Steel structure buildings are a new track for the high-quality development of the steel industry, related manufacturing industries, and the construction industry.

Due to the characteristics and advantages of steel structures, as well as the solid industrial foundation of China's steel and manufacturing industries, steel structure buildings have broad development prospects and will certainly become a new track for the high-quality development of China's steel industry, related manufacturing industries, and construction industry, as well as a new growth point for local economic development." On November 15, Xia Nong, vice president of the China Iron and Steel Association, pointed this out at the on-site meeting on "Developing Green Production of Section Steel and Promoting Standardized Construction of Steel Structures."

Against the backdrop of the development of steel structure buildings becoming a necessary option for expanding the application space of steel materials, the Shanxi Steel Industry Association, Shanxi Steel Structure Association, and Shanxi Environmental Protection Industry Association hosted this meeting in Quwo, Linfen, Shanxi Province. The meeting was organized by Shanxi Jinnan Steel Group Co., Ltd. Attendees included Zhang Haideng, first-level inspector of the Ministry of Industry and Information Technology's Raw Materials Industry Department, Xia Nong, Liu Yi, executive vice president of the China Steel Structure Association, Li Xin, deputy director of the Shanxi Provincial Department of Industry and Information Technology, Qiao Feihong, deputy mayor of Linfen City, Xie Li, executive vice president of the Shanxi Steel Association, Li Haiwang, president of the Shanxi Steel Structure Association, Wu Bin, county party secretary, Zhang Tianfu, deputy secretary of the Jinnan Steel Party Committee and president, as well as leaders from relevant departments, industry experts, representatives from financial institutions, cooperative enterprises, and media representatives.

How to achieve standardized construction? Experts at the meeting proposed: "Design is construction; construction considerations must be integrated into the design phase. We must adhere to a product-oriented mindset in the design of steel structure buildings, and based on standardized products, utilize digital and intelligent technologies to empower the entire steel structure industry chain."

"Jinnan Steel has a complete range of specifications and sufficient inventory for section steel, with over 600 specifications for section and galvanized section steel, achieving a full range of commonly used specifications from No. 3 angle steel to 600H section steel, which can meet the needs of different customers and allow for immediate delivery. In the future, we will gradually expand the varieties, types, and specifications of section steel production to contribute to the standardized construction of steel structures," said Zhang Tianfu.

The development of steel structures is insufficient and requires large-scale application of rolled section steel.

"Promoting steel structures is an important area for expanding new demands for steel consumption, and at the same time, steel structures will bridge the collaborative development of green steel and green buildings," Zhang Haideng stated at the meeting.

According to research and estimates by the China Steel Structure Association, in 2023, the total processing volume of steel structures in the industry is approximately 112 million tons, a year-on-year increase of 10.89%, which is higher than the crude steel output of most countries; the proportion has broken through 10% for the first time, doubling compared to ten years ago; there are 11 provinces and cities in the country with a steel structure output value exceeding 10 billion yuan, accounting for 84.42% of the national total steel structure output value, with a year-on-year increase; the top five provinces in terms of net profit are Zhejiang, Shandong, Anhui, Jiangsu, and Hubei, with an annual net profit of 9.285 billion yuan, accounting for more than half of the total net profit of all provinces.

"It is worth noting that China is a major steel structure country, but not a strong steel structure country," said Yu Yinquan, a national master of engineering surveying and design and chief engineer of the China Academy of Building Standard Design. Currently, the development of steel structures in China faces issues such as homogenization of competition, escalating price wars, low levels of collaborative operation in the industry chain, difficulty in expanding the scale of general steel structure components, poor connection between steel product standards and steel structure design specifications, and a weak talent pool for integrated design and construction of steel structures, resulting in significant gaps with developed countries in many aspects.

Taking the section steel products used in steel structures as an example. Rolled section steel has superior cross-sectional performance, low cost, low emissions, and high manufacturing efficiency, but it has not been well applied in China. "More than 60% of the steel used for steel structures in China is made from welded steel plates, while hot-rolled section steel only accounts for 15% to 20% of the steel used for steel structures, whereas in developed countries, hot-rolled steel accounts for 40% to 50%, indicating a huge potential for the application of hot-rolled section steel," Liu Yi compared.

