(1) The gap between my country and the world’s advanced countries in scaffolding technology and application

The formwork support system has developed correspondingly with the advancement of formwork engineering technology. Support systems in many countries have developed into distinctive construction tools, forming various series of products. For a long time, wooden supports and bamboo supports have been commonly used as support systems for wooden formwork projects. At the beginning of the 20th century, the United Kingdom first applied steel pipe supports composed of connectors and steel pipes, and gradually improved and developed into fastener-type steel pipe supports. Because this kind of bracket has the characteristics of simple processing, flexible disassembly and assembly, convenient transportation, and strong versatility, it was quickly promoted and applied to countries around the world. Various forms of fastener steel pipe supports have been formed in many countries and have become one of the most commonly used formwork supports.

In the 1930s, Switzerland invented the adjustable steel pillar, which is a single-tube pillar that can adjust the height of the steel pillar using a solenoid device. Because this kind of pillar has the characteristics of simple structure and flexible assembly and disassembly, it has been widely used in various countries. Its structural forms include exposed thread type and closed thread type. Compared with steel pillars with exposed threads, steel pillars with closed threads have the advantages of preventing mortar and other dirt from adhering to the threads, protecting the threads, and not being damaged during use and transportation. Therefore, threaded closed steel pillars are more commonly used in some European countries. Since the 1980s, in order to increase the functionality of steel pillars, many countries have made improvements to the turntables and top accessories of steel pillars, greatly increasing the functionality of steel pillars. Some have also attached foldable tripods to the bottom. The single-tube pillar can be installed independently, which is more conducive to the assembly and disassembly of the steel pillar.

In the 1950s, the United States first successfully developed the portal scaffold (portal scaffolding). Because it has the characteristics of simple assembly and disassembly, good load-bearing performance, safe and reliable use, it has developed rapidly. By the early 1960s, Europe, Japan and other countries had introduced and developed this kind of scaffolding, and formed various specifications of door-type bracket systems. In France, Germany, Italy and other countries, formwork bracket systems such as trapezoidal, quadrilateral and triangular, which are basically similar to the portal bracket structure, have also been developed and applied. In countries such as Europe and Japan, portal scaffolds are used the most, accounting for about 50% of all types of scaffolds. Many countries have also established many professional companies that produce various portal scaffolding systems.

Since the 1960s, socket-type steel pipe supports have been widely used. The structure of this bracket is basically similar to the fastener-type steel pipe bracket, except that multiple sockets are welded on the vertical pole instead of fasteners, which avoids bolt work and loss of fasteners. It can be assembled by inserting horizontal bars and diagonal bars into the sockets. Formwork supports in various sizes. There are many types of this kind of brackets with different functions. They are commonly used in European countries, and have also been used in Southeast Asia and my country. Among them, the bowl-buckle bracket developed by the British company SGB is in a leading position in both design and technology. It can connect horizontal bars or diagonal bars in four directions simultaneously in a bowl-shaped socket. In recent years, Germany has developed a socket-type multi-functional bracket that can connect eight horizontal bars or diagonal bars in different directions at the same time. According to German experts, this kind of bracket is more advanced than the bowl-buckle bracket.

The earliest scaffolding used in Japan was wooden scaffolding. In the 1950s, fastener-type steel pipe scaffolding began to be widely used. In 1953, the United States first developed portal scaffolding. Soon European countries also introduced and developed this kind of scaffolding, forming various specifications of portal scaffolding systems. In 1955, many construction companies in Japan began to introduce this kind of portal scaffolding, but at that time, the application of Japanese fastener-type steel pipe scaffolding still dominated. Later, due to the continuous occurrence of safety accidents on fastener-type steel pipe scaffolding, it was reported that 2,856 people were injured or killed in one year. Therefore, after another collapse accident of fastener-type steel pipe scaffolding occurred in 1958, the safety of scaffolding was put on the agenda. Special emphasis is placed on the safety of scaffolding. Because portal scaffolding is easy to assemble and disassemble, has good load-bearing performance, is safe and reliable, it has begun to be widely used in some projects.

Gateway scaffolding was first used in support projects of subway and expressway. In 1956, Japan's JIS (Japanese Industrial Standards) standards for scaffolding were formulated. In 1963, the Ministry of Labor also formulated some regulations on scaffolding and supports in the labor safety and health regulations. In this way, portal scaffolding has become an indispensable construction tool in building construction. In 1963, some of Japan's larger construction companies developed, developed or purchased portal scaffolding. It is widely used in engineering. In 1965, with the increase in high-rise buildings in Japan, the use of scaffolding was also increasing. In 1970, various scaffolding rental companies began to proliferate. Since leasing scaffolding can meet the requirements of construction companies and reduce corporate investment, door doors The application of scaffolding is growing rapidly.

