1 Scope
This technical standard is applicable to the assembly and installation construction of steel structure engineering for general industrial and civil buildings.

2 Construction Preparation

2.1 Equipment and Main Tools

• EquipmentAccording to the weight of the components and site conditions, select overhead cranes, truck cranes, or crawler cranes, etc.
• Main equipmentLifting rigging, welding machine, wooden blocks, steel shims, wrenches, pry bars, torque wrenches, jacks, straight rulers, tape measures, etc.

2.2 Materials and Semi-finished Products

• Steel componentsThe model and manufacturing quality must meet the requirements of design and construction specifications.
• Connecting materialsWelding rods, bolts, etc. should have quality certificates and comply with current national standards.

2.3 Operating Conditions

• Check the quantity upon entry against the component detail list, and verify the qualification certificate and related technical documentation.
• Check whether the components are damaged or deformed during transportation and stacking. If there are any issues, they must be corrected, repainted with a protective coating, and re-inspected.
• Review whether the assembled steel components meet the quality standards.
• The installation site foundation should be solid and have sufficient equipment and personnel working space.
• Confirm that the previous process has completed acceptance, handover, and inspection procedures.

3 Operating Processes

3.1 Process Flow
Job preparation → Component installation → Connection and fixation → Inspection and acceptance

3.2 Assembly of Steel Trusses (Steel Skylight Frames)

• The form of the roof truss refers to Figure 9-46 of the "Construction Manual for Steel Structures."
• Place the half-frame structure on the assembly platform, level it, and then spot weld it, completing the welding in order.
• Trusses with low lateral rigidity require reinforcement after welding. After flipping and verifying the dimensions, continue welding (see Figures 9-47, 9-48).
• When the truss exhibits distortion or angled bends, correction is made using mechanical or flame methods.
• When there is a conflict between the rise of the arch and the span, the value of the rise should take precedence.
• Repairs should be made promptly when the node angles or dimensions do not match.
• Both vertical and horizontal assemblies must ensure that the supports are secure to prevent sinking, which could affect the arching (refer to Figures 9-49 to 9-51).

3.3 Steel Column Assembly

• Multi-segment columns can be assembled on the ground and then lifted as a whole, and the number of segments to be assembled must be determined based on the crane's capacity.
• Configure the corresponding platform and fixtures according to the column cross-section.
• Each section of the column should be aligned with the centerline. When assembling multiple sections of the column, pull the lines on three sides and pay attention to controlling the verticality.
• The node flange plate misalignment needs to be corrected within the allowable tolerance, using a chain hoist and ear plate for alignment.
• Nodes must have connection board constraints, which should be removed after welding and cooling.
• After welding is completed, flip over, level, and recheck the dimensions, then cut off the restraint plate and ear plate.

3.4 Steel Beam Assembly

• The hollow steel beam can be assembled in a horizontal or vertical configuration, with the following process:
  Component positioning → Assembly platform positioning → Leveling → Stretching reference line → Ordinary bolt positioning → High-strength bolt installation → Preliminary tightening → Final tightening → Dimension verification
• The lateral stiffness of lightweight steel structure beams is relatively weak, so a multi-point lifting method should be used during hoisting to prevent deformation.

3.5 Assembly of Spatial Arch Trusses

The elevation positioning of the string rod can be controlled using the water pipe communication method.

Process flowIt seems that there is no content provided for translation. Please provide the text you would like me to translate into English.
Body frame manufacturing → Overall assembly positioning → Calibration inspection → Joint welding → UT testing → Post-welding calibration → Coating → Final inspection

Select appropriate lifting equipment and establish a horizontal assembly platform.

The frame is used for truss assembly after acceptance.

During assembly, the deformation after welding is controlled by restraining nodes through the tire tooling.

The butt joint of the steel pipe uses a liner pipe groove form, and the gap is adjusted by a tensioner.

3.6 Installation of Steel Columns

3.6.1 Types of Steel Columns

• Divided by layers: single-layer, multi-layer steel columns.
• According to length: long column, short column.
• According to the cross-section shapes: mouth-shaped,工-shaped, round, type II, type III, etc.

