Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard is a revision of JG/T 225-2007 Corrugated metal ducts for prestressed concrete. The following technical changes have been made with respect to JG 225-2007:
——The classification according to the number of corrugations is canceled (see 3.1 of Edition 2007);
——The designation method is modified (see 3.2; 3.2 of Edition 2007);
——The drawing of structure of corrugated metal duct is added (see 4.1.1 and 4.1.2);
——The specification of corrugated metal flat duct is modified (see 4.4.2; 4.4.2 of Edition 2007);
——The radial stiffness is modified to local transverse load resistance and uniformly distributed load resistance (see 4.5; 4.5 of Edition 2007);
——The meaning of symbols is modified (see 4.5; 4.5 of Edition 2007);
——The requirements for connecting ducts are added (see 4.7);
——The test method of external load resistance (see 5.3; 5.3 of Edition 2007);
——The test method of leakage resistance after bending (see 5.4.2; 5.4.2 of Edition 2007);
——The requirements for type inspection batch are modified (see 6.3.2; 6.3.2 of Edition 2007);
——The inspection result judgment rules are modified (see 6.4; 6.4 of Edition 2007);
——The requirements for corrugated metal duct connection are added (see 9.4);
——Annexes A and B are modified.
This standard was proposed by the Ministry of Housing and Urban-Rural Development of the People's Republic of China.
This standard is under the jurisdiction of the Technical Committee on Construction Engineering Quality Standardization of MOHURD.
The previous editions of this standard are as follows:
——JG/T 3013-1994;
——JG/T 225-2007.
Corrugated metal ducts for prestressed concrete
1 Scope
This standard specifies the classification and designation, requirements, test methods, inspection rules, packaging, marking, transportation, storage and use of corrugated metal ducts for prestressed concrete.
This standard is applicable to metal ducts made of galvanized or non-galvanized low-carbon steel strips with spiral folded bite and corrugated profile, which are used to reserve holes in post-tensioned prestressed concrete structures or members.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 2518 Continuously hot-dip zinc and zinc alloy coated steel sheet and strips
3 Classification and designation
3.1 Classification
The products may be generally divided into standard and reinforced ones, or into round and flat ones by their section shape.
3.2 Designation
Product designations shall be composed of codes, specifications and categories:
Example 1:
A standard round duct with nominal inner diameter of 70mm is designated as JBG-70B.
Example 2:
A reinforced round duct with nominal inner diameter of 70mm is designated as JBG-70Z.
Example 3:
A standard flat duct with nominal inner major axis of 67mm and nominal inner minor axis of 20mm is designated as JBG-67×20B.
Example 4:
A reinforced flat duct with nominal inner major axis of 67mm and nominal inner minor axis of 20mm is designated as JBG-67×20Z.
4 Requirements
4.1 Structure
4.1.1 The structure of round corrugated metal duct is shown in Figure 1.
In mm
Keys:
d——the inner diameter of round duct;
t——the thickness of steel strip;
hc——the corrugated height.
Figure 1 Structure of round corrugated metal duct
4.1.2 The structure of flat corrugated metal duct is shown in Figure 2.
In mm
Keys:
b——the major axis in flat duct;
h——the minor axis in flat duct;
t——the thickness of steel strip;
hc——the corrugated height.
Figure 2 Structure of flat corrugated metal duct
4.1.3 The corrugated direction of corrugated metal duct should be right.
4.1.4 The width L of overlapping part of folded bite of corrugated metal duct shall not be less than 8 times of the thickness t of steel strip and shall not be less than 2.5mm. The sectional structure of the folded bite is shown in Figure 3.
In mm
Keys:
L——the width of overlapping part of folded bite of corrugated duct;
t——the thickness of steel strip.
Figure 3 Sectional structure of the folded bite of corrugated metal duct
4.1.5 The top and root of the raised corrugation between the folded bite parts of the corrugated metal duct shall be circular arc transition, without folding angle.
4.2 Materials
4.2.1 The corrugated metal ducts shall be made of galvanized or non-galvanized low-carbon steel strip. If galvanized steel strip is used for the purpose above, its performance shall meet the requirements of GB/T 2518. If non-galvanized steel strip is used, its performance shall meet the requirements of GB/T 716; Other metal materials which have been proved to be suitable may also be used. The steel strip shall be attached with product certificate or quality certificate.
4.2.2 The minimum steel strip thickness of corrugated metal duct shall be in accordance with those specified in Tables 1 and 2.