(2) Comparison of the application and promotion of scaffolding in China and Japan

Japan has developed and researched various specifications of scaffolding and accessories, and there are more than 460 scaffolding and accessories manufacturers. , far more than steel formwork manufacturers. For example, frame scaffolding includes portal scaffolding, H-shaped scaffolding, plug-in scaffolding, etc.; socket-type scaffolding includes bowl-buckle scaffolding, disc-type scaffolding, jack-type scaffolding, slot-type scaffolding, etc., as well as fastener-type scaffolding. scaffold. Most scaffolding fasteners use steel plate fasteners, and there are many types and a wide range of applications.

Among the various types of scaffolding mentioned above, portal scaffolding is still the main type, accounting for about 50% of its usage.

The development direction of Japanese formwork and scaffolding projects is as follows:

1. Product safety. Especially for products such as scaffolding and scaffolding boards, the design requires not only easy assembly and disassembly, but also safety and reliability. When scaffolding is erected, there must be safety railings and net fences around it, and there must be no gaps between the joints of the scaffolding boards to prevent debris from falling out. Falling hurts people.

2. Product diversification. Different types of engineering construction can use formwork and scaffolding for different purposes. In civil engineering, in addition to steel formwork, various special steel formworks are designed according to different project requirements, such as road formwork, bridge formwork, dam formwork, tunnel formwork, shaft formwork, chimney formwork, etc., and have reached standardized design. In addition, there are wood plywood formwork, steel frame or aluminum frame glued formwork, plastic formwork, etc. There are more types of scaffolding, including frame scaffolding, socket scaffolding, fastener scaffolding and special scaffolding, which can be used according to project requirements.

3． Product lightweight. Japanese formwork workers are aging. Therefore, the labor intensity of construction workers must be reduced. The design of building formwork and scaffolding must be lightweight, easy to assemble and disassemble, and beautiful in appearance. New products must be continuously developed. For example, the thickness of the profiled steel scaffolding board developed is 1.2mm, each 3-meter-long board weighs only 10.5KG, and each 3-meter-long aluminum alloy scaffolding board weighs only 7.8KG.

4. Environmental protection requirements of products. Japan has very high requirements for environmental protection, and the disposal of waste formwork and scaffolding must comply with environmental protection requirements. According to reports, due to the environmental impact of damaged wood plywood formwork, the use of steel-framed wood glue formwork and steel formwork is increasing.

There is a big gap between the technical level of scaffolding in my country and Japan. There are only 2-3 steel formwork factories in Japan, but there are more than 450 portal scaffolding factories and accessory factories. Japan also relied on single-tube fastener scaffolding in the 1950s. Due to the constant occurrence of construction casualties, portal scaffolding was widely used in the 1960s. Because portal scaffolding is easy to assemble and disassemble, has good load-bearing performance, is safe and reliable, and especially the Ministry of Labor has stipulated the safe use of scaffolding, portal scaffolding has become the leading scaffolding for construction companies. Among all types of scaffolding, its usage accounts for 50% About %, Japan attaches great importance to the safety of scaffolding. Different purpose scaffolds and supports are used according to different project requirements, which can provide a good working environment for construction workers and ensure construction safety. It requires strict railings and net fences around the scaffolding, and scaffolding boards. There should be no gaps between joints to prevent debris from falling and injuring people. According to the Scaffolding Industry Association, in the past 10 years, there have been no casualties in Japan due to scaffolding quality and safety issues. This is indeed not easy.

Scaffolding in my country is mainly fastener-type steel pipe scaffolding. There are very few professional scaffolding factories, the technical level is low, and the production process is backward. In particular, a large number of bamboo scaffolding is still in use, and the safety cannot be guaranteed. Portal scaffolding has been widely used in many domestic projects and achieved good results. However, later construction units used portal scaffolding in fewer and fewer construction projects, and many manufacturers that produced portal scaffolding also closed down or changed production. Why do portal scaffolding dominate all types of scaffolding in Europe, the United States, and Japan, but our country has only promoted its use for a few years and has not developed. Instead, it has retreated to using fastener scaffolding and bamboo scaffolding? There are many reasons, among which the main reason is product quality problems such as the steel pipe specifications used do not meet the design requirements, the mast stiffness is small, it is easy to deform during transportation and use, the processing accuracy is poor, the service life is short, etc.

In addition, domestic climbing frame construction methods are also widely used, but safety management measures have not kept up, and safety accidents continue to occur. Bowl-buckle scaffolding is one of the currently promoted and applied scaffolds, and production plants have been established across the country. There are more than 40 factories. Most of these factories have crude equipment and backward production processes, making it difficult to guarantee product quality. In addition, more than 50 manufacturers have been established to produce upper and lower bowl-buckle plug parts. Many of them have arbitrarily changed the design of the bowl-buckle plug in order to reduce costs, so that the stress performance of the components cannot meet the design requirements, which will lead to safety accidents during construction. Therefore, my country's technical level of scaffolding must be further improved, the use of backward bamboo scaffolding must be restricted, the product quality and safety of scaffolding must be supervised, and specific management measures must be taken. It is necessary to learn lessons from the promotion process of portal scaffolding so that my country's scaffolding technology level and product quality can continue to improve and develop.