1                             Welding of structural Componetns

1.1                        Welding workers must pass the examination and be certified. Certified welding workers must conduct welding within the category that passed examination and be certified.

1.2                        The first and second level welding seams required in design must be checked for inner defects with ultrasonic detection. When ultrasonic could not judge the inner defect, radiation defect detection shall be applied.

1.3                        The surface of welding seam shall not have defects such as crack, flash, etc.  The first and second level of welding seams shall not have defects such as abscess, slag inclusion, crater crack, arc scratch, etc. First level welding seam shall have no defects like undercut, underfill, root retraction, etc.

2                             connection of FastenerS

2.1                        Permanent normal bolt shall be fastened firmly and reliable, the exposed thread shall not less than 2 rounds.

2.2                        The fabricating factory and installing company for steel structure shall conduct anti-slip coefficient of friction surface and re-check test respectively on friction surface for high-strengthen bolts. To the friction surface treaded on site, ant-slip coefficient of friction surface shall be tested separately at site of which the results shall comply with design requirements.

2.3                        Fastening sequence and torsional moment of initial fastening and secondary fastening of high strength bolts shall comply with the design requirements and applicable industrial standard Specifications for Design, Construction and Acceptance of High Strength Bolt Connection of Steel Structure (JGJ82).

 

2.4                        After final screw of set of high strength bolts, the exposed bolt thread shall be 2-3 round; among which it is allowed that 10% of the exposed thread is 1 or 4 rounds.

 

2.5                        The connecting friction surface of the high strength bolt shall be clean and dry, shall not have bur, welding splash, welding scar, oxidized iron skin, dirt, etc.  Unless it is required by the design the surface shall not be painted.

 

2.6                        High strength bolt shall be able to go into the bolthole freely.  The enlargement of the bolthole shall not use gas cutting, the hole enlargement number shall be permitted by the designer, the diameter after hole enlargement shall not be more than 1.2 d (d is the boltm diameter).

3                             fabrication of Steel parts and component

3.1                        Steel cutting surface and shear plane shall not have crack, slag, lamination, or edge missing which larger than 1 mm.

 

3.2                        Corrected steel surface shall not have obvious dent or damage, the scratch depth shall not be more than 0.5 mm, and shall not be more than 1/2 of the allowable tolerance of thickness of the said steel.

 

3.3                        When edge processing is necessary for gas-cut parts or mechanical-cut parts, the planed thickness shall not be less than 2.0 mm.

4                             Assembling and installation of steel elements

4.1                        The distance between flange welding and web welding of H beams shall  not be less than 200 mm.

5                             installation of Single level structure

5.1                        General regulations

5.1.1                   The acceptance of steel structure inspection shall be executed after arrive check and acceptance, at site and inspection of fastener installation and fabrication.

 

5.1.2                   Regarding the measurement and correction of installation and high strength bolt installation, technique test or evaluation shall be conducted before installation, and make relevant construction technique and plan based on this.

 

5.1.3                   The detection of installation deviation, shall be conducted after the structure has formed space rigid unit and fastened.

 

5.1.4                   While installing, strictly control the construction load on roof, floor and platform. Never apply construction load and snow load on girder, purlin, roof, floor and platform boards higher than designed.

 

5.1.5                   After forming the space rigidity, apply secondary pouring with fine stone concrete, and grouting materials for the intervals between column bottom board and foundation top surface.

 

5.2                        Foundation and Supporting Surface

 

5.2.1                   The positioning axis, foundation axis, elevation, size and fastening of anchor bolts shall comply with the design requirements.

 

5.2.2                   When the foundation top surface acts directly as the supporting surface for columns, or the embedded steel sheets or supporting stand as supporting surface for columns, the allowable tolerance of the bracing plane, anchor bolt position shall comply with the regulation in Table 1.

 

Table 1 Allowable Tolerance of bracing plane, foundation bolts positions

Items		Allowable Tolerance (mm)
Bracing plane	Elevation	±3.0
	Levelness	L/1000
Foundation bolt	Bolt center shifting	5.0
obligated hole center shifting		10.0

 

 

5.2.3                   When mortar bed is to be adopted, the mortar bed’s allowable tolerance shall comply with the regulation in Table 2.

 

Mortar bed’s Allowable tolerance(mm)                       Table 2

Items	Allowable Tolerance(mm)
Top elevation	0.0-3.0
Levelness	L / 1000
Position	20.0

 

5.2.4                   Foundation bolt (anchor bolt)’s size deviation shall comply with Table 3.  The thread of anchor bolt shall be protected.

 

anchor bolt size Allowable tolerance(mm)                     Table 3                                    

Items	Allowable tolerance (mm)
Exposed length of bolt	+30.0 0.0
Thread length	+30.0 0.0

 

5.3                        Installation and Correction

 

5.3.1                   Steel structure deformation and paint damage caused during transportation and handling shall be corrected and repaired.

 

5.3.2                   Allowable tolerance of verticality and bending sector height of steel roof truss, truss, girder, and compression member shall comply with Table 4.

 

Table 4   Steel roof truss, truss, girder, and compression member

verticality and side bending elevation Allowable tolerance

Item		Allowable tolerance
Mid span vertical degree	H/250，and £15.0	l /250, and £15.0
Side bending elevation	l£30m	l /1000, and £10.0
	30m<l£60m	l /1000, and £30.0
	>60m	l /1000 and £50.0

 

5.3.3                   Allowable tolerance of verticality and plane bending of single storey steel structure shall comply with the regulation in Table 5.