3.6.2 Selection of Lifting Points
The position of the lifting point should be determined comprehensively based on the shape, section, length of the steel column, and the performance of the lifting equipment.

1. Generally, the elasticity and rigidity of steel columns are good, and can be used.A little bit of a hang.The吊耳 is set at the top of the column, and the vertical column body facilitates alignment correction. When limited by the length of the crane arm, the lifting point can also be set at one-third of the column length.Slant suspensionAt this time, the column body is tilted, making correction more difficult.
2. Correct.Slender steel columnTo prevent deformation, it should be adopted.Two-point or three-point suspension.It seems that your request may not contain any text to translate. If you provide the text you would like translated, I can assist with that!
3. If there are no dedicated lifting lugs, when directly using wire ropes for binding, it is necessary to pay attention to:
   • For square and round columns, the four corners should be done.Corner protection(Using a semicircular steel pipe or angle steel), to prevent the steel wire rope from being cut.
   • When the binding point is located on an I-shaped column, to prevent local squeezing deformation, it shouldAdd reinforced ribs.When hoisting the structured column, it should be at the binding point.Add support rods.It seems that your request may not contain any text to translate. If you provide the text you would like translated, I can assist with that!

3.6.3 Lifting Method
For large steel columns in heavy-duty workshops, single, double, or triple machines can be used for lifting based on the lifting equipment and site conditions.

1. Rotating methodThe crane swings while lifting the hook, allowing the steel column to rotate around the column base (refer to Figure 9-60 in the "Manual").
2. Gliding method: The crane hooks up to lift the steel column base. To reduce friction, it should be placed under the column base.Paving the runway(See "Manual" Figure 9-61).
3. Delivery methodWhen lifting with two or three machines, the auxiliary machine’s lifting point is set at the lower part of the steel column. It works in coordination with the main machine’s hook to walk or rotate and deliver the column base to above the foundation. Then, the auxiliary machine unloads, and the main machine is positioned (refer to "Manual" Figure 9-62).
4. Precautions for Dual Machine/Multiple Machine LiftingIt seems that there is no content provided for translation. Please provide the text you would like me to translate into English.
   • Prioritize using cranes of the same type.
   • Load distribution according to the capacity of the crane.
   • The load on each machine should not exceed 80% of its rated lifting capacity.
   • During operation, actions must be coordinated, using an iron beam to maintain the balance of the boom. The inclination angle should be small to prevent a single machine from becoming weightless, which could lead to overloading of other machines.
   • The command system should be unified, and subordinate commands must obey the overall commander.

3.6.4 Installation of Light Steel Structure Steel Columns

1. The portal frame columns often have varying cross-sections, with larger tops and smaller bases, resulting in a high center of gravity. After installation and fixation, if necessary...Add temporary supports.Prevent tipping.
2. The anchor bolts for the column base should be positioned using reliable methods (see "Manual" Figure 9-89). Measure the lengths of the right-angle sides and the diagonal. The position of the anchor bolts should be rechecked both before and after the concrete is poured to ensure that the foundation dimensions and elevations meet the design requirements.
3. Elevation adjustment, cross line alignment, verticality control, and installation methods refer to the general steel column process.
4. Installation allowable deviations shall be executed according to the national standard "Code for Acceptance of Construction Quality of Steel Structure Engineering" GB50205—2001.

3.6.5 Steel Column Correction
The calibration content includes: column base elevation, longitudinal and transverse cross lines, and column verticality.

