How to calculate the preload
Calculation of pre added axial force of steel support in deep foundation pit: firstly, add the pre added force to zero to calculate an anchor cable tension, which can ensure the stability of foundation pit against overturning, and then multiply it by 70 ~ 95% of the specification to get the pre added force
generally, the preloaded axial force of steel support in deep foundation pit is not more than 450kn, because the pile anchor structure is mostly sand, silt, or clay, and the uplift force of this stratum and anchor cable is limited. The preloaded force of 450kn means that the design tensile force reaches 450 / 0.95 ~ 450 / 0.7, which is basically the limit of ordinary anchor cable in this stratum. If it can not be met, it is necessary to consider densifying the anchor cable spacing
extended data:
basic requirements of deep foundation pit support:
1. The construction scheme of deep foundation pit support must be determined according to the design requirements, depth and on-site environmental engineering progress. After spinning, it shall be approved by the chief engineer of the unit and submitted to the chief supervision engineer for approval, and the construction can be carried out only when it meets the requirements of specifications and laws and regulations
2. The underground water level must be solved in the construction of deep foundation pit. Generally, light well point pumping is used to lower the underground water level to 1.0 meters below the bottom of foundation pit. A special person must be responsible for pumping water for 24 hours on ty, and the pumping records should be made. When the open ditch drainage is adopted, the drainage shall not be interrupted ring the construction period. When the structure does not have anti floating conditions, it is strictly forbidden to stop the drainage
3. During the excavation of deep foundation pit, the distance between multiple excavators should be more than 10m, and the excavation should be carried out layer by layer from top to bottom, and no deep excavation is allowed
The ladder or support should be g up and down the deep foundation pit, and it is forbidden to step on the support, and safety railings should be set around the pit5. When manually lifting earthwork, the lifting tools should be checked to see if they are reliable, and no one should stand under the bucket
When stacking materials and moving construction machinery on the side of deep foundation pit, a certain distance should be kept from the excavation edge. When the soil quality is good, it should be 0.8m away, and the height should not exceed 1.5m During the construction in rainy season, drainage measures must be taken to prevent rainwater and surface water from flowing into the deep foundation pit. During the excavation in rainy season, 15-30cm soil should be left above the elevation of the foundation pit, and the excavation should be carried out after sunny dayssuppose:
the designed applied prestress value is 300KN
the sectional area of the jack is 0.017671 M2
the applied prestress = the designed applied prestress value / sectional area of the jack = 300 / 0.017671/1000 = 1.70mpa
Axial Force: in architecture, the internal force that coincides with the axis of the member is called the axial force, which is represented by the symbol FN. When the member is in tension, the axial force is tension, which points away from the section; When the member is compressed, the axial force is compression, which points to the section (in building curtain walls, especially in frame supported curtain walls, it is also expressed as eccentric compression and eccentric tension). It is usually stipulated that the tension is represented by a positive sign and the pressure is represented by a negative sign.
the axial force of steel support should be calculated,
not pre added,
but 200kn.
For example, for a column, the structural resistance obtained by the parameters of material and so on is the design axial force
now test the column, first add some force, see, this force can be called pre axial force. Of course, different situations have different explanations
the calculation method is also different. The design pre axial force (the force per linear meter of straight brace along the line direction) is multiplied by the length of steel brace, and the axial force of diagonal brace is 1 / sin of straight brace with the same spacing α Times
Generally, the preload is not more than 450kn, because the pile anchor structure is mostly composed of sand, silt or clay, and the uplift resistance of this stratum and anchor cable is limited< br />now it is calculated by adjusting the current market value
before the reform, non tradable shares were not tradable, and 150 million non tradable shares were calculated at 1 yuan per share
but there is something wrong with the person who wrote the question
in my opinion, it's unreasonable to calculate the 150 million yuan as 1 yuan, but it has to be calculated according to the net assets. The title does not say how much the net assets per share is. Therefore, the answer to this question is 70000 yuan, which is not very appropriate.