The Development of Precast Concrete Elements in China

 

There is a history of more than 60 years about precast concrete elements in China. It can be divided into four stages.

1. The First Stage

In the 1950s,our government carried out the fisrt “Five Year Project”. Under the influence of the former Soviet Union, we started to use the prefabricate construction. During this period, there are precast columns, precast crane beams, precast roof beams, precast roof slabs, precast skylight frame and so on. Except for the roof board, small crane beams and frames with small spans, most of the precast elements were made on the site. If the precast elements were made in the factory, the factory would usually be built near the site. All in all,at that time, precast fabrication is a part of construction on the site.

2. The Second Stage

At the end of the 1960s and in the begging of 1970s,with the development of small prestressed elements, many precast plants came into being in the cities and the countries. They produced precast elements used in the residential buildings(core slabs, plates, purlines, hanging tiles, etc.),the industrial buildings(roof borad, F panels,channel panels, etc.) ,both the residential buildings and the industrial buildings(V folded panels, Saddle panels, etc.).The precast industry came into being.

3. The Third Stage

In the middle of the 1970s,the government calls on people to set up many precast factories. Until the middle of 1980s,we have set up several ten thousand of factories that produce precast elements .During this period,there are precast elements as follows.

1. Residential precast elements: side fascia, prestressed big floor, prestressed round hole perforated panels, precast concrete balcony, etc.

2. Industrial precast elements: crane beams, precast columns, prestressed roof truss, roof panels, roof beams, etc(as shown in figure 2)

In terms of technology, the production of the precast elements firstly changed from the handwork to mechanical work, and then changed from mechanical work to production line.

4. The Fourth Stage

In the 1990s,it’s hard for the factories to get enough profit. The big factories in the city closed down, and the small precast elements used in residential buildings were made by the small factories in the countries. However, some factories in the countries produced hollow slab of poor quality, which also made the precast construction unqualified. After 1999,some cities have carried out rules to prevent the production of precast core floor slabs. Then all the construction are made of cast-in-place concrete. It was a big hit for the precast production.

When it comes to the 21th Century, things changed. It seems that the cast-in-place construction system no longer meets the need of our construction fully, for it has some obvious weakness. Facing the problems, we calls on the “the industrialization of construction” and “the industrialization of residential buildings”. There will be more and more opportunities for the development of precast elements.

In recent years, under the guide of the government, the industrialization of construction develops fast. At the same time, the universities and some related agencies increase the research on precast elements, which gets good results.