Ⅰ. Steel column installation for steel structure construction
1. Installation sequence of steel column:
① Foundation setting out → ② binding → ③ hoisting → ④ correction → ⑤ final fixation
2. Installation method of steel column:
(1) Setting out:
A. Elevation control:
In this structural steel construction project, iron parts and "middle bars" are controlled according to the depth of concrete cup mouth, the elevation of steel column bottom and the embedded elevation in the center of the bottom of the cup mouth during the construction of concrete foundation (φ30 steel bars), the elevation of top surface of "middle reinforcement" is based on the elevation of steel column bottom, and the elevation error of iron parts is controlled in ± Within 1mm.
To ensure the steel column is embedded in the foundation accurately and firmly φ On the 30 "middle reinforcement", weld a steel plate with thickness of 20 at the bottom of H-shaped steel column, as shown in the figure below.
When installing structural steel column, clean the foundation cup mouth first, and check the embedded elevation control "middle reinforcement" in the foundation（φ The actual height of 30 steel bars) is not necessary because the elevation embedded in the foundation construction has been controlled precisely, and no additional iron pad is needed. The method is simple, fast and efficient for the treatment of steel column feet. The construction is fast and the force is reasonable. When the column is lifted, it can be adjusted freely in several directions when the elevation is unchanged.
B. Before installation, the vertical and horizontal axis reference lines of the foundation plane shall be placed on the top of the cup mouth by woodworking ink bucket as the installation and positioning line of steel column.
(2) Column binding and hoisting:
A. after the steel column enters the site, the steel column shall be arranged according to the position of the lifting plan, and the model and number shall be checked to see if they are correct. The plane position of steel column after entering the site is shown in the following figure.
B. Before the column is lifted, a horizontal line shall be drawn with red oil paint 2300mm upward from the bottom of the column, so as to recheck the plane elevation datum before and after the installation and fixation.
C. the column installation belongs to vertical hoisting. In order to keep the suspended column drooping and facilitate the positioning, the binding point is determined at the lower part of the bracket. In order to prevent the sharp edges and corners of the column edge from damaging the lifting rope during hoisting, the rubber belt of the old car is used to separate and cover the edge and corner lifting rope. Pay attention to binding firmly and easy to remove.
D. temporary steel ladder and high-strength bolt installation fixture of working platform shall be bound on the steel column.
E. in order to avoid the free swing of the suspended column, hemp rope should be used to tie the upper part of the column bottom as a restraint rope and adjust the direction.
F. according to the site conditions, the rotation method is adopted for hoisting
After the preparations before hoisting are ready, the trial hoisting shall be carried out first. When the height of the steel column is 200 mm above the ground, the hoisting shall be stopped to check whether the rigging is firm and whether the crane is stable. After confirming that there is no problem, the crane can be directed to slowly lift, rotate to the top of the cup mouth, and then slowly descend. When the distance between the bottom of the column and the design position is 40-100 mm, adjust the two datum lines of the column body and the foundation to reach the accurate position, direct the crane to descend to the position, and temporarily fix the column with steel wedge (or wood wedge) and wind rope to remove the hook.
• Key points of rotation method:
The method of lifting the column by rotating the column around the column base is called rotation method, as shown in figure a below. When the column is hoisted by rotation method, in order to improve the hoisting efficiency, when the steel column enters the site, the binding point of the column, the center of the column base and the center of the cup foundation should be placed on the arc with the crane stop point as the center and the distance from the stop point to the binding point (i.e. the turning radius of the column), as shown in Figure B below.
The steel column hoisting is shown in the figure below:
(3) Preliminary correction of column:
The column should be corrected on the side with large deviation first, and then on the side with small deviation.
A. The correction of column generally includes plane position, elevation and perpendicularity.
B. When the steel column is hoisted in place, it is one-time alignment, and generally it does not need plane re correction. For the elevation of the column, it has been used before hoisting φ The embedded "middle reinforcement" can accurately control the elevation. Generally, it only needs to be checked, and it does not need to be corrected. Therefore, the steel column correction is mainly to correct the verticality and recheck the elevation.
C. In this project, the perpendicularity of the column is observed, and two theodolites are used for measurement and correction.
• First, place the theodolite on one side of the column, align the longitudinal center wire with the baseline of the column base, and then fix the screws of the horizontal plate.
• Measure the center line of the column and observe from bottom to top. If the vertical center line is aligned, that is, the column is vertical. If it is not aligned, the column shall be adjusted until it is aligned with the longitudinal center line of theodolite.
• Measure the horizontal line in the same way so that the center line of the other side of the column is perpendicular to the horizontal axis of the baseline. After the column is accurately positioned, the column can be fixed.
• Verticality correction of steel column: distance adjusting screw rod and steel wedge are used. Due to the small contact surface of the long side of the column, the base plate is set during the construction. The details are as follows.