1. Correction of single-layer structural steel columns.
   • Column base elevation adjustmentAccording to the actual length of the steel column, the flatness of the column base, and the distance to the top of the shoe, adjust the foundation elevation to ensure that the elevation at the top of the shoe is the target. This can be achieved byAdjust the nut.Control the elevation of the base plate, with an accuracy of ±1mm. The gap at the bottom of the column must be filled with non-shrink mortar. The strength and stiffness of the anchor bolts must be verified.
   • Crosshairs alignment: Use the alignment of the side points of the column bottom plate with the foundation cross lines to achieve point-line coincidence. During alignment, the crane should not unhook and should slowly lower to the specified elevation. To allow for errors, the screw holes can be appropriately enlarged and fixed by welding the upper pressure cover plate.
   • Column verticality correction: AdoptedRope methodThe observation was conducted at 90° with two theodolites. After correcting the adjustment by modifying the bottom nut, the upper nut was tightened and fixed after verifying that there were no errors. The fastening force of the anchor bolts can be referenced in Table 1, and double nuts or nuts welded to the rod can be used.

Table 1 Foundation Bolt Tightening Force

Bolt diameter (mm)	Tightening axial force (kN)
30	60
36	90
42	150
48	160
56	240
64	300

2. Correction of Steel Columns in High-Rise and Super High-Rise Steel Structures
   • Key controls: elevation, axes, and verticality.
   • First floor column correctionSame single-layer structure. Note that the reinforcement around the rigid steel column needs to be properly arranged for operation.
   • Control of upper column elevationIt seems that there is no content provided for translation. Please provide the text you would like me to translate into English.
     • According toRelative Elevation MethodInstallation: After the steel column is in position, connect the ear plates with high-strength bolts (without tightening). Use a pry bar to make fine adjustments to the gap, measure the elevation at the top of the column, and after it meets the requirements, drive in steel wedges to restrict downward movement, controlling the elevation deviation within 5mm.
     • Using the elevation of the top of the first-level columns as a reference, convert the control lines for each column top. If the deviation exceeds 5mm, adjust using low-carbon steel plate shims.
   • Crosshair CalibrationThe horizontal and vertical crosshairs should be as aligned as possible. In case of deviation, adjustments can be made on the side of the connecting ear plate.Insert a 0.5–1.0mm shim plate.By tightening the hexagon bolts for adjustment, the adjustment amount each time should be within 3mm, and significant deviations should be adjusted over 2-3 times.NoteThe positioning axis of each column must be surveyed from the ground control axis and cannot use the axis of the lower column.
   • Verticality calibrationIt seems that there is no content provided for translation. Please provide the text you would like me to translate into English.
     • Step one (cable-free wind correction)Insert steel wedges or use a jack on the side where the column is inclined. After adjusting the column top axis to zero offset, tighten the high-strength bolts (refer to "Manual" Figure 9-64). The bolt holes of the temporary connection ear plates should be 4.0mm larger than the bolt diameter to accommodate manufacturing tolerances.
     • Step Two (Alignment after Beam Installation)After installing the upper, middle, and lower beams, use cables, jacks, steel wedges, or hand winches for realignment (refer to "Manual" Figure 9-65). The weld shrinkage value can be found in "Manual" Table 9-59.
   • The allowable dimensional deviations for the profiles of single-layer and multi-layer steel columns can be found in "Handbook" Table 4-179 and Table 4-180.

3.7 Steel frame installation

3.7.1 Lifting Reinforcement
The lateral stiffness of the steel frame is poor and must be reinforced before hoisting.

• Single machine hoisting (with one or multiple points using a flat iron bar) is common.Reinforce the lower chordIt seems that your request may not contain any text to translate. If you provide the text you would like translated, I can assist with that!
• Double-machine hoisting shouldReinforced upper stringIt seems that your request may not contain any text to translate. If you provide the text you would like translated, I can assist with that!

3.7.2 Binding Requirements
The binding point must be set atAt the roof truss nodeTo prevent bending deformation of components at the lifting points.

3.7.3 Positioning and Fixing

1. After the first truss is in place, it should be on both sides.Set up the guy line.Fixed; it can be fixed to the wind guard column at the end.
2. After the second roof frame is in place, useRafter adjusterCheck verticality, fix the supports at both ends (bolted or welded) → Install vertical supports → Install horizontal supports → After checking without errors, asModel roomThe subsequent installations will proceed accordingly.