In recent years, national policies have mentioned vigorously developing steel structure buildings and proposed to "increase the application of hot-rolled H-section steel, improve the standardization level of components, promote standardized design, and advance the collaborative development of intelligent construction and industrialization of buildings." These are all directions for the transformation of the steel structure industry and are also essential for promoting standardized construction of steel structures.

"China urgently needs to develop a complete set of technologies to promote the large-scale application of rolled section steel," Yu Yinquan believes. "We should comprehensively enhance the efficiency of the steel structure industry from four aspects: supply of section steel (mainly addressing the coordination issue between section steel supply and building use), design technology (mainly addressing the standardization of components, nodes, systems, and efficient design), construction application (mainly addressing the digitalization and intelligence of steel structure manufacturing and on-site construction), and implementation evaluation (mainly establishing a reasonable quality assurance system and evaluation mechanism)."

Zhang Shen, digital technology director of the Central South Architectural Design Institute and director of the Engineering Digital Technology Center, believes that "steel structures are a direct reflection of the manufacturing industry in the construction industry, and we should learn from the manufacturing industry to reduce marginal costs through standardization, productization, and scaling, becoming pioneers in digital and standardized design."

Without standardized design, there is no standardized construction.

So how to achieve standardized construction? "Without standardized design, there is no standardized construction," Zhang Shen believes. Industrialization of construction must start from the design end, achieving supply chain-oriented design and design for manufacturing and assembly (DFMA).

It is reported that the traditional design model is characterized by "throwing wall design," meaning we design, you manufacture, without considering manufacturing requirements, repeatedly modifying until the task is done correctly. DFMA, on the other hand, means deeply understanding the importance of design to quality, integrating manufacturing and assembly into the early design phase, and getting it right the first time. Anything unsuitable for industrial production is not considered a design option (except for projects not suitable for industrialization). "We must also break down the barriers between design and construction, promoting the integration of design, processing, production, and construction to complete integrated project delivery," Zhang Shen emphasized.

Construction is based on design, but standardized construction is a systematic project that requires coordinated development across the entire industry chain. It is understood that the Steel Association has organized and completed research on the topic "Guiding Opinions on Vigorously Promoting the Coordinated Development of the Steel Structure Building Industry Chain," which has been submitted for decision-making reference to relevant ministries.

"We should actively create a policy environment conducive to the development of steel structure buildings," Zhang Haideng emphasized, highlighting the importance of standards and improving the standard system of the steel structure building industry chain. This includes strengthening the connection between steel standards and steel structure building specifications, improving the cross-industry steel structure standard system, promoting the standardization and modularization of high-performance steel and steel structure components, and unifying standards and specifications across the steel and downstream industry chains. Xia Nong revealed that the Steel Association is promoting the integration of building design specifications with steel standards and is currently working on the revision and improvement of standards such as the National Standard for Steel Structure Design, the Industry Standard for Prefabricated Steel Structure Residential Building Technology, and the Group Standard for Main Component Dimensions of Prefabricated Steel Structure Residential Buildings.

Li Haiwang introduced that the Shanxi Steel Association has proposed an initial, immature collaborative development model. This model suggests that steel production plants produce section steel varieties and specifications that meet the personalized design (lightweight) of steel structures, gradually reaching over 80%, and a reasonable section steel library can be established through statistical analysis of existing steel component varieties and specifications (much larger than the current section steel library); steel structure processing plants are mainly responsible for processes such as cutting, bending, drilling, and coating of components, and can achieve product-based settlement upon delivery; on-site installation units achieve over 80% assembly installation and can realize completion settlement.

The fundamental basis of this model is the standardized design of the entire industrial chain. Li Haiwang stated that through standardized design, design institutes can directly select standardized steel from steel mills, and steel structure manufacturers basically do not need to produce welded steel anymore. This will significantly improve production efficiency, save costs, and achieve energy conservation, carbon reduction, and green construction.

