The selection of bottom type of steel grain silo and its influence on foundation cost

short construction period and standard High degree of transformation, low foundation cost and other characteristics.

In the process of structural design, the choice of steel silo foundation type should be taken into account in addition to nature factors (address, hydrology, freezing, superstructure form, load size, etc.) on the project

1. Composition of steel silo foundation

Steel silo foundation is different from other buildings. Besides buried underground parts, it also includes silo bottom and supporting structure. According to different silo types, steel silo can be divided into flat-bottomed silo and hopper bottom silo.

2. Reasonable choice of steel silo bottom type

The bottom of steel silo is generally divided into two forms: flat bottom and hopper bottom. From the perspective of technology and application, it is advisable to choose hopper bottom silo, because it has the advantages of no grain residual and no need for sweep auger. From the economic point of view, however, there are some limitations of the application of hopper bottom silo, practice has proved that only applies to the bottom of the hopper silo diameter under the l0m, capacity is not more than 1500 t, larger than the diameter of the steel silo is according to the material inside the silo, and natural flow angle, the material of natural flow Angle is smaller, the greater the height of the cone is needed, and the nature of grain flow Angle in the 40 or so commonly,

So when the diameter of the steel silo is large, the upper beam of the foundation support structure is greatly increased. 15 m diameter hopper bottom steel silo, for example, to meet the needs of the silo equipment under process, based on supporting structure of ring beam height at least more than 8 m, plus a large storage, silo material within the overall centre of gravity is too high, and the increase of the support structure, heighten under-bin structure, such as the change of the silo based on the hopper bottom cost compared with flat bottom silo more than 40% .

3. Engineering case analysis

SRON Silo has 4 large steel silos, single silo capacity of 2500 t, 15 m in diameter, the original design unit using vibration pile foundation, 400 mm diameter, column 12 m long, single pile bearing capacity of 48 t, support structure is divided into two layers inside and outside ring, outer ring 12 root, the inner ring 8, 20 concrete pillars in total, outer ring needle on the beam elevation 8-4 meters, for the end of each half plate under concrete 6 m diameter steel cone hopper, the basis of steel silo is the most common column support ring beam in the design of structure, Due to the single silo concrete foundation cost budget has amounted to 460,000 yuan, far beyond the upper steel plate warehouse cost 30,000 yuan, so signed contract cannot be execution, after negotiation instead of flat steel silo, although steel silo part add two layer board, but the base height reduces 4 m, at the same time supporting the single silo price is 240,000 yuan, total cost reduce nearly 1 million yuan.

It can be seen from the above analysis that when the diameter and storage capacity of steel silo are large, the choice of bottom type is different, and the difference of foundation cost is obvious. Therefore, when the diameter of steel silo is larger than l0m, flat bottom steel silo should be preferred. On the premise of meeting the same performance, the project cost can be greatly reduced.