3.7.4 Combined Lifting
To reduce high-altitude operations, the skylight frame can be pre-assembled on the roof truss at ground level, ensuring that the skylight frame is positioned between the two lifting slings during binding to guarantee overall stability (see "Manual" Figures 9-66, 9-67).

3.7.5 Verticality Correction

Theodolite methodPlace the theodolite at the top of the column, with a horizontal distance a from the axis, and set a corresponding point on the opposite column. Measure a distance a from the center line of the truss to ensure that the three points are aligned to ensure verticality (refer to "Manual" Figure 9-67).

Plumb bob method: Pull a long steel wire along the lower chord side under the truss, project the centerline of the upper chord to the same distance measuring scale, and correct it with a plumb bob.

3.8 Steel Beam Installation

3.8.1 Installation of Steel Crane Girders

1. Lifting methods
Determine the best方案综合 based on the weight of the crane beam, the crane capacity, site conditions, and construction schedule requirements.

• Before the roof installationYou can use single machine hoisting, double machine lifting, or utilize a pulley system on the columns (the columns need to be calculated and secured with guy wires), with a crane assisting on the other end. For the improvised lifting end, a rope must be used to pull the beam away from the support to ensure a smooth lift.
• After the roof installationThe best solution is to use a pulley system at the end of the truss or on top of the column for lifting. This method requires a load-bearing capacity calculation for the truss binding points or the top of the column.
• Suspension Point SettingRecommended for useTool-type lifting earsEnsure safety, reliability, and convenience.

2. Correction
The calibration content includes elevation, longitudinal and lateral axes (straightness and track gauge), and verticality.

• Elevation AdjustmentIt seems that there is no content provided for translation. Please provide the text you would like me to translate into English.
  After the installation of all the crane beams within the span is completed, use a leveling instrument (accuracy ±3mm/km) to measure the elevation at both ends of each beam. The standard value is obtained by calculating the weighted average of all data, then calculate the required thickness of the cushion plate at each point and use a jack to lift the end of the beam, inserting wedge blocks underneath.NoteElevation adjustment can be carried out before or after the installation of the roof structure.
• Axis CorrectionIt seems that there is no content provided for translation. Please provide the text you would like me to translate into English.
  After installing the inter-column supports to form the frame, measure the correct axis from the column base to the top of the bracket, and determine the design distance from the center line of the crane beam to the axis line. Pull a long steel wire along the center line of the beam top surface (or use a theodolite) to adjust each beam end's displacement. The design can utilize a circular hole at one end of the lower flange of the crane beam and an elliptical hole at the other end, along with a jack and hand hoist for fine-tuning, and finally use iron wedges to secure it.
• Verticality calibrationIt seems that there is no content provided for translation. Please provide the text you would like me to translate into English.
  Hang the hammer ball from the flange of the crane beam and measure the horizontal distance from the measuring line to the upper and lower parts of the web. By adjusting the wedge, make the upper and lower distances equal to ensure verticality. This correction can be carried out simultaneously with the correction of the longitudinal and transverse axes.
• Timing of CalibrationIt seems that there is no content provided for translation. Please provide the text you would like me to translate into English.
  • Small and medium-sized crane beams: hoisting can be done before and after the roof installation.
  • Heavy crane beam: should be atAfter the roof installationCarry out to avoid the elongation of the bottom chord of the truss leading to an increase in track gauge.

3. Allowable deviation

• The permitted deviation for the installation of steel gantry crane beams is shown in Table 9-60 of the "Manual".
• The allowable deviation of the dimensions of the steel truss is shown in Table 4-182 of the "Manual."

3.8.2 Installation of Lightweight Steel Structure Inclined Beams

1. Lifting methods
The span of the portal frame diagonal beams is large, and the lateral stiffness is small. To ensure safety and quality and improve efficiency, maximum assembly should be done on the ground, and the entire structure should be lifted and positioned.

2. Lifting Method

• Optional single machineTwo o'clock, three o'clock, or four o'clock.Lifting, or usingIron leverTo reduce the pressure of the rigging on the beam.
• For long-span components, it is possible to use.Dual machine hoisting"and take care to prevent lateral instability of the oblique beam."

