The research aims at assessing the various European and Chinese standards relative to the type and quality of Steel Beams and Concrete used in construction endeavours. Through literature review and case studies analysis, the paper attempts to discern the inherent significant difference in the quality standards of the UK and Chinese construction industry, emphasising guidelines applicable to the use of structural steel and reinforced concrete in building infrastructures. With the growing concerns over the quality of Chinese steel beams and concrete by the UK construction industry, it is essential to analyse the reasons for the questions sparked. This study aims to do so through literature analysis.
Research Question: To investigate the significant difference between the European and China standards of quality for concrete and steel beams.
European & Chinese Construction Standards
The Building and Construction Design guidelines specifically highlight the code of practice for the particular use of construction feed-stock, raw materials and construction materials like steel or concrete in every country across the globe. This specific research aims to understand the difference in the quality standards of materials such as steel and concrete in construction structures, emphasising the UK and Chinese Construction industries. The European standards for using steel and concrete in various structures have been highlighted in charters that promote Construction Industry sustainability and at other platforms for multiple vendors and steel manufacturers to conform to when planning for production. These standards and quality codes are adopted by the UK construction industry and other vendors across the world to ensure that these construction materials provide the desired functionality and optimum performance in structures that they are a part of, thus facilitating the sustainable development objective along with enhanced performance (Engineering Employers Federation, 2015)
The UK steel, the standard organizatorganisationting the UK steel industry, frequently publishes updates regarding the design and construction practices and guidelines in relation to steel and its alternative forms, including new steel and reused steel. Some of these material standards relative to the design and quality of construction materials include the British Standard “BS 5950 Structural Use of Steelwork in Building” and Eurocode 3 “EN 1993 Design of Steel Structures”. The UK industry establishes various other standards in European nations, including manufacturing, transporting, marking and cutting steel, alternative steel and concrete for construction structures (Building and Construction Authority, 2012).
There are European and Chinese standards established for the proper use, preparation, testing and packaging of Concrete. The core European standard for the specifications, performance, manufacturing and conformity is the EN-206-1 which is termed the framework standard providing leverage to the British concrete standard BS-8500. This standard provides detailed technical specifications and guidelines for cement, admixtures, and aggregates to be used in buildings. The Chinese national and industry standard for concrete that provides exact specifications regarding concrete quality control is GB- 50146-12, along with other national standards like DT/L 5100-2400 for hydraulic concrete and GB-10424-2003 for concrete used in railway works and masonry.
Vendors must adhere to these British and European Standards that also encompass areas like quality assurance standards relevant to the materials and performance testing procedures and guidelines. Most countries have their code of practice for the optimum use of materials like concrete and steel in accordance with the European standards and an additional practice code designed to cater to materials manufactured outside the European standards. The figure below illustrates the parameters of such processes against the reference standards to be followed, which provides a clear indication that almost all of the processes involved must be completed by the quality standards implicated by the governing organisations.
Figure 1: Steel Testing Procedures
The Chinese market is the primary hub for its growing construction industry, with the imports of cement, slabs, and steel materials such as beams, plates, piles and bars experiencing a boom. The Chinese steel materials used in buildings and other construction structures are imported across European countries. Although the Chinese quality standards for concrete and steel beams adhere to the same European acceptable standards (as illustrated in figure 1 above), there has however been a growing concern over the last few months with regard to the quality of steel products like beams and piles by the UK steel industry. What exactly is this difference in the quality of construction materials sparking this concern?
The UK construction standards focus on the sustainability of the construction industry and the need for public safety and quality relative to the design of permanent and temporary construction structures or buildings. The quality system explicitly highlights areas of focus like traceability and reusability of construction materials, emphasising the chemical and physical composition of the construction materials like concrete and steel products. The testing guidelines and quality assurance procedures highlighted by the UK industry state that the supplier or fabricator of the construction material must ensure aspects like durability, mass and dimensional tolerance to promote best construction practices. Procedures for individual marking, curing, transporting and testing of new and reusable steel for beams, plates and other products are highlighted through these guidelines. TEST reports, manufacturer test certification and relevant material documentation relative to such products are mandatory for the material to be used in buildings (Building and Construction Authority, 2012).
Although the Chinese Steel industry has set a similar standard in Europe, the legislative authorities' standard, which ensures the implications standard of Chan’s industry, is difficult to assess. One method is material traceability with the ease of tracing back to the source of a steel product to learn about its raw materials. It's the ability to identify a specific steel or concrete product through quality assurance functionality and identification. While guidelines stress the material traceability aspect, material reusability is also emphasised, reflecting the construction material's ability to be reused in a structure and manifest desired performance. Factors like mixing steel grade, proper marking and corrosion protection coating have been highlighted.
