In 2011, China's steel production reached a record high of 627 million tons. With unprecedented pressure to conserve energy and reduce emissions, and the advocacy of a low-carbon economy and sustainable development, steel-structured housing has received widespread attention from all sectors of society. During this year's Two Sessions, many representatives offered suggestions on promoting the development of steel-structured housing.

　　What are the actual values of steel-structured housing? Let's do some calculations on steel structures.

　　Achieving low-carbon construction and sustainable development of residential buildings

　　Steel-structured housing is a green building of the 21st century and an effective way for China to reduce carbon emissions and promote sustainable development.

　　Low-carbon construction: The CO2 emissions of constructing steel-structured housing are approximately 480 kg/㎡, a reduction of more than 35% compared to the 740.6 kg/㎡ of traditional concrete.

　　Material saving: The self-weight of high-rise steel-structured residential buildings is approximately 900-1000 kg/㎡, while traditional concrete is approximately 1500-1800 kg/㎡, a reduction in self-weight of about 40%.

　　● Significantly reduces the consumption of resources such as cement and sand and gravel, thereby significantly reducing carbon emissions during mining, smelting, and transportation;

　　● Steel-structured housing construction does not require wooden formwork and scaffolding. If its market share increases by 5 percentage points, it can reduce deforestation equivalent to 9,000 hectares of forest;

　　● Reduced building self-weight also saves about 30% of underground piles;

　　Water saving (reducing wastewater discharge): Steel-structured housing mainly uses on-site prefabricated construction, significantly reducing water consumption and wastewater discharge during construction. If its market share increases by 5 percentage points, it will reduce wastewater discharge equivalent to the total water volume of 10 West Lakes;

　　Energy saving (saving operating energy consumption): CCA lightweight grouting wall has good self-insulation function, which is 3 times that of traditional brick walls, significantly reducing operating energy consumption.

　　Land saving (improving land use efficiency): The "tall, large, light, and strong" characteristics of steel structures make it easy to achieve high-rise buildings, which can improve the use efficiency of land per unit area; the usable floor area increases by 5%-8%, and the number of parking spaces in the underground garage can increase by 10%-20%. In today's context of high land prices and parking difficulties, its socio-economic value is particularly prominent;

　　Environmental protection: Prefabricated construction reduces noise pollution, wastewater discharge, and dust pollution at construction sites; reduces sand and gravel mining and construction waste discharge, protects the environment, and creates a new era of architectural civilization;

　　Main material recovery and recycling: When buildings are demolished, the recovery rate of the main structural materials of steel-structured housing is over 90%, reducing construction waste discharge by about 60% compared to traditional concrete.

　　● Effectively responds to the national call to "promote a circular production mode," and the recovery and recycling of steel can serve as a strategic resource reserve for the country;

　　● Reduces the land resource occupation caused by the landfill of construction waste and the pollution of surface and groundwater by harmful substances in the waste (construction waste accounts for about 40% of the total national garbage);

　　Turning waste into treasure, resource utilization of industrial waste: Industrial waste is mainly used as the main material in composite walls, turning waste into treasure—CCA wall panels mainly use quartz sand tailings; lightweight grouting filling materials mainly use industrial waste such as fly ash, effectively responding to the national call to "promote the resource utilization of industrial waste."

　　Promoting the transformation and upgrading of China's residential industry

　　Steel-structured housing fully complies with the modern development ideas of the residential industry, which are "standardized design, factory production, prefabricated construction, and integrated decoration." It is an effective way for China to bid farewell to the era of on-site manual masonry, promote changes in the production methods of residential buildings, and promote the transformation, upgrading, and sustainable development of residential buildings.

　　Standardized building design:

　　● Steel structure technical specifications are complete, design software is readily available, and steel structure components have precise dimensions, so it is easy to achieve "coordination of building and component modules and dimensions," thereby improving design and construction efficiency.

　　● Steel structure components have strong generality and interchangeability, adapting to prefabricated construction and industrial construction requirements.

