, as shown in Figure 5, that is, a positive compressive stress is generated between the surface of the reinforced concrete column 1 and the arc-shaped cross-section steel plate 6, thereby ensuring that the arc-shaped cross-section steel plate 6 and the reinforced concrete column 1 surface to transfer shear stress and work together. When the torsion-shear type high-strength bolt 5 reaches the fastening force required by the design, the plum blossom head is cut off, and the transverse pre-tension force generated by the fastening is also reached. Reaction force, according to the principle that the action force is equal to the reaction force, the surface of the reinforced concrete column 1 reacts to the inner side of the arc-shaped cross-section steel plate 6

, as shown in Figure 5, thus forming a self-balancing structural system. Weld the reinforcing bars of the planting head with the arc-shaped cross-section steel plate 6 in sections, and then weld all the seams of the arc-shaped cross-section steel plate 6 with groove butt welding, so that all the arc-shaped cross-section steel plates 6 are connected as a closed whole, Fix the steel wire mesh sheet on the reinforcement head and the torsional shear type high-strength bolt support bracket 4, and spread the high-grade cement fireproof mortar mixed with fireproof powder layer by layer. The thickness of the fireproof mortar is determined by the fireproof grade of the structure.

Claims (7)

[Claim 1] A method for strengthening an outsourced prestressed fastening type concrete filled steel pipe column, characterized in that it comprises the following steps: (1) Check and repair the original reinforced concrete columns, polish and clean the surface; (2) Drill holes on the reinforced concrete column and implant steel bars; the diameter of the implanted steel bars is 16-25mm, and the implantation depth is 160-250mm; (3) Brush high-temperature-resistant structural glue on the surface of the reinforced concrete column, and then cover the surface of the reinforced concrete column with steel plates that have been opened in sections. The hole diameter of the steel plate is larger than the diameter of the planting bar, and the planting bar is exposed to the surface of the steel plate by 20-40mm; (4) Insert torsion-shear type high-strength bolts on the bolt support bracket of the steel plate, tighten the torsion-shear type high-strength bolts, so that the steel plate can establish a pre-tension force laterally, and use the principle of equal force and reaction force to make the torsion-shear type high-strength bolts and steel plates A positive pressure is generated between them, so that there is a friction force of shear resistance, so that the steel plate is close to the surface of the reinforced concrete column; (5) All the seams of the steel plates are welded by grooves, so that all the steel plates are connected as a closed whole; (6) Weld and weld the steel bars of the planting bar head and the steel plate firmly; then outsource the steel mesh cement mortar with high grade and mixed with fireproof powder. [Claim 2] An outsourcing prestressed fastening concrete-filled steel pipe rectangular column, including a rectangular reinforced concrete column (1), is characterized in that: there are 4 pieces wrapped around the four corners of each section of the rectangular reinforced concrete column (1) Angle-shaped steel plates (2), rectangular steel plates (3) with the same height as the angle-shaped steel plates (2) are installed between the angle-shaped steel plates (2); each surface of each section of the reinforced concrete column (1) has two Vertical seams, torsional shear type high-strength bolt support brackets (4) are arranged between the vertical joints, and torsional shear type high-strength bolts (5) are worn on the torsional shear type high-strength bolt support brackets (4). The angle-steel-shaped steel plate (2) and the rectangular steel plate (3) have holes according to the planting bars of the reinforced concrete column (1), and are hung on the surface of the rectangular reinforced concrete column (1) through the holes, and the rectangular steel plate (3) and the angle-steel-shaped The steel plates (2) are fixed and connected as a whole with torsional shear type high-strength bolts (5). [Claim 3] The outsourcing prestressed fastening concrete-filled steel pipe rectangular column according to claim 2 is characterized in that: the angle-steel-shaped steel plate (2) is an L-shaped equal-leg angle-steel section, and the rectangular steel plate (3 ) is a straight section. [Claim 4] The outsourcing prestressed fastening concrete-filled steel pipe rectangular column according to claim 2 is characterized in that: a steel wire mesh is spot-welded on the outer layer of the rectangular steel plate (3), and it is brushed with fireproof powder. High grade cement fireproof mortar. [Claim 5] An outsourcing prestressed fastening type steel tube concrete cylinder, comprising a circular reinforced concrete column (1), characterized in that: the surface of the circular reinforced concrete column (1) is closely attached to the surface according to the size of the column diameter There are 4 to 8 arc-shaped cross-section steel plates (6), and the arc-shaped cross-section steel plates (6) are divided into several sections according to the height of the column, and torsional shear type high-strength bolt brackets (4) are arranged at the ends of the joints. The torsional shear high-strength bolts (5) are worn on the torsional shear high-strength bolt support bracket (4), and the arc-shaped cross-section steel plate (6) of each section is provided with holes according to the planting bars of the reinforced concrete column (1). And hang on the surface of the reinforced concrete column (1) through the hole, and the arc-shaped cross-section steel plates (6) are fixedly connected as a whole by torsional shear type high-strength bolts (5). [Claim 6] The outsourcing prestressed fastening concrete-filled steel tube cylinder according to claim 5, characterized in that: the arc-shaped cross-section steel plate (6) is 1/4 arc-shaped or 1/8 arc-shaped shaped section. [Claim 7] The outsourcing prestressed fastening type concrete filled steel tube cylinder according to claim 5 is characterized in that: a steel wire mesh is spot-welded on the outer layer of the arc-shaped cross-section steel plate (6), and it is brushed with fireproofing The thickness of the high-grade cement fireproof mortar with powder is determined according to the fireproof grade.

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