Factory production, site hoisting, leading the industry-Xiamen prefabricated construction industry is forming

Prefabricated building construction site (data picture)

A few days ago, the implementation of the first batch of prefabricated construction industrial bases in our province recognized by the Ministry of Housing and Urban-Rural Development has passed the evaluation of the Provincial Department of Housing and Urban-Rural Development, Xiamen Zhixin Construction Technology Limited’s Prefabricated Building Industrialization Production Base and China Communications Third Aviation New Building Industrialization Production Base were Impressively set up.

In recent years, the development of prefabricated building products represented by the two leading companies in Xiamen has covered many fields such as PC (prefabricated reinforced concrete) components, subway shield tunnel segments, and municipal comprehensive pipe corridors etc.. Based in Xiamen, it also covers the surrounding areas, such as Fuzhou, Zhangzhou, Putian and Quanzhou etc., the scale of production bases has initially formed, and the concept of green ecological development has also been recognized at the national level. 

The state proposes to strive to make the prefabricated buildings accounted for 30% of the newly built building area within 10 years. At the moment, Xiamen's prefabricated construction industry has ushered in a good opportunity for development.

The market is vast and the scale of the industry is beginning to appear

In the scorching summer sun, Xiamen Zhixin Construction Technology Limited’s prefabricated building industrial production base which locates in Shenqing Industrial Park, Jimei District, a batch of steel bars which are ready to be sent to Jinjiang are stacked neatly, and the prefabricated composite boards which just come down from the PC component automatic production line are also ready to go.

Workers are assembling molds in Xiamen Zhixin Construction Technology Limited production workshop

"In the traditional on-site pouring process, this process has to be completed manually on site, which is time-consuming and laborious, and accuracy cannot be guaranteed. Now, with the most advanced Italian Schnell automated steel processing equipment, it is sent to the construction after the factory processing. At the site, the bending angle of each steel bar is standardized, and the machining accuracy error can be controlled within 2 mm." said Ye Zhijie, chairman of Xiamen Zhixin Construction Technology Co., Ltd.

Xiamen Zhixin Construction Technology Co., Ltd., covering an area of 370 acres, is equipped with 2 PC component automated production lines, one automated steel processing line, and  one metro shield segment production line. PC laminates, laminated beams, and external Wall panels, interior wall panels, prefabricated stairs and other products, as well as subway shield segments and laminated pipe corridors for municipal projects, are continuously shipped to Putian, Quanzhou, Fuzhou and other places. Since its commissioning, Zhixin Construction Technology Co., Ltd. has supplied more than 20,000 cubic meters of concrete prefabricated components to the society, and has completed a number of real estate projects, as well as the production of prefabricated components for multi-site pile foundation projects, track and municipal engineering projects.

The Metro segment is the key product of CCCC Sanhang Prefabrication Yard in recent years. Its production, from concrete blanking to steam curing, cooling, and water curing, all relies on intelligent systems, which truly achieves industrial automation. Since 2010，CCCC Sanhang has been undertaking the precast segmental box girder assembly of BRT in Xiamen， the prefabricated assembly of CCCC Sanhang in the municipal area of Xiamen, especially in the construction of the municipal integrated pipe gallery, has been developing well. 

The prefabricated integrated pipe gallery in Jimei new town area is unique. It adopts the "long line matching prefabrication" construction method to improve the anti settlement and anti permeability capacity of the pipe gallery and improve the structural durability. The "skeleton" reinforcement cage of Meishan road pipe gallery around the East Sea area is prefabricated by moulding to ensure that the processed reinforcement cage is horizontal and vertical, which is more in line with the requirements of the drawings and specifications. The industrialization of prefabricated building in Xiamen has already begun.

Obvious advantages, faster and more reliable

"The construction period has been shortened by about one third, and the number of workers on each floor has been reduced from 60-70 to 7-10, which greatly saves the cost." Ye Zhijie introduced that this is the highest prefabrication rate of residential commercial housing in our province - Xiamen Haicang Longhu Chunjiang Bi'an phase II Building #1.

Prefabricated building construction site (data picture)

As the first project in Xiamen which to adopt a prefabricated shear wall structure, the 4th to 29th floors of the building adopt a factory-customized, on-site installation model, and realize full decoration delivery, with a total prefabrication rate of 47.38%. During the process of design, BIM Technology is introduced to realize the collaborative design of architecture, structure, hydropower, HVAC, interior design, and other specialties etc., to achieve the purpose of saving cost, saving construction period and protecting the environment.

As a test of Xiamen prefabricated building in the residential  housing, Xiamen prefabricated building construction site observation meeting, Fujian prefabricated building site observation meeting and other activities are held here, attracting thousands of people from construction companies, design companies, construction companies, supervision companies, teachers and students of civil construction major in Colleges and universities to exchange and discuss, It plays a greater role in promoting the development of prefabricated buildings in our province.

Xiamen Haicang Longhu Chunjiang Bi'an phase II Building #1 capped (data picture)

Located in the electronic city of Jimei-Xiamen International Innovation Center project, it is also one of Xiamen’s recent representative works of prefabricated buildings. Its 2-1# building, 2-2# building and 5-3# building are adopted to prefabricated construction, with a prefabrication rate of 15.1%. The project is optimized according to the characteristics of the prefabricated building at the plan stage to ensure the modularization and standardization of prefabricated components. In the production of prefabricated components, each single component is coded uniquely, and a QR code is derived through the PCIS (prefabricated component intelligent production management) system, and the process of component production, acceptance, transportation, and installation process are tracked to realize the whole process management of digital construction. "Component production can be traced to improve production efficiency, ensure product quality, reduce component production costs, and expand and optimize construction models." Ye Zhijie said.

