CN106677552A - Method for solidifying steel pipe column through external sleeveing of circular steel pipe concrete - Google Patents

Abstract

The invention provides a method for reinforcing a steel pipe column with a circular steel pipe concrete jacket, which is characterized in that it includes the following steps: step 1, grinding and derusting the surface of the original steel pipe column; step 2, setting a circular steel pipe with a jacket around the original steel pipe column, The outer circular steel pipe covers the original steel pipe column; step 3, pouring filler between the original steel pipe column and the outer outer circular steel pipe. The invention applies the steel pipe concrete structure to the reinforcement project of the steel pipe column, and proposes a method for partial or overall reinforcement of the damaged steel pipe column by outsourcing the steel pipe concrete. When the local reinforcement is performed, the outer steel pipe mainly acts as a hoop, and when the overall reinforcement is outer, the outer steel pipe It can not only bear the external force together, but also produce the hoop effect, which provides a new idea for the reinforcement method of the steel pipe column.

Description

A method for reinforcing steel pipe columns with outer-coated circular steel pipe concrete

technical field

The invention relates to a method for reinforcing a building structure, in particular to a method for reinforcing a steel pipe column with a circular steel pipe concrete jacket.

Background technique

Concrete filled steel tubes can give full play to the advantages of steel tubes and core concrete, and can make up for the respective shortcomings of these two materials. It has the advantages of high bearing capacity, good ductility, good energy consumption, and good seismic performance. At present, it is widely used in multi-storey, high-rise and super high-rise buildings, long-span bridges, large-scale industrial plants and other structures. It is convenient for construction, shortens the construction period, and reduces cost and achieved good economic results. In the existing steel pipe concrete, concrete is poured in the steel pipe to form a solid composite structure, so as to increase the strength and rigidity of the steel pipe. Patent Publication No. CN1538012A "Hollow Concrete Steel Tube" proposes a combination of two coaxial steel tubes with unequal diameters to fill the gap between the inner and outer tubes with concrete to form a hollow interlayer concrete tube column to ensure the strength of the column. , to increase the cross-sectional area and reduce the self-weight of the structure. This structure has a good application prospect in new construction. It is usually a new composite structure formed by fixing two steel pipes of equal length and then pouring concrete. However, this patent relates to a reinforcement method for building structures. Before reinforcement, the service structure may be in a stressed state because it cannot be completely unloaded, resulting in strain lag between the original components and the newly added parts, and some newly added materials. As for the problem of lower utilization rate, there is no in-depth study on the mechanical mechanism of this structural reinforcement method.

In recent years, with the improvement and innovation of steel structure forms and designs, the application of steel pipe columns has developed rapidly. For example, in the construction of infrastructure such as power transmission and communication; a large number of steel pipe columns are used in buildings such as industrial plants and workshops. areas, industrial areas and acid rain-prone areas. As an important supporting structure, its structural performance directly affects service or production safety and economy. If it is replaced as a whole, the installation and transportation costs are higher, especially in remote areas. In addition, power transmission or production needs to be stopped during construction, which will affect normal life and production.

For damaged steel pipe columns, currently commonly used reinforcement methods include enlarging section method, outsourcing steel reinforcement method, and external FRP reinforcement method. This patent intends to apply the steel pipe concrete structure to the reinforcement project of the steel pipe column, and proposes a method of partially or integrally reinforcing the damaged steel pipe column by outsourcing the steel pipe concrete. The steel pipes can not only bear the external force together, but also produce a hoop effect, which provides a new idea for the reinforcement method of the steel pipe column.

Contents of the invention

For the problems existing in the prior art, the technical scheme adopted by the present invention for solving the problems existing in the prior art is as follows:

A method for reinforcing a steel pipe column with a circular steel pipe concrete jacket, comprising the following steps:

Step 1. Grinding and derusting the surface of the original steel pipe column;

Step 2, setting a round steel pipe around the original steel pipe column, and the round steel pipe wraps the original steel pipe column inside;

Step 3, pouring filling material between the original steel pipe column and the jacket circular steel pipe.

The filler is self-stressing self-compacting concrete, which is composed of the following components by weight: cement: water: sand: stone=1:0.23~0.33:0.85~1.08:0.92~1.09.

The filler also includes a water reducing agent in an amount of 0.8-2.5% by weight.

The self-stressing self-compacting concrete is composed of the following components in parts by weight: cement: water: sand: stone = 1:0.33:0.85:0.97, and also includes a water reducing agent of 0.8% by weight .

The self-stressing self-compacting concrete is composed of the following components in parts by weight: cement: water: sand: stone = 1:0.28:0.90:1.01, and also includes a water reducing agent of 1.2% by weight .

The self-stressing self-compacting concrete is composed of the following components in parts by weight: cement: water: sand: stone = 1:0.23:1.08:1.09, and also includes a water reducing agent of 2.5% by weight .

The outer jacket steel pipe coincides with the geometric center of the original steel pipe column, or is arranged eccentrically according to the bearing condition.