The manufacturing dimension of steel wedge is shown in the figure below:
(4) Final alignment and fixation of steel columns:
After the steel column is hoisted in place, the column correction mainly involves the adjustment of elevation and the correction of verticality; The correction method can use tools such as wind rope, Jack, crowbar and steel wedge (or wooden wedge) to apply vertical force and lateral force of pulling, jacking, supporting and prying to the steel column.
Adjust the verticality, positioning axis and elevation of the column. After confirming the correctness, the gap between the steel column and the foundation cup mouth shall be poured with C40 fine stone concrete. The expansive high strength grouting material is preferred.
Ⅱ Protection of site components:
1) The unloading of components shall be careful to prevent damage and prevent collision and extrusion between members.
2) The members shall be stacked in order at the designated site, and the number of layers stacked by steel beams shall not exceed 3 layers to prevent the members from squeezing and deformation.
3) Before hoisting, oil, sediment and dust on the surface of the components shall be cleaned.
Ⅲ The placement of components and the requirements for the site
1) When unloading, the components are unloaded directly near the installation position and within the radius of rotation of the crane. Mark the number clearly with a clear color pen to facilitate lifting.
2) The components are placed in order in the site, and a certain gap is reserved between adjacent components to facilitate binding.
3) The site shall be solid and flat, and the components shall not be polluted due to rain and snow, and the vehicle with 30 ton level can be walked.
Ⅳ Steel structure building installation
Preparation before hoisting of steel column:
Before hoisting the steel column, the cable wind rope shall be tied to the column body. The lifting point shall be at the bracket position, and the double wire rope shall be set up and down, and the snap ring can be checked to be qualified before entering the next work. Before hoisting the steel column, the positioning axis, foundation axis and elevation, cup opening size and the height of the bottom standard of the steel column must be inspected and handed over and accepted. The number, outline dimension, screw hole position and diameter of the steel column shall be comprehensively reviewed. After confirming that it meets the requirements of design drawings, draw out the installation center line and the lower end elevation line of the steel column.
Ⅴ Steel column hoisting
(1) installation method of steel column
Before lifting the steel column, the wooden board shall be fixed at the column foot to prevent damage to the column foot and other structures.
Special hoisting steel wire rope is used for steel column binding. Wood or rubber sheet shall be used to prevent damage to the steel column.
The steel column is installed by a 25t truck crane. When the steel column is lifted, the crane shall hook and rotate the arm while lifting the steel column to make the steel column vertical away from the ground.
(2) positioning adjustment and temporary fixation
When the steel column is lifted to 200mm above the base cup mouth, it will be stable, and it will fall slowly at the base cup mouth. Avoid hitting the concrete edge of the foundation cup mouth during falling. After implementation, use special angle ruler to check, adjust the steel column to make its positioning line coincide with the foundation positioning axis. Three people are required to operate the adjustment, one person moves the steel column, one person helps to stabilize and the other person conducts the test. The positioning error is controlled within 2mm.
(3) when adjusting the elevation of the steel column, place the pad iron at the bottom of the cup foundation, use the level to super level the bottom plate elevation of the steel column as the top elevation of the pad iron, so that the elevation after the steel column is in place can meet the design elevation requirements, mark the elevation datum point on the column body, and then use the level to measure the installation elevation after it is installed in place.
(4) the verticality of the steel column shall be preliminary adjusted by the level ruler. Then two theodolites are used to observe from both sides of the column at the same time, and the adjustment is carried out by relying on the cable wind rope. As shown in the figure below:
Diagram of verticality adjustment of steel column
(5) after the adjustment, use eight iron wedges to position the gap between the bottom of the steel column and the base of the cup mouth, and then spot weld the column to make it stable.
Ⅵ Steel beam installation
Steel beams must be stacked in order on site for this steel work in construction. Sleepers must be placed in the middle of each layer of steel beams. Two lifting points for steel beam hoisting are selected on both sides of the center of gravity of the steel beam. The two lifting points should be 800mm away from the support and the middle of the span, and the distance between the two lifting points should be increased according to the length of the steel beam.
To ensure safety and prevent the sharp edge of the steel beam from cutting the steel wire rope, the steel wire rope shall be protected, the angle of the sling shall not be less than 450, and the steel beam shall be directly tied and rolled with the steel wire rope or lifted with a special fixture.
Before hoisting the steel beam, install the safety rope on the steel beam. When hoisting, hang two sliding ropes at both ends of the steel beam. Two people pull two sliding ropes respectively. The hoisting speed of the steel beam must be slow. In order to ensure safety, personnel should not stand directly under the beam. The cloth bags specially used for placing high-strength bolts are put on both ends of the steel beam. When the steel beam is hoisted above the position, the steel beam is put in place. The falling speed of the steel beam is controlled at 3m / min. two installers are arranged at both ends of the steel column head to prepare for the installation of the steel beam. When the steel beam is close to the in place position, two installers should hold the upper flange of the steel beam with their hands respectively, drag the steel beam to the in place position, and prepare to install the high-strength bolts.
