Formwork technology of the mountain stone from the traditional wooden formwork bamboo shed scaffolding transition to the introdu
From the transition of traditional wooden formwork and bamboo shed scaffolding to the introduction of composite steel formwork and steel pipe fastener scaffolding as the main body of multi-variety and multi-standard formwork, the development of formwork technology in China has gone through a long period of time. What problems exist in China's current formwork technology? What needs improvement? Qiu Minghua, the chief engineer of Beijing Aoyu Formwork Group, once visited Canada to study the construction of North America and understand the formwork technology there. He said that some advanced foreign practices have inspired China's existing formwork technology.
In general, China's formwork scaffolding technology has developed, from traditional wood formwork, bamboo shed scaffolding to steel frame wood plywood formwork, early split formwork support, hydraulic sliding form, door type scaffolding, bowl buckle scaffolding Etc., also developed a steel frame bamboo plywood template. Subsequently, the all-steel large formwork template conforming to China's national conditions, climbing scaffolding of various power sources, and the introduction of steel frame wood plywood large formwork, hydraulic climbing formwork and various types of scaffolding were developed. In recent years, all-steel large formwork, bamboo plywood formwork and wood plywood formwork have developed rapidly and become the mainstream formwork used in construction.
Template scaffolding company is small
For some reasons, there are still some problems in the template scaffolding technology in China. Compared with some developed countries, there is still a certain gap. In the late 1970s and early 1990s, when China began to introduce and apply foreign formwork technology, some formwork companies in industrialized countries have begun to enter the stage of industrialization and specialization research and development. However, at that time, the reform of the construction industry system, under the cruel low price, extremely non-standard market competition mechanism, most of our companies could not take into account the development of new technology and new products.
There are many template scaffolding companies in China, but the scale is generally small, mainly playing the role of material supplier. The products are not matched, not systematic, and the applicability is very limited. The template and scaffolding, the template and the template, the scaffolding and the scaffold are not related to each other. For example, the all-steel large template is only applicable to the wall, and has no connection with the floor template of the wood plywood template. .
The engineer of Qiu Minghua said that the foreign template technology is developing internationally in the depth direction and doing a good job in the sales and intensification of the template. For example, the HARSCO company in the United States is already an enterprise group with large production scale and advanced production technology. Most of these enterprises are specialized subcontracting and setting up specialized enterprises to improve management and technical capabilities, which can strengthen the competitiveness of enterprises and acquire more business in the market, so that their human resources and equipment resources can be more Utilization, production efficiency is improved.
Material quality level needs to be improved
The material quality and product quality level of domestic formwork products are not high, resulting in extremely serious material consumption and many safety hazards. The most obvious is the low-quality and high-consumption wood veneer formwork and steel pipe scaffolding that are commonly used in China's construction projects. The foreign Visa wood board template adopts phenolic resin glue and double-sided film, which can be used for 30 to 50 times. The domestic wood glue board template is mostly urea-formaldehyde glue surface plywood, which is generally used no more than three or five times. A great waste of timber resources. China's steel formwork, steel frame formwork, steel support and steel pipe scaffolding mainly use plain carbon steel, which has a large amount of steel, poor corrosion resistance and short service life. Therefore, the amount of steel consumed is large and the labor intensity is large. The qualified rate of steel pipes and fasteners is less than 10% of the total, causing frequent construction safety accidents.
Qiu Minghua engineer said that North America's formwork technology has a relatively complete technical system. On the whole, most American companies use high-efficiency templates. The template is light in weight, large in board surface, strong in bearing capacity, easy to achieve the effect of clear water concrete. It is also relatively simple to assemble, materials and maintenance are simple, saving labor, using Life expectancy is also relatively long. North American template materials have a lot of one-time investment, but in the long run, the cost is not high. Qiu Minghua said that the building structure in North America includes plate structure, steel structure, wood structure and mixed structure. They often choose different template scaffolding techniques depending on the structure. Most of the slab-type concrete structures are made of aluminum stencils. The stencil consists of aluminum I-beams and wood plywoods, which are composed of large wall stencils, horizontal stencils and column stencils. The tower structure generally adopts a wooden beam floor formwork support system and a modularized early split floor formwork system.