PSI - Issue 36

Mykhailo Hud et al. / Procedia Structural Integrity 36 (2022) 79–86 Mykhailo Hud / Structural Integrity Procedia 00 (2021) 000 – 000

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risk of brittle destruction of the structure, especially at the junction of the wall with the bottom, which not only increases the consumption of steel but also causes additional difficulties in its manufacture and installation. American lifeline American Water Works Association (2003) and American Society of Civil Engineers (1984) has created a collection of useful information which collects vulnerability studies performed for 552 types of studied reservoirs under the action of twelve past earthquakes (from 1933 to 2003). The published report included parameters: soil acceleration (PGA), diameter, height, height to diameter ratio, level of filling, types and degree of damage, but unfortunately did not contain detailed information on the oscillations of the earthquake to which the structure was subjected, material properties or the thickness of the plate of the tank, or the basis of the project on which the plate was distributed. For this reason, it is not possible to make a detailed assessment of the seismic process of the project presented in this section on the basis of the description of the damage alone. Each tank was assigned one of five damage states from 1 to 5. If the tank had multiple damage, it was assigned the most serious damage condition by Barabash et al (2019). The damage conditions are as follows: type of damage 1 (DS1) no damage; type of damage 2 (DS2) is a small damage - damage to the roof, slight loss of contents, damage to the attached pipes; type of damage 3 (DS3) is a moderate damage - deformation of the "elephant's foot" without loss or slight loss of content; type of damage 4 (DS4) is a large damage - deformation of the "elephant's foot" with significant loss of content, serious damage; type of damage 5 (DS5) is a complete damage - destruction of the structure. 2. Analytic and finite element calculation The load-bearing elements of steel structures of tanks are calculated according to the limit states in accordance with building codes and regulations by DBN B.2.6-198: 2014 "Steel structures. Design standards" and DBN B.1.2-2: 2006. Loads and impacts: Design standards. Regulatory loads acting on the structure of tanks, as well as load factors are taken in accordance with DBN B.1.2-2: 2006. Calculation of tank walls for strength by Barabash et al (2019). At a height l from the bottom of the tank wall is hydrostatic pressure (Fig. 3.): ( ) x P y h x   where: is a the density, is a the height of the wall to the calculated level of the liquid.

Figure 4. Steel cylindrical tank volume of 4500 m 3 by American Society of Civil Engineers (1984).

Figure 3. Calculation scheme of the vertical cylindrical tank by American Society of Civil Engineers (1984).

If the wall is still exposed to excess pressure u P then full pressure: u u P y h x P    When the biaxial stress state in the shell there are meridional forces N 1 and annular forces, N 2 related by the relationship by Veletsos (1976): 1 2 N N where: r 1 , r 2 is a radius of curvature, respectively, in the meridional ( )

P

 

r r

1

2