Ⅶ Installation of retaining structure and support corner brace
1) Installation of roof purlin: when the main structural steel forms a frame section, the roof purlin is hoisted to the main beam of the roof with a crane and installed manually. The purlin can also be manually pulled onto the roof with a white synthetic rope for installation. After the installation of purlin, the purlin support is installed in time.
2) Wall purlin installation: when the main structure forms a frame section, the construction personnel stand on the scaffold platform and pull the wall purlin to the installation position with white comprehensive rope.
3) Corner brace installation: after the main body is welded, the corner brace is connected.
Ⅷ Measurement and correction of steel column
Verticality correction of steel column
When the steel column is installed and corrected, two theodolites are set up on the control line with 90 degree translation of 1 meter each other, and the theodolite operators observe the small steel ruler on the top of the column, measure the deviation of the steel column and direct the correction.
A. Control the verticality of the steel column between the first hoisting joints.
B. Steel column calibration is divided into four steps:
initial calibration during initial tightening; Re-calibration before final tightening; Tracking and monitoring during welding process; Final result measurement after welding.
The perpendicularity can be roughly controlled with a long level before the initial tightening, and it can be accurately corrected after the frame is formed. After welding, retest shall be carried out, and the measurement results shall be compared with those at final tightening, so as to be the basis for the next construction.
C. Verticality measurement method of C steel column
Initial correction: the perpendicularity of the steel column is preliminary adjusted with a level ruler.
Accurate correction of steel column perpendicularity: one column grid is used as an installation section for the hoisting of the main frame until the hoisting of three continuous complete sections is completed
After the whole is formed, the measurement correction can be inserted. Two theodolites are used to observe from both sides of the column at the same time, and the wind rope is used for correction and adjustment.
Ⅸ Steel structure survey
2) Elevation control of steel column
Based on the elevation reference point of the plane layer where the steel column is located, the deviation value of the horizontal elevation of the steel column is measured with the level gauge and the correction is directed.
3) Steel beam measurement
After the steel column is hoisted and corrected, the +1.00m control point shall be measured to each steel column according to the site level as the basis for vertical transfer of elevation and the elevation of beam installation; Pop up the center line of the steel beam on the surface of the steel beam.
The control axis is measured to the column body to control the beam position offset; The accuracy of beam elevation is controlled according to the control point of column elevation. Set up theodolite on the floor platform, and then look at the cross angle to the axis of the corresponding beam. Aim at the center line of the upper surface of the beam to the other end with theodolite to see if the number coincides with the axis of the beam.
Calculation of survey and lofting data
In this project, the computer automatic query method is used to calculate the survey and lofting data. The specific steps are as follows:
1) The establishment of data model
Firstly, according to the design coordinates and the dimension relationship of each building in the design drawing, the building, building axis, control line to be lofted and so on are drawn in AutoCAD according to the proportion, and the data model is established.
2) Survey and lofting data query
After drawing the survey loft data model, the survey loft data such as the angle and distance between the known basis (axis control pile, lofted axis, etc.) and the control line to be lofted are queried by using the command of dist of AutoCAD.
3) Advantages of computer automatic query
The method of computer automatic query is used to obtain the required measurement and positioning data. It is not only convenient to calculate, but also has high precision. The distance precision can be set to 0.1mm, 0.01mm, and the angle precision to 0.0 ", 0.00" or higher according to the actual situation.
Ⅹ Construction of high strength bolt
1. Preparation before installation
1) Test and inspection of high strength bolt
Anti slip coefficient test
The project adopts class 10.9 large hexagon high-strength bolts. The anti slip coefficient test of high-strength bolts shall be conducted by taking the most representative thickness of the plate in the project for test, and three groups shall be made.
The size of the specimen plate is as follows:
Axial force test
Randomly select the bolts to be installed at the construction site, and 8 sets of bolt pairs are selected for re inspection in each batch.
2) Transportation and storage of high strength bolts
The form, size and technical conditions of high-strength bolt connecting pair shall be manufactured and supplied by the manufacturer according to batch, with factory certificate and high-strength bolt connection pair, which shall conform to the provisions of national standards gb1228-1231-84 and gb3632-3633-83. High strength bolts with large hexagon for steel structure
The connecting pair consists of a bolt, a nut and two washers. The combination of use shall meet the national standards, and the high-strength bolt connection pair shall be supplied with storage and transportation in the same batch.
The high-strength bolt connecting pair shall be installed and placed lightly during loading, unloading, transportation and storage to prevent the packing box from being damaged or damaged.