3. Selection of Lifting Points

• The suspension points of the large-span diagonal beams must be determined through calculations.
• For components with low lateral stiffness and a large web thickness-to-width ratio, it is essential to prevent twisting damage. Focus on controlling the number of lifting points and the synchronization and coordination of dual machine lifts. If necessary, steel wires can be set up between the large hooks of the two machines to maintain a fixed distance and prevent mutual dragging.

4.梁柱连接 4. Beam-column connection

• The connection end plates of the inclined beams and steel columns can be divided into vertical, horizontal, and inclined placements (see "Manual" Figure 9-90).
• Connections usually use high-strength bolts, which have high requirements for installation accuracy.

5. Allowable deviation
The permissible deviations for the installation of portal frame light steel structure houses shall be executed in accordance with the national standard "Quality Acceptance Specifications for Steel Structure Engineering Construction" GB50205-2001.

3.8.3 Installation of Steel Beams in High-rise and Super High-rise Steel Structures

1. Special tooling

• The installation of the main beam uses special fixtures, which should be set on both sides within a range of 500mm from the ends of the steel beam to prevent falling objects from heights.

2. Installation Sequence

• A column typically has 2 to 4 beams, in principle.Vertical components from bottom to topInstall item by item.
• The steel beam of the same column, fromThe middle span begins, symmetrically extending towards both ends.Extended installation.
• The same cross-steel beam, according toUpper beam → Middle beam → Lower beamInstall in the correct order.

3. Measurement and Welding Control

• When installing the main beam between columns, the columns need to be spread apart, and measurements must be adjusted continuously, taking into account the reserved deviation value and welding shrinkage.
• The welding of joints between columns and between beams and columns should be coordinated. Usually, the top beam of a section of the column can be welded first, then...From bottom to topWeld the joints of the beams and columns in each layer. The joints between columns can be welded first or welded last.

4. Installation of secondary beams

• Next beam can be taken.Three-layer串吊To improve efficiency.

5. Control of Levelness

If the level exceeds the standard, the main reason is the positioning of the connection plate or the error of the screw hole, measures can be taken.Replace the connection plate.orRe-drilling after filling the weld hole.Method handling.

The allowable deviation for levelness at both ends of the same beam is(L/1000) + 3, and must not exceed 10mm.

3.8.4 Installation Sequence of Portal Steel Frames

1. Install the single steel column → Adjust the height of the column → Correct the displacement of the longitudinal and transverse axes → Preliminary calibration of verticality → Temporary fixing → Adjustment beyond tolerance → Final fixing.
2. The inclined beams should be leveled on wooden pads on the ground and assembled using high-strength bolts.
3. Installation should start fromTwo rigid frames near the gable wall with inter-column supports.Start by installing all components such as purlins, supports, and corner braces within this section.
4. Except for the two initial installed rigid frames, the remaining rigid frames between them.Bolts for purlins, wall beams, and eaves purlinsIt should be tightened again after calibration.
5. The degree of tightening of various supports isDo not bend the components.As a principle.
6. When installing purlins and wall beams, tension rods should be set up and tightened, butMust not cause the component to bend.It seems that your request may not contain any text to translate. If you provide the text you would like translated, I can assist with that!
7. If the span is long, it can also be.Install two steel frames starting from the middle.Install in the order of column → inter-beam → roof slant beam → support → purlins, and after forming a stable spatial system, extend to both ends.
8. During the construction process, in accordance with the need for structural stability, measures can be taken to prevent overturning due to strong winds.Guy wireIt seems that your request may not contain any text to translate. If you provide the text you would like translated, I can assist with that!

