Yu Yonghui Song Jieren Yang Yulong Zhejiang University Civil Engineering Department Hangzhou 327 is very convenient, has good economic value and is worth promoting. In high-rise buildings, whether it is a shearing wall or a load-bearing structural system such as a cylinder, the bolts are indispensable connectors in the formwork engineering. Pull bolts currently in use,

Yu Yonghui Song Jieren Yang Yulong Zhejiang University Civil Engineering Department Hangzhou 327 is very convenient, has good economic value and is worth promoting.

In high-rise buildings, whether it is a shearing wall or a load-bearing structural system such as a cylinder, the bolts are indispensable connectors in the formwork engineering.

At present, the bolts used are generally inconvenient, such as inconvenient, labor-intensive, and low-utilization. However, the unit price is low, although the amount is large, it is not taken seriously. In this paper, it is proposed that the structural improvement of the drawing bolt can be simplified, and the purpose of simplifying the loading and unloading process, improving the production efficiency and reducing the cost can be achieved.

1 The shortcomings of the currently used pull bolts are the round rods used in the pull bolts, which are divided into two types: combined type and integral type.

The disadvantage of the combination type 1 is that the outer tie rod is complicated to process, the price is high, and the top cap is taken out by a special tool, which is inconvenient to use.

There are two main types of the outer pull rod inner rod pull rod integral pull bolt. The first type is that the whole bolt is left in the shear wall, the protruding end is cut by electric welding, and then the cement mortar is used for sealing, and the cut part is overlapped. Reuse of welding 23. Its main disadvantages are cumbersome and time-consuming, requiring technical workers to operate. To cut a piece of wood that pulls the bolt head, you need a woodworker 1.5, cut a pair of pull bolt heads, need a welder and a small worker 0.5. The material is poorly reusable. Since the lap welding requires a fixed lap length, the welded portion is short for each use, and can only be used two to two times. , costing materials and electricity. It takes 13 welding rods to weld the bolt head. Considering the lap welding when it is used repeatedly, the root pair pulling bolt requires 1.5 welding, 20, and corresponding power consumption. The first type is to use a plastic tube to reserve a hole in the shear wall. The pull bolt is placed in the plastic tube, and the whole root is pulled out when the mold is removed, and the whole bolt can be reused, and the reserved hole is filled with a silicone material. Its main disadvantage is its poor waterproof performance. Since the retaining bolts are not suitable for the underground outdoor wall due to the remaining holes, they are also specially treated when used for the outer wall of the above ground portion, so the use is limited. The spacing of the templates is difficult to control. Since the pull bolt can be pulled out, the spacing of the wood formwork is difficult to strictly control, resulting in uneven thickness of the shear wall, which is likely to cause engineering quality accidents. The material cost is high. For shear walls with waterproof requirements, it needs to be filled with silica gel material, which is difficult to reduce the construction cost.

Fasteners 改进 2 Improvements The structurally improved pull bolts consist of internal and external tie rods and connectors. The length of the external thread at both ends of the tie rod is the thickness of the shear wall minus 220, which is the length of the joint. According to the thickness of the shear wall in the project, it is processed into a series with a tolerance of 50 stomach for 200=18,1; The outer pull rod considers the template raft outer pull rod connecting member inner pull rod pulls the clamping position HM pet 3 shaped fasteners, the length can be processed into 2501 and the wrench clamping position is processed at the end, convenient loading and unloading; the connecting piece full length 30 internal thread use The improved method of the pull-on bolt is like a splicing water pipe. When the template is supported, it is only necessary to rotate the two connecting members of the two outer pull rods and the inner rod of the strip into a body to form a pull bolt similar to the current one. When the template is removed, the outer pull rod is unscrewed and reused for easy removal. The inner tie rod connector is used in a secondary manner and remains in the shear wall.

The advantage of the raft stencil wall is that it can be reused. If it is used properly, the scrap rate is extremely low, the connecting parts are easy to process, the cost is low, and it does not need to be removed. It is more labor-saving than the current combined pull-up bolts, and the parts are connected by threads. It is easy to assemble and disassemble, saves man-hours, and does not require technical workers to operate. When the mold is unscrewed, the difficulty of demoulding is greatly reduced, and the template is not easily damaged. The inner tie rod is tightly combined with the shear wall. After the mold is removed, it is only required to be sealed with cement mortar at the end of the pull bolt. The shear wall has a fixed waterproof performance.

3 Improved technical and economic performance From the improved method of using the bolt, it is easy to use, and has good waterproofness, and fully meets the requirements of use in technology. Take the Guoxin Square People's Building project at Xinhua Road, Hangzhou as an example to illustrate the economic performance of the improved bolts. The project was constructed by Zhejiang Tongli Construction Co., Ltd. The general cost of the project is as follows: the total construction cost is 80 million yuan, the construction area is 25,000, the main building height is 88.60, the frame structure is framed, the podium is 7 floors, the frame structure is high, and the basement is 4.5. The engineering shear wall More, the shear wall area of ​​the upper structure is about 88002, the shear wall area of ​​the basement is about 200,12, the total area of ​​the shear wall is 10800, and most of them are external walls, and the shear wall as the inner wall requires construction. Has a waterproof function. The project requires 45,000 tie bolts. If the improved type of pull bolt is used, the economic analysis of the direct cost compared with the current pull bolt can save 90,000 yuan of improved pull bolts, each of which can save 1.5 welding rods, but increase the joints. And the cost of processing the thread, consider the external tie rod can be reused, and each can reduce the cost by 062 yuan, saving a total of 0.2, 4.5 types of work quantity, work efficiency, processing time, labor saving, labor day, worker wages, labor day, saving cost The working efficiency of 90,000 electric welders' bolt heads in Yuanjiao is described in Section 1 of the article; the wages of workers are calculated according to the average wage of Hangzhou's migrant workers, and the wages of the welders are calculated by two welders plus a small worker.

The above list is only part of the direct cost, which has saved 0.9 +1.17 = 20,700 yuan. If the remaining maintenance costs such as the rental maintenance fee of the welding machine and the corresponding electricity fee management fee, and the indirect cost plan profit tax are included, the economic benefit of the improved bolt puller is more obvious.

4 Improved use prospects The market demand is large and growing. High-rise buildings with a shear wall as a load-bearing system, even with a basement, have a shear wall area of ​​more than 2,500,12, which means that tens of thousands of bolts need to be pulled. At the same time, with the development of the economy and the maturity of technology, the construction of large cities is moving towards large-scale high-rise development, and the demand for high-rise buildings in medium-sized cities is also increasing. All these development trends show the need for pulling bolts in the future. Will grow bigger and bigger. In addition, the improved tension bolts will be used in the construction of special structures due to their ease of use.

Processing is easy, and the operating costs of processing companies are low. Due to the low precision of the improved pull bolts, no advanced instruments and tools are needed, and even the small gold factory has sufficient capacity to process. In terms of its production technology and operating costs, its requirements are lower than those of concrete prefabricated panels that are now spread across the country. Therefore, whether it is the establishment of a new processing plant, or the transformation of the enterprise to produce improved pull bolts, the difficulties encountered will be relatively small.

Promote the application of the application and its countermeasures. The unit price of the improved type of pull bolts is relatively low, so it is necessary to mass production, the economic benefits will be significant, and standardized production is required, and the standards should be formulated by the construction management department. Through standardization, the range of use of improved tension bolts can be expanded. Each construction unit has its own accessory purchase channel. Therefore, the promotion and application of the improved type of pull bolts requires the construction management department to set up a number of fixed-point production enterprises to replace the original parts manufacturers of the construction unit.


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