Steel structures play a crucial role in modern construction due to their high durability, excellent load-bearing capacity, and flexibility. Steel is widely used in various types of buildings, from factories to skyscrapers. However, to ensure quality and safety, the processing of steel structures must strictly adhere to technical procedures and standards.
This article will provide you with detailed information from the technical requirements of steel structure fabrication to the erection procedures and quality control, helping readers gain a more comprehensive view of this field.
Technical requirements for steel structures fabrication and erection work
1.1 Steel Quality
The selection and inspection of steel types is a rigorous process, ensuring compliance with technical requirements and contracts. The mechanical properties (steel grade) must comply with design regulations, and the steel type must match the signed contract.
When steel is delivered to the construction site, a strict inspection process is carried out. Engineers, supervision consultants, and investors jointly check the quality certificates of the steel batch and prepare an acceptance report for the materials. Next, based on the quantity and type, steel samples are cut according to the Vietnamese standard TCVN 197:1985 to conduct mechanical property tests.
Vietnamese Standard TCVN 197:1985 is a technical regulation that specifies the methods for sampling and preparing steel specimens for mechanical and physical property testing. This standard plays a crucial role in the quality control process of steel used in construction, ensuring that the material meets technical requirements and safety standards for building projects.
The sampling process is recorded in minutes, and the steel samples are sealed before being transferred to an independent testing unit. This unit must be approved by the supervisor, and the testing process is monitored by all relevant parties.
The test results are an important basis for determining whether the steel batch meets the standards for use in the project. At the same time, these results are also used as a basis for finalizing the material supply contract. This process ensures that only quality steel is used, contributing to the safety and durability of the structure.
Pebsteel’s outdoor steel structure construction project
1.2 Steel Cleaning and Rust Removal
The process of cleaning and removing rust from steel is an important step before fabrication and erection. The steel surface must be completely cleaned, removing dust, oil, grease, and rust layers. Common methods include mechanical sanding, sandblasting, or chemical treatment.
For heavily corroded steel, specialised rust removal techniques may be required. Thorough cleaning not only improves the adhesion of the protective coating but also ensures the long-term durability of the steel structure.
If the steel is yellowed, it does not need to be cleaned. However, if the rust layer reduces the steel cross-section by more than 2%, the steel should not be used.
1.3 Steel Fabrication
Steel fabrication includes activities such as cutting, bending, and shaping steel according to the design drawings. This process requires high accuracy to ensure components fit perfectly when assembled.
Modern fabrication technologies such as plasma cutting and CNC bending are used to achieve high accuracy and good productivity. For complex shapes, special fabrication techniques may be required. Dimensional checks after fabrication are an important step to ensure compliance with technical specifications.
1.4 Steel Reinforcement Installation
Steel reinforcement installation requires accuracy and strict adherence to design drawings. The steel bars must be placed in the correct position, ensuring specified spacing and coverage. The use of positioning devices and temporary supports is necessary to maintain the correct position of the steel during concrete pouring. Thorough inspection after installation, including measurements and comparison with drawings, is an important step before proceeding to the next stage.
- For beams, floors, stairs: Use the beam and slab formwork positioning system that has been pre-fabricated and installed.
- For columns and walls, a grid system must be deployed on the floor to determine the position of column and wall bases. Mark the cross-section of column and wall bases and adjust the waiting steel to ensure the protective layer as per design regulations, then proceed with steel installation.
- The steel protective layer should follow the design regulations for each component.
- The main steel frame needs to be positioned and installed to ensure stability and correct component shape.
- Stirrups need to be constructed according to the specified spacing. Determine the position of the first stirrup, then use a ruler or measuring rod and mark with chalk on the main steel for workers to tie the stirrups. Stirrups should be arranged with alternating hook points to ensure rigidity and stability for the structure.
1.5 Steel Joining
Steel joining is an important technique in fabrication and erection, especially when creating long or complex structures. Common steel joining methods include welding, wire tying, and using mechanical connectors. The choice of joining method depends on design requirements, expected loads, and environmental conditions.
- For floor beams, steel joints should be placed outside the danger zone, unless otherwise specified. It is not permitted to join more than 50% of the steel at one cross-section.
- The joining length should follow design regulations, with a minimum joining length of 30d for compression zones and 40d for tension zones (limited use).
