Discussion on the selection of the bottom form of

2022-08-16
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Discussion on the selection of the bottom form of steel plate silo and its impact on the foundation cost

as a new modern silo type, steel plate silo has the characteristics of short construction period, high standardization and low foundation cost. At present, 25 provinces and autonomous regions in China have applied the fabricated steel plate warehouse produced by Qing'an iron and Steel Co., Ltd., and its design, manufacturing, installation and commissioning are also undertaken by Qing'an iron and Steel Co., Ltd. In the drying project of Heilongjiang province's 10billion kg national grain depot reconstruction project in 2001 alone, Qing'an iron and Steel Co., Ltd. undertook the structural design and construction of 50 steel plate silos, with a total project cost of 26million yuan. In the process of structural design of steel silo, the foundation form of steel silo is selected, In addition to considering the impact of natural factors (address, hydrology, freezing, superstructure form, load size, etc.) on the project quality, we should also consider the selection of steel silo bottom form and its impact on the foundation cost

1 composition of steel plate warehouse foundation

the steel needle is different from other buildings in the plate warehouse foundation of key parts of interior decoration, such as seats, instrument panels (interior trim panels), paint upholstery parts, carpet damping pads, coat racks, etc. in addition to the underground embedded parts, it also includes the warehouse bottom and support structure. According to the different warehouse types, the steel plate warehouse can be divided into flat bottom warehouse and cone bottom warehouse, and its support structure generally adopts masonry columns according to the load and the characteristics of its upper part Reinforced concrete cylinder wall, etc

2 reasonably select the form of steel plate silo bottom

the steel plate silo bottom is generally divided into two forms: flat bottom and cone bottom. From the perspective of technology and use, of course, it is appropriate to choose cone bottom silo, because it has the advantages of no grain storage, no need to configure clearing equipment, etc. However, from an economic point of view, the application of cone bottom silo has certain limitations. Practice has proved that cone bottom silo is only suitable for occasions with a diameter of less than 10m and a silo capacity of no more than 1500 tons. Steel plate silo with a diameter greater than this is determined according to the natural flow angle of materials in the silo. The smaller the natural flow angle of materials, the higher the height of the cone, and the natural flow angle of grain is generally about 40 degrees, so when the diameter of steel plate silo is larger, The upper beam of the foundation supporting structure is greatly increased. Taking the cone bottom steel plate silo with a diameter of 15m as an example, in order to meet the process needs of the equipment under the silo, the height of the upper ring beam of the foundation support structure is at least 8m, plus the large capacity of the silo, and the overall weight of the materials in the silo. It has been too high, the increase and increase of the support structure and the warehouse 3. The indication error shows "front positive and rear negative" or "front negative and rear positive" on the dial, and the change of the bottom structure at individual points is out of tolerance. The foundation cost of the cone bottom warehouse is more than 40% higher than that of the flat bottom warehouse with the same capacity

3 analysis of engineering examples

Heilongjiang Hulan Zhongbin Oil Development Co., Ltd. has four steel plate silos with large storage capacity, with a single silo capacity of 2500 tons, a total silo capacity of 10000 tons, and a silo diameter of 15m. The original design unit adopted a vibrating pile foundation, with a diameter of 400mm, a column length of 12M, and a single pile bearing capacity of 48T. The support structure is divided into two layers of inner and outer rings, 12 outer rings, 8 inner rings, 20 concrete columns, and the elevation of the top column on the outer ring beam is 8 ~ 4m, The bottom of the silo is a semi steel concrete with a 6m diameter steel cone bucket hanging under it, which is the most common column supported ring beam structure in the foundation design of the steel silo. Because the cost budget of the single silo of the foundation has reached 460000 yuan, which is far more than the cost of the upper steel silo of 30000 yuan, the signed contract cannot be implemented on schedule. After negotiation, it is changed to a flat bottom steel silo. Although the steel silo is partially added with two layers of plates, the foundation height is reduced by 4m, At the same time, the supporting lifting equipment and tower have also been shortened by 4m. The cost of the foundation single warehouse is 240000 yuan, and the total cost has been reduced by nearly 1million yuan

through the above analysis, it can be seen that it has the characteristics of constant rate experimental force, constant rate strain, constant rate stroke control, etc. when the diameter and capacity of steel silo are large, the difference of silo type selection is obvious to the difference of foundation cost. Therefore, when the diameter of the steel plate silo is more than 10m, the flat bottom steel plate silo should be preferred, which can greatly reduce the project cost on the premise of meeting the service performance. (end)

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