Storage of high strength bolt warehouse
1. the high-strength bolt connection pair shall be cleaned according to the specification, batch number and supply date of the packing box, and shall be kept in the indoor warehouse, and the accumulation shall not be higher than 3 layers. The indoor moisture-proof, long-term dry, rust and dirt contamination shall be prevented, and torque coefficient shall be prevented from changing. The bottom layer shall be more than 300mm above the ground level.
2. when installing on site, the quantity of high-strength bolts required on the day shall be issued. The rest should be kept properly. Do not put it in disorder, damage the thread, and be contaminated with dirt.
3. before using the long-term storage high-strength bolt connection pair, a comprehensive quality inspection shall be conducted again. If any abnormal phenomenon is found after unpacking, the inspection standard shall be conducted according to the relevant provisions of national standards gb1228-1231-84 and gb3632-3633-83. It can be used after being qualified.
3) Construction management of high strength bolts
1. Construction Manager
When carrying out the construction of this high-strength bolt, the high-strength bolt manager shall be determined first to be responsible for the project management, quality management and guidance of the construction personnel.
2. weather management (climate conditions)
In principle, no operation shall be carried out during rainfall and snowfall. If rain or snow fall occurs during operation, the speed shall be accelerated to lock the unfinished ones
3. friction surface management
Before tightening, the friction surface shall be inspected first. If there are any attachments to reduce bearing capacity of friction surface, such as rust, oil, paint and residue, metal brush, sandpaper and oxygen acetylene flame shall be used for removal.
4) Construction of high strength bolts
1. final tightening of temporary bolts
Before inserting high-strength bolts, temporary bolts shall be used to tighten the connection tightly, if the materials of the connection parts are bent or warped, they shall be corrected.
If the difference of holes is within 2mm, it can be corrected by cutter.
If the difference of holes exceeds 2mm, reasonable treatment methods such as replacement of panel shall be adopted based on consultation with management personnel, and gas cutting and reaming are not allowed.
2. high strength bolt insertion
The nut and gasket of high-strength bolt shall pay attention to the installation direction, and install according to the following figure.
When inserting bolts, pay attention not to attach rust, dust, oil, etc. to the bolts. In addition, do not force into the bolt hole during construction to avoid damaging the thread.
3. initial tightening
After the temporary fixing bolts are locked, confirm the compactness of the components.
After initial tightening, mark with white marker through bolt nut, gasket and component.
When using the inspection wrench, although the torque value can be confirmed by the contact sound, it is easy to over tighten if the mechanism continues to apply force, so it should be noted.
4) Final tightening
After initial tightening, use special fastening wrench to lock until the neck is broken.
In principle, the bolts inserted on the same day shall be screwed out on the same day.
Industrial steel building has a wide range of applications and can be used in factories, warehouses, office buildings, stadiums, hangars, etc. to be used. It is suitable not only for single-storey large-space buildings, but also for the construction of multi-storey or high-rise buildings.
What are the architectural features of industrial steel building?
What is the reason why more and more people are choosing industrial steel building?
What types of construction are available for industrial steel buildings?
Insulation: Avoid heat transfer on both sides of the metal roof to ensure that the ambient air temperature is stable. The thermal protection function is realized by filling thermal protection materials (usually used glass wool and stone wool) under the metal roof plate. The heat conservation effect is expressed by the U-value and the unit is W/M2K. The thermal insulation performance is determined by the following factors: raw material, density and thickness of the thermal insulation cotton; the humidity of the thermal insulation wall, the method of connecting the metal roof plate and the underlying structure (to prevent the phenomenon of the "cold bridge"), the repeated ability of the metal coating to heat radiation.
Daylight: Improve indoor lighting during the day by means of skylights and save energy. When installing daylight panels or daylight glass at certain positions on the metal roof, the duration of the daylight should be adjusted to the metal ceiling panel and the connection between the daylight and the metal ceiling panel should be treated watertight.
Beautiful: The metal roof of the industrial steel building has a good texture and a pleasant color.
Check the heat expansion and contraction: check the contraction shift and direction of the metal roof plate. Make sure that in areas with high temperature differences the metal roof plate is not damaged by heat expansion and contraction.
Anti-avalanche: install snow barriers on the metal roof in snow-covered areas to prevent a sudden fall of snow.
Anti-ice caps: industrial steel building can prevent rain and snow from forming ice caps on the mould.
The frame of the industrial steel building is the main structure of the system frame. It is a flat structure consisting of columns and frames. All horizontal water loads and most vertical loads are transferred to the foundation via the plant frame. In industrial buildings, the industrial steel building frame has the following three most common types of construction;
1. The single-storey steel structure factory building frame is a single-storey frame formed from the stacked column of the factory building and the frames anchored to the top of the column (the column top can be called the system bent when the column top is foldable).
2. A rigid one-storey frame, a one-storey frame formed by a rigid connection of columns with an equal or gradual cross-section and frames on the top of the column.
