CN101538939B - Construction Method of Preset Nut Type Steel Concrete Composite Column Formwork Fixing Device - Google Patents

Abstract

The invention discloses a pre-installed nut type steel concrete composite column formwork fixing device and a construction method. The device is mainly composed of templates, nuts, screw rods, PVC sheath pipes, inner keels, and outer keels. The nut is welded on the shaped steel column, the formwork is surrounded by the outer edge of the shaped steel column, the outer keel ring is set outside the formwork, the inner keel is set between the formwork and the outer keel, one end of the screw is threaded with the nut, and the PVC sheath is sleeved on the screw , the other end of the screw is fixed on the outer keel through a "3"-shaped buckle. The invention has the advantages of simple structure, low cost, convenient and fast construction, solves the problem of fixing the formwork of the steel-concrete composite column, facilitates on-site construction operations, and reduces workload and labor intensity. The inner and outer keels, formwork and screws can be reused repeatedly, saving costs, ensuring the safety of formwork construction and improving the quality of concrete column formation, and using ordinary materials, the cost is economical and easy to popularize and apply.

Description

Construction Method of Preset Nut Type Steel Concrete Composite Column Formwork Fixing Device

technical field

The invention relates to a construction method of a formwork fixing device for a steel-concrete composite column, and belongs to the technical field of building construction.

Background technique

With the rapid development of urban construction, more and more super high-rise buildings have emerged in the city. In order to meet the requirements of height, space change and structural force, quite a few super high-rise buildings have adopted steel-concrete composite structures. The steel column is installed in the composite column, and the steel column cannot be perforated at will. When the formwork used to cast the column concrete is fixed, it is impossible to set the tension screw to bear the lateral pressure of the column formwork like the ordinary concrete column. It is labor-intensive and time-consuming to weld the half-stayed screw on the steel column to fix the formwork, and the screw cannot be used repeatedly. Therefore, it is of great practical significance to design a new formwork fixing device for steel-concrete composite columns and to propose a targeted construction method. .

Contents of the invention

The object of the present invention is to aim at the above-mentioned deficiency that existing steel concrete composite column formwork fixation exists, provide a kind of structure simple, cost is low, the construction method of preset nut type steel concrete composite column formwork fixing device is simple and fast.

First purpose of the present invention is achieved like this, the construction method of preset nut type steel concrete composite column formwork fixing device, comprises the following steps:

1) According to the lateral pressure design of concrete pouring, design and prepare nuts, screw rods, PVC pipes, and determine the arrangement spacing of nuts on steel columns;

2) Position the welding nut on the shaped steel column and set out the wires, and weld the nut according to the direction of the column axis. The weld seam height is 4mm, and the position error is controlled within 3mm. 3) Before installing the formwork, screw one end of the screw into the nut with a wrench and put it on the PVC pipe;

4) Determine the position of the template hole according to the nut positioning diagram on the steel column, draw the template hole diagram, and drill holes in the template according to the drawing, and the hole corresponds to the position of the nut;

5) Install formwork, inner keel, and outer keel. The formwork is made of 18mm thick plywood. The formwork stands on the periphery of the steel column. The inner keel is made of 50mm×100mm wooden squares, which are vertically arranged outside the formwork with a spacing of less than 200mm. The outer keel is Φ48×3.5 mm double steel pipe, the outer keel is set on the outer periphery of the inner keel, and the inner keel squeezes against the formwork and the outer keel.

6) The screw rod passes through the opening of the formwork, and the other end of the screw rod is fixed on the outer keel through a "3"-shaped buckle.

The double steel pipes of the outer keel are connected and fixed by means of tension screw rods.

According to the calculation formula of lateral pressure of concrete pouring and the mechanical performance of nuts, screws and welds, the specifications and spacing of screws are calculated and designed, and the nut size, specification and arrangement spacing and welding requirements are determined; the calculation process is as follows:

① Calculation of the standard value of the column formwork load The calculation formula for the lateral pressure of the newly poured concrete is the smaller value in the following formula:

$f=0.2{2\mathrm{\γ}}_{c}t{\mathrm{\β}}_1{\mathrm{\β}}_2\sqrt{V}$ F＝ _γcH

Where γc - the gravity density of concrete;

t—the initial setting time of newly poured concrete;

T - mold temperature of concrete;

V - concrete pouring speed;

H - the total height from the calculation position of the concrete side pressure to the top surface of the newly poured concrete;

β1——Correction coefficient for admixture influence;

β2——correction coefficient for concrete slump influence.

②Calculation of column formwork panels

The panel directly bears the load transmitted by the formwork, and is calculated according to the three-span continuous beam under uniform load, and the calculation is as follows

(1) Bending strength calculation

f=M/W<[f]

where f—calculated value of flexural strength of panel (N/mm2);

M - the maximum bending moment of the panel (N.mm);

W——net section resistance moment of panel;

[f]——design value of flexural strength of panel, take 15.00N/mm2;

M=0.100ql2

Where q——load design value (kN/m);

(2) Shear calculation

T=3Q/2bh<[T]

(3) Deflection calculation

v=0.677ql4/100EI<[v]=1/250

③Calculation of the inner keel of the wooden square

The vertical corrugated wooden square directly bears the load transmitted by the formwork, and is calculated according to the three-span continuous beam under the uniform load, and the calculation is as follows

(1) Bending strength calculation

Bending calculation strength f=M/W

(2) Shear calculation

The formula for calculating the maximum shear force is as follows: Q＝0.6ql

Sectional shear strength must satisfy: T=3Q/2bh<[T]

(3) Deflection calculation

The maximum deflection is less than 400.0/250.