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Steel is often added to concrete to prepare reinforced concrete HC and High performing concrete, HPC for use in buildings and other structures. Forster (1994) defines HPC or High performance concrete as an optimised mix of carefully selected materials assembled according to design guidelines with appropriate marking, curing, batching, transportation and consolidation to reflect high performance and load balance in structures. Reinforced concrete is largely used along with high-strength concrete HSC in buildings to increase the durability and tensile strength of the structure. These concrete structural variations include steel products like steel bars, piles and sheets or plates. Therefore the performance of this concrete would largely depend on the quality of admixtures, including steel products. Chinese steel plates are imported to European countries, and questions have been raised regarding the chemical composition of steel that has been used in beams and bars. (Engineering Employers Federation, 2015).
As per the publication by UK Steel, an active member of The Engineering Employers Federation (EEF), the trade body issued a safety warning on 3rd March 2015, reflecting the quality of Chinese structural steel products like plates and beams. According to Ian Rodgers (2015), UK Steel's director, there was quality concern regarding imported Chinese steel sections and structural steel bars that had entered the UK construction market. These steel products did not fully comply with or adhere to the European and British standards of steel structure designs. There had earlier concerns regarding Chinese reinforcement bars and the quality of admixtures used for preparing RC or Reinforced concrete.
According to the UK Steel official, the European standard guidelines highlight structural steel standards as applying to non-alloy steel, which means steel that does not include an addition of certain elements to enhance durability. The guidelines also state the acceptable levels of additional elements added to steel in order for the material to be branded as a non-alloy. All steel products relative to the non-alloy specifications need to meet these defined limits to ensure that the weldable functionality is enhanced and that there is no further need for including additional welding parameters or aspects. The quality of non-alloy steel will have a significant impact on the performance and sustainability of building structures, including the augmentation of security fundamentals relative to the construction structures.
The imported Chinese steel bars and beams have, however, been reported as containing high levels of elements like Boron and Chromium that do not meet the non-alloy requirements of the European and British standards. The growing concern over elevated levels of additional elements to Chinese steel has been frequently highlighted over the past few months, raising serious questions regarding the use and import of Chinese steel. (Engineering Employers Federation, 2015).
The Chinese vendors use such elements by adding them to steel to benefit from the tax rebate that applies to exporting such alloy materials. These structural steel products, however, do not meet the standards outlined by European design and construction guidelines for using structural steel. It is also noteworthy that these alloys will have a less positive impact on steel, especially when it is being welded, since such elements pose a serious threat to functionality, including the efficiency of the welding process, often resulting in material cracks that can only be detected after 48 hours depicting problems in production and design.
Similarly, there have been concerns regarding the quality of concrete in China's Construction Industry. As per the publication from Wired UK (2013), low-quality concrete was found in the construction of China's tallest Skyscraper in Shenzhen in 2013, and it was found that the composition of cement contained unprocessed, coarse sea sand particles that resulted in the building's construction is halted. The optimum cement or concrete typically consists of carefully selected proportions of crushed gravel or rock and other proper admixtures. State officials found sea sand particles in almost 15 buildings. The UK industry also has published notifications regarding the quality of reinforced concrete bars being sold in the UK market with emphasis on the chemical composition of the admixtures.
Further research has also revealed that Chinese imported steel plates and beams contain higher copper levels (Ian Rodgers, 2015). UK steel has strictly suggested avoiding alloyed steel products, especially in the welding process and ensuring additional care and vigilance when using steel products like plates, bars and sections during welding. Practitioners have been asked to thoroughly check alloyed steel products before processing them for constructional use as structural steel is increasingly used in heavy machinery domains and construction. UK Steel, the primary trade body for the UK steel industry and steel vendors in the UK affiliated with the organisation through membership, places strong importance on the quality of construction materials. According to the director, this was the second warning issued for the quality concerns regarding Chinese imported steel plates, beams and bars. (Ian Rodgers, 2015)
In another publication by UK steel in Oct 2014, there were concerns regarding the quality of steel used in imported Chinese steel rebars and beams. The supply chain functional area relative to the reinforced steel was notified of the quality standards reflected by these rebars and Chinese steel beams, stressing the practices to ensure that structural steel that was at present available in the market was compliant with the European and British certification scheme. This was also brought to the attention of the UK Certification Authority for Reinforcing Steels- CARES, highlighting how the Construction material deviated from the traceability requirements associated with the CARES standards (Engineering Employers Federation, 2015).
