Dear Friends,

In India, We are now using Earthquack design using IS1893 part-4 ED:2005.

Please make avalable this code in PVElite.

Alternatevly, can any one suggest method by which this can be checked.

Hirak,

There is something that concerns me regarding part 4 Section II paragraph 13 of IS-1893. This paragraph states that a consideration in using this Code is that "the mass and stiffness is more or less uniformly distributed along the height." In some vessel designs this may be the case, but in many other cases, this may not be true.

Note also in Section 17 Design Shear Force and Moment that this method works out a single equivalent force that is then used to obtain the moment at the base of the structure. PV Elite must be able to determine a seismic shear force at each level of interest. It seems that this method is somewhat simplified and does not lend itself to what is required for a complete analysis.

Dear Scott,

Should I understand that this is the reason for which IS 1893 Part 4 - 2005 has only the simplified method included? That the Dynamic Response method is not suitable for most of the pressure vessels?

Please be informed that the Help is not completely correct regarding the importance factor I. If the design is according IS 1893 Part 1 - 2002 the reference is correct. However, if the design is according IS 1893 Part 4 - 2005 the reference should indicate something different, but it still refers to Part 1, Table 6. Part 4 gives other factors and for vertical vessels (category 1 structures) is should be 2.