4 Quality Standards

4.1 Main Control Project

All measuring instruments used during the installation process must be inspected and verified to be qualified by the metrology department before they can be used.
4.1.2 The measuring tools used for the fabrication, installation, acceptance of steel structures, and civil construction should be calibrated according to the same standard and maintained at the same accuracy level.
4.1.3 The positioning axis lines of the building, the foundation axis lines, elevations, the specifications of the anchor bolts, and their fastening must comply with design requirements.
4.1.4 When the basic top surface is directly used as the bearing surface for columns or when embedded steel plates/bearings are used as the bearing surface, the allowable deviation of the bearing surface relative to the position of the anchor bolts (anchor bolts) should comply withTable 2Requirements.

Table 2 Allowable deviations for support surfaces and anchor bolt (foundation bolt) positions (mm)

Project	Allowable deviation
Bearing surface
Elevation	±3.0
Levelness	L/1000
Anchor bolts
Bolt center offset	5.0
Reserved hole center offset	10.0

4.1.5 When using seat paste pads, the allowable deviation should comply withTable 3Regulation.

Table 3 Allowable Deviations of the Grouting Pad Plate (mm)

Project	Allowable deviation
Top surface elevation	0.0, -3.0
Levelness	L/1000
Location	20.0

4.1.6 When using a cup mouth foundation, the allowable deviation of the cup mouth dimensions should comply withTable 4Regulation.

Table 4 Allowable Tolerances for Cup Mouth Dimensions (mm)

Project	Allowable deviation
Bottom elevation	0.0, -5.0
Cup mouth depth H	±5.0
Verticality of the cup opening	H/100, and should not be greater than 10.0.
Location	10.0

4.1.7 In the installation of multi-layer and high-rise steel structures, the positioning axes, column positioning axes, elevation levels, the specifications and locations of anchor bolts, and their fastening should comply with design requirements; where there are no specifications, it should execute according to Table 11.2.1 of the "Code for Acceptance of Construction Quality of Steel Structure Engineering" GB50205-2001.
4.1.8 Deformations and coating detachment caused by the transportation, stacking, and hoisting of steel structures must be corrected and repaired.
4.1.9 The design requirements for the tightly pressed joints are that the contact area should be ≥70%, should be closely fitted, and the maximum edge gap should be ≤0.8mm.
4.1.10 The allowable deviation of verticality and lateral deflection for steel frames (supports), trusses, beams, and compressed members can be found in Table 10.3.3 of the "Code."
4.1.11 The allowable deviation of the overall verticality and overall plane curvature of single-layer steel structures can be found in "Specification" Table 10.3.4.
4.1.12 The allowable deviation for the installation of multi-layer columns can be seen in Table 11.3.2 of the "Specification."
4.1.13 The allowable deviations for the overall verticality and overall planar curvature of multi-story and high-rise steel structures are specified in Table 11.3.5 of the "Specification."
4.1.14 The connection of high-strength bolts with ordinary bolts in multilayer plate stacking should be checked with a test hole device and meet the following requirements:

• When using a test probe with a nominal diameter of aperture less than 1.0mm, the pass rate should be ≥85%;
• When using a hole plug with a size greater than the nominal diameter of the bolt by 0.3mm, the pass rate should be 100%.

4.2 General Items

4.2.1 The allowable deviation for pre-assembly is specified in Appendix D, Table D of the "Quality Acceptance Specifications for Steel Structure Engineering Construction" GB50205-2001.
4.2.2 The allowable dimensional deviation for anchor bolts (foundation bolts) is as follows:Table 5It seems that your request may not contain any text to translate. If you provide the text you would like translated, I can assist with that!

Table 5 Allowed Deviations for Anchor Bolt (Foundation Bolt) Dimensions (mm)

Project	Allowable deviation
Exposed length of the bolt	+30.0, 0.0
Thread length	+30.0, 0.0

4.2.3 The center lines and elevation reference points for main components such as steel columns should be marked completely.
4.2.4 When steel trusses (or beams) are installed on concrete columns, the deviation of the support center from the positioning axis shall be ≤10mm; when using large concrete roof slabs, the spacing deviation between steel trusses (or beams) shall be ≤10mm.
4.2.5 The allowable deviation for the installation of steel columns can be found in Appendix Table E.0.1 of the "Standards."
4.2.6 The allowable deviation for the installation of steel gantry beams or similar components that directly bear dynamic loads is shown in Appendix Table E.0.2 of the "Code".
4.2.7 Allowable deviations for the installation of secondary components such as purlins and wall brackets are as follows.Table 6It seems that your request may not contain any text to translate. If you provide the text you would like translated, I can assist with that!

