Steel column assembly

1 Steel column assembly sequence:

① Foundation pay-off →② strapping →③ lifting →④ correction →⑤ Finally fixed.

2 Steel column installation steps:

(1) Construction pay-off:

a. Elevation control:

In this project, according to the depth of the concrete bottle mouth and the elevation of the steel column bottom, the concrete foundation project is constructed in the middle of the bottle bottom to manipulate the steel parts and the "middle bar" (φ30 construction steel bar). The top elevation of the "middle bar" is based on the elevation of the steel column bottom, and the elevation error of the steel parts is controlled within ±1mm.

In order to ensure that the steel column is precisely and firmly placed on the φ30 "middle bar" in the base, a thickness of 20 thick steel plate is raised by electric welding at the bottom end of the H-shaped steel column.

In the installation of the steel column, the basic bottle opening is cleaned first, and the specific relative height of the elevation control "middle bar" (φ30 construction steel bar) of the basic embedded parts is checked. In view of the precise manipulation of the elevation control "middle bar" reserved during the construction of the basic engineering has been completed, and the padded iron is no longer needed. With this method, the solution of steel column foot is extremely simple, convenient and efficient. The construction of the project is fast and the bearing capacity is effective. When the column is hoisted, the three directions should be adjusted at will under the premise of constant elevation.

b. Before construction, place the basic plane vertical and horizontal coordinates to the reference point on the top of the bottle with the carpenter's ink fountain line as the steel column installation positioning line.

(2) Column strapping and hoisting

After the steel column a enters, place the steel column according to the position of the hoisting plane design drawing, and check whether the model specification and serial number are correct.

b. Before hoisting the column, it is necessary to draw a straight line with red paint from the bottom of the column 2300mm upwards, which is convenient to assemble and fix the left and right before and after the follow-up visit plan elevation standard.

c. column assembly belongs to the longitudinal vertical lifting, in order to ensure that the suspended column remains loose, conducive to place, clearly binding point under the ox leg column. In order to avoid sharp edges and corners of the column and damage to the rope during hoisting, separate it with old car rubber strips and suck it at the corner rope. Pay special attention to strong binding, and easy to disassemble.

d. steel column should be tied up temporary steel stairs, high-strength bolt assembly platform fixture.

e. In order to prevent the hanging column from shaking at will, it is necessary to tie the top end of the bottom of the column with fine twine, as a restriction of the rope slide, and adjust the direction.

f. Rotation method for hoisting according to site conditions:

After the preparatory work before lifting is ready, the first test lifting is carried out. When the relative height of the steel column lifting from the ground is 200mm, the lifting should be stopped to check whether the sling is firm and the crane is stable. After determining that there is no problem, you can guide the crane to slowly lift, turn to the top of the bottle, and then slowly lower. When the design part of the column bottom spacing is 40 ~ 100mm, adjust the two reference points of the column and the foundation to achieve the specific position, guide the crane to lower in place, and use steel wedges (or wood wedges) and wind rope to temporarily fix the column. The lifting hook can be removed safely.

· Key points of rotation method: The method of lifting the column around the concrete column by lifting the hook and rotating the lifting equipment is called rotation method, as shown in the figure below. When hoisting columns by rotating method, in order to improve the efficiency of hoisting, the binding point of the column, the center of the concrete column and the basic core of the cup should be made at the entrance of the steel column, with the stopping point of the lifting equipment as the center point, and the distance between the stopping point and the tying point (that is, the minimum turning radius of the hanging column) as the arc of the half longitude (commonly known as the three-point arc).

(3) Column basic correction: column correction should first correct the side with large error, and then correct the side with small error.

a. The calibration work of the column generally includes three specific contents: plan position, elevation and vertical Angle.

b. When the steel column is hoisted in place, it is a combination and generally does not require plan correction. For the elevation of the column, because the elevation has been accurately manipulated with the φ30 embedded part "ribs" before hoisting, generally only need to check, no longer need to correct. Therefore, the correction of steel column is usually the correction of vertical Angle and follow-up elevation.

c. The column calibration work should be carried out synchronously with measuring instruments. In this project, the vertical Angle of the observation column should be measured and corrected with two theodolites.

· First, place the level on one side of the column so that the longitudinal middle wire points to the reference line of the column base, and then fix the screws of the level plate without moving.