④Calculation of double steel pipe outer keel

The maximum bending moment Mmax, the maximum deformation vmax, and the maximum support force Qmax are obtained through the calculation of the continuous beam.

Bending calculation strength f=M/W

⑤Screw calculation

Calculation formula: N<[N]=fA

Among them, N——the pulling force on the pulling bolt;

A - the effective area of the pull bolt (mm2);

f——Design value of the tensile strength of the pull bolts, to be taken as 170N/mm2.

The invention has the advantages of simple structure, low cost, convenient and quick construction, can solve the problem of fixing the formwork of the steel-concrete composite column, greatly facilitates on-site construction operations, and reduces on-site workload and labor intensity. After the steel concrete column concrete is poured and hardened, use a wrench to rotate the screw to remove the screw, outer and inner keels and formwork. Not only the inner and outer keels and formwork can be recycled and reused, but also the screw can be recycled and reused, which greatly saves the material of the screw and ensures It ensures the safety of formwork construction and the quality of concrete column forming appearance, and uses common materials, which is economical in cost and easy to popularize and apply.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is the structural representation that shaped steel column of the present invention is a circular steel pipe;

Fig. 2 is a schematic structural view of the H-shaped and cross-shaped material of the steel column of the present invention.

In the figure: 1 nut, 2 screw rod, 3 template, 4 inner keel, 5 outer keel, 6-shaped steel column, 7 PVC pipe, 8 "3"-shaped buckle

Detailed ways

Embodiment one

The pre-installed nut-type steel concrete composite column formwork fixing device in this example is used for the steel column as a round steel pipe, as shown in Figure 1, and the specific construction steps are as follows:

1. The shaped steel column 6 is made of round steel pipe, and the nut 1 is made of an elongated nut. Position the nut 1 on the round steel pipe column and set out the wire. Welding personnel weld the nut in the direction of the column axis. The weld seam height is 4mm, and the position error is controlled within 3mm. . The gap between the nut 1 and the steel pipe wall is relatively large, and the welding seam height is 4mm.

2. Before installing the formwork, screw the screw 2 into the nut 1 with a wrench, put the PVC pipe 7 on the screw 2, and adjust the direction.

3. Determine the opening position of the formwork according to the position diagram of the steel pipe column nut, draw the opening diagram of the formwork, and arrange special personnel in the woodworking processing plant to cut the material and open the hole according to the drawing to ensure that the position is accurate and reduce the deviation from the position of the nut.

4. Install formwork 3, inner keel 4, and outer keel 5 successively. The template is made of 18mm thick plywood, the inner keel is made of 50mm×100mm wooden squares, set vertically, and the spacing is not greater than 200mm, and the outer keel is made of Φ48×3.5mm double steel pipes, with a spacing of Not greater than 400mm.

5. Fix the screw rod on the double steel pipe of the outer keel through the "3"-shaped buckle 8 to bear the side pressure of the formwork. Finally constitute the M14 elongated nut 1 shown in Figure 1, the Φ14 screw rod 2 with threads at both ends, the PVC pipe 7 of the sheath screw rod, and the steel concrete column formwork fixture of the formwork 3, the inner keel 4, and the outer keel 5.

Embodiment two

The preset nut-type steel column concrete composite column formwork fixing device of this embodiment is used for H-shaped and cross-shaped steel columns, as shown in Figure 2. It has the same basic structure as that of Embodiment 1, except that the preset nut It is pre-welded on the 6-column web of the steel column. Before the formwork is installed, screw the screw 2 into the nut 1 with a wrench, put the screw 2 on the PVC pipe 7, and then install the column formwork 3, the inner keel wooden square 4, and the outer keel double steel pipe 5.

Except above-mentioned embodiment, the present invention also can be the concrete combination column formwork fixing of the shaped steel column of other structural forms, construction implementation.

Claims (2)

1. the job practices of a preset nut type steel-reinforced concrete compound pier template fixing device is characterized in that may further comprise the steps:

1) according to the design of the lateral pressure of concreting, design preparation nut, screw rod, pvc pipe is determined the arrangement pitch of steel column top nut;

2) on steel column, unwrapping wire is located in the welded nut position, carry out the nut welding by the mast axis direction, weld bead height 4mm, site error is controlled in the 3mm, and the face of weld of steel column is parallel with template, and the bigger side parallels plate in slit is arranged between nut and the steel column;

3) with spanner one end of screw rod is screwed into nut before template is installed, puts pvc pipe;

4) determine the template position of opening according to the nut network for location on the steel column, draw template perforate figure, according to drawing perforate on template, perforate is corresponding with nut location;

5) mounting template, keelson, outer keel, template adopts the thick veneer of 18mm, template stands in the steel column periphery, keelson adopts 50mm * 100mm flitch, vertically be arranged on the template outside, spacing is less than 200mm, and outer keel adopts the two steel pipes of Φ 48 * 3.5mm, outer keel is located at the keelson periphery, and keelson squeezes and withstands template and outer keel.

6) screw rod passes the template perforate, and the other end of screw rod passes through " 3 " shape snap fit on outer keel.

2. the job practices of preset nut type steel-reinforced concrete compound pier template fixing device according to claim 4 is characterized in that the two steel pipes of described outer keel are connected and fixed by Screw arbor with nut at both-ends.

Images