- For load-bearing steel with a diameter of 18mm or more, it must be bent at the joint. After bending, the two joined ends must be concentric (necking).
1.6 Steel Spacing for Concrete Protective
Layer Spacing steel to create a concrete protective layer is an important step in ensuring the long-term durability of the structure:
- Spacers must be pre-cast to ensure rigidity and good load-bearing capacity, avoiding breakage during construction.
- Each beam spacing position should use at least 2 spacers to ensure beam frame stability and limit twisting.
- For upper layer steel spacers in slabs, in normal cases, steel with a diameter of 10mm or 12mm should be used. For special cases: Choose appropriate steel based on specific requirements of the design drawings and construction conditions.
1.7 Concrete Pouring Process
The concrete pouring process is the final but extremely important step in steel fabrication and erection work. Concrete must be poured carefully to avoid displacing the installed reinforcement. Use vibrating equipment to compact the concrete, removing voids and air bubbles, but care must be taken not to affect the position of the reinforcement.
Steel Structure Fabrication and Erection Process
2.1 Incoming Material Inspection
Before beginning the fabrication process, a thorough inspection of incoming materials is necessary. This includes verifying the steel type, dimensions, thickness, and surface quality of steel plates, bars, pipes, and other accessories.
Check the mill certificates and conduct mechanical tests if necessary to ensure the materials meet the project’s technical requirements. Additionally, inspect the storage and preservation conditions of the materials to avoid issues such as rust or deformation.
This thorough inspection helps ensure the quality of the final product and avoids potential problems during the fabrication process.
Steel structure erection and construction process
2.2 Steel Cutting
After material inspection, the next step is cutting and processing the steel according to technical drawings. This process is carried out using modern cutting equipment such as plasma or laser cutting machines, depending on the steel type and thickness.
Cutting must ensure high accuracy in dimensions, angles, and shapes. Cut edges need to be cleaned and smoothed to prepare for welding.
During the cutting process, attention should be paid to optimising material use to minimise waste. At the same time, safety regulations must be followed when using high-power cutting equipment.
2.3 Assembly and Gusset Plate Fabrication
Assembly, also known as steel networking, is an important step in steel structure fabrication. Cut components are arranged and temporarily fixed in their design positions.
This process requires high accuracy and often uses measuring equipment such as total stations to ensure precision. Simultaneously, gusset plates – small steel plates used to connect larger components – are fabricated.
Gusset plates are cut, drilled, and bent according to technical requirements. Accurate assembly helps minimise errors during welding and ensures the final structure achieves high accuracy according to the design.
2.4 Assembly Welding
After assembly, welding is carried out to connect the components together. The assembly welding process requires high skill from welders and the use of appropriate welding equipment depending on technical requirements.
Before welding, surface cleaning and weld edge preparation are necessary. The welding process must follow approved welding procedures to ensure weld quality. During welding, attention should be paid to controlling heat-induced deformation, using welding techniques such as symmetrical welding or sequential welding to minimise residual stress and deformation.
2.5 Steel Structure Straightening
After welding, the steel structure may be deformed due to high temperatures. The straightening step is necessary to bring the structure back to its correct shape and dimensions according to the design.
This process can be carried out by mechanical methods such as using hydraulic jacks, hammers, or by thermal methods such as local heating. Straightening requires experience and high skill to avoid affecting the integrity of the structure.
During the straightening process, regular checks of the structure’s dimensions and shape using accurate measuring devices are necessary. For complex structures, simulation software may be needed to predict and control the straightening process.
2.6 Welding of Gusset Plates and Reinforcing Ribs
After straightening, gusset plates and reinforcing ribs are welded to increase the rigidity and load-bearing capacity of the structure. Gusset plates and reinforcing ribs are welded into positions predetermined in the design drawings.
This welding process also follows approved welding procedures and is performed by certified welders. Special attention should be paid to controlling deformation during welding, using techniques such as symmetrical welding or sequential welding.
After welding, thorough inspection of the welds using non-destructive testing methods such as ultrasound or X-ray is necessary to ensure joint quality.
2.7 Surface Cleaning and Shot Blasting
After completing the welding and straightening process, the steel structure surface needs to be thoroughly cleaned to prepare for the coating process. First, remove water marks, oil, grease, and other dirt using mechanical methods such as sanding, polishing, or using cleaning solvents.
