Calculation Method Study Of Big Box Inverted Siphon Transverse Thermal Stress On Temperature Drop

The overall trend in distribution of water resources in our country is less south than in the north, to alleviate this problem, enhance the economic development power, the nation implementation of The South-to-North Water Transfer Project. The Middle Route works in 2014, effectively alleviated the current situation of water shortage in North China. Inverted Siphon as cross buildings used in the The South-to-North Water Transfer Project, for meeting the needs of lose water, whereby large cage chamber Prestressed Concrete Inverted Siphon has birth, for buried concrete Inverted Siphon structure, thermal stress has been neglected, but thermal stress of Inverted Siphon in the construction concerned more, the recent literature has pointed out that the effect of temperature load on buried concrete Inverted Siphon, for this, author believes it is necessary to focus on its thermal stress.To calculate the thermal stress of box Inverted Siphon structure, author start with one-chamber Inverted Siphon, based on the general material of concrete, its thermal conductivity procedure is commonality, so it learned relevant literature, assuming Inverted Siphon slab is the semi-infinite slab, temperature change is harmonic change, resolving concrete Inverted Siphon temperature field answer, taking temperature difference for engineering control load, from the temperature field analytical solutions simplify temperature difference function, it has the same type function with concrete railway bridge standard temperature difference functions, which further illustrates the common problems of concrete structure of heat conduction, so the author will reference the bridge temperature difference function to the Inverted Siphon. According to the temperature difference function, calculation Inverted Siphon thermal stress, concrete Inverted Siphon thermal stress including self-restraint stress and framework-restraint stress, the total stress is the sum of the two parts stress. Self-restraint stress formula derivation and framework-restraint stress derivation can see in the relevant sections of the article, there is no described.Based on one-chamber Inverted Siphon thermal stress formula, it derived the double-chamber, three-chamber Inverted Siphon thermal stress calculation formula. When calculating multi-chamber Inverted Siphon framework-restraint stress, the structure statically indeterminate number of times is higher, the author, according to the Structural Mechanics and qualitative analysis, it has been simplified to a certain extent, came to the conclusion, multi-compartment box Inverted Siphon thermal stress calculation can be simplified the single chamber thermal stress calculation, this conclusion greatly simplifies the multi-compartment Inverted Siphon thermal stress calculation, improving calculation formula practicability. for examples of double-chamber, three-chamber Inverted Siphon, the author calculated their thermal stress, and use ANSYS finite element simulation, by comparing the formula results with finite element results, whether it is double-chamber or three-chamber, the calculation results can anastomosis with the finite element results, it could be generalized; it also found, when prestressed concrete Inverted after construction is completed, it will produce considerable thermal stress in the cooling period of winter, threat structure safety, structural safety should be strengthened supervision during working.Finally, using fold line temperature difference distribution function on the highway bridge, it derived multi-compartment box Inverted Siphon calculation formulas, and adopt the same project examples, comparing with index calculation function, it found that the relative error were less than 10% between the two in the calculation results, the author believe that this calculation method can also be widely used.