The truss bar is a closed type of tie S-bar, which can make the precast members and the main structural members overlap more firmly, have stronger integrity, have good seismic resistance, and is suitable for use in aseismic areas.

Through the investigation in Hong Kong, the thickness of PCF plate is mostly 100mm.

PC technology has long been applied in China, but there is no corresponding technical specification and policy support, so how to integrate and match foreign advanced technology with China’s existing design standards, Finally, it is necessary for the design unit to make a lot of discussions and tests through the accessory factory and the construction site to cooperate with the relevant departments to form the industry standard, so that the technology can be truly mastered and widely applied in domestic projects.

PC technology Precast concrete component technology ▼ ▼ Through research on customer needs and product finalization, the production mode of factory prefabrication and on-site assembly can be realized to improve product quality and performance, so as to improve product production efficiency.

The PC construction method has formed a complete and reliable design, production and construction process.

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• In terms of PC application scope, refer to the Hong Kong model.

（2） Comparison of member reinforcement methods: the PCF members in Hong Kong mode adopt ordinary direct-anchored tie bars, the concrete slab has no reinforced structure, the rigidity of precast members is small, and the strength can not be guaranteed.

• The thickness of PC outer wall shall be reduced as much as possible, and the rich calculation experience and careful reinforcement scheme of PCF in Japan shall be used to reduce the thickness of outer wall from 95mm to 85mm, so as to increase the use space.
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The peripheral protection system is in the form of pure PCF, and the stair segment is a PC component.

Japanese PC project site photos: a rough comparison between the Japanese model and the Hong Kong model (I).

The intuitive feeling of visiting the basic situation of the PC residential project in Tai Kok Tsui, Hong Kong: there are more than 50 residential buildings in the whole community, each of which is a 58-storey super high-rise residential building, and the standard PCF exterior wall system is adopted for all of the eight households in each unit.

All major construction groups in Japan have perfect design and manufacturing methods, which are equivalent to industry standards; It is backed by the experience and data accumulated through the strong experimental bases and practical projects of these construction groups; Japan is a country with many earthquakes.

Therefore, the evaluation of whether Japanese buildings use PC does not only refer to which components, but also depends on the percentage of PC used, such as 80% PC, or even 100% PC, and the whole building is fully factory assembled.

Except for the five parts of balcony, staircase, bay window, air conditioning panel and PCF wallboard, beams, columns and floors, including the overall bathroom and kitchen, can be used.

The PCF members of the Japanese model adopt longitudinal and transverse two-way truss bars, which can ensure that the precast members have sufficient rigidity and strength in the process of membrane removal, transportation, hoisting and storage, and will not produce cracks and excessive deflection deformation.

At the same time, the Hong Kong Building Supervision Department is specially set up to carry out quality control and quality supervision on PC.

The pure Japanese PC structural system cannot be fully used under the existing national specifications.

Specific operation measures: In the project of Shanghai Vanke Golden City Plot B04 designed by Shanghai Zhongsen independently completed by the Chinese Academy of Sciences, the following measures are taken in combination with the construction methods of two PCs and the characteristics of the 90-small house type: • The main body of the structure adopts the shear wall system to make the indoor small space as complete as possible.

（3） The comparison of the relationship between PCF and the main body of the structure The PCF in Hong Kong mode is a purely external component and does not participate in the stress work of the main body of the structure, so the structural reinforcement is relatively simple.

There is no corresponding calculation software, check calculation method, or corresponding specification to follow.

Hong Kong PC Technology In order to support the implementation of housing industrialization, the Hong Kong government has offered a 10 percentage point discount on the floor area ratio index for projects using PC technology compared with projects without PC system.

The PCF in Japan mode can work with a certain thickness inside the PC and the reinforcement protection layer of the structural exterior wall or frame column, so as to reduce the thickness of the exterior wall and increase the usable area.

The direct-anchored reinforcement is an open tie bar with relatively simple structure, which is only suitable for use in non-seismic areas such as Hong Kong.

There are not many restrictions on Japanese PC structural components.

We cannot add part of the PCF to the calculation of the main body of the structure.

Plate Bolt Anchor

Comparison of the application scope of PC: Hong Kong PC structural components mainly include balcony, stairs, bay windows, air conditioning panels and PCF wall panels, which are mainly used in high-rise residential and apartment buildings, mostly shear wall structural systems; At present, the application of PC components of beams, columns and floors is only used for a small number of primary and secondary school frame structures below five floors.

Hong Kong PC project site photos ▲ Dajiao Tsui residential project 2.

Compared with the Japanese model, it is relatively rough, simple in nodes, and less skilled in technology than Japan, but it has no regulatory restrictions and is highly operable.

• In terms of the relationship between the PC and the main body of the structure, the PC does not participate in the main body work, and is purely plug-in, so that the project can get the approval of the relevant departments and be legalized as soon as possible in the case of tight construction period and unable to carry out experimental inspection At the same time, the advantages of Japanese PC construction method are brought into play.

The detail nodes are handled carefully, the safety performance is good, the waterproof measures of the joint are firm, and the configuration of the external components is more beautiful and humanized.

The project scale is roughly estimated to be 2 million to 3 million square meters of building area.

Cracks and large deformation will occur during the construction process such as transportation and hoisting, so reinforcement equipment must be adopted to prevent the damage of the members, which will increase the construction cost.

（4） Comparison of scope of application: The Hong Kong PC model is a model that has been simulated and simplified on the basis of the Japanese model in recent years to adapt to the local situation in Hong Kong.