Essential Measures for Protecting Finished Steel Components

From leaving the factory to the completion of installation, steel components undergo multiple stages, including transportation, stockpiling, and hoisting. Inadequate protection at any stage can result in coating damage, component deformation, or corrosion of connection surfaces. The following outlines the necessary protection measures across four key areas: factory coating, loading/unloading and transport, on-site stockpiling, and installation.

 

I. Protection Requirements After Factory Coating

 

After shot-blasting and primer application, steel components must remain undisturbed in a drying chamber for at least four hours to allow the coating to cure fully. Nylon slings or lifting gear equipped with rubber corner protectors must be used during handling; direct contact between steel wire ropes and the coated surface is strictly prohibited. Inspected and approved components should be stacked in designated zones by identification number, with a maximum stack height of three layers. Timber dunnage (square timber) at least 50 mm thick must be placed between layers and aligned vertically to prevent localized indentation.

 

II. Protection During Loading, Unloading, and Transport

 

Specialized lifting frames or spreader beams should be used for loading and unloading, with lifting points positioned on either side of the component's center of gravity. Transport vehicle beds must be lined with rubber mats or used conveyor belts, and exposed elements-such as high-strength bolt connection plates and shear studs-should be wrapped in foam board or corrugated cardboard. Steel columns with a slenderness ratio exceeding 120 require temporary horizontal bracing to prevent bending or torsional deformation. Once loaded, components must be secured with tensioners, using soft padding between the securing points and the components. Transport during rainy weather requires the use of waterproof tarpaulins to prevent water ingress into tubular sections.

 

 

III. On-Site Stockpiling: Site Conditions and Protection

 

The stockpiling area must be level with effective drainage, and the ground bearing capacity must be at least 100 kPa. Components of different types should be stored in separate zones marked with identification signage. The bottom layer of components must be elevated at least 200 mm above the ground using concrete piers or specialized timber dunnage, with dunnage spacing not exceeding 3 meters. Standard steel must be stockpiled separately from weathering steel and galvanized components to prevent contact corrosion. The primer and topcoat used for coating repairs must be of the same brand and model as the factory-applied coating; they must be stored on-site in a cool, dry place.

 

IV. Protection of Finished Components During Installation

 

Before hoisting, remove weld spatter and burrs from bearing plates; do not strike the surfaces where bolted connections are made. After the final tightening of high-strength bolts at beam-column joints, apply a sealing primer to the connection area within 24 hours. During welding operations, use fire-resistant blankets to shield existing coatings within a 500mm radius to prevent damage from weld spatter. Place rubber pads or old canvas between temporary guy ropes and steel columns. When stacking subsequent components on a completed floor level, concentrate the load above the main beams; ensure the point load does not exceed 70% of the design load, and use steel plates to distribute the pressure.

 

V. Protection During Subsequent Processes and Prior to Acceptance

 

During concurrent work involving MEP (mechanical, electrical, and plumbing) systems or curtain wall installation, welding brackets directly onto steel beam flanges or drilling holes in them is prohibited; use pipe clamps or fixtures for temporary connections instead. Before spraying fire-resistant coatings, remove loose rust and oil stains from the surface without scratching the primer. Prior to handover and acceptance, inspect all exposed steel components; repair damaged coatings using a four-step process-cleaning, primer, intermediate coat, and topcoat-ensuring the dry film thickness in the repaired area is at least 90% of the original design value.

 

Adhering to these essential protection measures for finished steel components can significantly reduce damage rates and repair costs after the components arrive on-site. The construction contractor should incorporate these protective measures into the specific construction plan, assign dedicated personnel for daily inspections, and maintain photographic records.