The cross-sectional shape of the steel pipe column is circular or polygonal.

The circular steel pipe with outer jacket is formed by butt-welding two semicircular steel plates on site, and the circular steel pipe with outer jacket has a thickness of 3-10 mm.

This patent proposes a method for reinforcing steel pipe columns with circular steel pipe concrete, which uses the advantages of steel pipe concrete to solve the hidden safety problems of old damaged steel pipe columns such as corrosion and cracking, as well as the high cost of overall replacement of steel pipe columns; At the same time, the internal hollow steel pipe column can still lay wires, pipes, etc., without affecting normal use. The specific advantages are as follows:

1. Compared with the overall replacement, the steel pipe column strengthened by this method can not only reduce the waste of natural resources and social resources, but also improve the bearing capacity and deformation capacity, prolong its service life, and has the advantages of short construction period and low cost.

2. The idea of this reinforcement method is to convert the amount of longitudinal bars and stirrups in the method of enlarging the cross-section into jacketed steel pipes, and use the jacketed steel pipes to achieve a good effect on the original steel pipe column without increasing the amount of steel used. The hoop effect improves its bearing capacity and ductility.

3. Compared with other reinforcement methods, the outer steel pipe reinforcement structure can moderately reduce the cross-sectional area, reduce the self-weight, and save the project cost.

4. Creatively combine the technology of self-stressing concrete and self-compacting concrete to obtain a new type of self-stressing and self-compacting concrete, which makes this new type of high-performance concrete have good fluidity, stability, uniformity and compactness, and It is introduced into the steel pipe concrete structure for engineering reinforcement.

5. The jacketed steel pipe can be used as a template for pouring filling materials, which is easy to operate, convenient to construct, shortens the construction period, reduces engineering costs, and has high reinforcement reliability.

6. The composite reinforced structure belongs to a new type of steel tube concrete structure, which combines the advantages of both the steel tube concrete structure and the enlarged section reinforcement method, and can greatly improve the bearing capacity and ductility of the original steel tube column. Compared with the existing reinforcement method Has a strong technical advantage.

7. Relevant data show that compared with the new structure, the use of reinforcement and reconstruction can save 40% of the investment and shorten the construction period by about 50%. The investment recovery speed of reinforcement is also 3-4 times that of the new structure, and the economic benefits are significant. At the same time, strengthening and repairing the existing structure can avoid the waste of natural resources and social resources, which has high social benefits.

8. The jacket steel pipe in this patent adopts a circular steel pipe structure, which has a good restraint effect on concrete, and its axial compression performance and seismic performance are better.

Description of drawings

Fig. 1 is a schematic diagram of a cross-sectional structure of a reinforced part of a steel pipe column of the present invention;

Among them: 1-outer round steel pipe, 2-steel pipe column, 3-filling material.

detailed description

Through the following examples, in conjunction with the accompanying drawings, the technical solution of the present invention will be further specifically described. A method for reinforcing a steel pipe column with a circular steel pipe concrete jacket includes the following steps:

Step 1, grinding and derusting the surface of the original steel pipe column 2;

Step 2: Install a round steel pipe 1 around the original steel pipe column, and the round steel pipe 1 covers the original steel pipe column 2;

Step 3: Pouring filling material 3 between the original steel pipe column 2 and the jacket circular steel pipe 1 .

Filler 3 is self-stressing and self-compacting concrete. It is the key to the success of this patented reinforcement method that the outer steel pipe can provide good restraint to the original steel pipe column. The pouring quality of the concrete filled in the gap between the inner and outer steel pipes directly affects the restraint of the steel pipe. Ordinary concrete or inorganic grouting materials will make it difficult to vibrate the post-cast filling material, and the construction quality cannot be guaranteed, and the shrinkage of the filling material will create a gap between the filling material and the steel pipe, making it difficult to exert the restraint effect of the jacket steel pipe and weaken the The supporting effect of the filler on the jacket steel pipe brings serious safety hazards.

Self-compacting concrete has good working performance, and can be densely filled in various structures without vibration, which can reduce the strength of concrete operations, avoid noise pollution caused by vibration, and simplify construction procedures. The main function of self-stressing concrete is to bear the load, through its own chemical energy and under appropriate constraints, the concrete can form self-stress, improve the mechanical properties such as elastic modulus, bonding force, impact modulus and fatigue resistance, and It can make concrete bear load more effectively, save material and reduce self-weight. Self-stressing and self-compacting concrete can give full play to their respective advantages. Due to the increase of compactness, the impermeability, frost resistance and corrosion resistance of concrete are all increased.

The self-stressing self-compacting concrete in this patent is composed of the following components by weight: cement: water: sand: stone=1:0.23~0.33:0.85~1.08:0.92~1.09, which also includes weight parts 0.8-2.5% water reducer.

Example 1

The self-stressing self-compacting concrete is composed of the following components in proportion by weight: cement: water: sand: stone = 1:0.33:0.85:0.97, and also includes 0.8% water reducing agent by weight.

