**: China Science Daily.
Reporter Liu Runan.
In the early days, there were people who put forward the concept of civil engineering development in the spirit of the Olympics – faster, longer and stronger – but this is no longer in line with the current development situation. Wang Yuanfeng, director of the Carbon Neutrality Technology and Strategy Research Center of Beijing Jiaotong University, pointed out that "the development concept is out of sync with the times, which is the biggest challenge facing civil engineering and construction projects. ”
Recently, the 3rd National Academic Exchange Conference on Sustainable Civil Engineering Theory and Practice and the Academic Exchange Meeting of the Academic Committee of Engineering Earthquake, Foundation and Green Building of Hebei Civil Engineering and Architecture Society was held in Shijiazhuang. The experts and scholars at the meeting discussed topics such as design strategies and technical paths to achieve carbon neutrality in buildings, design methods for carbon reduction in civil engineering, and comprehensive utilization of solid waste.
Establish an evaluation system for carbon-neutral buildings.
According to the 2019 State of the Global Building and Construction Industry Report released by the International Energy Agency and the United Nations Environment Programme, carbon dioxide emissions from the global building industry increased by 2% from 2017 to 2018, reaching an all-time high.
In 2021, the "Opinions on Promoting the Green Development of Urban and Rural Construction" issued by the General Office of the Communist Party of China pointed out that there are still problems in China, such as lack of integrity, lack of systematization, low livability, and insufficient inclusiveness, and the construction mode of mass construction, mass consumption, and large emissions has not been fundamentally reversed.
At the meeting, Guo Zhenwei, deputy director of the Green Building Research Center of the Chinese Society for Urban Studies, pointed out that there are still many difficulties for the construction industry to achieve carbon neutrality, such as "in the building operation stage, it is difficult for medium and high-rise buildings to achieve zero carbon emissions on their own; In the whole life cycle of a building in 50 to 70 years, it is difficult to achieve zero carbon emissions; There are various emission reduction pathways, and regional factors lead to differences in the same type of projects. There are many participants at the same time, and the duration is long".
Considering the above issues, in 2022, the Chinese Society for Urban Studies and others compiled the Guidelines for the Evaluation of Carbon Neutral Buildings, which established an evaluation system from the aspects of building performance, building carbon emission measurement, carbon offset measures and carbon neutrality statements, and divided carbon-neutral buildings into bronze, silver, gold, and platinum grades according to specific technical requirements, so as to guide carbon emissions in the process of building design and construction.
Guo Zhenwei said that the constraints on the implementation basis, offset measures and application conditions of building carbon offsets will help guide buildings to achieve high-quality and zero carbon emissions from easy to difficult, in a step-by-step and orderly manner.
Design for sustainable net-zero carbon.
Pointed roofs, long beams, wooden columns, and modern timber structure systems give the Hebei Provincial Building Science and Technology R&D Center, which is one of the venues for this conference, a unique aesthetic.
It is the largest modern wood structure building in China in terms of unit size and span, reducing carbon emissions by 1,400 tons compared with concrete structure buildings of the same scale. In addition, the use of ground source heat pump system, solar hot water, solar power generation and other green energy-saving technologies further reduce the energy consumption of the whole life cycle of the building.
As a result, Wang Yuanfeng's team came up with the idea of generative design. He introduced that when designing bridges, 1680,000 bridges. Then, the big data analysis method is used to calculate the sustainable indicators of reliability, carbon emissions, and cost, and the relationship between the basic parameters and the sustainable indicators is obtained, and finally the most sustainable bridge design scheme is obtained.
This transforms the traditional technical and economic design into sustainable design, and increases the sustainable limit state on the basis of the traditional bearing capacity and durability limit state, and finally achieves the goal of sustainable development. Wang Yuanfeng said.
Based on an analysis of 58 buildings in China, Arup Engineering Consultant (Shanghai)** Peng Liu suggested that in order to achieve net-zero carbon design and construction, engineering strategies should be developed as early as possible in the early stages of the project to minimise embodied and operational carbon.
For the redevelopment of 1 Poseidon Square in London, UK, we designed a holistic approach to achieve net-zero carbon emissions, such as using 2,800 square meters of paving materials and roof cladding from other demolished buildings, replacing 65% of the cement with blast furnace slag, reducing carbon emissions by 665 tons. We have also developed a waste** strategy to fully optimize our energy consumption systems and M&E systems. Liu Peng introduced.
Explore the path of building technology.
In recent years, Beijing Jiaotong University, in collaboration with Arup Engineering Consulting (Shanghai)**, has assessed the maturity of building technologies and found that only 10 percent of them are fully commercially mature53% and 36% of technologies that are about to be commercialized84%。
Achieving carbon neutrality in the construction industry requires revolutionary technologies and systems. Wang Yuanfeng said that in the future, it is necessary to vigorously promote the research and development of green and low-carbon technologies.
Under the pressure of achieving the "dual carbon" goal, experts and scholars in the civil engineering and construction industry are trying to find a technical path to take off the "high carbon" hat.
As an important means to realize modern industrial construction, prefabricated buildings have obvious advantages in material saving and emission reduction. "In the traditional building construction stage, construction waste can reach 500 tons of square meters and 600 tons of square meters, while the waste generated by prefabricated buildings is only 200 tons of square meters. The prefabricated building also greatly reduces the use of formwork and plastering mortar, thereby reducing carbon emissions by 12% and 14%. Fu Sujuan, deputy chief engineer of Hebei Provincial Institute of Building Research, said.
Ultra-low energy buildings can minimize energy consumption during the operation phase by improving the performance of the envelope. Fu Sujuan said that the team is working on combining the two, solving the problems of thermal bridge and air tightness, and compiling technical specifications for prefabricated ultra-low energy buildings.
At the meeting, Yang Jian, deputy dean of the School of Naval Architecture, Ocean and Civil Engineering of Shanghai Jiao Tong University, introduced the application case of recycled fiber in civil engineering: glass fiber composite materials known as FRP have strong heat resistance, good corrosion resistance and high mechanical strength.
In addition, the experts at the meeting also mentioned that the research and development and engineering practice of bamboo structures, the application of low-carbon solid waste-based cementitious materials, and intelligent construction technology will all contribute to energy conservation and carbon reduction in the civil engineering and construction industry.