　　Factory production of components:

　　● Since most of the components and parts of steel-structured housing are precisely prefabricated in the factory, the processing accuracy and quality are unmatched by traditional on-site operations;

　　● On-site construction workers are transformed into assembly workers, reducing the labor intensity of workers and ensuring higher quality.

　　On-site prefabricated construction:

　　● All components of steel-structured housing are prefabricated in the factory. On-site construction involves connecting, assembling, and installing components into a whole using reliable methods such as bolts and welding, building houses like assembling cars;

　　● Various processes can be carried out in a three-dimensional cross-operation, improving construction efficiency, and shortening the construction period by more than 1/3;

　　● Dry operations largely replace wet operations, significantly reducing on-site construction workload and pollution emissions. The general material saving rate is over 20%, and the water saving rate is over 60%;

　　● Few hidden engineering projects make quality control and supervision easier, effectively avoiding problems such as shoddy workmanship in traditional construction, or quality and safety risks caused by a lack of responsibility from construction personnel;

　　● Prefabricated construction methods require less construction site space;

　　● Significantly reduces the amount of on-site work, reducing the number of on-site construction and management personnel, effectively solving the problem of "labor shortage";

　　● Related advanced building energy-saving technologies are easier to apply.

　　Integrated civil engineering and decoration:

　　The surface of CCA board walls is very smooth and does not require plastering;

　　The wall uses a light steel keel frame structure system, which is convenient for pre-embedding pipelines and easy to achieve an integrated building decoration solution, reducing resource and material waste;

　　Integrated embedded integrated decoration technology comprehensively improves the quality of residential decoration.

　　Improving housing quality and comfort

　　Improving the common quality problems of traditional residential walls, such as leakage and cracking;

　　The sound insulation performance of the wall is effectively improved;

　　The CCA board integral grouting composite wall with self-insulation function avoids the disadvantages of poor fire performance of external wall external insulation or internal insulation systems (such as: CCTV, Shanghai, and Shenyang fires);

　　The CCA board grouting wall, which does not condense and has a breathing function, provides a dry and comfortable living space;

　　Unlimited opening of doors and windows improves lighting and ventilation, enhancing comfort.

　　No load-bearing walls inside the unit, allowing for open-plan layouts and easy spatial division or functional renovations. This improves adaptability to changes in family structure and extends the lifespan of the building.

　　Enhancing building's earthquake resistance and disaster prevention capabilities, creating a safe home.

　　Since 1900, earthquakes in China have killed 550,000 people, accounting for 53% of global earthquake deaths. The reasons include that, for a long time, Chinese residential buildings were mainly brick or brick-concrete structures, with insufficient earthquake resistance. Most earthquake deaths resulted from being crushed or suffocated. Collapsed buildings blocked roads, severely hindering post-earthquake rescue efforts.

　　As one of the countries most frequently hit by earthquakes, after the 1923 Great Kantō earthquake, the Japanese government made a resolute decision to improve the earthquake resistance of buildings. The following year, it issued the world's first building earthquake resistance code and conducted precise calculations of the earthquake resistance of each building. Particularly after the 1995 Great Hanshin earthquake, it was found that 83.3% of deaths were caused by building collapses, and 12.8% by fires. Subsequently, Hyogo Prefecture, the epicenter, implemented the "Phoenix" plan, requiring buildings to withstand an 8-magnitude earthquake. The Japanese government proposed a "zero deaths" plan. The Central Disaster Prevention Council formulated the "Emergency Policy Guidelines for Earthquake-Resistant Construction" in 2005, aiming for a 90% earthquake-resistant rate for buildings and components by 2015. Therefore, advanced anti-seismic measures such as steel structures and lightweight materials with excellent earthquake resistance have been widely used, and almost all old buildings have been reinforced using steel structures of various shapes, such as X, K, and Y.

　　In the Great East Japan Earthquake of March 11 this year, a 9.0 magnitude earthquake, the highest level in human history, hit Japan, followed by a once-a-millennium tsunami. It has been proven that Japan withstood the test of the 9.0 magnitude earthquake; the earthquake itself did not cause significant damage to buildings.

　　The excellent earthquake resistance of steel structure housing has once again been proven.