Example 2

The self-stressing self-compacting concrete is composed of the following components in proportion by weight: cement: water: sand: stone = 1:0.28:0.90:1.01, and also includes 1.2% water reducing agent by weight.

Example 3

The self-stressing self-compacting concrete is composed of the following components in proportion by weight: cement: water: sand: stone = 1:0.23:1.08:1.09, and also includes 2.5% water reducing agent by weight.

Experimental measurements show that the fluidity of the self-stressing self-compacting concrete prepared in this patent is good, and the degree of expansion is in the range of 645-655mm. With the reduction of the water-cement ratio in the formulas of the above three groups of embodiments, the viscosity of the concrete slurry increases. Large, for the standard 150×150×150mm sample block, the cubic compressive strength increases, which are 45MPa, 54MPa, and 61MPa in turn.

The outer round steel pipe is formed by on-site butt-welding of two semicircular steel plates, and the thickness of the outer outer round steel pipe is 3-10 mm.

GB50936-2014 stipulates that the wall thickness of hollow concrete filled steel tubes (that is, the structure in which the outer steel tube contains a layer of hollow concrete and no steel tube inside) should not be less than 3mm. After experimental research, our research group found that the welded steel pipe with a wall thickness of 2.5mm would crack open and could not continue to restrain the inner core concrete. Therefore the jacket circular steel pipe 1 minimum thickness of this patent is set as 3mm.

Relevant literature shows that most of the CFST columns used in actual engineering are steel pipes with a wall thickness of less than 10 mm, and those with a wall thickness > 10 mm are rarely used, and steel pipes with a wall thickness > 20 mm are used in very few cases. When reinforcing steel pipe columns, the newly added section size is very small, only 100-200mm. Considering the matching of the newly added steel area and the newly added concrete area, the wall thickness of the outer steel pipe may not be very large, and may even be thinner than the inner steel pipe wall. Therefore, this patent adopts a circular steel pipe with a wall thickness of 3-10 mm, which not only meets the specification requirements, but also reduces the consumption of steel, which is more economical.

The scope of protection of the present invention is not limited to the above-mentioned embodiments. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the scope and spirit of the present invention. If these changes and modifications fall within the scope of the claims of the present invention and their equivalent technologies, the intent of the present invention is also to include these changes and modifications.

Claims (9)

1. a kind of method that overcoat circular steel tube concrete reinforces steel pipe column, it is characterised in that：Comprise the following steps：

Step one, original steel pipe column surface polish eliminate rust；

Step 2, overcoat round steel pipe is set in original steel pipe column periphery, the overcoat round steel pipe coats original steel pipe column Including；

Step 3, between original steel pipe column and overcoat round steel pipe pour inserts.

2. a kind of method that overcoat circular steel tube concrete reinforces steel pipe column, it is characterised in that：Comprise the following steps：Described fills out Charge is seif-citing rate self-compacting concrete, and the concrete by weight, is made up of the component of following proportioning：Cement：Water：Sand： Stone=1：0.23~0.33：0.85~1.08:0.92~1.09.

3. a kind of method that overcoat circular steel tube concrete reinforces steel pipe column, it is characterised in that：Comprise the following steps：Described fills out Charge also includes that weight portion is the water reducer of 0.8-2.5%.

4. a kind of method that overcoat circular steel tube concrete reinforces steel pipe column, it is characterised in that：Comprise the following steps：It is described from Stress self-compacting concrete, in parts by weight, is made up of the component of following proportioning：Cement：Water：Sand：Stone=1:0.33:0.85: 0.97, also including water reducer that weight portion is 0.8%.

5. a kind of method that overcoat circular steel tube concrete reinforces steel pipe column, it is characterised in that：Comprise the following steps：It is described from Stress self-compacting concrete, in parts by weight, is made up of the component of following proportioning：Cement：Water：Sand：Stone=1:0.28:0.90: 1.01, also including water reducer that weight portion is 1.2%.

6. a kind of method that overcoat circular steel tube concrete reinforces steel pipe column, it is characterised in that：Comprise the following steps：It is described from Stress self-compacting concrete, in parts by weight, is made up of the component of following proportioning：Cement：Water：Sand：Stone=1:0.23:1.08: 1.09, also including water reducer that weight portion is 2.5%.

7. a kind of method that overcoat circular steel tube concrete reinforces steel pipe column, it is characterised in that：Comprise the following steps：Described is outer Set steel pipe overlaps with original steel pipe column geometric center, or carries out eccentric setting according to carrying situation.

8. a kind of method that overcoat circular steel tube concrete reinforces steel pipe column, it is characterised in that：Comprise the following steps：Described steel The cross sectional shape of tubing string is circular or polygonized structure.

9. a kind of method that overcoat circular steel tube concrete reinforces steel pipe column, it is characterised in that：Comprise the following steps：Described is outer Set round steel pipe is formed by two pieces of semi-circular sheet steel scene butt weldings, and described overcoat round steel pipe thickness is 3 ~ 10mm.