The stiffness of precast members is small, and the strength cannot be guaranteed.

At the same time, the Hong Kong Building Authority Building Services Department is specially set up to control and supervise the quality of PCs.

The pure Japanese PC structure system can not be fully used under the existing national specifications.

It is roughly estimated that the scale of the project is 2-3 million square meters of building area.

The truss reinforcement is a closed tie S reinforcement, which can make the precast members overlap with the main structural members more firmly, with stronger integrity, and good seismic resistance, and is suitable for use in earthquake resistant areas.

Comparison of member reinforcement methods: PCF members in Hong Kong mode use ordinary straight anchor tie bars.

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

PC technology precast concrete component technology ▼▼ realizes the production mode of factory prefabrication and on-site assembly by studying customer demand and product finalization, aiming to improve product quality and performance, so as to improve product production efficiency.

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

• The thickness of PC external 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 external wall from 95mm to 85mm, so as to increase the use space..

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

We cannot add a part of PCF to the calculation of the main structure, and there is no corresponding calculation software, checking method, and corresponding specification to follow.

1.

Hong Kong PC Technology In order to support the implementation of housing industrialization, the Hong Kong government has given 10 percentage points discount to projects using PC technology in terms of floor area ratio index compared with projects not using PC system.

Fixing Socket Cross Pin Nail Plate

Site photos of Hong Kong PC project ▲ Dajiaozui residential project 2.

All major construction groups in Japan have perfect design and manufacturing methods, which are equivalent to industry standards; It is backed up by the experience data accumulated from the rich test bases and practical projects of these construction groups; Japan is an earthquake prone country, and the PC method has formed a complete and reliable design, production and construction process.

Intuitive perception of the basic situation of visiting the PC residential project in Hong Kong’s Tai Kok Tsui: 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 used for all of the 8 households in each unit.

Reinforcement equipment must be used to prevent member damage, which will increase the construction cost.

PC technology has been used in China for a long time, but there is no corresponding technical specification and policy support at present, so how to integrate and match foreign advanced technology with China’s existing design standards, Finally, it is necessary to cooperate with relevant departments to form industry standards.

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

The design unit needs to do a lot of research and test work through the accessory factory and the construction site to truly master this technology and apply it widely in domestic projects.

The peripheral system is in the form of pure PCF, and the stair section is a PC component.

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

There are no too many restrictions on Japanese PC structural members.

• At the same time, the advantages of Japanese PC construction method are brought into play.

（2） .

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.

• In terms of the relationship between the PC and the main body of the structure, the PC does not participate in the main work, and is considered purely as a plug-in, so that the project can be approved by the relevant departments and legalized as soon as possible when the construction period is tight and the experimental inspection cannot be carried out.

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

Except for balcony, stair, bay window, air conditioning panel and PCF wallboard, beams, columns and floors, including integral toilet and integral kitchen, can be used.

Comparison of the application scope of PC: Hong Kong PC structural members mainly include five parts: balcony, stair, bay window, air conditioning panel and PCF wallboard, which are mainly used in high-rise residential buildings and apartments, mainly shear wall structural system; At present, the application of PC components of beams, columns and floors is only used in a small number of frame structures below five floors, such as primary and secondary schools.

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

The concrete slab has no reinforcement structure.

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

The PCF members of the Japanese model use longitudinal and transverse two-way truss reinforcement, which can ensure that the precast members have sufficient stiffness and strength during the process of membrane stripping, transportation, hoisting and storage, and will not produce cracks and excessive deflection deformation.

Specific operational measures: In the project of Plot B04 of Shanghai Vanke Golden City designed by PC independently completed by Shanghai Zhongsen, Chinese Academy of Sciences, the following measures are taken in combination with the two PC construction methods and the characteristics of 90 small units: • Shear wall system is adopted for the main body of the structure to make the small indoor space as complete as possible.

Cracks and large deformation will occur during transportation, hoisting and other construction processes.

The directly anchored steel bar is an open tie bar with relatively simple structure, which is only applicable to non seismic areas such as Hong Kong.