· Measure the axis of the pillar and observe from bottom to top. If the vertical axis points, that is, the column is vertical, and the error rule needs to adjust the column until it points to the vertical wire of the level.

· Measure the horizontal line in the same way so that the other axis of the column is perpendicular to the horizontal coordinate of the reference line. After the column is accurately positioned, it is possible to carry out fixed income on the column.

· Vertical Angle correction of steel column: pitch ball screw and steel wedge are selected, because the contact area of short side of the column is small, the pad block is set during construction, and the detailed node drawing is as follows.

(4) Steel column final correction fixed:

After the steel column is hoisted in place, the adjustment of the column height and the correction of the vertical Angle are mainly carried out in the correction work. The correction method can use wind rope, hydraulic jacks, pry bars and steel wedge (or wood wedge block) tools, etc., to increase the vertical and lateral force of pulling, jacking, supporting and prying on the steel column.

Adjust the vertical Angle, axis and elevation of the column. After confirmation, the gap between the steel column and the foundation bottle mouth shall be cast with C40 bean stone concrete to determine the density. The preferred choice is to use swelling high strength grouting material.

On-site component safety protection

1) Prefabricated components should be unloaded to avoid destruction, and butt fasteners should avoid impact and extrusion between each other.

2) The prefabricated components shall be stacked neatly in the designated place, and the stacking layers of the steel beams shall not exceed 3 layers to avoid the extrusion deformation between the prefabricated components.

3) The oil stains, fine sand and dust on the surface of the prefabricated components should be cleaned before hoisting.

Component placement and site specification

1) When unloading the prefabricated components, the prefabricated components shall be unloaded directly around the installation mode and within the minimum turning radius of the crane. The serial number is clearly marked with a clear color pen to facilitate lifting.

2) The prefabricated components are placed in the place, and a certain gap is embedded near the butt fastener, which is conducive to bundling.

3) The provisions of the place are firm and smooth, do not pollute the environment because of rain and snow, and can walk 30 DWT vehicles.

Steel structure engineering

Prepare before hoisting steel columns

Before hoisting the steel column, tie the wind rope to the column first, consider the lifting point in the leg column, choose the left and right areas of the double galvanized steel wire rope, and the positioning pin can be checked and accepted before entering the next step. Before lifting the steel column, it is necessary to regularly inspect the axis of the steel column, the premise center line and elevation, the specifications of the bottle mouth and the elevation of the cup, and apply for the acceptance of the work handover project, and carry out a comprehensive verification of the serial number, size, wire hole position and caliber of the steel column. After checking the design conditions, draw the assembly axis at the left and right ends of the steel column and the elevation line below the column.

Steel column hoisting

⑴ Steel column installation steps

Set the woodworking board at the position of the concrete column before hoisting the steel column to avoid damaging the concrete column and other structures.

Special type galvanized steel wire rope should be used for steel column strapping. The strapping must be made of square or rubber to avoid damage to steel column.

Steel column installation use 25 tons crane to carry out lifting, steel column lifting, the crane should be hooked, side boom, so that the steel column vertical distance from the ground.

(2) In place adjustment and temporary fixed

When the steel column is lifted to the top of the basic bottle mouth part 200mm, make it stable, slow fall against the basic bottle mouth, and prevent bumping against the concrete edge of the basic bottle mouth in the landing link. After implementation, use a special square to check and adjust the steel column so that the positioning line overlaps with the foundation axis. When changing, three people should actually operate, one person to move the steel column, one person to help smooth, and the other person to test. The position error is controlled within 2mm.

(3) When adjusting the elevation of the steel column, a pad is placed at the basic bottom end of the bottle mouth, and the elevation of the bottom plate of the steel column is used as the top elevation of the pad, so that the elevation after the steel column is in place reaches the elevation specified in the design scheme. The elevation measuring point is calibrated on the column, and the assembly elevation is measured with the level after the assembly is in place.

(4) Steel column vertical Angle correction use a level to carry out basic adjustment of the vertical Angle of the steel column. Then two levels are observed simultaneously from both sides of the column and adjusted with the help of wind ropes. As shown in the picture below:

(5) After the adjustment is completed, the basic gap between the bottom end of the steel column and the bottle mouth is accurately positioned with eight iron wedges, and then welded on the body of the column to make it firm.

