Can repeatedly‑circulated old steel support continue to serve building construction projects?

Steel support belongs to high‑turnover temporary construction component.After multiple project cycles,metal material will accumulate fatigue damage,accompanied by corrosion,bending,thread wear and other aging phenomena.Old steel support cannot be directly put into construction site without inspection.Comprehensive appearance screening shall be carried out firstly.Check tube wall for penetrating cracks,obvious plastic bending,deep corrosion pits penetrating wall thickness.If above‑mentioned defects exist,such steel supports must be scrapped and shall not be repaired for secondary use.For components with slight surface rust and minor paint peeling,rust removal and anti‑corrosion coating repair can be implemented.Thread structure is another inspection focus.Severe thread abrasion will cause failure of height adjustment function.Connecting pin hole deformation will lead to locking failure.For large‑quantity aged steel supports,sampling mechanical compression test is necessary besides visual inspection.Sampling products are selected from different batches with long turnover time to detect actual ultimate bearing capacity.If measured bearing value drops below design allowable index,corresponding batch shall be eliminated.Enterprises should build service‑life files for reusable steel supports,record turnover times,damage condition and inspection records.It is forbidden to mix uninspected old steel supports and brand‑new products on same construction working zone.Even qualified old steel supports after inspection shall be applied to medium‑low load working conditions preferentially,and sufficient safety coefficient shall be reserved in structural calculation.In overseas engineering market,second‑hand steel support has partial market demand in some regions.But cross‑border trade of old supporting components must attach complete inspection documents to prove product safety performance.Blind usage of aged steel support without assessment will bring great potential safety hazard to formwork construction.

References

GB/T 7714‑2015：

HUANG Q.Safety assessment and scrapping standard for recycled temporary steel supporting components[J].Construction Safety,2022,37(08):52‑56.

MLA 9th：

Huang,Qiang."Safety Assessment and Scrapping Standard for Recycled Temporary Steel Supporting Components."Construction Safety,vol.37,no.8,2022,pp.52‑56.

APA 7th：

Huang,Q.(2022).Safety assessment and scrapping standard for recycled temporary steel supporting components.Construction Safety,37(8),52‑56.