What common on-site errors affect the safety of adjustable screw jacks?

Most safety problems of adjustable screw jacks in construction are caused by non-standard on-site operation rather than product quality defects.Summarizing and avoiding common construction errors is crucial to ensure the stability of scaffolding and formwork support systems.The most frequent error is excessive extension of the threaded rod.Many workers overextend the screw thread to pursue convenient height adjustment,resulting in too long exposed thread section and insufficient effective support length.The extended thread part has poor structural rigidity and is prone to bending deformation under vertical load,causing local frame settlement and inclination.The second common error is irregular base placement.Screw jack base plates are placed on uneven ground,sundries or soft soil without foundation leveling and compaction,leading to unbalanced stress of the jack and gradual sinking during construction.The third error is continued use of defective jacks.On-site personnel often reuse bent,rusted,thread-damaged and deformed screw jacks to save materials.Damaged jacks have reduced bearing capacity and hidden fatigue cracks,which may break suddenly under load and cause frame collapse.In addition,blind overload support is a serious safety hazard.Using conventional light-load hollow jacks for heavy-load formwork support far exceeds the product’s ultimate bearing limit.Random removal of jack support points and arbitrary reduction of support density will also destroy the uniform stress system of the whole frame.Construction management needs to strengthen on-site technical supervision,standardize jack installation and use specifications,eliminate irregular operations,and ensure that all adjustable screw jacks work within the standard load and effective adjustment range to guarantee overall construction safety.

References

GB/T 7714‑2015：

REN Q.Analysis and prevention of common safety errors of adjustable screw jacks in construction[J].Construction Safety,2022,37(08):29-33.

MLA 9th：

Ren,Qi."Analysis and Prevention of Common Safety Errors of Adjustable Screw Jacks in Construction."Construction Safety,vol.37,no.8,2022,pp.29-33.

APA 7th：

Ren,Q.(2022).Analysis and prevention of common safety errors of adjustable screw jacks in construction.Construction Safety,37(8),29-33.