Steel beam assembly

The steel beams must be placed neatly in the site, and the wooden tie must be placed in the middle of each layer of steel beams. The two lifting points of steel beams should be considered to be on both sides of the center of gravity point of the steel beam. The two lifting points should be 800mm apart from the support and the middle span, and the distance between the two lifting points should be increased appropriately according to the length of the steel beam.

To ensure safety, avoid the sharp edge of the steel beam cutting galvanized steel wire rope, will carry out safety protection of galvanized steel wire rope, lifting rope Angle is not less than 450, steel beam application of galvanized steel wire rope immediately binding rolling can also use special fixtures to carry out lifting.

Before lifting the steel beam, use the steel wire rope on the steel beam, and hang two rope on each side of the steel beam, and two people pull two rope, and the steel beam gradually lifting rate must be slow. In order to ensure safety, the staff should not stand under the beam. Special cloth bags for placing high-strength bolts are carried on both sides of the steel beam. When the steel beam is lifted to the place in place, the steel beam is gradually put in place, and the steel beam descending speed is maintained at 3 meters /min. Two installation workers are arranged on each side of the steel column to prepare for assembling the steel beam in advance. When the steel beam is close to the place, the two installers should hold the flange plate of the steel beam in their hands, drag the steel beam to the place, and prepare to assemble high-strength bolts in advance.

Rack structure and support point corner brace assembly

1) Steel purlin assembly: when the main structure forms a structural section, the steel purlin is lifted to the roof bearing beam with a crane, and the assembly is manually dispersed, and the steel purlin can also be pulled up to the flat roof with a white harness rope for assembly, and the steel purlin is installed and assembled in time.

2) Wall steel purlin assembly: When the main structure forms a structural section, the construction team stands on the steel pipe scaffolding software and pulls the wall steel purlin to the installation mode.

3) Corner brace assembly: After the actor finishes welding, the corner brace connection is carried out.

Steel column accurate measurement correction

1) Steel column vertical Angle correction

When the steel column is assembled and corrected, two levels are set up on the control line that moves 1 meter from each other 90 degrees and then view them in the same direction. The level operator observes the small steel tape measure on the top of the column, detects the error of the steel column and guides the correction.

A Control the flatness of the steel column of each bow lifting section.

B steel column calibration is carried out in four steps: initial correction at the beginning of twisting; Re-check before final twist; Tracking and testing of welded joints; Electric welding after the final result of accurate measurement.

The vertical Angle should be roughly manipulated with a large level before the initial screw, and accurate correction should be carried out after the structure is generated. After the electric welding, the retest should be carried out, and compared with the accurate measurement results after the final screw, it will be used as the construction basis for the next project.

C steel column perpendicularity measurement method

Initial correction: Use a level to adjust the vertical Angle of the steel column.

Steel column vertical Angle accurate correction: the main body structure hoisting with one column distance as an assembly segment, to be completed in three consecutive detailed segments

Accurate measurement correction can be inserted after the overall population is generated. Observe at the same time with two levels from the two sides of the column, and apply the wind rope to carry out calibration and adjustment.

Two, steel frame structure accurate measurement

2) Steel column elevation control

Based on the elevation reference point of the plane layer of the steel column, the error value of the level of the steel column is measured by the level instrument, and the correction is directed.

3) Precise measurement of steel beam:

After steel column hoisting and correction is completed, 1.00m reference point is cast to each steel column according to the reference point on the spot as an important basis for longitudinal transmission of elevation and beam assembly elevation; The axis of the steel beam pops out of the surface of the steel beam.

The control center line is thrown into the column to adjust the position deviation of the beam; The accuracy of beam elevation is adjusted according to the reference point of column elevation. Set up a level on the building software, look back at the cross corner to the center line of the corresponding beam, use the optical theodolite to look at the main beam surface axis to the other end, to see whether the number and the beam center line overlap.

Measurement of lofting database

In the construction, the measurement of lofting database uses the automatic query method of electronic computer. The procedure is as follows:

1) Construction of database system

First of all, according to the coordinates of the design scheme of each building in the design drawing and the correlation between the specifications, the house building, the center line of the house building, and the lofting control line to be constructed are made in AutoCAD according to the proportion, and the database system is created.

2) Check the survey lofting database

After the completion of the measurement lofting database system, Dist and other commands of AutoCAD were used to check the Angle of view, distance and other measurement lofting data information of the known basis (center line control pile, constructed lofting center line, etc.) and the lofting control line to be constructed.