3. Multi-layered frame, a multi-layered frame formed by joining columns and floor supports (or specialist works) and roof supports or roof supports.
Having learned so much about industrial steel building, it is also a difficult problem to select from many manufacturers the one with high quality and low price. Qingdao Xinguangzheng Steel Structure Co., Ltd. has been a Chinese pioneer in industrial steel building for several years. You can work with customers from design to completion to ensure that all technical requirements are met.
The main material of commercial steel building is light steel keel synthesized from hot-dip galvanized steel strip through cold rolling technology. After accurate calculation and support and combination of auxiliary parts, it has reasonable bearing capacity and can replace traditional houses.
What are the progress of commercial steel building?
What is the future development of commercial steel building?
What are the necessary steps in the commercial steel building construction process?
1. The house has good safety performance. commercial steel building is anti-seismic, anti-typhoon, fire-proof and anti-insect and ants. The service life of the main building body can reach 90 years, the overall performance is good, it is not easy to be destroyed by earthquake force, and the building quality and safety performance are better.
2. The house is low-carbon, energy-saving, green and environmentally friendly, and can be reused. The steel of commercial steel building can be recycled and has little impact on the environment during construction and dismantling. Most of the other supporting materials can also be recycled, which meets the requirements of environmental protection; moreover, most of the materials are green building materials, which can meet the requirements of the ecological environment and are beneficial to health.
The steel structure used in commercial steel building will continue to develop into high-strength steel, which will greatly increase its yield point strength; in addition, new types of steel must be rolled, such as H-shaped steel (also known as wide flange steel) and T-shaped steel and profiled Steel plates, etc. to meet the needs of large-span structures and super high-rise buildings.
Steel structure is divided into light steel and heavy steel. There is no uniform standard for judging, and many experienced designers or project managers often cannot fully explain. They can be comprehensively considered and judged based on some data.
1. Purge device
This device uses a high-pressure fan, and multiple sets of elastic blowing nozzles with different angles are arranged in the auxiliary chamber of the chamber to blow and clean the projectiles remaining on the surface of the workpiece.
2. Import and export sealing
The inlet and outlet sealing devices of the workpiece are all made of rubber spring steel plate. In order to prevent the projectile from splashing out of the cleaning room during shot blasting, there are multiple reinforced seals at the inlet and outlet of the workpiece, which are characterized by strong elasticity, long life, and sealing effect. Superb.
3. Dust removal system
The dust removal system is mainly composed of a bag filter, a fan, and a dust removal pipeline. The dust removal efficiency can reach 99.5%.
This is the relevant knowledge about the commercial steel building for you to get more information about it. If you want to order a commercial steel building, you must choose Qingdao Xinguangzheng Steel Structure Co., Ltd., because they can provide the commercial steel building with most high-quality and suitable price.
How much do you know about the Agricultural steel building?
When you consider the building materials used in a new construction project, you will feel uneasy. In fact, by choosing steel (rather than wood, stone, brick, etc.), you have already taken the first step to ensure that the completed project produces the best results. Steel is attractive because of its unparalleled strength-to-weight ratio, ductility, price, aesthetics, and consistency of composition from the beginning. There are more and more applications of agricultural steel building in agricultural production. Let’s take a look below.
What is the significance of the development of agricultural steel building?
How to set the power supply in agricultural steel building?
What are the components of the agricultural steel building organization?
What is the significance of the development of agricultural steel building?
The economic benefits of the development of agricultural steel building are good. First of all, the entire building does not require beams and bars, and the cost is only two-thirds of the light steel structure, and the larger the span, the lower the cost. In addition, the construction of agricultural steel building can greatly shorten the construction period, and the daily construction area can reach 1000m, which greatly saves the construction of machinery and labor costs.
The social effect of the development of agricultural steel building is significant. The construction period of modern large-scale projects is closely linked to economic benefits. Because we have adopted agricultural steel building development, the construction of the project is completed ahead of schedule, which creates good conditions for agricultural production units to put into use in advance, and the social effect is significant.
How to set the power supply in agricultural steel building?
1. The main distribution box in the agricultural steel building should be installed near the power source, and the distribution box should be installed near the electrical equipment or power-using area.
2. The distribution box in the agricultural steel building is made of iron plate.
3. The distribution box in the agricultural steel building should be equipped with a working neutral terminal board and a protective neutral terminal board.
4. The metal box, metal base and shell must be protected and connected to zero. The distribution box must be protected from rain and moisture. There must be a secondary leakage protector in the distribution box, and each electrical equipment should have its own dedicated switch box, which must implement "one machine, one switch, one leakage, one box", equipment and lighting are disconnected, all power distribution The boxes are all equipped with doors and locks, and a dedicated person is responsible for keeping them, and a regular inspection and maintenance system is implemented.
