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Technical Standard
AGICO Cement International Engineering Co., Ltd. specialized in professional manufacture of steel silo. This Enterprise Standard proposed and drawn up by AGICO shall be formulated as a basis for production and inspection with a view to ensure quality of products best under the circumstances which China national standard and industry standard have not been drafted yet till now.
Technical Standard
Scope
This standard defines technical standard, inspection methods, inspection rules, etc. of AGICO Steel Silo.
This standard is applicable to AGICO Steel Silo.
Normative Reference
The following normative documents contain provisions which, through reference in this text, constitute provisions of this Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative documents referred to applies.
GB50205
Code for constructional quality acceptance of steel structures
GB50300
Unified standard for constructional quality acceptance of building engineering.
Technical Requirements
AGICO Steel Silo shall be in accordance with the standard and be constructed under design drawing and technical requirements approved by the process of standard. Raw materials used by main components shall be attached with quality certificate. Steel structure shall be accordance with requirements of GB50205.
Quality requirements:
After intermittent welding is used to stiffener and silo wall, slag should be cleared out of welding zone. If welding mark is evident on the external silo, it shall be treated with anti-corrosive paint for two times and finish for one time. High frequency stud welding may be also used to stiffener and wall of galvanized steel silo.
Installation requirements:
Auxiliary hole shall be closely tight without leakage of rain and water percolation. Upper and bottom planes of silo shall be kept horizontal without wavy form after cutting. The undercut shape of silo shall be correct and avoid serious defects.
Appearance quality requirements:
Guardrail shall not have obvious deformation.The surface of silo shall be smooth without serious convex-concave. For galvanized steel silo, galvanized layer shall be relatively complete without the large area off.
Geometric tolerance of silo requirements:
3.7.1 Diameter tolerance of silo shall be not more than ±5‰ of that according to its design size. (≤±100mm)
3.7.2 Quality tolerance of silo shall be not more than ±5‰ of diameter of that according to its design size.
For liquid container, Quality tolerance of silo shall meet requirements in Table 1 below according to its diameter.
Table 1
| Diameter (D) | Tolerance |
|---|---|
| D≤15m | ≤75mm |
| 15m＜D≤25m | ≤125mm |
| D＞25m | ≤150mm |
3.7.3 Vertical tolerance of silo shall be not more than ±5‰ of height of that according to its design size. (≤±50mm)
For liquid container, if height to diameter ratio of silo is less than 1.2, perpendicularity may not be inspected.
3.7.4 Height tolerance of silo shall be not more than ±3‰ of height of stiffener according to its design size.
3.7.5 Vertical tolerance of stiffener shall be not more than ±2‰ of height of that according to its design size.
Inspection methods
4.1 Welding quality inspection
Welding quality shall take three-grade inspection method according to GB50205.
4.2 Installation quality inspection
4.2.1 Auxiliary hole installation inspection: Observation inspection
4.2.2 Horizontal cutting inspection of upper and bottom planes of silo: Observation inspection
4.2.3 The undercut shape inspection of silo: Observation inspection
For liquid container, silo shall have a loading test: Observation in 48 hours
4.3 Appearance quality inspection
4.3.1 Guardrail inspection: Observation inspection
4.3.2 Surface inspection of silo: Observation inspection
4.4 Geometric tolerance inspection of silo
4.4.1 Diameter tolerance inspection of silo
In process of building, first choose one point respectively from upper, middle and lower section of silo in the height direction. Upper point is 2m away from the top, lower point is 1.5m away from the bottom, middle point is at 1/2 distance between upper point and lower point. And then take circumference measurements based on 3 points for 3 results using steel tape, the final circumference result is obtained on average.
4.4.2 Quality tolerance inspection of silo
Quality tolerance shall be the difference between maximum and minimum diameters of the measured plane 1.2m away from basic plane at lower part of silo.
4.4.3 Vertical tolerance inspection of silo
With help of theodolites and steel tape, deviation from two directions which are perpendicular to each other shall be measured.
4.4.4 Vertical tolerance inspection of silo
choose 3 points to measure it using steel tape.
4.4.5 Vertical tolerance inspection of stiffener
Plumb line and measure it using steel ruler.
Inspection rules
5.1 Each project shall be inspected by the company quality inspection personnel before delivery and acceptance.
5.2 Steel silo acceptance shall be the following inspection and record:
- A. Welding quality inspection
- B. Installation quality inspection
- C. Appearance quality inspection
- D. Geometric tolerance inspection of silo