 

Table 5  Allowable tolerance of verticality and plane bending  (mm)

Item	Allowable tolerance
Main structure whole vertical degree	H/1000, and £25.0
Main structure’s whole plane bending degree	L/1500, and £25.0

 

5.3.4                   Centerline and elevation bench mark of major components like steel column shall be marked properly.

 

5.3.5                   When steel truss (or girder) is installed on concrete column, the tolerance of its base center to positioning axis shall not be more than 10 mm; In case of using large concrete roof slabs, tolerance of steel truss (or beam) pitch shall not exceed 10 mm.

 

5.3.6                   The Allowable tolerance for steel column installation shall comply with regulations in Table 6.

 

Table 6 The Allowable tolerance for column installation

in single level steel structure

Item			Allowable tolerance(mm)
Shifting of column stand centerline to positioning axis			5.0
Elevation of column bench mark	Column with crane beam		+3.0 -5.0
	Column without crane beam		+5.0 -8.0
Bending elevation			H/1200，and £15.0
Verticality of column axis	Single storey column	H£10 m	H/1000
		H>10m	H/1000, and £25.0
	Multi-link column	Single column	H/1000，and £15.0
		Total height	35.0

6                             installation of multi-storey steel structure

6.1                        General regulations

 

6.1.1                   The length dimension of structures such as column, girder, and support shall include deformation value such as welding shrinkage allowance.

 

6.1.2                   While installing column, each column’s positioning axis shall introduce directly form ground control axis, not form the axis of the column underneath.

 

6.1.3                   Installation inspection of steel structure shall be conducted after inspection at different stages like material arrival at site, welding, fastening, fabrication, etc.

 

6.2                        Foundation and supporting surface

 

6.2.1                   The positioning axis of building, positioning axis and elevation of columns on foundation, anchor bolt’s size and positioning, anchor bolt fastening shall comply with the design requirements.  When no clear design requirements is available, it shall comply with the regulation of Table 1.

 

6.2.2                   In multi-storey building, when the foundation top surface acts directly as the supporting surface for column, or the pre-buried steel sheet or supporting stand as supporting surfaces for column, the allowable tolerance of the supporting surface, anchor bolt position shall comply with the regulation in Table 1.

6.2.3                   In multilevel building, allowable tolerance of mortar bedding shall comply with the regulation in Table 2.

6.2.4                   Anchor bolt size tolerance shall comply with Table 3.  The thread of anchor bolt shall be protected.

 

6.3                        Installation and Correction

 

6.3.1                   The tolerance of column installation shall comply with Table 6.

 

Table 6       Allowable tolerance of Column installation                                         

Items	Allowable Tolerance (mm)
The shifting of stand axis of ground column to positioning axis	3.0
Column positioning axis	1.0
Verticality of single link column	H/1000，and £10.0

 

6.3.2                   The allowable tolerance of verticality and side bent elevation of major steel girder, secondary girder and compression member shall comply with Table 5.

 

6.3.3                   Multi-storey and high rising steel structure’s entire verticality and the entire planar bending shall have allowable tolerance complying with the regulation in Table 7.

 

Table 7  Allowable tolerance of whole verticality and whole plane bending               

Items	Allowable Tolerance (mm)
Main structure’s whole verticality	(H/2500+10.0)，and £50.0
Main structure’s whole plane bending degree	L/1500，and £25.0

 

6.3.4                   We must have complete label to items such as the centerline of steel column, which is major structure, and its elevation datum.

 

6.3.5                   When the steel parts are installed on the concrete column, the deviation of its stand center to positioning axis shall not be larger than 10 mm; When large concrete room board is involved, steel truss (or girder)’s interval deviation shall not be more than 10 mm.

 

6.3.6                   The Allowable tolerance of steel column installation shall comply with Table 5.

7                             Pressed metal Sheet workS

7.1                        Pressed metal sheets shall be reliably connected on the supporting parts. The connection length shall comply with the design requirements, and shall not be less than the regulation in Table 8.

 

Table 8 Pressed metal sheet connection length on the supporting structure

Items		Connection Length (mm)
Section height>70		375
Section height<70	Room slope<1/10	250
	Room slope>1/10	200
Wall		120

7.2                        Pressed modeling metal sheet installation shall be leveled, straight; on the surface there shall be free of any construction residue or dirt. The lower end of eaves and wall shall be straight; there shall not be any untreated wrong holes.

8                             painting workS

8.1                        General Regulations

 

8.1.1                   The environmental temperature and relative moisture while painting shall comply with the requirement of product instruction. When the instruction has no clear requirements, the environmental temperature shall be between 5-38°C, relative moisture shall not be more than 85%.  During painting there shall not be any dew on the surface, the painted parts shall not be exposed to rain within 4 hours after painting.

8.2                        Anti-corrosion Painting

8.2.1                   The rust cleaning before painting shall comply with design requirements and current standards.

8.2.2                   Paint, painting times, the thickness of painting shall comply with the design requirements.

8.2.3                   When the steel structure is exposed, or located at an environment, which has corrosive agents and the design has special requirements, shall conduct paint adhesive force test.  When the paint completeness reach 70% or above, the paint adhesive force shall comply with the qualified standards.

8.3                        Anti-fire Painting

The thickness of thin painting anti-fire paint shall comply with the fireproof limit’s extremity’s requirement.  For thick painted fireproof paint’s, 80% and above area shall comply with the design requirements of fire-resisting extremity.  And the thinnest point shall not be less than 85% of the design requirement.