What are the components of the agricultural steel building organization?
(1) Structure made of cold-formed thin-walled steel;
(2) Structure made of hot-rolled light section steel;
(3) Structure composed of welded and high-frequency welded lightweight steel;
(4) Structure made of round tube, square tube, rectangular tube, etc.;
(5) Structure made of components welded from thin steel plates;
(6) The structure made by the combination of the above various components.
Qingdao Xinguangzheng Steel Structure Co., Ltd.. has been committed to providing customers with agricultural steel buildings and perfect after-sales service so that customers can invest easily, use them with confidence, and have no worries.
1. The positioning axis and supporting surface elevation of the foundation are out of tolerance:
The positioning axis of the foundation and the elevation of the supporting steel cylinder exceed the allowable deviation.
The reasons are as follows:
There are errors and deviations in foundation survey control network, foundation survey setting out and elevation finding.
The foundation formwork is not firmly set up, the pouring concrete blanking is too high, and the concrete is vibrated and impacted, which makes the formwork displacement and causes the datum line deviation.
Or the use of steel ruler, theodolite, level without calibration, there are errors.
Or construction wrong drawings, axis wrong, without strict inspection.
Or if the foundation bearing surface is not plastered and leveled twice, the concrete will shrink and sink.
Or the embedded steel plate (or support) is not fixed.
Because the foundation positioning axis and bearing surface are out of tolerance, the column installation axis and bearing elevation will be out of tolerance, which will affect the quality of the whole structural steel construction installation project.
(1) The accuracy of basic survey control network, instruments and measuring tools used for basic survey setting out and leveling shall be accurate. Before use, they must be checked or verified by the measurement department. If problems are found, they shall be adjusted in time to prevent errors or accumulated errors, resulting in axis and elevation exceeding the allowable deviation.
(2) The foundation formwork for steel structure construction must be firmly supported with sufficient strength and rigidity. When pouring concrete, cutting and vibrating, it is necessary to prevent from striking the formwork and causing displacement. In the process of concrete pouring, the positioning axis and elevation shall be checked regularly with measuring tools or suspension lines. If any deviation is found, the pouring and vibration shall be stopped, and the work shall be carried out after reinforcement and adjustment. Before the final setting of concrete, the surface of foundation concrete shall be plastered and leveled twice. For the embedded steel plate or bearing, the elevation and levelness shall be aligned twice, and the concrete at the bottom shall be dense. The steel plate or support of foundation support column shall be provided with necessary fixing devices to ensure correct position and elevation.
(3) When the elevation and levelness of the steel plate or support on the vertical and horizontal axis of the foundation and column bearing surface are out of tolerance, measures shall be taken according to the degree of deviation. When the out of tolerance is not serious, it can be solved by shifting the column base, reaming and packing the base plate. If the deviation is serious and cannot be adjusted, it should be studied with relevant departments to work out a feasible correction scheme before treatment.
2. Foundation anchor bolt thread damage:
The foundation anchor bolt thread is damaged, and the nut cannot be screwed and tightened during the column installation.
The causes of bolt thread damage are as follows:
Anchor bolts are impacted or improperly kept during transportation, loading and unpacking, resulting in serious thread corrosion.
Or the bolts were not protected after burying and were damaged by outside.
Or the bolt is used as electric welding zero line on site, and the thread is damaged due to arc burn.
Or the bolt is used as the binding point of the pulling force of the traction rope.
Due to the damage of bolt thread, it is impossible to screw in nuts to fasten steel columns and other components, which affects the transmission and stability of structural force.
(1) When the anchor bolts are transported, packed and unpacked, the thread protection shall be strengthened. After being smeared with industrial vaseline oil, they shall be wrapped and bound with plastic film to prevent thread damage and corrosion. And should be stored separately, should not be mixed with other parts and components, so as to avoid mutual impact damage thread.
(2) After the anchor bolt is embedded, it shall not be used as the fulcrum of bending processing, the neutral line of electric welding machine, or the binding point of traction force. When lifting components, proper operation shall be carried out to prevent the thread from being damaged by horizontal lateral impact force.
(3) The screw thread of the bolt has been damaged, and the following treatment methods can be adopted: when the damaged length of the screw thread does not exceed its effective length, the steel file can be used to trim the screw thread, so as to smoothly screw in the nut. When the length of thread damage of local foot bolt exceeds the specified effective length, the length of original thread section can be cut by gas cutting; Then, with the same material and specification as the original bolt, one end of the bolt is processed into thread, and the butt end section is made into 30º-- 45º. After butt welding with the lower end of the groove, the corresponding diameter specification and length of the steel casing sleeve into the joint, welding reinforcement. After casing reinforcement for steel work in construction, the diameter of the bolt will be larger than that of the base plate, which can be solved by appropriately enlarging the diameter of the base plate.