Standardized construction cannot be separated from the large-scale application of rolled profiles, and it relies on digital and intelligent empowerment. The path for large-scale application of rolled profiles researched by Yu Yinquan's team has many similarities with the model of the Shanxi Steel Association, but also proposes a supplementary measure: 'We need to study efficient construction and installation technologies based on intelligent construction at the construction site, as well as research testing and certification technologies to support the quality of steel structures, and evaluation technologies to form a driving mechanism for the application of rolled profiles.'

Liu Yi believes that it is necessary to strengthen standardized design to achieve 'fewer specifications, more combinations', increase the variety and specifications of profiles and pipes, and accelerate the digitalization process of the entire steel structure processing and manufacturing.

Standardized construction will also drive the development of green steel.

During this on-site meeting, the attending leaders and guests also visited the Jin Nan profile workshop 4 and the Taizihu heavy steel villa project, which are typical application results of Jin Nan Steel's green profiles.

'The Taizihu heavy steel villa model project used dozens of tons of profiles, and it took only two months from breaking ground to moving in. Compared with traditional brick-concrete structures, the Taizihu heavy steel villa has advantages such as fast construction speed, high safety factor, good insulation effect, being green and environmentally friendly, and high intelligence,' Zhang Tianfu introduced. The 4th and 5th profile workshops of Jin Nan Steel are also entirely built with profiles, and the group has also utilized green profiles to construct a photovoltaic bracket intelligent manufacturing project.

In fact, standardized construction of steel structures also imposes requirements on green steel. In response to national industry policy needs, it is urgent to comprehensively improve the efficiency of steel structure manufacturing and installation processes, and reduce energy consumption and carbon emissions throughout the construction process.

In recent years, Jin Nan Steel has invested heavily in building new green production lines for profiles, focusing on establishing a domestic influential production base for profiles and galvanized products, gradually adjusting its main products from ordinary construction steel such as rebar and wire to green profile products such as I-beams, angle steel, channel steel, H-beams, galvanized angle steel, and galvanized channel steel, striving to make the group a global benchmark enterprise for green profiles with a complete range of specifications, high delivery efficiency, and excellent transaction services.

Why can Jin Nan Steel's profiles be called green steel? First, it recycles coke oven gas and converter gas to produce ethylene glycol and LNG, meeting the requirements of CCUS (carbon capture, utilization, and storage) technology paths, achieving zero carbon emissions; second, it fully utilizes hydrogen energy as a new energy source, reducing the use of fossil fuels such as oil and LNG, creating a green low-carbon logistics; third, it practices the concept of green steel, gradually replacing traditional thermal power generation with photovoltaic and wind power generation, reducing carbon dioxide emissions. 'After adopting the steel-coke joint and steel-coke co-production process, the carbon emissions per ton of steel can be reduced to about 1.4 tons, which is better than the advanced level of carbon reduction in the industry,' Zhang Tianfu stated.

Yu Yinquan took the expansion and renovation project of the Xiaojiahe branch of Beijing University Affiliated Primary School as an example. All components of this project used rolled profiles and derivative products. According to the research and calculation of carbon emissions and carbon reduction throughout the steel structure manufacturing process for this project, the carbon emissions from component assembly and welding account for about 79.77% of the entire component production process; the total weld length is 6089.5 meters, while the total weld length for traditional projects is 9595.1 meters, resulting in a 36.5% reduction in total weld length, and the proportion of reduced carbon emissions is 0.365 x 0.7977 = 0.291, meaning a comprehensive carbon emission reduction of 29.1%. This case proves that the application of rolled profiles in steel structure buildings can significantly reduce carbon emissions.

According to the '14th Five-Year Plan for the Steel Structure Industry and the 2035 Vision Goals' released by the China Steel Structure Association in October 2021, by 2035, the application of steel structure buildings in China will reach the level of moderately developed countries, with steel structure usage exceeding 200 million tons per year, accounting for more than 25% of crude steel output, and the proportion of steel structure buildings in new construction area gradually reaching about 40%, basically achieving intelligent construction of steel structures. Attending guests believe that to achieve this goal, it is especially necessary to strengthen the technological innovation capabilities of the steel structure industry and promote the coordinated development of the steel structure industry. At the same time, it is necessary to strengthen standardized design, promote the research and development of green products, and actively adopt digital and intelligent technologies to empower the entire industrial chain of steel structures. (China Iron and Steel Industry Association)