Table 6 Allowable Installation Deviations for Secondary Components such as Purlins and Wall Brackets (mm)

Project	Allowable deviation	Inspection method
The center of the wall rack column is offset from the positioning axis.	10.0	Steel ruler inspection
Verticality of wall bracket columns	H/1000, and should not be greater than 10.0.	Theodolite or plumb line + steel measuring tape
The curvature height of the wall shelf upright.	H/1000, and should not be greater than 15.0	Theodolite or plumb line + steel measuring tape
Verticality of the wind-resistant truss	h/250, and should not be greater than 15.0	Plumb line + steel ruler
The spacing of purlins and wall beams.	±5.0	Steel ruler inspection
The curvature height of the purlin.	L/750, and should not be greater than 12.0.	String line + steel tape
The deflection of the wall beam is high.	L/750, and it should not be greater than 10.0.	String line + steel tape

Note: H - height of the wall support column; h - height of the wind-resistant truss; L - length of the purlin or wall beam.

4.2.8 The installation of steel platforms, steel ladders, and railings shall comply with the current national standards "Fixed Steel Vertical Ladders" GB4053.1, "Fixed Steel Inclined Ladders" GB4053.2, "Fixed Protective Railings" GB4053.3, and "Fixed Steel Platforms" GB4053.4. Allowable deviations are as follows:Table 7It seems that your request may not contain any text to translate. If you provide the text you would like translated, I can assist with that!

Table 7 Allowable Deviations for the Installation of Steel Platforms, Steel Ladders, and Guardrails (mm)

Project	Allowable deviation	Inspection method
Platform height	±15.0	Level instrument inspection
Platform beam levelness	L/1000, and should not be greater than 20.0	Level instrument inspection
Platform pillar verticality	H/1000, and should not be greater than 15.0	Theodolite or plumb line + steel measuring tape
The load-bearing platform beam is subject to lateral bending.	L/1000, and should not be greater than 10.0	String line + steel tape
Verticality of the load-bearing platform beam	h/250, and should not be greater than 15.0	Plumb line + steel ruler
Verticality of the elevator shaft	L/1000, and should not be greater than 15.0	Plumb line + steel ruler
Railing height	±15.0	Steel ruler inspection
Spacing between railing posts	±15.0	Steel ruler inspection

4.2.9 The allowable deviation for the fit gap of on-site weld seams is as follows:Table 8It seems that your request may not contain any text to translate. If you provide the text you would like translated, I can assist with that!

Table 8 Allowable Deviations for Joint Gaps in Field Welds (mm)

Project	Allowable deviation
No gap between the pads.	+3.0, 0.0
There is a gap in the pad.	+3.0, –2.0

4.2.10 The surface of the steel structure should be kept clean, and the main surfaces must be free from scars, mud, and other impurities.
4.2.11 The allowable deviations for the installation of multi-layer and high-rise steel structures are provided in Appendix Table E.0.5 of the "Code."
4.2.12 The allowable deviation of the total height of multi-layer and high-rise main structures is shown in Appendix Table E.0.6 of the "Standard."

5 Finished product protection

5.1 When steel structures are stored on-site, the ground should be solid and well-drained; components must be elevated by 200mm and must not be placed directly on the ground.
5.2 During transportation, handling, and lifting of steel structures, reliable reinforcement and protection measures should be implemented to prevent deformation.

6 Quality Issues to Pay Attention To

6.1 The installation of single-layer steel structures should preferably followFirst vertical components, then planar components.In order to control vertical cumulative errors and ensure engineering quality, the sequence is carried out.
6.2 During construction, measures should be taken in a timely manner according to the structural spatial stability.Guy wireTake anti-wind measures to prevent the frame from toppling over.