3. The setting of mortar base plate of column base does not meet the requirements:
The mortar base plate of column base is set randomly, and the elevation, levelness and position do not meet the design and specification requirements.
The reasons are as follows:
The surface of the foundation is not treated and leveled, so that the base plate can not bear the force smoothly, and the surface is uneven and uneven;
The base plate is not reasonably arranged according to the stress requirements, so that the base, base plate and foundation can not bear uniform pressure, so that the settlement of base slurry is uneven, and the elevation and levelness can not meet the requirements.
If the setting of open base plate does not meet the requirements, it can not transfer the load evenly, which will reduce the mechanical performance of the column and affect the stability of the superstructure.
(1) In order to make the base plate group transmit the force to the foundation smoothly, the base plate should be closely combined with the base slurry on the foundation surface. The uneven foundation surface shall be chiseled and leveled.
(2) The location and distribution of the base plate should be correct. Generally, according to the stress area of the steel column base plate, the base plate, the base plate and the foundation should be arranged in the center of the steel plate and the stress concentration position on both sides or near the two sides of the anchor bolt, so that the base plate, the base plate and the foundation can fully bear the pressure load, and bear the force uniformly together to avoid partial bias Concentrated stress or deformation of the base plate occurs when the anchor bolts are tightened.
(3) The area of the base plate directly bearing the load should meet the needs of the stress, which should be determined by calculation, and the area should not be too large or too small. Too large will cause waste, too small will cause local concentrated overload of foundation and affect the overall and uniform stress of foundation. The thickness of the base plate is generally within the range of 4 ~ 25 mm, each group is no more than 3 pieces. The base plate has a 10 ~ 12 mm thick steel plate, the length of the base plate is 100 ~ 300 mm, and the width is 50 ~ 120 mm. When setting the mortar, use non shrinkage cement mortar with strength not lower than 30MPa. As the steel column is mainly installed with cushion plate to adjust the elevation and levelness, the elevation and levelness shall be found when grouting, and the allowable deviation shall comply with the specification, and the supervision shall be strengthened. Before the base plate is grouted, the rust, oil stain and burr on the surface of the base plate shall be cleaned, so that the base plate can be firmly combined with the concrete when grouted and grouted; The length of the base plate group exposed to the outside of the base plate edge is about 10 ~ 20 mm.
4. Before the installation of steel column, the foundation is directly installed without inspection:
Before the installation of steel column, the axis and elevation of the foundation, the position and elevation of the anchor bolt and the concrete quality of the foundation are not checked in advance, so the installation is carried out directly. In this way, there may be out of tolerance without repair, which will cause structural installation difficulties, increase the steel column installation stress and affect the installation accuracy, and even cause quality hazards.
Before the installation of steel column, the positioning control line, foundation axis, elevation, anchor bolt position, elevation and concrete quality of foundation shall be pre checked. If the deviation is found, measures shall be taken to correct and adjust to the allowable deviation range of the specification. For elevation inspection, the measured data shall be compared with the pre inspection data of steel column size and elevation, and the error of the two shall be eliminated when the support base slurry pad or anchor bolt nut is adjusted. The allowable deviation of foundation support surface, anchor bolt position and base slurry pad shall meet the requirements of the specification. The quality of foundation concrete shall be dealt with in accordance with relevant regulations.
5. Don't check the dimension of steel members, deal with deformation and quality defects before installation
Before the installation of the structure, the external dimensions of the steel members are not checked, and the deformation and quality defects of the members are handled.
Although the steel components have passed the quality inspection before they are processed in the factory, they may fail to be inspected, or new deformation and damage may occur in the transportation and stacking of the components. If the review is not carried out before the installation, these problems can not be dealt with in time before the installation, which will affect the installation quality of the steel structure and cause installation difficulties or permanent quality defects.
Before the installation of steel members, the steel members shall be carefully checked in advance:
It includes checking the model and quantity of the component, the overall dimension of the component, the relevant dimensions between the supporting surfaces and the installation holes, and marking the datum line of the axis of the component. Check whether the component is deformed, and correct and repair the deformation error if there is any.
Whether the connecting plate, splint and other accessories of the component are complete and whether the position and size are accurate. Inspect whether the surface quality of the welding area of the component and the friction surface of the high-strength bolt connection meet the requirements and whether it is polluted.
Whether the member nodes are complete and whether the center of gravity of main components is marked.
Whether the surface of the component is polluted, whether the paint falls off, etc.
Pre inspection records of components shall be made; For the components with deformation and defects exceeding the allowable deviation, they shall be corrected and repaired on the ground before installation, and can be installed after they are qualified.
6. The perpendicularity of steel column installation is out of tolerance:
The verticality deviation of steel column exceeds the allowable value in design or code
When the steel column is manufactured, the deformation control measures are not taken or the bending deformation is not straightened.