Foreword II 1 Scope 2 Normative references 3 Classification and designation 4 Requirements 5 Test methods 6 Inspection rules 7 Packaging and marking 8 Transportation and storage 9 Use Annex A (Informative) Quality inspection record of corrugated metal duct for prestressed concrete Annex B (Informative) Selection of corrugated metal duct for prestressed concrete
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard is a revision of JG/T 225-2007 Corrugated metal ducts for prestressed concrete. The following technical changes have been made with respect to JG 225-2007:
——The classification according to the number of corrugations is canceled (see 3.1 of Edition 2007);
——The designation method is modified (see 3.2; 3.2 of Edition 2007);
——The drawing of structure of corrugated metal duct is added (see 4.1.1 and 4.1.2);
——The specification of corrugated metal flat duct is modified (see 4.4.2; 4.4.2 of Edition 2007);
——The radial stiffness is modified to local transverse load resistance and uniformly distributed load resistance (see 4.5; 4.5 of Edition 2007);
——The meaning of symbols is modified (see 4.5; 4.5 of Edition 2007);
——The requirements for connecting ducts are added (see 4.7);
——The test method of external load resistance (see 5.3; 5.3 of Edition 2007);
——The test method of leakage resistance after bending (see 5.4.2; 5.4.2 of Edition 2007);
——The requirements for type inspection batch are modified (see 6.3.2; 6.3.2 of Edition 2007);
——The inspection result judgment rules are modified (see 6.4; 6.4 of Edition 2007);
——The requirements for corrugated metal duct connection are added (see 9.4);
——Annexes A and B are modified.
This standard was proposed by the Ministry of Housing and Urban-Rural Development of the People's Republic of China.
This standard is under the jurisdiction of the Technical Committee on Construction Engineering Quality Standardization of MOHURD.
The previous editions of this standard are as follows:
——JG/T 3013-1994;
——JG/T 225-2007.
Corrugated metal ducts for prestressed concrete
1 Scope
This standard specifies the classification and designation, requirements, test methods, inspection rules, packaging, marking, transportation, storage and use of corrugated metal ducts for prestressed concrete.
This standard is applicable to metal ducts made of galvanized or non-galvanized low-carbon steel strips with spiral folded bite and corrugated profile, which are used to reserve holes in post-tensioned prestressed concrete structures or members.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 716 Cold-rolled carbon structural steel strips
GB/T 2518 Continuously hot-dip zinc and zinc alloy coated steel sheet and strips
3 Classification and designation
3.1 Classification
The products may be generally divided into standard and reinforced ones, or into round and flat ones by their section shape.
3.2 Designation
Product designations shall be composed of codes, specifications and categories:
Example 1:
A standard round duct with nominal inner diameter of 70mm is designated as JBG-70B.
Example 2:
A reinforced round duct with nominal inner diameter of 70mm is designated as JBG-70Z.
Example 3:
A standard flat duct with nominal inner major axis of 67mm and nominal inner minor axis of 20mm is designated as JBG-67×20B.
Example 4:
A reinforced flat duct with nominal inner major axis of 67mm and nominal inner minor axis of 20mm is designated as JBG-67×20Z.
4 Requirements
4.1 Structure
4.1.1 The structure of round corrugated metal duct is shown in Figure 1.
In mm
Keys:
d——the inner diameter of round duct;
t——the thickness of steel strip;
hc——the corrugated height.
Figure 1 Structure of round corrugated metal duct
4.1.2 The structure of flat corrugated metal duct is shown in Figure 2.
In mm
Keys:
b——the major axis in flat duct;
h——the minor axis in flat duct;
t——the thickness of steel strip;
hc——the corrugated height.
Figure 2 Structure of flat corrugated metal duct
4.1.3 The corrugated direction of corrugated metal duct should be right.
4.1.4 The width L of overlapping part of folded bite of corrugated metal duct shall not be less than 8 times of the thickness t of steel strip and shall not be less than 2.5mm. The sectional structure of the folded bite is shown in Figure 3.
In mm
Keys:
L——the width of overlapping part of folded bite of corrugated duct;
t——the thickness of steel strip.
Figure 3 Sectional structure of the folded bite of corrugated metal duct
4.1.5 The top and root of the raised corrugation between the folded bite parts of the corrugated metal duct shall be circular arc transition, without folding angle.
4.2 Materials
4.2.1 The corrugated metal ducts shall be made of galvanized or non-galvanized low-carbon steel strip. If galvanized steel strip is used for the purpose above, its performance shall meet the requirements of GB/T 2518. If non-galvanized steel strip is used, its performance shall meet the requirements of GB/T 716; Other metal materials which have been proved to be suitable may also be used. The steel strip shall be attached with product certificate or quality certificate.
4.2.2 The minimum steel strip thickness of corrugated metal duct shall be in accordance with those specified in Tables 1 and 2.
Contents of JG/T 225-2020
Foreword II
1 Scope
2 Normative references
3 Classification and designation
4 Requirements
5 Test methods
6 Inspection rules
7 Packaging and marking
8 Transportation and storage
9 Use
Annex A (Informative) Quality inspection record of corrugated metal duct for prestressed concrete
Annex B (Informative) Selection of corrugated metal duct for prestressed concrete