The initial notification in August last year reflected the Chinese structural materials' noncompliance with the European standard BS 4449. There were three complaints or reports by UK steel, and all three were related to imported Chinese structural material products in the UK market. Ian Rodgers (2005) specifically stated that it has become increasingly important for fabricators and construction organisations that non-European steel rebars, concrete rebars and beams be evaluated for conformity with the design and construction guidelines, especially the traceability requirements.
Another publication by the UK steel trade body in January early this year highlighted how the imported Chinese steel bars and rebars had increased levels of boron that was outside the acceptable scope of British and European Standards catering to the use of structural steel. As per Chinese records, there is only a minimum amount of elements added to the steel beams and bars imported to the UK and currently available in the European market to reap benefits from the tax rebate for the 'alloy' category, but the UK officials claim that a significant portion of the Chinese steel bars and beams contain almost eight parts per million and beyond of Boron amounts. Evidence has been collected through samples tested for conformity to established criteria for steel use, and samples with Boron limits of 30ppm have been discovered through these testing procedures. (Engineering Employers Federation, 2015)
According to the Welding Institute, the primary certification and training organisation for welding procedures, a professional engineering institute and a reputable research and technology centre, the recommended optimum Boron limit of 5ppm is acceptable, excess of which would require additional changes to the standard welding procedure. The particular risk with Chinese rebars and beams is that each beam needs to be tested for Boron Limits for Fabricators and construction companies to assess which specific welding technique to employ, which can create considerable difficulties. This raises questions regarding importing Chinese construction materials with special emphasis on the cost-effectiveness and quality considerations relative to the safety and durability of construction and building structures. The welding institute suggests that additional practices relative to an excess of 5ppm of Boron would entail additional changes to the welding technique, including added vigilance for acceptable consumable hydrogen levels, slower welding, and increased input of heat during the process. This is a significant suggestion for Fabricators currently working with Chinese Steel products like rebars and beams.
The institute has also further recommended that an optimised welding procedure be developed, including the recommended practices highlighted for materials with an excess of Boron levels to ensure efficiency in the welding process and to safeguard against risks such as material cracks, dried surface, improper storage, consumables not appropriately controlled, beam diameter and other aspects about elevated levels of Boron in structural steel. UK steel and the UK construction industry place significant emphasis on sustainability of construction endeavours and the improvement of weld procedure development which is also why Chinese quality standards of steel beams and concrete bars have raised concerns in the UK Market. (Engineering Employers Federation, 2015). There is considerable emphasis on the use of sustainable steel in British Construction Projects; hence, steel products sold in the UK market must conform to European guidelines and standards.
The Chinese Steel and Concrete Industry is a growing market experiencing a boom in steel materials exports. The Chinese design and quality standards relative to the use of construction materials are noteworthy for largely catering to the local and global construction markets. However, with the significant difference in the particular steel standards relative to structural steel and its use between Chinese and European Guidelines, it is yet to be seen how the construction industry responds to the growing concerns as Chinese steel products are exported widely across global markets specifically the European construction market. As per the recent Article by Joseph Ash (2015) published in April this year, the elected Chairman of the China Iron and Steel Association apprised the industry in February 2015 about the rising growth of the steel market in China and how it was contributing to the overall economy. He further stressed that China should now focus on the quality and efficiency of steel products apart from production, which is a relief for the UK steel industry as well as most of the fabricators and members of the Construction Industry. The Chinese Concrete industry needs to evaluate the quality of concrete used in buildings locally and globally.
The European and Chinese construction industries have refined and established quality standards and guidelines for the manufacturing, design, use and quality or performance testing of the construction materials like concrete and steel. Although the quality standards have slight variations in terms of chemical compositions with respect to alloy materials, the dynamics do not reflect expanded deviation. The concerns of the UK steel industry regarding the Chinese steel rebars and beams and the questions raised relative to Chinese concrete quality are valid to some extent as the UK industry gives prime significance to sustainable measures in Construction. As per the EEF (2015), British Steel production largely contributes to the UK economy, with steel exports worth £4.9bn in 2013 and a £2.4bn contribution to the UK’s balance of trade. The overall economic contribution amounts to £9.5bn a year through tax revenues and supply chain support, with the British Steel industry employing approximately 20,000 people. The BES 6001 standard ensures sustainable steel production with quality values focusing on material traceability and reusability. Further, there are established European guidelines for properly using concrete in buildings. The various European and Chinese standards for cement, as well as steel products, are readily available from their restive official web-pages
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