GB/T 38808-2020 in English

GB/T 38808-2020 systematically stipulates the technical requirements for corrugated web steel for the first time. Its innovation is reflected in the design of the web corrugated structure. Compared with traditional flat web H-steel, it has the advantages of 30% increase in shear bearing capacity and relaxed web height-to-thickness ratio limit.

Comparison of key technical parameters

Selection suggestions

Among the 38 standard specifications provided in Appendix A of the standard:

• BH349-BH520 series are recommended for small and medium spans (≤12m)
• BH645-BH778 series are recommended for large span structures
• BH1028-BH1536 series are recommended for super high-rise buildings

Welding quality control

Special provisions in Article 6.3 of the standard:

1. Single-sided welding can be used for web thickness ≤4mm, double-sided welding is required for web thickness >4mm
2. The height of the weld leg shall be the larger value of 0.6tw and 0.5tf (tw is the web thickness, tf is the flange thickness)
3. Corrugation forming deviation requirements: amplitude difference ≤2mm and ≤a0/10, wavelength difference ≤3mm

Design considerations

According to clause 5.1.1.2 of the standard, special attention should be paid to the following:

• The equivalent flat plate theory shall be used for the local stability verification of the corrugated web
• In seismic fortification areas, the ratio of web amplitude to wavelength should be controlled within the range of 1:6~1:8
• Q235NH/Q355NH weathering steel should be used for exposed environments (Article 6.1.3 of the standard)

Acceptance management process

According to the requirements of Chapter 8-10 of the standard:

1. Batch inspection of each batch ≤600m of the same grade
2. If the weld sampling failure rate is ＞5%, the entire batch will be rejected
3. 10 items of the quality certificate must be verified (Article 10.1.2 of the standard)

Compared with traditional welded H-beam specifications, this standard has the following:

• New requirements for corrugated geometric parameter control (wavelength 150-300mm, amplitude 15-40mm)
• Introducing 7 sets of web thickness-height matching relationships (Table 1)
• For the first time, the eccentricity of the corrugated web is stipulated to be ≤1.5mm (Table 2)

Typical application case: A sports stadium uses BH645×300 steel, which saves 19% of steel and reduces the weight of components by 23% compared with the traditional solution.