 Dr. Lin Zhizhi, inspector and deputy director of Xiamen Construction Bureau, said that compared with traditional technology, the use of prefabricated construction can greatly reduce the material and labor consumption of structural engineering such as steel bar binding, concrete pouring, formwork and scaffold support, and greatly reduce the workload of on-site masonry engineering. Therefore, it can effectively alleviate the current contradiction between high labor cost and labor shortage in the construction field. In addition, due to the use of mechanized hoisting operation, it can also improve the construction environment and reduce the labor intensity of construction personnel.

According to Lin Zhizhi, the larger the amount of production in the factory, the less the amount of on-site operation, which can shorten the on-site construction period, and reduce a series of expenses such as the cost of temporary facilities, management cost, and the salary of management personnel. For example, the prefabrication rate of Longhu Chunjiang Bi'an Phase 2 1# building project is high, using interspersed construction, cross-working, and simultaneous interior and exterior decoration, which is about 4 months ahead of the contract period. The quality of construction has also been greatly improved, effectively reducing the honeycomb and pockmark problems of traditional cast-in-place concrete, saving water and electricity, reducing losses, reducing material waste and site pollution.

Leading the industry and showing the green concept to the whole country

The two leading prefabricated construction enterprises in Xiamen have made rapid progress in exploring green operation and ecological development, and the achievements are outstanding.

In the pre mixed concrete workshop of CCCC Sanhang, the reporter saw that raw materials were automatically transported into the mixing tank by pipelines. When the dust amount exceeded a certain range, the monitor issued an alarm, and the spray system began to remove dust, and spray water mist to attach the dust particles to the ground to purify the air. However, the recycling of a large amount of sewage produced in the mixing process of concrete is an important part of the green measure in the Prefabrication Plant. After the sewage is transported and recycled by special pipes, it is used to clean the mixer, the conveying pipeline and the mixing tank. The mixing transport vehicles are equipped with leakage proof bags at the discharge port to reduce the concrete falling during discharge process and cause environmental pollution.

Chen Wu, general manager of the prefabrication plant of CCCC Sanhang (Xiamen) Engineering Co., Ltd. said that green production is not an independent and single project, but a systematic project.  The green operation of the Prefabrication plant includes a series of links, such as reduction from the source, process control, and terminal regeneration. Therefore, the factory is arranged in a completely closed environment, and the dust is confined in the production area from the source.

Segments ready for departure on the plant of CCCC Sanhang  

Xiamen Sanhang Concrete Co., Ltd., which provides high-quality concrete for CCCC Plant, has obtained the three-star certification (the highest level) of the National Green Building Materials Evaluation Mark. It is the only concrete manufacturer with intellectual property rights and the highest level of information management. Through the dedicated ERP management system, the Internet plus production is implemented. The company also has a demonstration laboratory approved by the Provincial Department of Housing and Urban-rural Development, and participated in the preparation of "Fujian Province's Green Production Management Regulations for Ready-Mixed Concrete" and other provincial and municipal standards and regulations.

From 16th to 17th, the National Seminar on Green Production Frontier Technology and Management of Ready-Mixed Concrete Industry hosted by Concrete Branch of China Construction Industry Association and Concrete Branch of Fujian Construction Industry Association was held in Xiamen. Xiamen's experience in green production management of ready mixed concrete was highly affirmed by the participating experts. When visiting the concrete production plant of Xiamen Zhixin group, a demonstration enterprise of green production in China's concrete industry, the experts at the meeting had a flash in front of their eyes: there was no sound of traditional mixing station, and there was no dust in the sky. From the raw material yard to the belt conveyor, and then to the mixing plant, the whole production process is fully closed operation. The yard is equipped with a spray and dust suppression device, timing spray, installing the pulse dust collector at the top of the mixing floor metering layer, mixing layer and powder tank, effectively avoiding the dust rising in the storage and transportation of raw materials. The ash inlet is equipped with an emergency spray device. Once the soft and hard pipe joints are loose, fall off or damaged in the process of conveying powder, resulting in pipe burst, the high-pressure nozzle spray device is immediately started to "spray rain and dust". The last link of green production is equipped with a complete concrete recovery and separation system and pressure filtration system. Concrete waste and waste water are recycled after treatment, so that no waste water and waste slurry are discharged.

So, Zhang Tong, General Secretary of the concrete branch of China Construction Industry Association, said that the prefabricated construction industry in Xiamen has achieved standardized and standardized green production, which can play a leading role in the country“.  We should take these advanced practices back and introduce them to the national enterprises and local construction industry associations. "

As a matter of fact, Xiamen, as the only area in the province that has fully realized the green production management of ready mixed concrete, has continuously explored the green production management of ready mixed concrete in recent years, leading the industry to upgrade from the traditional resource-consuming industry to a green and environmentally industry. According to the information from Xiamen Construction Bureau, all the 28 qualified mixing plants in Xiamen have obtained the star-level green building materials identification, with the standard reaching rate of 100%, ranking among the top in the country, and the industry is developing in an orderly and healthy way.