3) The advantages of automatic viewing of electronic computers

The method of automatic viewing by electronic computer is used to obtain the required measurement and positioning data information, which is not only convenient for measurement and high precision, but also can be combined with the actual situation to set the pitch precision to 0.1mm, 0.01mm, and the Angle precision to 0.0 ", 0.00 "or higher.

Third, high-strength bolt engineering construction

1. Preparatory work for assembly

1) Testing and testing of high-strength bolts

Anti-slip coefficient experiment

This project selects 10.9 class large hexagonal high-strength bolts, and the experiment of anti-slip coefficient of high-strength bolts should be carried out only with the most symbolic thickness plate in construction, and 3 groups are made.

Load test

Select randomly from the batch of anchor bolts to be installed at the construction site, and pick up 8 sets of anchor bolts each time for re-inspection.

2) High-strength bolt transport and storage

Transport

The high toughness bolt connection pair is made and supplied by the manufacturer according to a batch of supporting facilities, with product certification, the way, specifications and technical standards of the high toughness bolt connection pair must comply with the relevant provisions of the national industry standards GB1228-1231-84 and GB3632-3633-83. Large hexagon high-strength bolts for steel frame structure

The connecting pair is composed of an anchor bolt, a nut or two sealing rings. The application composition must meet the requirements of national industry standards, and the high-toughness bolt connection pair must be supplied with supporting facilities in the same batch.

The high-toughness bolt connection pair should be light and carefully handled during loading, unloading, transportation and storage processes to avoid damage to the packing case and damage to the anchor bolts.

High strength bolts warehouse storage

1. The high-toughness bolt connection pair shall be cleaned according to the specifications, production batch number, serial number and supply date of the packing box, classified and stored, stored in the warehouse in the room, the deposition need not be higher than 3 layers, indoor moisture proof, long-term cleaning, rust prevention and dirt contamination, to avoid changes in torque coefficient. The lowest layer should be more than 300mm above the relative height of the road surface.

2. In the construction site installation, it should be distributed according to the total number of high-strength bolts required on the day. The rest, keep it safe. Do not mess up, damage the screw, be stained by dirt.

3. When the long-term storage of high-strength bolt connection is used, it is also necessary to make a full range of product quality inspection again, and when abnormal conditions are found after unpacking, it should also be tested. The inspection standard is carried out according to the relevant provisions of the national industry standards GB1228~1231-84 and GB3632~3633-83. It is assessed to be up to standard and then applied.

3) Construction management of high-strength bolt engineering

1. Engineering construction management personnel

In the process of carrying out the construction of the high-strength bolt, first understand the high-strength bolt management personnel, and make them act as project management, quality control and specific guidance to the construction team.

2. Temperature management methods (natural conditions)

Precipitation, snow under normal circumstances do not work, such as in the operation of precipitation, snow, should increase the speed and not tighten the card

3. Friction surface management methods

Before tightening work, the first friction surface inspection, if there is rust, oil, architectural paint, sediment and other accessories to reduce the bearing capacity of the friction surface, the use of metal brush, sandpaper, O2-acetylene gas flame to remove.

4) High toughness bolt engineering construction

1. Final screw of temporary bolt

Before inserting the high toughness bolt, in order to make the connection close, the temporary bolt is first fastened. If the raw material of the connection part is bent, it needs to be adjusted.

When the hole difference is within 2mm, the reaming drill can be used to adjust.

If the difference between the holes exceeds 2mm, under the premise of consultation with the manager, effective treatment methods such as changing the plate are used to repair, and oxygen cutting drilling can not be done.

2. Insert the high-toughness bolt

Nuts and gaskets of high toughness bolts need to pay attention to the assembly orientation, and assemble according to the following figure.

When inserting a bolt, do not adhere rust, dust, oil, etc., to the bolt. In addition, it is not necessary to force into the bolt hole during the construction process to prevent damage to the screw.

3. Initial twist

After locking the temporary fixed bolt, determine the compactness level of the member.

After the initial screwing, according to the bolt nuts, gaskets and prefabricated components with a white marker to carry out the identification application monitoring wrench, although the torque value can be determined by touching the sound, but the organization is very easy to screw again, need to pay attention to.

4) Final twist

After the initial screw is finished, the special tightening screw should be applied to carry out locking until the neck is broken.

The bolts inserted on the same day will be unscrewed on the same day under normal circumstances.

The final screw is normally connected to the middle of the head to the top.

5) High strength bolt construction steps