Or the length of the column is large, the rigidity is poor, and the elastic or plastic deformation occurs under the action of external force.
Or due to the unreasonable hoisting technology and procedure, the roof panel is bent and deformed under the action of temperature, wind and external force.
Or there is deviation in the span size of the roof truss, the external force is used to force the connection during the installation, resulting in the over deviation of the verticality of the steel column.
This will lead to the deflection of the steel column and affect the bearing capacity and stability.
(1) Anti deformation measures shall be taken for assembly and welding of steel column, and the deformation during fabrication shall be corrected in time. When transporting and stacking steel columns, the supporting points should be appropriate to prevent bending deformation under the action of self weight. The out of plane stiffness of long column is poor, so the lifting point should be selected at 2 / 3 of the total length of the column to prevent deformation. If the span size of steel roof truss exceeds the deviation, it should be corrected before installation to prevent forced connection and bending deformation of column body.
(2) When the steel column is hoisted to the foundation plane in place, the vertical and horizontal axis above the column base plate should be aligned with the foundation line, so as to prevent the deviation of span size, which will lead to the horizontal tension or thrust when the column head is installed and connected with the roof truss, so as to make the column body bending and deformation, and carry out appropriate control.
(3) When the roof slab is hoisted after the connection and installation of the steel column and the tail-stock, it should be carried out symmetrically and synchronously from the edge of the two slopes in the center of the top chord to the middle, so as to prevent the bending deformation of the steel column caused by the lateral concentrated pressure generated by the one slope. Without the permission of the design, the steel column and other connected components shall not be used for horizontal dragging or vertical hoisting of heavy components and equipment, and the column bending deformation or damage to the connecting structure shall be prevented.
(4) If the bending steel column is elastic deformation, it can be restored to its original state after the external pressure is removed; If it is plastic deformation, it can be corrected by adding temporary support above or at the top of the bending part of the steel column before correction, so as to reduce the load-bearing gravity, and then fixing one side reaction frame at the bending part, and using jack for correction. If the rigidity of the steel column is large, it can be corrected by heating the bending convex surface with oxyacetylene flame, and then applying jacking force.
7. Steel column installation height is out of tolerance：
Height dimension or relative position of steel column after installation (±) The elevation dimension is out of tolerance, which makes the difference between the total height of each column and the height deviation of the bracket.
The reasons are as follows
Foundation elevation is incorrect or deviation occurs.
The length and dimension of steel column during the production stage are out of tolerance.
Or when the foundation elevation is adjusted and treated during installation, it is not combined with the actual length (height) of steel column, which will cause the positive or negative difference of the height dimension or elevation dimension of the steel column after installation.
Because of the over tolerance, it is difficult to install and adjust the components connected with it, which makes it difficult to correct and takes time.
(1) During the foundation construction, the elevation size should be strictly controlled to ensure the accuracy of elevation. The elevation dimension of the upper surface of the foundation shall be adjusted according to the actual length of the steel column or the elevation dimension of the bracket supporting surface, so as to make it consistent with the height and elevation dimension of the steel column after installation.
(2) During the manufacturing process of steel column, the length and size (including the total length and the length of each position specified in the design, the length and size within the allowable positive and negative deviation range, and the positive excess value not allowed) and the correct size of the total length and bracket of the steel column without contact point shall be strictly controlled. The latter can be adopted to weld the column body first, and the column base plate and column head plate shall not be welded temporarily, In case of out of tolerance, adjust before welding the base plate or upper column head plate of the column, and finally weld the base plate and column head plate of the column.
Qingdao Xinguangzheng Steel Structure Group completed Qingdao Haier Yungu Supporting School Project on August 31, 2022.
Mexico galvanized prefab steel layer house building with cages Project
Project address: Mexico
Area: 120m * 16m * 7m
Detailed parameters: Hot-dipped galvanized steel beam, steel column with zinc thickness 100um. Purlins are 275g/m² zinc which
life span can reach 15-20 years.The reasonable design of the feeding regulator ensures the regulator move stably, and the birds will not run away and get stuck.
Project Area: 23408 sqm
Project Usage：Pakistan Cola workshop
Project Location: Lahore, Pakistan
Project weight of steel structures： 760 tons.
Wall & Roof：0.5mm galvanized steel sheet +50mm glass wool+0.4mm galvanized steel sheet.
Span: Multi-Span 100m and 50m
Total Height: 12m
Project picture of Pakistan Prefabricated Steel Structure Construction Cola Workshop :
A brief introduction to you about our company first, then you can contact me if there is suitable project in the future.
1200 workers, 360000 ㎡ non-dust workshop, 25 years experience, CE, ISO9001, ISO9712, ISO3834, BV, SGS certificated, one hour reach Qingdao port, our company, as a manufacture, this is how we keep good quality and competitive prices for global valued customers.
We provide steel building design, farm house design, manufacture and installation service.