Next, proceed with shot blasting to create surface roughness, helping to enhance the adhesion of the paint layer. The shot blasting process uses metal particles, sand, or other abrasive materials blasted at high pressure onto the steel surface. The surface roughness after shot blasting needs to meet the technical requirements of the coating system to be used.
After shot blasting, careful inspection of the surface is necessary to ensure uniform cleanliness and roughness.
2.8 Finishing Coat for Steel Structure
The final step in the steel structure fabrication process is the finishing coat. This process begins with applying a primer coat to enhance adhesion and provide corrosion protection.
Following are intermediate and final coating layers, depending on the protection and aesthetic requirements of the project. Coating can be done by high-pressure spray painting or manual brushing for small or hard-to-reach areas.
Strict control of environmental conditions such as temperature and humidity during painting is necessary to ensure coating quality. After painting, check the paint thickness, adhesion, and colour uniformity. Finally, the finished steel structure needs to be carefully preserved during transportation and installation to avoid damage to the coating.
Quality Control Process
The quality control process is an essential and indispensable step in the processing and installation of steel structures. When steel is delivered to the construction site, it must undergo a rigorous inspection process to ensure that it meets all necessary safety and quality standards. This process follows the Vietnamese standard TCVN 197:1985, ensuring consistency and reliability in steel quality assessment.
3.1 Visual inspection
This is the first and important step in the quality control process. Experts carefully inspect each steel bar to detect surface defects such as cracks, rust, or deformation. They also check if the steel has been damaged during transportation. Visual inspection can detect many potential issues that could affect the performance of the steel in the structure.
3.2 Dimensional inspection
An extremely important step to ensure that the steel meets the specified technical parameters. Technicians use accurate measuring tools to verify the length, width, diameter, and other dimensions of the steel bars. Small errors in dimensions can lead to major problems during installation and affect the structural integrity of the construction.
3.3 Mechanical property testing
An important part of the quality control process. Steel samples are randomly taken and undergo tests such as tensile testing, bending testing, and hardness testing. Tensile testing assesses the tensile strength and elongation of the steel, while bending testing checks the ductility and deformation resistance.
Hardness testing provides information about the steel’s wear resistance and load-bearing capacity. All these tests follow strict standards specified in TCVN 197:1985.
3.4 Chemical composition analysis
The final step in the quality control process. This is usually done using techniques such as Laser-induced breakdown spectroscopy or X-ray fluorescence spectroscopy. This analysis determines the exact proportion of elements in the steel, including carbon, manganese, silicon, and other elements.
The correct chemical composition is crucial as it directly affects the properties of the steel such as strength, weldability, and corrosion resistance.
Implementation of steel structure fabrication and installation at AEON shopping centre
Importance for Construction Experts
Understanding and correctly applying steel structure processing standards is a key factor for professionals in the construction industry.
- More accurate project budgeting is one of the most important benefits that construction experts can achieve from mastering these standards. By understanding the factors that affect the cost of steel structure processing, from the diameter of steel bars to labor and equipment requirements, engineers and project managers can create more accurate budget estimates.
- Improved quality control is another significant benefit. When construction experts thoroughly understand the technical requirements and quality inspection procedures, they can implement more effective quality control measures throughout the construction process.
- Enhanced compliance with industry standards is also an important aspect. The construction industry is tightly regulated, with many different regulations and standards. By mastering and correctly applying steel structure processing standards, construction experts can ensure that their work always complies with legal requirements and regulations.
- Better risk management is another crucial benefit. Understanding the standards and procedures helps construction experts identify and minimise potential risks in the process of handling and installing steel structures.
Pebsteel’s steel structure construction project
The fabrication and erection process of steel structures demands precision and strict adherence to technical standards. From inspecting input materials to final coating, each step is crucial in ensuring the quality and safety of the construction. Proper application of standards not only enhances construction quality but also improves project management efficiency, from budgeting to risk control. For construction professionals, staying updated and complying with the latest standards is a key factor in ensuring the success and sustainability of future projects.
At Pebsteel, you’ll find detailed information, real-world projects, and in-depth consultations from our team of experienced engineers. For assistance, contact Pebsteel via email at [email protected] or phone: (+84) 908 883 531 for immediate advice!
